Mary Ann Wilson

Mary Ann Wilson

Climate Change and the Blob

 Climate Change, Species Performance  No Responses »
Sep 252020
 

Carcasses of 6,540 common murres washed onto this beach near Whittier, Alaska, on January 1 and January 2, 2016. Researchers blame a marine heat wave that diminished the murres’ key food supply.David B. Irons

The Blob, that large mass of warm water off the coast of North America, was a massive marine heat wave that wreaked havoc on marine life for three years not long ago. A new study published on September 25, 2020, shows that in the past 40 years, marine heatwaves have become considerably longer and more pronounced in all of the world’s oceans. “The recent heatwaves have had a serious impact on marine ecosystems, which need a long time to recover afterwards—if they ever fully recover,” said Charlotte Laufkötter, a marine scientist at the University of Bern in Switzerland and the lead author of the study. “Some of these couldn’t even have occurred without climate change.”

Using statistical analyses and climate simulations, her team found that major marine heatwaves have become more than 20 times more frequent due to human influence. While they only occurred every hundred or thousand years in the pre-industrial age, they are projected to become the norm. If we are able to limit global warming to 1.5 degrees, marine heatwaves will occur once every decade or century. If temperatures rise by 3 degrees, however, the Blob will visit the world’s oceans every decade or even every year.

In their analysis of sea surface temperature between 1981 and 2017, they noted that in the first decade of that period, 27 major heatwaves occurred which lasted 32 days on average, reaching maximum temperatures of 4.8 degrees Celsius above the long-term average temperature. But from 2007 to 2018, 172 major events occurred, lasting an average of 48 days and reaching peaks of 5.5 degrees above the long-term average temperature. Sea temperatures usually fluctuate only slightly. Week-long deviations of 5.5 degrees over an area of 1.5 million square kilometers—an area 35 times the size of Switzerland—present an extraordinary challenge to marine organisms.

History of the Blob

The Blob was first detected in late 2013, continued spreading throughout 2014 and 2015, and then resurfaced again in September 2016. It got its name in June 2014 when it reached a size of 1,000 miles (1,600 km) long, 1,000 miles (1,600 km) wide, and 300 feet (91 m) deep. By the time it was done, it had been the longest marine heat wave (MHW) on record, and had expanded to more than one million square miles in area, covering waters from Alaska down to Mexico.

This marine heat wave was compounded by a lower than usual water circulation resulting in a static upper layer of nutrient-poor sea water. From 2015-2016, the Blog was responsible for the deaths of about 1 million seabirds; specifically the common murres (Uria aalge), according to a study published on January 15, 2020.

It was also responsible for the unusual mortality event (UME) involving California sea lions which occurred from January 1, 2013 to September 30, 2016 along the California coast, mostly along Central and Southern California. Total strandings included 8,122 juvenile California sea lions documented, with 93% stranding alive (n=7,587, of which 3,418 were released after rehabilitation) and 7% (n=531) stranded dead.

Number of juvenile sea lions that stranded by year. The horizontal line is the mean number of Sea lions stranding from 2006-2012 (pre-UME) and the dotted lines are plus/minus one standard deviation. The years in which the UME occurred are in color.

 

To see past blog posts about California sea lions during this time period, see The Plight of the California Sea Lion and The Plight of the California Sea Lion, Part 2.

Kelp Forests

The Blob also adversely affected the temperate kelp forests, which are among the most productive and species-rich marine ecosystems in the world. A study published on September 9, 2020 found that from 2014-16, kelps declined in abundance from Baja, Mexico to Alaska, mostly in the southern and northern California ecoregions.

Data from 469 sites from Alaska, to Baja California were analyzed, including 373 species (assigned to 18 functional groups). For this ambitious endeavor, a team of scientists and countless volunteers from 14 different organizations documented the northward migration of kelp forests due to warming waters. Each region had a different type of volunteer divers collecting the information—from undergraduate students and tourist divers in California to women from fishing communities at Isla Natividad in Mexico, known as “Las Sirenas del Mar,” who were trained as divers and have been active participants in the underwater community-based monitoring program.

By analyzing the data from each separate group and area as a whole, the researchers found that edges of the distribution are more sensitive and kelp is migrating northward. But the researchers also noticed that as the kelp migrates, only the species that eat it directly appear to migrate with it. This leaves a broken food web behind.

Across the entire region, declines in phytoplankton and zooplankton abundance corresponded with the anomalously warm water temperatures and reduced nutrient availability (i.e., nitrate concentrations) in the photic zone.

The results suggest that coastal communities that are dependent on kelp forests will be more impacted in the southern portion of the California Current region, highlighting the urgency of implementing adaptive strategies to sustain livelihoods and ensure food security.

 

References

University of Bern, Marine heatwaves are human-made

Laufkötter C, Zscheischler J, Frölicher TL, High-impact marine heatwaves attributable to human-induced global warming, Science : 1621-1625

Wikipedia, The Blog (Pacific Ocean)

Eric Wagner, ‘The blob’ revisited: Marine heat waves and the Salish Sea

Piatt JF, Parrish JK, Renner HM, Schoen SK, Jones TT, Arimitsu ML, et al. (2020) Extreme mortality and reproductive failure of common murres resulting from the northeast Pacific marine heatwave of 2014-2016. PLoS ONE 15(1): e0226087. https://doi.org/10.1371/journal.pone.0226087

NOAA Fisheries, Office of Protected Resources, 2013-2016 California Sea Lion Unusual Mortality Event in California

Tim Stephens, Sarah Buckleitner, Cooperative research effort documents northward migration of kelp forests

Beas‐Luna, R, Micheli, F, Woodson, CB, et al. Geographic variation in responses of kelp forest communities of the California Current to recent climatic changes. Glob Change Biol. 2020; 00: 1– 17. https://doi.org/10.1111/gcb.15273

Images

Carcasses of 6,540 common murres, David B. Irons, The ‘Blob,’ a massive marine heat wave, led to an unprecedented seabird die-off

Figure 1, Number of juvenile sea lions stranded by year, NOAA Fisheries, California Sea Lion Data

 

The Impacts of Global Warming on Upwelling in the California Current

 Climate Change, Northern California, Southern California, Species Performance, Upwelling  No Responses »
Nov 282018
 

Near Bixby Creek Bridge on PCH

From southern British Columbia to the Baja California Peninsula, winds blow southward along the coast. Combined with the rotation of the earth, these winds cause the surface layer of the ocean to move offshore. Seawater then wells up from beneath the surface to replace the water that was pushed away. When this deep cold water arrives at the surface, it brings nutrients which are more abundant at depth than they are at surface. The sunlit nutrients stimulate blooms of microscopic phytoplankton—the base of the marine food web—which propagate up the food chain to zooplankton, filter feeders, fish, marine birds, top predators, and marine mammals.

This is the process of upwelling in the California Current, a coastal upwelling zone which exists along the edges of eastern boundary currents in the northeastern Pacific. Its abundant concentration of phytoplankton renders it among the most productive of the world’s marine ecosystems. Many species that rely on its food source live here year-round; others migrate from quite a distance—like leatherback turtles from Papua New Guinea, shearwaters from New Zealand, and tuna and loggerhead turtles from Japan.

The first hypothesis about how upwelling might be affected by climate change was put forth in 1990 by Andy Bakun, a professor of marine biology and fisheries at the Pew Institute for Ocean Science. He proposed that increasing greenhouse gas concentrations would strengthen winds in the California Current and similar upwelling systems: the Benguela Current off southwestern Africa, the Canary Current off northwestern Africa including its northern extension off the Iberian Peninsula of southwestern Europe, and the Peru-Humboldt Current off western South America.

During the warmer months, Bakun observed that air over land warms more rapidly than air over the ocean, which causes the low pressure system over the land to intensify relative to the high pressure system over water. The increasing pressure gradient between them results in stronger upwelling-favorable winds. Hence, greenhouse warming leads to an acceleration of coastal upwelling.

Since then there have been several studies assessing trends in upwelling-favorable winds, with mixed results. However in 2014, a coherent pattern emerged. William Sydeman, president and senior scientist at Farallon Institute for Advanced Ecosystem Research, produced a meta-analysis of published studies, each with more than 20 years of observational or model-derived data. Results showed this upwelling intensification trend is observed at higher latitudes, specifically the California, Benguela, and Humboldt upwelling systems, which he thought “may reflect stronger warming trends observed toward the poles than the equator.”

Ryan Rykaczewski

A 2015 study confirmed these findings and projected the trend would continue. Ryan Rykaczewski, a fisheries oceanographer at the University of South Carolina, compared estimates of historical greenhouse gas concentrations from 1861-2005 to projected greenhouse gas concentrations from 2006 to 2100 if global temperature rises 4 to 5 degrees Celsius. That’s the “business as usual” scenario, which is the worst trajectory and the one we’re on. His analyses of 21 coupled atmosphere-ocean general circulation models showed increased coastal upwelling toward the pole and decreased upwelling toward the equator.

“The high-pressure system over the ocean is expected to move towards the pole with future global warming,” Rykaczewski said. “This means that the location of the maximum gradient in pressure—and hence, the location of strong, upwelling favorable wind—will move towards the pole (or north, for those of us in the northern hemisphere) as well.”

Rykaczewski et al 2015

What that means for the California Current is shown above, in the outline of the west coast on the left, with projected changes in upwelling illustrated in color. Yellow and red indicate increased upwelling, which is what Bakun’s hypothesis says we should expect. Blue means decreased upwelling. The dotted areas are where the changes are large enough that it’s statistically significant. In the north there’s little to slightly positive change, but south of the California-Oregon border there’s decreased upwelling. You can also see it in the plots to the right—the colored lines represent different models and the thick black line is the mean of all those models.

The scenario is as Bakun had described: During the warmer months, a strong pressure gradient forms between the continental low pressure system over California (and the desert southwest) and the North Pacific high pressure system that is found offshore of California. By Bakun’s account, this should increase upwelling-favorable winds everywhere. But Rykaczewski suggested two elements were absent from his hypothesis:

1. The influence of humidity on atmospheric pressure—that is, pressure is a function of temperature and humidity, not just temperature alone.
2. The potential movement of the pressure systems.

“It’s the movement of the high pressure system that is the most obvious and consistent of these elements, at least in the projections of climate models,” he said. “The actual reason that the high-pressure system moves north is still an area of scientific research, but likely has to do with the increased heating in the tropics and the greater convection that is stimulated as a result.”
Could the ridiculously resilient ridge (RRR) put the brakes on the North Pacific high pressure system? The RRR is an area of high atmospheric pressure that has disrupted the North Pacific storm track since 2012. While it is typical for a high pressure ridge to form over the West Coast during winter, which explains why eastward-moving Pacific storm often veer north before reaching California, this ridge has become increasingly persistent and pronounced since 1948.

Rykaczewski did not think that the presence of the RRR would prevent movement. “Rather, I think the question is whether the presence of the RRR is somehow related to the poleward movement of the North Pacific High overall,” he said. “The scientific jury is still out. The complication is that things like the RRR are episodic and last for a period of months, while the shift in the high pressure system is something that occurs over a period of several decades.”

When stronger upwelling upwelling-favorable winds occur, they bring a surge of nutrients to surface waters. But they can also harm marine life by causing turbulence in surface waters, disrupting feeding and worsening ocean acidification. That’s because upwelled water is naturally rich in carbon dioxide. The earth’s oceans have already absorbed about a third of the CO2 that humans have emitted into the atmosphere since the beginning of the Industrial Revolution. This increased CO2 causes upwelled water to be more acidic, threatening calcifying species, including oysters, clams, sea urchins, shallow water corals, deep sea corals, and calcareous plankton. Also, when there’s an abundance of phytoplankton, those that are not eaten eventually die and float down into deeper waters, where bacteria use available oxygen to decompose them. When too much oxygen in the deep waters is used for this bacterial decomposition of the phytoplankton, the result is a condition known as hypoxia. This could harm bottom-dwelling marine life, shrink open-water habitat for top predators, and increase the number of invasions by hypoxia-tolerant species like Humboldt Squid, a species thought to have benefited from an expansion of hypoxic waters and which rapidly expanded its range into the northeast Pacific Ocean in the late 1990s.

On the other hand, weaker upwelling may limit nutrients at the surface, negatively affecting primary production. Winters with extremely weak upwelling are associated with slower growth in fish and lower reproductive success for seabirds.

Studies have shown that certain species are more sensitive to different parts of the year in terms of upwelling. Some are more sensitive to the variability in the winter-time upwelling, and some are more sensitive to the variability in the summer-time upwelling. Over recent decades, the timing of upwelling has trended toward later and shorter upwelling seasons in the northern portion of the California System and longer upwelling seasons in the southern portion.

Rykaczewski et al (2015)

However, Rykaczewski’s projections show the opposite will happen. This figure shows the same changes as the previous figure, but as a function of the month of the year along the horizontal axis and the latitude along the vertical axis. In the central and Northern California coastline, models project intensification in April and May (note the strong upwelling beginning in April, which may indicate a longer upwelling season). But south of the 40th parallel (Mendocino) you see a weaker upwelling in late July to early August at the peak of the upwelling season.

A seasonal-scale change can predict animal distribution as well as survivability. For example, in 2005 central California seabirds and rockfish as well as Oregon zooplankton were hit hard by a weak and delayed upwelling. It was particularly hard on species whose reproductive cycles depend on early upwelling, rather than the cumulative amount. The northern portion of the California Current had one of the most delayed onsets in the 40-year record, and resulted in the reproductive failure of Cassin’s Auklet.

It can take a long time for the signal of a trend to be greater than the natural variability that happens on shorter time scales. Anthropogenic changes in upwelling will emerge primarily in the second half of the century. Still, it is apparent that ecosystems respond to even small changes in average conditions of pH and CO2, even within the context of a larger range of natural variability. Even more worrisome is that climate change is likely to produce a combination of stressors for which we may have no reference.

Originally published in Catalina Marine Society’s OceanBights, p. 5

References

Mike Jacox, NOAA Southwest Fisheries Science Center, Monterey, CA, What do we expect to happen in the California Current under climate change?, Pacific Fishery  Management Council, January 25, 2018

Tim Stephens, Tracking of top marine predators reveals Pacific Ocean hot spots, UC Santa Cruz Newscenter, June 22, 2011

Andrew Bakun, Global Climate Change and Intensification of Coastal Ocean Upwelling, Science, January 12, 1990

Andrew Bakun, David B . Field, Ana Redondo-Rodriguez, Scarla J. Weeks, Greenhouse gas, upwelling‐favorable winds, and the future of coastal ocean upwelling ecosystems. Global Change Biology, Volume 16, Issue 4, pp. 1213-1228, February 2, 2010

W. J. Sydeman,, M. García-Reyes, D. S. Schoeman, R. R. Rykaczewski, S. A. Thompson, B. A. Black, S. J. Bograd, Climate change and wind intensification in coastal upwelling ecosystems, Science, Vol. 345, Issue 6192, pp. 77-80, July 4, 2014

Ryan R. Rykaczewski, John P. Dunne, William J. Sydeman, Marisol García-Reyes, Bryan A. Black, and Steven J. Bograd, Poleward displacement of coastal upwelling-favorable winds in the ocean’s eastern boundary currents through the 21st century, Geophysical Research Letters, Vol. 42, pp. 6424–6431, July 14, 2015

Ryan Rykaczewski, University of South Carolina, Interview Nov 16 & 17, 2018

Swain, D. L., Horton, D. E., Singh, D., and N. S. Diffenbaugh, Trends in atmospheric patterns conducive to seasonal precipitation and temperature extremes in California, Science Advances, Vol. 2, no. 4, e1501344, April 1, 2016

What is Ocean Acidification?, National Ocean Service, NOAA

Barbara Juncosa, Climate change may be sparking new and bigger “dead zones”, Scientific American, October 3, 2008

California’s Fourth Climate Change Assessment, Coast and Ocean Report, California’s Fourth Climate Change Assessment,  August 27, 2018

Bryan A. Black, William J. Sydeman, David C. Frank, Daniel Griffin, David W. Stahle, Marisol Garcia-Reyes, Ryan R. Rykaczewski, Steven J. Bograd, William T. Peterson, Six centuries of variability and extremes in a coupled marine-terrestrial ecosystem, Science, Vol. 345, Issue 6203, pp. 1498-1502, September 19, 2014

Franklin B. Schwing, Nicholas A. Bond, Steven J. Bograd, Todd Mitchell, Michael A. Alexander, Nathan Mantua, Delayed coastal upwelling along the U.S. West Coast in 2005: A historical perspective, Geophysical Research Letters, Volume33, Issue22, October 7, 2006

Images

Near Bixby Creek Bridge on PCH – Mary Ann Wilson

Ryan R. Rykaczewski – Amanda Netburn

Rykaczewski et al 2015 – Ryan R. Rykaczewski

Rykaczewski et al 2015 – Ryan R. Rykaczewski

Weeding a Seaweed: Managing Sargassum horneri

 Invasive Species, Southern California  No Responses »
Feb 042018
 

Mature s. horneri

Sargassum horneri (S. horneri) is a large alga native to the shallow reefs of eastern Asia. As a key species in the Northwest Pacific ecosystem, S. horneri is a primary producer, a biofilter of nutrient runoff, and a traditional food source for the people who live in Japan, Korea, and China. The seaweed beds also provide a habitat for fish, sea urchins, abalones and turban shells. But in California, it grows more densely than many native species, creating a canopy that blocks sunlight from other plants, including the giant kelp (Macrocystis pyrifera) which is native to the California coast. This may impact animals relying on the kelp to hide or for food.

For example, in 2015, local researcher and oceanographer Jon Council said in The Catalina Islander that sea lions “use giant kelp like duck blinds and dart out into anchovies and smelt. Without the kelp, they don’t have that cover.” Because of warmer-than-normal water temperatures brought on by a late-season El Nino and tremendous surge generated by Hurricane Marie in August of 2015, the kelp was devastated. While adult sea lions can adjust, pups are a lot slower and have to work a lot harder to get to the bait balls.  Also, some species, such as smelt, lay their eggs in the fronds or leaves of the kelp. So for sea lion pups, the smelt are now fewer and harder to catch.

Commonly referred to as sargassum, S. horneri was first detected in Long Beach Harbor in 2003 – at that time the only place outside its native range. By April 2006 it was found off Santa Catalina Island north of Big Fisherman’s Cove near Two Harbors and USC’s Wrigley Institute. In 2009, it was also found in the marine park in Anacapa Island. It has since spread rapidly across the Channel Islands and halfway down Baja California, and is still actively spreading. Since 2013, it has become more dominant on the reefs which have historically been dominated by giant kelp.

The problem is twofold: the invasive seaweed grows very fast, especially in the winter and spring; and once established, eradication is impossible. Hence its nickname, “devil weed.” It is highly fecund as well as monecious, which means it has male and female gametes. Theoretically, a single individual can start a whole new population. It is well suited to short and long range dispersal; and if ripped off the substrate while reproductive, the buoyant plants can drift long distances on currents and drop gametes as they go. Once established, populations continue to spread locally.

Lindsay Marks

Lindsay Marks, a PhD candidate at the University of California, Santa Barbara (UCSB), spearheaded recent investigations on the invasion. In May of 2017, she gave a presentation about the ecology of S. horneri and her attempt to remove it with the help of a giant underwater vacuum tube known as the Super Sucker.

To find out how its stages of growth and relative biomass compared to native species in the same area, Marks and her team have been sampling the native algal community at Isthmus Reef, located on the front side of Catalina Island, every three months since 2014.

What they found was an inverse seasonal pattern between the native kelp and the invasive algae—the native species have higher biomass in the summer and fall, and as they later decline, S. horneri -increases. “You could look at this sargassum as just filling an empty niche,” Marks said, “or taking advantage of this opportunity where the native species may be underutilizing their limited resources like space and light.”

To find out whether marine protected areas (MPAs) can resist invasion, she collaborated with researchers Jenn Caselle and Katie Davis at UCSB to study it at Anacapa Island because it has three marine protected areas: the no-take old reserve established in 1978, the new state marine conservation area (SMCA) established in 2003 which allows fishing of spiny lobster, and the no-take new reserve established in 2004.

Sargassum Survey

In the old reserve, there is a much larger number of predators like lobsters than in the unprotected areas on the backside of the island. Because of the higher number of lobsters, there are less sea urchins which are lobsters’ preferred prey. Sea urchins eat algae, so there’s a lot less kelp in the unprotected areas. Conversely, fewer predators live outside the protected areas, which results in many more herbivorous urchins and less native kelp.

The researchers suspected that this biological difference in communities might also be responsible for the differences in the S. horneri biomass. Since the invasive alga is very opportunistic and prospers in places where native algae do not, they surmised that perhaps there would be less S. horneri in areas with healthy robust kelp communities and more of the sargassum in degraded areas.

As expected, Marks and her team did not find a lot of S. horneri in the old reserve. They think this was because the sargassum was experiencing more intense competition and shading from native algae and therefore had less resources available.

Lindsay Marks in the Field

However, on the backside of Anacapa where fishing is allowed, they saw very little of S. horneri as well. These sites were characterized by “urchin barrens” where enormous numbers of sea urchins graze all available algae, including both kelp and Sargassum. While this is an alternative scenario for resistance to invasion by sargassum, it is certainly a less desirable state of the ecosystem.

In the newer MPAs established in 2003 and 2004, there were much higher levels of S. horneri. The researchers surmised that urchins will eat anything if hungry enough, but given the choice they prefer the taste of kelp over S. horneri. A follow-up project Marks called “Algae Buffets” bore out these expectations. Given a choice between samples of giant kelp, southern sea palm (Eisenia arborea), and S. horneri, the urchins favored the two common native kelps. The reason?  S. horneri is a fucoid alga, and these typically have chemical defenses against herbivories, so it probably doesn’t taste very good.

Thus MPAs may be able to resist invasion only if they’re more established, with mature kelp forest communities and more predators controlling herbivore populations. “It will be interesting to see as these newer MPAs continue to mature, whether or not sargassum will impede that progress,” Marks said.

In an attempt to weed the seaweed, Marks used an underwater vacuum device called a Super Sucker as part of a National Oceanographic and Atmospheric Agency (NOAA) Fisheries pilot project. The gentle vacuum transports algae from divers to the surface where it can be sorted for bycatch and bagged for disposal. A similar device has already been used on coral reefs around the island of Oahu in Hawaii to reduce invasive algae there.

Vacuuming S. horneri using the Super Sucker

In February of 2015, Marks—along with Adam Obaza of NOAA Fisheries, Sam Ginther, a graduate student at Cal State Northridge, and a group of volunteer research divers—cleared fourteen 60 m2 areas of S. horneri on the leeward side of Catalina Island. Since it was too difficult to remove tiny recruits from seaweed beds, they chose February when the alga was biggest but also the least dense, and also before it was reproductive.

So understanding the life cycle of S. horneri is paramount to launching a successful removal. While native algae are perennial, meaning they live through multiple reproductive cycles, S. horneri is an annual species. It’s much more abundant in the summer time, sometimes reaching 1000’s of individuals per meter squared, due to the peak in recruits. As the season progresses from fall to spring, it becomes much less abundant.  But in terms of biomass, recruits contribute very little in the summer.  That changes in the winter and spring, when there’s a huge boom of biomass.

In all they removed more than four tons of material in three days. They returned in September 2015, when they expected to find the most of the new recruits based on their seasonality data. Initially, they had reduced recruitment by about 50% in the removal plots compared to control plots. Sounds impressive, but unfortunately that 50% reduction turned into a 25% reduction as those populations matured and grew up. Marks was disappointed. “We sort of sped up the self-thinning process but all we really did was slow population growth,” she said.

Wrigley Sunset

Marks surmised that the warmer waters deterred the growth of native kelp, which had essentially disappeared from the region where they were working on the leeward side of Catalina near Wrigley, which meant the native species were unable to colonize the spaces the reef we created by clearing sargassum. She thought they would have seen less of it the following year if native kelp had been able to reclaim those spaces.

Dr. Bill Bushing, a marine biologist who was one of the first to discover sargassum on Catalina Island, observed that there was very little of it during August and September of 2009, at which time the water was cooler than the previous five years when sargassum became a problem. “Possible reasons may include the limited light reaching the subtidal rocky reefs due to the thick native kelp canopy, or the cooler water temperatures directly affecting the growth of sargassum,” he wrote in California Diver back in 2014.

Native kelp and the invasive alga share a similar temperature range of what they can survive in—10° to 25°C (50 to 77°F) for S. horneri and 5° to 20° C (42° to 72°F) for giant kelp. But Marks said that it was possible that in the upper threshold the sargassum might have a little bit of a leg up. In the last few years, we’ve had unusually warm water in southern California and native kelps have all but disappeared from the leeward side of Catalina while sargassum has continued to thrive.

Two hurricanes in 2014, Marie in August and Odile in September, may have also deterred the growth of native kelp. While Marks was hesitant to comment on the role of those particular hurricanes, she suggested that any loss of native kelp would facilitate the sargassum.

“It’s well known that invasions do better in more disturbed habitat,” she said. “So maybe this former water event has removed what we would think would be primary competitors of Sargassum – the larger species of algae like kelp. And that frees up additional resources like space and light for the invasive species.”

Lindsay Marks with Mature S. horneri

To investigate whether increased wave disturbance facilitates the disturbance of the invasion of S. horneri, Marks has been turning herself into “Hurricane Lindsay”—ripping out the bigger species of algae, and then allowing the invasion to occur in order to see what grows back in its place. She hopes to understand what is excluded, and whether or not sargassum does better in these areas where the natives have been compromised.

For the Super Sucker’s next phase of abatement and management, NOAA has handed off the Super Sucker to Los Angeles Waterkeeper. Their target is Palos Verdes, specifically Malaga Cove where the sargassum is patchy in distribution (compared to Catalina where it has become ubiquitous in some areas), and the kelp populations are more established.

“The idea is that after removals, there’ll be enough of the native species to recolonize the space that’s been created, create a foothold, and then prevent the invasive algae from becoming abundant there,” Marks said.  “So hopefully LA Waterkeeper will have more success working in places that are not so heavily invaded.”

Though it seems like Catalina has been abandoned, Marks thinks the situation there is neither hopeless nor permanent. “I think the kelp will come back,” she said. “It’s not uncommon for there to be a few years of low abundance, especially following major, El Niños, but it’s cyclical. I think kelp may have a harder time coming back in areas where sargassum is really dense, but I think it will eventually. In the last year or so I’ve started seeing new kelp plants growing back here and there.”

LA Waterkeepers: (from left to right) David Coles, Alex Rappaport, Michael Murrie, and Ian Jacobson

Los Angeles Waterkeeper launched their Invasive Species Campaign in early 2016, treating invasive species as a form of biological pollution. As the proliferation of Sargassum horneri continued, its widespread distribution threatened potential lasting ecological consequences to native habitats. LAW decided to dedicate the resources of their dive program to address the current invasion with the hope of developing practical removal methods, establish a more informed dive community, and aid in the development of recommendations that will address future non-native introductions.

LA Waterkeepers: (from left to right-)Adam Obaza, Hannah Ake, and Katie Nichols

Their pilot study, headed by Dive Program Manager Ian Jacobson, began in September 2016. Five volunteer divers removed more than 100 lb. in two days in an area next to a healthy kelp forest, which is the reference site. There is one S. horneri reference site which is untouched, and two experimental sites, one of which sargassum has been removed once, and another in which sargassum will have been removed a second time by February 2018. The reason for the double removal plot is to find out if regular maintenance is more effective.

L.A. Waterkeepers: Hannah Ake surveys S. horneri

Jacobson started seeing new sargassum recruits in late September 2017, but it won’t be until May of next year before they have data. Jacobson will be looking at whether the removals reduce density over time. If successful, they will develop a strategy to control and abate the sargassum, as well as protect kelp forests in certain areas. For example, say a small sargassum population is found in a harbor and gets caught in boat hulls or anchors, and is then reintroduced in a new area.  “If we can effectively control both populations in a very coordinated way, then that could be one buffer to potential expansion and potential distribution to novel areas,” he said.

Neither Jacobson nor Marks is even thinking about eradication. “Management, control, abatement— those are the terms we’re using,” Jacobson said. “And it’s premature to say how effective any strategy is, because our studies aren’t complete yet. Call me next year at this time.”

I plan to take him up on his offer, so stay tuned. In the meantime—if you’re a certified diver, you can help track the spread of marine invasive species by reporting sightings of S. horneri and a new one not discussed here, the edible seaweed Undaria Pinnatifida. If you come across either of these species, take a close-up photograph so you can upload your observation to MarineInvasives.org or the iNaturalist app. Include the name of the species, its location, how many you saw, the water depth, life stage, and habitat. Make sure you don’t remove the invasive algae since it spreads easily. And before you leave the dive site, check your gear and anchor, and remove any hitchhiking seaweed.

Marineinvasives.org has useful resources, including information on both invasive species, and a map of all the places where these species have been recorded. iNaturalist is a user-friendly app you can download on your phone and also use on your computer. After you upload your pictures and observations of Sargassum and Undaria to the project named “Marine Invasives Reporting App,” fellow iNaturalist contributors can verify your species ID and provide useful feedback. LA Waterkeeper has trained 30 LAW divers how to identify sargassum, report it using iNaturalist, and conduct monitoring surveys for the Pilot Project. And rather than give your GPS location, you can just drop a pin on a map.

Also, LA Waterkeeper has been giving presentations to local clubs since 2016 so contact them if you’re interested.

As Marks said, “It’s a slow process, we’re building momentum, we’re moving in the right direction.” So get involved and help the effort to weed this seaweed.

Originally published in Catalina Marine Society’s OceanBights, p. 7

 

References

Jim Haw, USC Dornsife Scientific Diving: An Analysis of Sargassum Horneri Ecosystem Impact, Scientific American, May 22, 2013

Jim Watson, Invasive seaweed adds to sea lions’ woes, The Catalina Islander, March 20, 2015

Miller, Kathy Ann & M. Engle, John & Uwai, Shinya & Kawai, Hiroshi. (2007). First report of the Asian seaweed Sargassum filicinum Harvey (Fucales) in California, USA. Biol. Invasions. 9. 609-613. 10.1007/s10530-006-9060-2

Lindsay Marks,  New Research Studies Spread and Ecology of Invasive Seaweed, National Park Services, May 11, 2017

Lindsay Marks, PhD candidate at the University of California, Santa Barbara (UCSB), Interview October 17, 2017

Bill Bushing, The Invasion of the “DEVIL WEED”: Sargassum horneri invading California waters,California Diver, July 22, 2014

Lindsay Marks, Sargassum horneri Information Sheet, University of California, Santa Cruz (UCSC), Ecology and Evolutionary Biology

Kelp Forests – a Description, NOAA National Marine Sanctuaries

Marks, Lindsay & Reed, Daniel & Obaza, Adam. (2017). Assessment of control methods for the invasive seaweed Sargassum horneri in California, USA. Management of Biological Invasions. 8. . 10.3391/mbi.2017.8.2.08.

Ian Jacobson, Dive Program Manager, L.A. Waterkeeper, Interview October 22, 2017

 

Images

Mature s. horneri – Lindsay Marks

Lindsay Marks –  Jessie Alstatt

Sargassum Survey – Lindsay Marks

Lindsay Marks in the Field – Jessie Alstatt

Vacuuming S. horneri using the Super Sucker – Adam Obaza

Wrigley Sunset – Lindsay Marks

Lindsay Marks with Mature S. horneri – Jessie Alstatt

L.A. Waterkeepers: (from left to right) David Coles, Alex Rappaport, Michael Murrie, and Ian Jacobson, Chris Glaeser – Chris Glaeser

L.A. Waterkeepers: (from left to right) Adam Obaza, Hannah Ake, and Katie Nichols – Ian Jacobson

L.A. Waterkeeper: Hannah Ake surveys S. horneri – Adam Obaza

Rising Sea Levels and the Public Trust Doctrine

 Climate Change, Coastal Erosion, Sea-Level Rise  2 Responses »
Aug 182017
 

Homes on Broad Beach

The California Ocean Protection Council and the California Natural Resources Agency have updated statewide guidance on sea-level rise to reflect new advances in ice loss science. Their new report, “Rising Seas in California: An Update on Sea-Level Rise Science,” notes that satellite data of West Antarctica show an increased loss of grounded land ice and accelerated loss of ice shelves, which buttress the grounded ice. If this continues, California’s shores could experience higher sea levels sooner that previously thought.

The problem is that the West Antarctic Ice Sheet lies on bedrock that is below sea level, in contrast to the Greenland Ice Sheet which is above sea level. If global warming is great enough to erode the floating ice that buttresses grounded ice, this would effectively uncork the bottle, unleashing an escalating and irreversible discharge of ice into the ocean. Such a loss could change the earth’s gravitational field and rotation, resulting in a higher rate of sea-level rise along California’s coast than the global average.

The precise magnitude and timing of when this would happen is unknown. But in a best-case scenario, research models show a seal level rise off La Jolla of about 6 inches by 2030 and one foot by 2050; while a worst-case scenario predicts the ocean will rise more than 1 foot by 2030 and 2 feet by 2050. The most extreme water-level increases will come after 2050, when ocean levels off Southern California could reach 2 to ten feet above 2000 levels by 2100.

The concern around an increased rate of sea level rise adds a new layer of legal complexity and overlaps current coastal planning. Even in the absence of sea level rise, poorly planned coastal development can be in harm’s way and affect public interests along the coastline. If not proactively and effectively managed, coastal development has the potential to reduce coastal access and degrade, destroy, and perhaps even privatize shorelines and tidelands.

Which brings us to the Public Trust Doctrine.

The Public Trust Doctrine is an ancient legal doctrine that goes back to Roman Law, under which some waters, tidelands and wildlife resources of the state are held in trust for all of the people, and the state acts as the trustee to protect these resources for present and future generations.

In California, this doctrine extends to the protection of navigable surface waters, to non-navigable tributaries of those waters, to aquatic resources, and to birds and other wildlife. Additionally, the courts have added the right of public access, and protection of the environment and recreation. Most importantly, this common law doctrine allows any person to bring a lawsuit against the state if it fails to fulfill its duty as trustee to manage these protected resources in accordance with the doctrine.  So how will the Public Trust Doctrine apply to private properties facing sea level rise?

In an effort to provide guidance to state and local governments, Stanford University’s Center for Ocean Solutions published two documents: Consensus Statement on the Public Trust Doctrine,  and The Public Trust Doctrine: A Guiding Principle for Governing California’s Coast Under Climate Change in July 2017. Authors included former leaders of the State Lands Commission, the California Coastal Commission, the California Department of Justice, the San Francisco Bay Conservation and Development Commission; as well as representatives of local government and a few academicians. The group met over the course of a year to develop a consensus interpretation of how the Public Trust Doctrine could apply to sea level rise, since it has not been fully fleshed out in the courts.  And because it’s a common law doctrine, the ultimate arbiter will be the courts.

Don Gourlie

One of the co-authors of the consensus statement, Don Gourlie, who is an Early Career Law & Policy Fellow at the Center for Ocean Solutions, reviewed the highlights in a webinar on August 16. He said that one of the main challenges the group focused on was the mean high tide line.

In 1935, the Supreme Court in 1935 defined the coastal property line as the mean high tide line, which is, of course, ambulatory. California courts have held that a coastal landowner’s property boundary continues to change because of the naturally changing location of the mean high tide line. The courts; however, have not reported cases specifically addressing the legal effect of permanent submergence on open ocean coastlines.

The mean high tide line is found by determining the average elevation of all high tides over the course of 18.6 years (one lunar epoch) and surveying where that elevation rests on the shore from time to time. A recalculation is due in 2022, and based on tide gauge data from around the state, it’s expected that the mean high tide elevation will increase a few inches through most parts of the state. When that occurs, the surveyed location of the property boundary will also change. The concern is that because this line in the sand, as it were, is so ambulatory, surveyed locations at any given point in time may not be useful in making long-term decisions about permanent structures.

The group suggested improving the way the mean high tide is located by increasing the number of tide gauges or surveys over a period of time to measure a boundary’s range of movement, and provide more resources for the State Lands Commission and other groups tasked with conducting those boundary determinations.

The mean high water line, or mean high tide line, is the boundary between public tidelands and uplands in California.

Four dynamic processes and how they may change the location of the mean high tide line.

Also, the ambulatory nature of the boundary is not very well understood by either the general public or relevant state agencies. That’s because property rights are assumed to have defined boundaries. Getting that information out there is important, which the group suggested could be done through through legislative discussion as well as disclosures of risks in coastal development permits.

Another problem is that the mean high tide line as a standard is actually challenging to apply on the open coast and not fully protective of public trust resources. The standard was initially developed through the federal courts and was applied in protected bays where there’s not much wave run-up. This and any issues relevant to the use of the mean high tide line on California’s open coast would benefit from discussion at the legislative level.

Local governments are likely worried that property owners will sue for losses due to erosion, inundation, and migration of the mean high tide line. On this, the group entirely agreed that the Public Trust Doctrine—as a background principle of property law in the state—would be a complete and successful defense to taking a claim. “What’s more likely to be challenged,” Gourlie said, “is if the state decides to regulate areas that are currently upland or private property that is likely to become public land in the future due to sea level rise.”

Seawall along Broad Beach

The group also tackled the issue of how permanent structures like seawalls would affect the movement of this boundary. Though there’s no California case on point to this effect, they noted that there are cases in other jurisdictions, as well as principles of property law recognized in California case law, which indicate that the placement of a physical structure that halts erosion or halts landward movement of water does not fix the legal shoreline boundary.

Once public trust tidelands are located, they need to be protected. “Identifying which areas should be included in the public trust is key,” Gourlie said. “Once that’s in place, government agencies should be systematic about considering and analyzing the expected effects of an action or decision on public trust resources; and not grant permanent grants that my adversely impact public land in the future.”

Other highlights:

  • Just as homeowners are required to clear space around their homes for fire prevention, we should protect our dynamic coastlines by not allowing activities that will encourage potential hard armoring of the coastline or the need to defend ourselves from sea level rise especially since this threat can be easily avoided. For activities that don’t take place on public trust land but affect them, decision makers should not undertake or authorize uses of uplands without appropriate safeguards for nearby public trust resources and uses.
  • Decision makers may need to review past decisions in response to new evidence concerning effects on public trust resources and uses and should retain this right to review. It’s also important to not grant permanent rights that may adversely impact public lands in the future.
  • Decision makers must consider and assert public interests in statewide policy making and long-term planning (e.g. creating or revising local coastal programs, local general plans, etc.).
  • Coordination among decision makers is essential, especially when locating shoreline property boundaries, in order to minimize conflict and avoid wasting resources.

 

References

Griggs, G, Árvai, J, Cayan, D, DeConto, R, Fox, J, Fricker, HA, Kopp, RE, Tebaldi, C, Whiteman, EA (California Ocean Protection Council Science Advisory Team Working Group), Rising Seas in California: An Update on Sea-Level Rise Science. California Ocean Science Trust, April 2017.

Sanda Mazza, Extreme sea-level rise could wreak havoc on California coast, experts warn,  April 18, 2017.

Environmental Law Foundation, et al., California’s Public Trust Document.

Center for Ocean Solutions, Story: The Public Trust Doctrine: A Guiding Principle for Governing California’s Coast Under Climate Change,  July 1, 2017

Center for Ocean Solutions, Consensus Statement on the Public Trust Doctrine: A Guiding Principle for Governing California’s Coast Under Climate Change, July 2017

Center for Ocean Solutions, The Public Trust Document: A Guiding Principle for Governing California’s Coast Under Climate Change, July 2017

Don Gourlie, Webinar: Public Trust Doctrine, Coastal Land Use, and Sea Level Rise, August 16, 2017

Images

  1. Homes on Broad Beach, Mary Ann Wilson
  2. Don Gourlie, coastalresilience.org
  3. The mean high water line, The Public Trust Document: A Guiding Principle for Governing California’s Coast Under Climate Change, p. 17
  4. Four dynamic processes, The Public Trust Document: A Guiding Principle for Governing California’s Coast Under Climate Change, p. 18
  5. Seawall along Broad Beach, Mary Ann Wilson

The Plight of the California Sea Lion, Part 2

 Northern California, Southern California, Species Performance  No Responses »
Apr 092017
 

Sea Lions at Pacific Marine Mammal Center, Orange County

This is the second part of a two-part series about the recent unusual mortality events of California sea lion (Zalophus californianus) pups. The first article investigated the reasons why thousands of emaciated pups have been stranded on California beaches. This article highlights the work of nonprofit organizations dedicated to rescuing and rehabilitating them.

 Rescue

A network of rehabilitation centers take in sick and injured marine mammals along California’s coast, and each center has their own jurisdiction: Sea World, serving the San Diego area; Marine Mammal Care Pacific Marine Mammal Center, Orange County; Marine Mammal Care Center Los Angeles, Los Angeles and Long Beach; California Wildlife Center, Malibu; Channel Islands Marine Wildlife Institute, Santa Barbara and Ventura Counties; The Marine Mammal Center, San Luis Obispo through Mendocino counties; and Northcoast Marine Mammal Center, Humboldt and Del Norte Counties.

All centers handles their own rescues except for Marine Mammal Care Center Los Angeles (MMCC). Along with local Animal Control agencies, MMCC relies on Peter Wallerstein, the director and founder of Marine Animal Rescue, which is an organization entirely devoted to the rescue of marine mammals. Their authorized territory extends as far south as Long Beach, west to Catalina Island, and north to Pacific Palisades. Of the 4500 marine mammals they’ve rescued since 1985, 90 to 95 percent are California sea lions. Why so many? One reason may be sheer numbers: Compared to the 300,000 sea lions in California, there are just 39,000 harbor seals— approximately the same ratio as the strandings. Wallerstein estimated that of the 395 rescues they’ve done this year, 30 to 40 were elephant seals, followed by a few harbor seals, fur seals, dolphins, and sea turtles.

The organization’s busiest time of the year is from January to June, when starving sea lion pups lose their fat and become stranded on the beach. In an ominous Facebook post on November 4, 2016, they showed two pups rescued within the last 24 hours and the caption: “Starting early this year.”

Because upper water fish are depleted due to the collapse of the food chain, nursing mothers are forced to dive much deeper than usual. While their pups are small and unhealthy, at least they are alive. The reasons being fat- and calorie-poor fish such as short belly rockfish are generally found deeper in the water column than the fat- and calorie-rich fish like anchovies, sardines, and mackerel.

Peter Wallerstein of Marine Animal Rescue

Since the public plays a big part in rescues of not just stranded sea lions but entangled or beached whales, dolphins, seals, and even sea birds, Peter Wallerstein offered some guidelines for beach-goers who spot a sea lion or any marine mammal in need of assistance.

The first thing to do, he said, is call the Marine Animal Rescue on their 24-hour, toll-free hotline at 1 (800) 39-WHALE anytime day or night, 365 days a year. I told Wallerstein that I had called the center in Malibu two different times, and each time they said they didn’t have enough room. The second time they came and posted signs warning the public to stay away, and then left.

“We try to bring them in even if they don’t have a place for them,” Wallerstein replied. “We’ll bring them to another quiet beach where they can be left alone, and then we’ll keep an eye on them. What’s helpful for that is when we do relocate it, we tag it, and if that animal comes back on the beach, that’s a re-strand and that gives us more power to try to force the center’s hand.”

I found out later that the California Wildlife Center can only take up to 25 sea lion pups, so the response you get depends on where you happen to be and of course, the number of stranded pups there are.

If you spot one and call the nearest center, Wallerstein asked that you stay in the area and maintain contact by phone with the rescuers. “It’s pretty difficult searching both sides of a crowded jetty a quarter mile long to find an animal,” he said.

But keep your distance. “Not only are they federally protected animals, they also bite ten times harder than a dog,” he said. “If they have domoic acid (a neurotoxin that causes amnesic shellfish poisoning), they might have seizures on the beach, or chase lifeguards and trucks.”

If they’re on land, don’t try to get them back to the water. “Once you bring it back into the water, it’s almost a one hundred percent chance they’re going to die,” he said. “If they’re on land, we’re going to come get them and we’re going to bring them to the rehab center. If they go back in the water, then they have absolutely no hope.”

On the other hand, “If they’re trying to get back to the water, never cut off their path. Do not pull it into the water. If it’s weak and emaciated, it won’t survive.”

Don’t feed them. “About a month and a half ago, we found one guy spoon feeding a sea lion,” he said. “Luckily the animal was hypothermic because as soon as it warmed up, it got extremely aggressive. And you don’t want to give sea lion pups that are starving food right away. They need to be hydrated first. You can tell if a sea lion is hydrated by their eyes – if they’re runny, they’re hydrated. You can’t tell if they malnourished because they may be bloated and look fine to you, but that might be a belly full of parasites.” Sea lions are like fish in that they get their fresh water from the food they eat, so the starving pups are also dehydrated. When they’re transporting a pup, they surprisingly give them a dog bowl filled with freshwater, which can determine if they live or die. But they don’t give them food.

Rehabilitation

Mitchell Fong of The Marine Mammal Center

Mitchell Fong, a volunteer with the Marine Mammal Center in Northern California for the past thirteen years, explained that some of the emaciated pups are missing half their normal weight or more. As with humans, when pups are that malnourished, their digestive system can shut down making it impossible for them to digest food. “We often don’t even offer fish initially,” Fong said. “What we’re doing is while we’re tube feeding them, we’re checking to make sure that the animal is truly digesting the food; so if liquid starts coming out of the tube and we see its undigested formula, we know that their stomach is not able to digest the last meal we gave them.”

When starving animals arrive at their facilities, they are often given electrolytes for their first few feedings to help hydrate them. The most severely emaciated sea lions can have the longest progression toward fish—which could include first electrolytes, then Emeraid, a formula containing amino acids, protein, vitamins, minerals, and water. The next step is fish smoothies without salmon oil, then fish smoothies with salmon oil, then whole fish. The fish they use is sustainably harvested herring.

Since I live in Southern California, I visited the Pacific Marine Mammal Center (PMMC) in Orange County in early September to take a look at their facility. Established in 1971, this was the first rehabilitation center for marine mammals in California. They’re also one of the smaller ones and hold up to 135 pups comfortably. They have just thirteen paid staff (some are part-time), but 188 volunteers.

As soon as the patients arrive, they’re weighed. That helps the animal care and veterinarian staff determine medication as well as food intake, since sea lions need to consume up to ten percent of their body weight each day. A physical exam follows. Critical care patients stay in one of two heated pens — where even the floors are heated and blankets are provided.

Michele Hunter & Wendy Leeds of PMMC with Mary Ann Wilson

“When these guys come in, they’re emaciated, they have no fat layer,” said Lead Rescue Coordinator Wendy Leeds, who has worked for the center since 1996. “It’s the fat that’s keeping them warm. So any food that we actually give them, they burn off all those calories just trying to stay warm.”

Procedures are done in the lab, which houses an x-ray machines, a portable ultrasound machine, and an infrared camera that allows them to see deeper abscesses. Emaciated animals are hydrated via subcutaneous injection (subq for short) in which electrolytes are injected right underneath a layer of skin, rather than intravenously, to hydrate them. Depending on the situation, they are also tube fed: While the animal is restrained, a biter is placed inside its mouth, and the tube goes through the biter and then down into its stomach. This way staff can pour or push the formula into its belly, starting them with what they call Formula A, a combination of unflavored Pedialyte, Karo syrup and Nutri-Cal.

Formula B consists of fish added to electrolytes. Each pup has their own individualized formula and the amount of fish added depends on where the pup is at in its recovery process. By the time a pup can handle medium-thick formula, they’re weaned to fish. They start with capelin, a small and lean forage fish which is neither oily not fatty, followed by herring, which is a lot more oily and fatty. It’s the herring that’s bulks them up. Michele Hunter, the director of animal care who has worked there since 1989, said, “In our busy season we go through 800 pounds of fish a day, yeah and it’s roughly a dollar a pound so that’s over eight hundred dollars we’re going through in fish a day.” But, she said, “We always want the highest quality of fish for these animals, because they’re sick animals.”

As they get healthier, the pups are moved to different pens. Each pen has heated floors and can be closed if it gets too cold and windy. The animals that can eat but are still pretty thin are placed in pens with no access to a pool, though they can be brought to a pool on an individual basis. They start eating from bowls of fish. If two animals start eating at the same pace, a shallow pool is placed in the pen and fish are added. It’s a good sign if they start competing together, because ultimately they have to compete for their fish. The goal is for them to graduate to bigger pools with five or ten other animals, throw all their fish in there and let them swim around and compete for fish. If they continue to steadily gain weight, they’re likely to be successful out in the wild.

California sea lions stay with their mothers from six months to a year before they’re weaned. They learn everything from them, including social cues and how to swim. Before bringing in a newborn pup, PMMC staff make sure the mother has not left it on the beach to go out and forage. Because most newborns need to be hand–reared, they come to depend on human interaction and bond with their caregivers who guide them and even teach them to swim. They will not be successful out in the wild, so they are placed in a zoo or aquarium.

The rest are kept wild; staff members and volunteers don’t talk to them, and any kind of interaction is kept to a minimum. The majority of pups are born mid-June, and since the rescues start around January or February, they are already weaned and have eaten fish. Unless the pup has an injury that will prevent them from being release, their chances of being returned to the wild are high.

Katie © The Marine Mammal Center

Case Study: Katie

Katie was spotted on June 21, 2016 at Pirate’s Cove, a beach in San Luis Obispo County. A male sea lion pup, he was named by his rescuer who at the time didn’t know his gender. Katie suffered from ataxia (lack of muscle coordination), a swollen jaw, an open wound on his chin, and malnutrition. His body weight was low but not terribly low with a body weight of around 20 kilograms (44 lbs.).

The Marine Mammal Center, which serves San Luis Obispo through Mendocino counties, has full-service veterinary hospital is in Sausalito, but they also have field offices in San Luis Obispo, Monterey, and Mendocino counties. Katie was brought to the San Louis Obispo office, where they injected subq fluids.

At the same time, they tube-fed him fish mash. They figured he could digest protein since he was not severely emaciated, and his swollen jaw and wound most likely inhibited him from eating fish. They also had to decide whether he could make the four and a half hour drive to their hospital in Sausalito. Based on their observations, they took him first to their office in Monterey Bay and obtained a fecal sample, which allows them to look for things like parasites and diseases.

The next day they transported Katie to the hospital in Sausalito, where the veterinarian staff examined the wound to see what caused it and if the wound itself was causing other problems. To examine him for structural damage, they anesthetized him and did an x-ray. Luckily there wasn’t any.  They put him on antibiotics and pain medication for his swollen jaw and chin wound. While in Sausalito the ataxia cleared up and Katie became quite active. Wong surmised that the wobbling that was initially observed may have been due to either his injury or hunger.

The facility in Sausalito, in contrast to the one in San Luis Obispo, has some deep pools of water so sea lions can swim and go after the fish, rather than eating the fish in small, shallow pools of water. Soon after getting there, they were able to transfer Katie from being tube-fed to eating fish. By the time he was released about a month later, his weight was 37.5 kg – close to double his weight when he was admitted.

Back to the Ocean!

Release

In July 2016, I was fortunate to see Katie and three other rehabilitated sea lions released by the Marine Mammal Center in Morro Bay. When they were let out of their individual cages, they touched noses and waddled to the ocean, as volunteers held boards and made a path for them. As soon as they hit water, one of them jumped up and immediately caught a fish. I was moved to tears.

 

Originally published in Catalina Marine Society’s OceanBights, p. 9

References

Mitchell Fong, volunteer with the Marine Mammal Center, Interview July 26, 2016

Peter Wallerstein, director and founder of Marine Animal Rescue, Presentation at Eco Dive Center in Culver City, August 16, 2016

Michele Hunter, director of animal care & Wendy Leeds, lead rescue coordinator; Pacific Marine Mammal Center, Interview September 4, 2016

 

Images

Sea Lions at Pacific Marine Mammal Center, Orange County: Gordon Kelly

Peter Wallerstein of Marine Animal Rescue: Mary Ann Wilson

Mitchell Fong of The Marine Mammal Center: Mary Ann Wilson

Michele Hunter & Wendy Leeds of PMMC with Mary Ann Wilson: Gordon Kelly

Katie: © The Marine Mammal Center

Back to the Ocean: Mary Ann Wilson

 

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Release of Rehabilitated California Sea Lions

 Species Performance  No Responses »
Aug 112016
 
Back to the Ocean!

Back to the Ocean!

On July 16, 2016, the Marine Mammal Center released four rehabilitated California sea lions in Morro Bay. After witnessing dead and dying sea lion pups in 2013 and 2015 on Malibu beaches, I was moved to tears to see these pups so excited to get back in the water. Here are their profiles. Note that the person who first finds the sea lion doesn’t know the animal’s gender but gets to name it.

 

Glenn

Glenn, a female California sea lion pup, was first rescued on February 18, 2016 at Oceano Dunes, San Luis Obispo County and released on April 15, 2016. She was re-rescued on May 4, 2016 at Del Monte Beach, Monterey County.

Reason for rescues: of maternal separation, malnutrition, fishing hooks caught on flipper, Pneumonia.

 

Sunset Willie

Sunset Willie, a female California sea lion pup, was first rescued on February 18, 2016 at Sunset Beach, Santa Cruz County and released on May 9, 2016. She was re-rescued on May 22, 2016 at Monterey Harbor, Monterey County.

Reason for rescues: maternal separation and malnutrition.

 

JaydenJayden, a male California sea lion pup, was rescued on May 20, 2016 at Oceano Dunes, San Luis Obispo County.

Reason for rescue: trauma to both eyes and malnutrition.
Note: Corneal Edema will be cleared up in seawater.

 

KatieKatie, a male California sea lion pup, was rescued on June 21, 2016  at Pirate’s Cove, San Luis Obispo County.

Reason for rescue: Ataxia (lack of muscle coordination), swollen right side of jaw, wound on chin, and malnutrition.

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Here’s the video of their release:

Video of Release: Gordon Kelly

Images

Glenn, Sunset Willie, Jayden, and Katie: courtesy of The Marine Mammal Center

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Mexico Bans Night Fishing and Gill Nets to Protect the Critically Endangered Vaquita Porpoise

 Baja California, Species Performance  No Responses »
Jul 222016
 
vaquita

Vaquita caught in fishing nets

Vaquita, which in Spanish means “little cow,” is a rare porpoise and the smallest and most endangered species of the cetacean order. Also called the Gulf of California Harbor porpoise (Phocoena sinus), it was discovered only in 1958, but by 2014 the estimated number of individuals dropped below 100, putting it in imminent danger of extinction. That number was revised to about 60 in May 2016.

Vaquitas are often caught and drowned in gillnets used by illegal fishing operations in marine protected areas within Mexico’s Gulf of California. More than half of the population has been lost in the last three years. The vaquitas are threatened primarily by gillnet fishing for the totoaba fish, another endangered species in the Gulf of California that is hunted for its swim bladder, which is considered a delicacy in China.

On Friday, July 22, 2016, United States President Barack Obama and Mexico’s President Enrique Peña Nieto committed to intensify bilateral cooperation to protect the critically endangered vaquita porpoise. Mexican authorities are banning night fishing and gill nets in an area inhabited by the endangered vaquita marina porpoise in the upper Gulf of California. The national fisheries commission said fishermen in the protected area of the gulf, known as the Sea of Cortez, will also have to leave and return from specially designated docks, to help enforce the measures. It said that gillnets, the use of which was already suspended in the area, are now prohibited permanently.

“The demand for illegal totoaba fish bladders is driving the vaquita’s demise. By strengthening bilateral cooperation, Mexico and the United States are pledging their commitment to save the world’s most endangered marine mammal,” said Dr. Frances Gulland, The Marine Mammal Center’s Senior Scientist and a member of the U.S. Marine Mammal Commission. “Enforcing a permanent ban on gillnets, developing alternative fishing gear, and increasing awareness among potential sellers and buyers of totoaba bladders will give the vaquita the greatest chance of survival.”

In March 2016, Dr. Gulland performed necropsies on three dead vaquitas that were discovered in the northern Gulf of California, determining their death as “trauma, entanglement.”

 

References

Associated Press, Mexico bans night fishing, gillnets for vaquita porpoise, July 20, 2016

Marine Mammal Center, www.marinemammalcenter.org

World Wildlife Federation, http://www.worldwildlife.org/species/vaquita

Image

Vaquita, World Wildlife Federation, http://wwf.panda.org/what_we_do/endangered_species/cetaceans/about/vaquita/

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The Plight of the California Sea Lion

 Southern California, Species Performance  1 Response »
Apr 102016
 
Westward Beach, Point Dume, Malibu April 12, 2015

Westward Beach, Point Dume, Malibu April 12, 2015

On a Sunday morning in March 2013, I spotted three dead California sea lion pups and two dying pups on the beach just south-east of the cliffs in Point Dume, Malibu. I called the Marine Mammal Care Center for help but they were overwhelmed and could not assist the pups. Two years later in April of 2015, I saw two dying sea lion pups just north-west of the cliffs. Someone called the CA Wildlife Center, and a representative came and put up signs that warned people to stay away and then left, saying there was no room for them.

During both years the National Oceanic and Atmospheric Administration (NOAA) declared an Unusual Mortality Event (UME) for California sea lions (Zalophus californianus). In 2013, more than 1600 California sea lions were stranded alive along the Southern California coastline and admitted to rehabilitation facilities in January, February, March, and April.  Seeing some strandings is normal, particularly from mid-April to mid-May, when most pups are weaned and begin foraging on their own. Pups remain with their mothers for the first 10-11 months of their life and become independent around May of the year after their birth. This coincides with the peak upwelling period in the California Current System (CCS) when primary productivity is at its maximum. If the upwelling fails, we may witness an UME. That’s what happened in 2009—a huge mortality event took place between May and August, a period characterized by the strongest negative upwelling observed in 40 years, resulting in unchar­acteristically warm sea surface temperatures.

Figure 1: Annual California Sea Lion Strandings

Figure 1: Annual California Sea Lion Strandings

But 2013 was unique because most of the strandings occurred in the first four months of the year and were located mainly in Southern California (see Figure 1).

This pattern not only repeated itself in 2015, but worsened. The strandings in 2015 occurred along the same stretch of coastline as they did in 2013, mostly from Santa Barbara through San Diego Counties.  But the total strandings during the first five months of 2015 totaled 3340 (see Figure 2), more than doubling the 1262 strandings during the same period in 2013. Moreover, the strandings in 2015 was more than ten times the average stranding level for the same five-month period from 2004 to 2012.’

Figure 2: California Sea Lion Pup and Yearling Strandings

Figure 2: California Sea Lion Pup and Yearling Strandings

The UME status allowed for the establishment of a panel of experts to determine the cause of the mortality. What the investigation found in both years was “a change in the availability of sea lion prey, especially sardines, a high-value food source for nursing mothers. Sardine spawning grounds shifted further offshore in 2012 and 2013,  and while other prey were available (market squid and rockfish), these may not have provided adequate nutrition in the milk of sea lion mothers supporting pups or for newly-weaned pups foraging on their own.”

Mark Lowry, a National Oceanic and Atmospheric Administration biologist, has collected sea lion scat from San Nicolas and San Clemente islands each season since 1981. Through the years, he has identified 133 different species, seven of which are commonly found in sea lions’ diets. The common prey are market squid and six kinds of fish—anchovies, sardines, two different kinds of mackerel, short belly rockfish, and pacific hake.

Of these forage, sardine and anchovy are fat- and calorie-rich while rockfish and squid are fat- and calorie-poor.  Lowry, who has completed his analyses of 2013 samples as well as the 2015 winter and spring samples, said in February 2016 that in 2013 and 2015, anchovy and sardine pretty much dropped out of their diet. As a result, the sea lions’ diet became incredibly diversified. Evidence of common fish include market squid, some hake—though hake is also down from what they normally eat, and short belly rockfish. “But mostly they’re targeting a group of non-common squid and octopus and non-common fish,” Lowry said. The spring 2015 samples showed the highest levels of non-common cephalopod—squid and octopus—and non-common fish he had seen in a long time.

Of the 127 non-common species found in their diet, 40-60 different species were seen in samples taken from San Nicholas Island in 2015. At San Clemente Island, where Lowry collects fewer samples, 40-45 non-common species were found. Two kinds of mackerel, Jack and Pacific, have increased at San Clemente but not at San Nicholas Island.

In April 2015, Lowry told the Los Angeles Times that he had found “mystery stuff — gooey bits of substance you’d expect from a diet of jellyfish or tube worms.” Though yet to be verified, his analysis now shows they were pyrosomes—free-floating colonial tunicates which are closely related to salp. “That’s very unusual,” Lowry said. “It’s the first time I’ve ever seen those. What that says is that sea lions can’t find what they normally eat, so they’re eating whatever they come across.”

In a report published by Royal Society Open Science, Sam McClatchie, Supervisory Oceanographer for Southwest Fisheries Science Center, predicted the temporal sequence of pup weights between 2004 and 2013 based on two variables: the relative abundance of sardine and anchovy, and the relative abundances of rockfish and squid.  When rockfish and squid are more abundant than sardine and anchovy, sea lion mortality increases. The six most common items in their diet are shown below with their corresponding calorie and fat content.

[supsystic-tables id=’1′]

 

Sharon Melin, a wildlife biologist with the NOAA Fisheries National Marine Mammal Laboratory, tracks sea lion pups’ weight gain and growth, and correlates them with inferred diet of mothers. From an analysis of scats from females collected from breeding sites between June and September over eight years, she defined four different diet types and what years the types were dominant.

  • Diet 1: low percentage of market squid and a high percentage of Pacific sardine (2002, 2005).
  • Diet 2: dominated by market squid and Pacific hake (2000, 2001, 2010, 2011).
  • Diet 3: comprised mostly of northern anchovy and Pacific sardine (2003).
  • Diet 4: dominated by market squid and rockfish (2009, 2012).

Average pup weights tended to be heavier in years represented by Diets 1 and 3, average in years with Diet 2, and the lightest pups occurred in 2009 and 2012 with Diet 4.

During three weeks of fieldwork on San Miguel Island in April 2015, Melin observed the sea lions traveling farther and diving deeper to find food. That’s generally not a problem for males since they can go wherever the food is. After the breeding season, some males migrate north as far as Alaska. But a mother is tied to the rookery island until her pup is weaned almost a year later. Females generally remain within 90 miles (150 km) of the breeding rookeries.

California sea lion females give birth to a single pup between May and June in large rookeries on offshore islands along California and Baja Mexico. The main US breeding rookeries are located on the Channel Islands and California sea lion pups are born on the islands of San Miguel, San Clemente, San Nicholas and Santa Barbara. Once a mother begins foraging for food, a sea lion pup will usually nurse, on average, every third day. While she’s away collecting food, she produces milk while her pup waits on shore and fasts. When she returns, she locates her pups with a “pup attraction call,” which is established shortly after birth when the mother and pup call to one another and the pup imprints on its mother’s distinct call. They also recognize each other by scent.

Lactating female California sea lions consume approximately 11% of their body mass in food per day. In addition, because lactating females are usually also pregnant during nine months of the 11-month lactation period, a diet that is insufficient to support both lactation and gestation may result in the resorption of the fetus or a premature birth.

In December 2014, Melin’s team satellite tagged twelve adult female-pup pairs. What they found was while many stayed around the island through much of December, by January they started seeing females taking off and not returning, which was indicative of their pups dying. So out of the original twelve, by March only six were still coming to San Miguel Island, and they were consistently diving to 400, 500, 600 meters.

This diving requires extraordinary physiology. To dive this deep, sea lions’ lungs collapse at about 225 meters down and then re-expand at the same depth upon ascent. This technique not only staves off decompression sickness, by keeping nitrogen out of the bloodstream, but also reduces the amount of oxygen delivered from their lungs to their bloodstream—preserving the oxygen within the sea lion’s upper airways. When they head back to the surface, the preserved oxygen re-expands into the lungs and prevents the sea lion from blacking out in the shallows.

“To have half of our sample diving into those kind of depths is unusual,” Melin said in a NOAA Fisheries podcast last April by which time only four females-pup pairs remained. “These females that were doing this deep diving, they were going very deep and they were going out into very deep water. They were also the four females whose pups are still alive, and we were able to capture their pups. And although their pups were not giant, healthy pups, they were alive.”

Lowry’s 2015 winter and spring findings concur. Short belly rockfish, one of the common fish showing up in his samples, are generally found deeper in the water column than anchovies, sardines, and mackerel. Furthermore, a lot of the non-common fish that were found live on or near the bottom of the ocean, like flat fish and different species of rock fish, as well as cusk eels—a group of marine bony fishes.

A downward trend for sardine abundance has been going on for a decade, and over a large area (five degrees of latitude). McClatchie’s report, which uses data from the Southwest Fisheries Science Center’s Rockfish Recruitment and Ecosystem Assessment Survey (RREAS), shows that during the decade from 2004 to 2014, market squid and rockfish increased, while sardine and anchovy fell to very low numbers off central and southern California, and around San Miguel Island in northern California where sea lions breed.

According to the Pacific Fishery Management Council (PFMC), which develops regulations for fisheries in the U.S. off the West Coast, the sardine biomass (the estimated weight of a stock of fish) reached a peak of 1.3 million metric tons in 2006, then dropped to an estimated 97,000 metric tons in 2015, a decline of more than 90% and significantly below the 150,000 metric ton threshold for this directed fishery. In April of 2015, the Pacific Fishery Management Council announced the closure of the 2015-16 U.S. Pacific sardine fishery, beginning July 1.

Sardine populations rise and fall naturally, cycling as ocean temperatures shift. But, says Tim Essington, a University of Washington professor of aquatic and fishery sciences, “Fishing makes the troughs deeper.” In a paper published in March, Essington showed that overfishing worsens the magnitude and frequency of the cyclical declines of sardines and other forage fish, such as anchovies.

His March 2015 study showed for the first time that fishing likely worsens population collapses in species of forage fish, including herring, anchovies and sardines.  To prevent complete collapse, the study recommended the use of risk-based management tools that would track a fishery’s numbers and halt fishing when they dipped too low. This strategy has the potential to not only ensure more fish for the sea lions, but long term stability in the fishing industry. Using simulations of this management strategy, researchers determined that by suspending fishing when a population falls below half of its long-term average, 64 percent of collapses could be prevented and average catch would be reduced by only two percent in the long term. Based on scientific recommendations by the Lenfest Forage Fish Task Force, Oceana suggests increasing the threshold for pacific sardines from 150,000 metric tons to at least 640,000 metric tons.

At the April 2015 PFMC meeting, assessment author Dr. Kevin Hill presented a Southwest Fisheries Science Center analysis of what the sardine population might look like in the absence of fishing (see Figure 3).  While it is clear that, with the lack of recruitment, the population would have declined greatly even in the absence of fishing, Hill’s analysis showed the population would have been four times higher in 2015 without fishing; that is, approximately 400,000 metric tons (purple line, ‘no fishing’) versus the current estimated 96,688 metric tons (blue line ‘2015 update’). Moreover, sardine harvests exceeded Maximum Sustainable Yield levels during the decline.

Figure 3: Sardine Stock Biomass

Figure 3: Sardine Stock Biomass

The U.S. population of California sea lions is currently estimated to be 300,000 animals, all on the Pacific coast. From an estimated population of about 10,000 animals in the 1950s, their numbers have grown rapidly since 1972 when the Marine Mammal Protection Act was implemented. Lowry, who also conducts annual aerial surveys of California’s pinniped populations, told the LA Times that the sea lion population is increasing at a rate of about 5.1% per year.

Unfortunately, we now have a large sea lion population coupled with a decline in food quality near breeding colonies. Until high-quality food increases again in the Southern California Bight, pup emaciation may become the norm.

Originally published in Catalina Marine Society’s OceanBights, p. 4 

References

Melin SR, et al, Unprecedented mortality of California sea lion pups associated with anomalous oceanographic conditions along the central California coast in 2009, California Cooperative Oceanic Fisheries Investigations Reports. 51: 182-194.

NOAA Fisheries, West Coast Region, 2015 Elevated California Sea Lions Strandings in California: FAQs

NOAA Fisheries, 2013-2016 California Sea Lion Unusual Mortality Event in California

Mark S. Lowry, Research Biologist, Marine Mammal and Turtle Division, Interview February 22, 2016

Louis Sahagun, Scat may contain clues to marine mammals’ Southern California deaths, Los Angeles Times, May 13, 2016

Sam McClatchie et al, Food limitation of sea lion pups and the decline of forage off central and southern California, Royal Society open science, DOI: 10.1098/rsos.150628. March 2, 2016

NOAA Fishwatch, Pacific Mackeral

Sharon Melin et al,California sea lions: An indicator for integrated ecosystem assessment of the California current system, California Cooperative Oceanic Fisheries Investigations Reports. 53: 140-152. 2012

NOAA Fisheries, Transcript: Sea Lion Strandings – The View from the Rookery, April 13, 2015

AMMPA California Sea Lion Fact Sheet

Winship et al., Food Consumption by Sea Lions: Existing Data and Techniques, Sea Lions of the World, DOI: http://doi.org/10.4027/slw.2006

Rich Press, NOAA Fisheries Science Writer, NOAA Fisheries, Transcript: Sea Lion Strandings – The View from the Rookery, April 30, 2015

Birgitte I. McDonald, Paul J. Ponganis, Lung collapse in the diving sea lion: hold the nitrogen and save the oxygen, Biol. Lett. 2012 8 1047-1049; DOI: 10.1098/rsbl.2012.0743. November 12, 2012

Pacific Fishery Management Council, Council Votes to Close 2015-2016 Pacific Sardine Fishery, April 13th, 2015

T.E. Essington et al, Fishing amplifies forage fish population collapses. Proceedings of the National Academy of Sciences of the USA. 2015;10.1073/pnas. April 6, 2015

Lenfest Forage Fish Task Force, Little Fish, Big Impact, April 2012

Oceana, Letter to Ms. Eileen Sobeck, Assistant Administrator for Fisheries, May 21, 2015, Agenda Item B.1.b Supplemental Open Public Comment 2

Washington Department of Fish and Wildlife, Conservation, California Sea Lion Fact Sheet

Images:

Emaciated California sea lion pup, D. Gordon Kelly, Westward Beach, Point Dume, Malibu, April 12, 2015

Figure 1, Annual California Sea Lion Strandings: NOAA Fisheries, West Coast Region, 2015 Elevated California Sea Lions Strandings in California: FAQs, Figure 1

Figure 2, California Sea Lion Pup and Yearling Strandings: NOAA Fisheries, 2013-2016 California Sea Lion Unusual Mortality Event in California, California Sea Lion Strandings

Figure 3, Sardine Stock Biomass: K.T. Hill et al, NOAA Fisheries, SWFSC-FRD, Assessment of the Pacific Sardine Resource in 2015 for USA Management in 2015-16, Fishery Impacts, Slide 12

 

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California’s Fish Population in Dramatic Decline

 Species Performance  No Responses »
Nov 032015
 
The bongo net (shown here) has been the standard CalCOFI sampler since 1978. Ships retrieve the nets at an oblique angle to collect fish larvae. CalCOFI sampling and equipment specifications must meet and follow rigorous standards

The bongo net (shown here) has been the standard CalCOFI sampler since 1978. Ships retrieve the nets at an oblique angle to collect fish larvae. CalCOFI sampling and equipment specifications must meet and follow rigorous standards.

Two independent long-term time series show four decades of declines within fish populations in the California Current, with no sign of reversal.

The data set from the California Cooperative Oceanic Fisheries (CalCOFI) and the data set from the power plant cooling water intakes (PPI) were taken from five sites along the California Coastline. Both sets exhibited dramatic declines from the 1970s to the 2000s: 78% for fishes entrapped by the power plants and 72% for the overall abundance of larval fishes in the CalCOFI time series.

“It is notable that these two very distinct data sets tell us that the larval fish populations collected by CalCOFI and near shore fish species observed by PPI data are both declining at nearly the same rates,” said Scripps researcher John McGowan, one of the authors of the study published in Marine Ecology Progress Series on October 28, 2015.

Overall, fishes with an affinity for cool-water conditions, such as northern anchovy, Pacific hake, and several rockfish and midwater fish species are among the most abundant in the California ecosystem. These have declined most dramatically off southern California with initial declines deepening after the 1989 to 1990 regime shift, when warm waters intensified, severely reducing the productivity of many coastal species.

The study’s conclusion: One of the most striking aspects of this study is the strong coherence between these two independent time series and the nearshore and offshore fish communities that they represent. Cool-water marine ecosystems are generally more productive than warm-water ecosystems, and it is apparent that changing ocean conditions have produced far more losers than winners across a range of fish communities in the southern California Current System over the past 40 years. Without the CalCOFI and PPI time series, such dramatic changes would likely not have been possible to document, as they are not observed so clearly in the commercial fishery data. Whether this is due to a movement of cool-water species northward or an overall decline throughout the California Current is a key question for future investigation.

 

References
J. Anthony Koslow,Eric F. Miller, John A. McGowan, Dramatic declines in coastal and oceanic fish communities off California

Mario Aguilera, California’s Fish Populations Are Declining, Oct 29, 2015

Jason Waite, Climate Change and the Central California Current System

 

Images

The bongo net (shown here) has been the standard CalCOFI sampler since 1978, CalCOFI

Return of the Giant Sea Bass, King of the Kelp Forest

 Species Performance  2 Responses »
Dec 292014
 

Back in April 2011, my friend and I were diving off Casino Point on Santa Catalina Island in chilly waters when we looked up and saw four large black fish. They were about four to five feet long, cruising slowly in around 20 feet of water at the edge of the kelp. To my friend they looked like underwater cows; to me they seemed more like mellow hippies on floating motorcycles. Whatever they were, I was in awe of them. We were told they were giant sea bass (GSB), Stereolepis gigas, which return to the waters off Catalina Island every summer, and we were the first to see them that year.

Measuring 8.9ft, this giant sea bass is the largest ever seen.

Measuring 8.9ft, this giant sea bass is the largest ever seen.

These apex predators have had a rough time, being nearly fished to extinction until saved by legislation. Commercial fishing of giant sea bass began in Southern California in1870 when fish were taken with hand lines. But as the take declined between 1915 and 1920, fishermen switched to gill nets, temporarily increasing catch. Commercial landings peaked in 1932 at 115 tonnes but then decreased rapidly. By 1935 most commercial fishing had shifted to Mexico. And by 1980 commercial landings in California waters had declined to 5 tonnes.
In 1981, the California State Legislature banned commercial and recreational fishing for giant sea bass, but still allowed commercial fishermen to retain and sell two fish per trip if caught incidentally in a gill net or trammel net. This law also limited the amount of giant sea bass that could be taken in Mexican waters and landed in California. The law was amended in 1988, reducing the incidental take to one fish in California waters.
After the moratorium was enacted in 1981, catches decreased substantially. From 1983 to 1992, incidental catches remained low, ranging from 1.7 to 5.9 tonnes.

But the moratorium didn’t prohibit fishing over giant sea bass habitats where they could be caught incidentally. Entangled giant sea bass that would exceed the catch limit if landed were discarded at sea or distributed among fishing boats.

Larry Allen

Larry Allen

Other fish have also suffered from nets and overfishing.  Soup fin sharks became scarce in the early 1940s, while leopard sharks declined in the mid-1980s. In a drastic move to save the fish, gill nets were banned as of 1994 from within three miles of southern California’s mainland.  This regulation signaled a turning point for fish populations. In a presentation given this past October, Dr. Larry Allen, biology department chair at CSUN, said the Proposition 132 ban on gill nets is what turned the tide for many commercially fished species.  “We’ve seen a response of halibut, a response of giant sea bass that we’ve published, a response of leopard sharks and soup fin sharks and a variety of other large elasmobranchs which seem to have gotten some relief from commercial fishing.”

Dr. Allen worked for 20 years before seeing a juvenile giant sea bass in 1993. His first observation:

“Last year while trawling in Newport Bay on a sampling trip for Cal Fish and Game’s BENES program targeting local sport fishes, something memorable happened…Almost as soon as the trawl had hit the deck, my chief research assistant, Motz (Tom Grothues), began yelling something about a black sea bass. I was on the back deck in an instant grumbling in disbelief. I had never seen or heard of a black (or now, more properly, a giant) sea bass being taken from inside Newport Bay in all of my 20 years of experience there. But, sure enough, there it was. An absolutely gorgeous little fish about 6 inches long. It was reddish-bronze in color with jet-black circular spots and huge black fins…From the likes of this tiny, elegant fish — the largest, the eldest, and most magnificent of our nearshore fish species will emerge.” (Western Outdoors News, 1993)

He was right.  A scientific monitoring program conducted quarterly by SCUBA divers with the Vantuna Research Group (see OceanBights Vol. 3 No 1) didn’t report any along Palos Verdes Point from 1974 to 2001. The giants were finally seen there from 2002–2004. That’s when Allen decided it was time to begin a study of giant sea bass. But his article entitled “The decline and recovery of four predatory fishes from the Southern California Bight” was turned down by Science, Nature and PNAS, because “there was one reviewer that simply didn’t believe our data. He thought we made it up,” Allen said. It was finally published 2008 in Marine Biology.

Juvenile giant sea bass

Juvenile giant sea bass

Giant sea bass start life as brightly colored orange juveniles with large black spots, and ride the sand riffles in shallow water. According to Allen, the juveniles gorge on opossum shrimp, while the darker adults eat pretty much anything they want including fairly large spiny lobsters which they are more than capable of sucking out of their crevices with their large, gaping mouths. As the only “megacarnivore” inhabiting the kelp beds in southern California, they also consume Pacific mackerel, ocean whitefish, midshipmen, stingrays, white croakers, small sharks, crabs, and mantis shrimp.

Historically, giant sea bass were distributed from Humboldt Bay to southern Baja California and the Sea of Cortez with populations concentrated south of Point Conception in shallow rocky reefs.  According to Allen, the current primary range is Pt. Conception south to about Punta Abreojos, Baja Mexico and in the northern Gulf of California (north of the Midriff Islands). “We think they occur off the coastline of southern Baja California, but if they occur there, they are probably in deep water — say 200 to 400 feet,” Allen said. “We also think they or their larvae migrate around the tip of Baja joining the populations on either side of the peninsula, based on anecdotal and personal observations as well as genetic data.”

Very little is known about giant sea bass, but their increasing numbers enable better research on lifespan, size, mating and population diversity. In recent years, scientists have determined that the Stereolepis gigas are not even related to sea bass. They’re in a completely different group of fish, the wreckfish (Polyprionidae) which are very distantly related to groupers.

To estimate age, Allen counted the number of annuli on otoliths from 64 heads, obtained from the Santa Barbara Fish Market between January 2010 and May 2013. These fish were incidentally caught by fishermen working between the Northern Channel Islands and northern Baja Mexico. When he counts the rings he places a dot on each ring to ensure accuracy. Then he figures out how much bomb radiocarbon it has, and fits that into the calibration curve of bomb radiocarbon present in the Eastern Pacific. Bomb radiocarbon was produced from atmospheric nuclear testing in the 1950s and shows a very distinct pattern in most oceans, as the atmospheric fallout worked its way into the bony structures of all fishes and invertebrates. In 2012 Larry Allen and Allen Andrews were the first to validate annual growth rings for one individual and provide a verified maximum age, 76 years, for giant sea bass using bomb radiocarbon validating techniques.

JR Clark and Parker House

JR Clark and Parker House

Wild, live fish are being studied at Catalina. Two of Allen’s students, JR Clark and Parker House, received WIES Wrigley Institute Summer Graduate Fellowships and spent three months diving off Catalina Island, first locating the giants’ aggregations, then trying to determine their size, densities, and mating behavior. They also hope to learn what impact their return will have on kelp bed fish populations. Grants and $6,000 dollars in crowd funding help to pay for the students’ underwater hydro-acoustic equipment and sea scooters.

To find the minimum population size around the entire island, they chose eight sites: four where they thought they’d see giants and four where they thought they wouldn’t see them, and did the back side as well as front side. Those eight sites were Johnson’s Rocks, Little Geiger, Empire Landing, Twin/Goat (between Goat Harbor and Twin Rocks), Italian Gardens, Casino Point, The Vee’s, and Little Harbor. There were 4 periods within roughly two-week long windows that sampling was conducted.

Sites with the most individuals and biomass were Little Harbor, Goat Harbor, and the Vee’s. At the Vee’s they saw an aggregation of 24 individuals in two different sampling periods. To accurately size giants underwater, the students use length-calibrated lasers and a GoPro video camera mounted on top of SeaDoo SeaScooters. Two laser beams calibrated four inches apart are pointed directly (90 degrees broadside) at an individual fish so that the laser dots are visible in the video. Stills are later extracted from video and then measured using a software program. Using length to weight relationships, biomass is determined for different areas.

Parker House and JR Clark underwater

Parker House and JR Clark underwater

Their calculated average biomass for the eight sites was 36.29kg/1000m2, which was higher than expected. House said this was due to the unexpected and very large aggregation at the Vee’s. The most individuals observed were 36 counted during the sampling period from July 15 to July 23, 2014. The least were seen during June with only nine individuals. The giants ranged from 0.9 to 2.7 meters while the majority were around 1.3 m (4.2 feet) in length.  The International Game Fish Association all-tackle world record for this species is 563 pounds 8 ounces, caught at Anacapa Island in 1968. But the largest one seen this summer was 2.7 meters or 8.9 feet and weighed at least 325 kilograms or 800 lbs, and is the largest ever measured.

“It was relatively easy to count the individuals as many stayed in a general area,” House said. “Many of them have different characteristics; some had many parasites on their face, or scars on their fins or sides, or blotches so you can more easily identify one fish from another, although they do change color.  Some would be near us and would show a certain color pattern, but once they moved away, you would see these patterns change. We think the changing of color pattern may be a signal for mating as well as communication to the other individuals.”

“Many fishes change color when they are ready to mate,” Clark added. “A good example is the kelp bass, which presents a yellow or orangey mask when males are in the spawning season. We have seen some color change, from a light to dark color type change. This has been previously described as a spawning type activity in giant sea bass.”

Parker House riding a SeaDoo SeaScooter

Parker House riding a SeaDoo SeaScooter

Another way to identify spawning and courting behaviors is by their sound. The students had just gotten down to one of their sites when they heard a BOOM — the sound of a very loud bass drum.  “The first time I heard it I thought something was wrong with my tank,” House said. “So I checked my pressure gauge to see if it had dropped, but it wasn’t us. We looked around and a giant sea bass was coming straight to us, and then he checked us out and took off. We think the sound could be either a call to try and get us away because they were courting in that area, or to see if we were potential mates.”

Spawning in giant sea bass has only been seen in an aquarium where there are just two individuals. Because of their size and the enormous amount of eggs the females carry — up to 60 million — GSB are thought to be group spawners, but Clark believes that they are pair spawners because they are frequently seen in pairs, even when they are in large aggregations.

Giant sea bass sounds are recorded by a hydrophone.

Listening in on a hydrophone.

The students use the sounds giant sea bass make to distinguish one fish from another and also to measure the density of giants in a specific area. Clark uses a DSG-Ocean Acoustic Datalogger, which is an omnidirectional hydrophone (underwater microphone) that can record data over many days. He distinguishes giant sea bass sounds from other fish by looking at the decibel range and sound frequency they produce and comparing them with giant sea bass sounds recorded in an aquarium. This enables him to analyze mating strategies and describe spawning behavior of giant sea bass in detail. “Although there may be some echoing in the sounds produced in the aquarium it will allow me to ground truth sounds and get a general decibel range to work with,” he said.

Whatever the giants spawning behavior is, their genetic diversity is small. Allen and Andrews used mitochondrial and nuclear microsatellite techniques to determine genetic diversity. They found all the giant sea bass, those in the northern Gulf of California, as well as off Southern California and Baja, were closely related. They’re basically one panmictic group — a panmictic population is one where all individuals are potential partners. “Our estimate is 152 breeding females, with maybe an upper limit of 500 and a range of 84 to 539,” Allen said. “So we’re dealing with a fish that’s not genetically diverse anymore; relatives are breeding with another, and we don’t know what that says to the ultimate sustainability of these populations. Sobering.”

A pair of giants

A pair of giants

However, the king of the kelp forest has returned. Recently a Giant Sea Bass Count was organized by researchers at the University of California, Santa Barbara and California State University, Northridge.  Recreational divers could report any sightings around Southern California during the first week of August. Giant Sea Bass sightings numbered 23. Their results can be seen at seasketch.org. Green dots indicate sightings and black X’s show where people reported that they dove but saw no Giant Sea Bass.

Next year’s giant sea bass count will probably be in early August, but check and “like” the Facebook page, The Giant Sea Bass Collective, to get updates.

Originally published in Catalina Marine Society’s OceanBights, p. 3, and reprinted in California Diver.


References

Giant Sea Bass, Stereolepis gigas

Dr. Larry Allen, “The Return of Giant Sea Bass off California,” Presentation at California State University, Fullerton; Wednesday, October 8, 2014

Holly A. Hawk & Larry G. Allen, Age and Growth of the Giant Sea Bass, Stereolepis gigas

IUCN Red List Data, Stereolepis gigas

California Department of Fish and Game, Giant Sea Bass

Current Results, Sharks, Seabass Rebound After Fishing Banned

Dr. Larry Allen, Target Species Profiles: Giant (black) Sea Bass (Stereolepis gigas)

Larry Parker House, CSUN marine biology graduate student, interview September 8, 2014

Brian (JR) Clark, CSUN marine biology graduate student, interview September 24, 2014

Images:

  1. A pair of giants: Parker H. House
  2. Largest giant sea bass ever measured at 8.9ft and 800+ lbs.: Parker H. House
  3. June 1906: world record at 428 lbs.: Library of Congress, Digital Collections
  4. Dr. Larry Allen: Mary Ann Wilson
  5. Juvenile giant sea bass: Phil Garner
  6. JR Clark and Parker House: CSUN Students Dive Into Marine Research on Catalina Island
  7. Parker House riding a SeaDoo SeaScooter: J.R. Clark
  8. Parker House and JR Clark: Parker H. House
  9. Listening in on a hydrophone: Parker H. House
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