Love ’em Or Hate ’em, Sea Lions Raise Concerns On The Columbia

(Click here for slideshow)

To some people, sea lions are smart, lovable creatures that shouldn’t be harmed in any way. To others they’re loud, destructive pests that need to be controlled.

As sea lion populations grow, both sides have gripes about how these hulking pinnipeds are being managed on the Columbia River.

Some want to see wildlife managers kill more sea lions to protect fragile runs of salmon and steelhead – especially as new research suggests sea lions may be eating a lot more fish than previously thought. Others say killing sea lions is scapegoating, and it won’t solve the bigger environmental problems that put the fish at risk in the first place.

This spring, around 2,400 barking sea lions piled into Astoria’s East Mooring Basin – astonishing biologists who have been monitoring them here for years. The sea lion numbers shattered last year’s record of 1,400 of these marine mammals in the marina.

A lack of food in the ocean and a big smelt run drew them in and soon California sea lions, which can weigh 700 pounds or more apiece, had taken over the Astoria docks that should be harboring boats. That alone is problem for Bill Hunsinger, who oversees those docks as a commissioner with the Port of Astoria.

“They’ve absolutely destroyed them,” he said. “You can’t bring people down to these docks when you have this type of situation.”

But the port’s damaged, unusable docks are only the beginning of Hunsinger’s problems with sea lions that he have been sinking boats, disturbing nearby hotel guests and even biting people and their dogs, he said.

And that’s on top of all the prized spring salmon they’re eating – at times plucking them right off the lines of recreational anglers.

“The fisheries are going to be lost,” he said. “I talked to three guys who went fishing two weekends ago. They had nine fish on and never got one to the boat. Lost ’em all to sea lions.”

Experts say the overall California sea lion population is as big as it’s ever been, thanks in part to the 1972 Marine Mammal Protection Act’s restrictions on hunting or harming them. Fish and wildlife managers with Oregon and Washington have killed about 70 sea lions on the Columbia to protect threatened and endangered salmon and steelhead. But Hunsinger and others say they should be killing more.

To protect fish runs from sea lion predation, Columbia River tribes are hoping to get authorization from Congress to kill more sea lions – beyond what the states of Oregon and Washington are authorized to kill.

Right now, Columbia River Indian tribes’ fish commission is using non-lethal hazing to try to deter sea lions from eating salmon at Bonneville Dam – the first bottleneck for fish on the river. As thousands of returning adult salmon and steelhead swim to their spawning grounds to reproduce, the dam slows them down and makes them easy pickings for sea lions.

Below the dam, tribal members chase down sea lions and shoot firecrackers at them to push the animals farther downriver and away from the bottleneck.

But with dozens of sea lions feeding near the dam, it’s not hard to find one tearing through a fish, thrashing his head out the water to break off a bite while sea gulls swoop down for the scraps.

This is what managers call a predation event. And according to Doug Hatch, a senior fisheries biologist for the Columbia River Inter-Tribal Fish Commission, non-lethal hazing with firecrackers can only do so much to prevent it.

“For the times that we’re hazing, it’s pretty effective,” Hatch said. “But as soon as we leave the animals will come back.”

Hatch said more sea lions should be killed to protect fragile runs of salmon and steelhead – not just at Bonneville but throughout the lower river.

Looming over the debate about managing sea lions is an ominous number. Last year, a federal study that tracked returning salmon from the mouth of the Columbia to Bonneville Dam found that 45 percent of the fish went inexplicably missing somewhere along the way.

“The smoking gun is sea lions,” Hatch said. “Sea lion abundance has increased tremendously over the past several years – particularly this year it’s much higher than we’ve seen it before.”

It’s unclear exactly how many of the missing fish were eaten by sea lions, but if all of them were, that’s a huge portion of the salmon people are spending millions of dollars trying to protect and restore – much bigger than the 2-5 percent rate of sea lion predation of salmon documented the U.S. Army Corps of Engineers at Bonneville Dam.

A new experiment this year aims to fill the gaps in what we know about how many salmon sea lions are eating in the Columbia. Scientists have tagged some sea lions with accelerometers that track the distinctive head-shaking motion they make when they eat salmon. Managers are hoping that the tags will allow them to get a better count on how many fish sea lions are eating in the 146 miles of the river below Bonneville Dam.

But no matter how many salmon sea lions are eating, people who love sea lions contend that it’s wrong to kill them for doing what they naturally do.

“Sea lions are beautiful, amazing animals,” said Ninette Jones of the Sea Lion Defense Brigade. “We have just been blown away by the outpouring of support for these animals.”

Jones’ group watches over sea lions in Astoria and at Bonneville Dam. She said sea lions have a natural predator-prey relationship with salmon and it’s actually people who have put salmon at risk of extinction. Given all the other environmental problems on the Columbia River, including the dams, she said, blaming sea lions is taking the easy, cheaper way out of the complex problems people have created on the river.

“The salmon populations were going extinct when there were no sea lions in the river back in the ’80s,” she said. “So to draw the connection that the sea lions are causing the extinction of salmon it’s basically scapegoating but it’s not going to address the real cause of the extinction of salmon. Even if they killed all the sea lions it’s not going to save the salmon.”

Jones also argues having state wildlife managers killing sea lions is encouraging people to take matters into their own hands and to shoot sea lions illegally. Earlier this month, her group found sea lions bleeding on the docks in Astoria from apparent gunshot wounds.

Robin Brown, marine mammal program lead with the Oregon Department of Fish and Wildlife, defended his agency’s policy of lethally removing some sea lions. The state only kills sea lions that have been identified and observed eating salmon below Bonneville Dam, he said, and the 73 killed since 2006 represent a tiny portion of the total population.

“We try to manage for the resource that’s at the greatest risk,” Brown said. “There are over 300,000 California sea lions in the population now and that population is at no risk whatsoever. Yet a lot of these salmon and steelhead populations have been reduced, granted through the actions of people over many years, but those very small populations of salmon and steeled are at great risk of extinction.”

Back in Astoria, port commissioner Bill Hunsinger disagreed with Jones about the effect of the government’s lethal removals. He said the government needs to increase its lethal removal of sea lions to prevent more people from taking matters into their own hands and shooting them illegally. But he doesn’t disagree that sea lions are beautiful.

“Well, they are. And they’re entertaining,” he said. “But they need to go entertain somebody else in someplace else.”

Soon many of the sea lions will leave the Columbia River for their breeding grounds farther south. But there’s little doubt they’ll be back – barking and eating fish again – next spring.

Read the original post: http://kuow.org/

Why Poop-Eating Vampire Squid Make Patient Parents

The mysterious vampire squid is not actually a vampire or a squid–it’s an evolutionary relict that feeds on detritus. (MBARI)

Squid and octopuses are famous for their “live fast, die young” strategy. At one-year-old or younger, they spawn masses of eggs and die immediately. But scientists have just discovered a striking exception, reported April 20 in the journal Current Biology.

Females of the bizarre species known as “vampire squid” can reproduce dozens of times and live up to eight years. This strategy is probably related to the vampire squid’s slow metabolism and its habit of eating poop.

These shoebox-sized animals have fascinated biologists since their discovery in 1903, not because of any actual vampiric habits, but because of their puzzling place within the cephalopods—the group of animals that contains squids and octopuses.

Vampire squid are neither a squid nor an octopus, and they’re tricky to study because they live hundreds of meters below the surface, in frigid water with very little oxygen.

In addition to eight webbed arms, they have two strange thread-like filaments, whose purpose—collecting waste for the vampire squid to eat—wasn’t understood until 2012. A clear picture of the habits and evolution of these animals remains elusive.

Take a Rest Between Eggs

Henk-Jan Hoving, currently at the Helmholtz Centre for Ocean Research in Kiel, Germany, began his investigation of vampire squid while at the Monterey Bay Aquarium Research Institute. For the spawning study, he worked with specimens that had been collected by net off southern California and stored in jars at the Santa Barbara Museum of Natural History.

Out of 27 adult females, Hoving and his colleagues found that 20 had “resting ovaries” without any ripe or developing eggs inside. However, all had proof of previous spawning.

As in humans, developing eggs are surrounded by a group of cells called a follicle. After a mature egg is released, the follicle is slowly resorbed by the ovary. The resorption process in vampire squid is so slow, in fact, that the scientists could read each animal’s reproductive history in its ovaries.

Counting 38 to 100 separate spawning events in the most advanced female, and estimating that at least a month elapsed between each event, Hoving and his co-authors concluded that adult female vampire squid spend three to eight years alternately spawning and resting.

This length of time is reminiscent of the deep-sea octopus who brooded her eggs for over four years. In both cases, the animals’ actual lifespan must be longer than their reproductive period, which suggests truly venerable ages for members of a group whose most common representatives live for just a few months. These long life spans are related to a slow metabolism and the chill of the deep sea—around 2 to 7 degrees Celsius, or 35 to 44 Fahrenheit.

Limited Calories, But Limited Danger

A single spawning event is not actually a strict rule for octopuses and squid. A few species are known to spawn multiple batches of eggs, even as they continue to eat and grow. However, all species reach a continuous spawning phase at the end of their lives.

Once a female starts to lay, her body is in egg-production mode until she dies, her ovaries constantly producing. That’s why the discovery of a “resting phase” in the ovaries of vampire squid was so surprising.

But this unexpected strategy makes sense in the context of a vampire squid’s lifestyle. The mass spawnings of other cephalopods are fueled by a carnivorous diet of fish, crabs, shrimp and even fellow squids and octopuses.

By contrast, the fecal material and mucus that make up most vampire squid meals are not nearly as calorie-rich. The animals may be simply unable to muster enough energy to ripen all their eggs at once.

There’s an advantage, however, to living in the food-poor, oxygen-poor depths of the ocean. Few large predators can survive there for long, so vampire squid are relatively safe—compared to their cousins, who are constantly on the run from fish, dolphins, whales, seabirds and each other.

When you face a high risk of being eaten on any given day, it’s a good idea to get all your eggs out as quickly as possible. But vampire squid are free to engage in leisurely, repetitive spawning. It’s the ultimate work-life balance: alternately popping out babies, then returning to business as usual.

The vampire squid was named for its fearsome appearance, but those “spines” are just soft flaps of skin. (MBARI)

A fossil cephalopod from the Middle Jurassic, thought to be an early vampire squid.

Read the original post: http://blogs.kqed.org/

Ray Hilborn Asks If the Drive for MPA’s is Environmentally Shortsighted

— Posted with permission of SEAFOODNEWS.COM. Please do not republish without their permission. —

SEAFOODNEWS.COM  [SeafoodNews]  April 29 2015

State and Federal Agencies Halt Commercial Sardine Fishing off California

Media Contacts:
Kirk Lynn, CDFW Marine Region, (858) 546-7167
Chelsea Protasio, CDFW Marine Region, (831) 649-2994
Carrie Wilson, CDFW Communications, (831) 649-7191

State and Federal Agencies Halt
Commercial Sardine Fishing off California

All large-volume commercial sardine fishing in state and federal waters off California has been prohibited as of Tuesday, April 28, 2015. The closing will remain in effect until at least July 2016.

“This may be an end of an era, but fortunately, the tough management decisions were made several years ago,” noted Marci Yaremko, CDFW’s representative to the Pacific Fishery Management Council (Council), and fishery manager for coastal pelagic species, including sardines.

At its April 12 meeting, the Council recommended regulations that prohibit directed commercial fishing for Pacific sardine (Sardinops sagax) in California, Oregon and Washington for the upcoming fishing season, which would have begun July 1, 2015, and run through June 30, 2016. In light of revised stock biomass information and landings data for the current season, the Council also requested the National Marine Fisheries Service (NMFS) close the fishery in the current season as quickly as possible. This closure takes effect today.

“The stock is in a state of decline, and now is too low to support large-scale fishing,” Yaremko explained. “Industry, government agencies and those looking out for non-consumptive interests have all worked together over the years to develop the harvest control rule we are using today, which defines when enough is enough.”

The Pacific sardine fishery in California was actively managed by the CDFW until 2000, when it was incorporated into the Council’s Coastal Pelagic Species Fishery Management Plan. Since then, the fishery has been actively co-managed by the Council, NMFS, CDFW and Oregon and Washington’s Fish and Wildlife agencies.

California’s historic sardine fishery began in the early 1900s, peaked in the late 1930s and then declined rapidly in the 1940s. A 20-year moratorium on the directed fishery was implemented in the late 1960s. In the 1990s, increased landings signaled the population’s recovery. Numbers have since dropped again, significantly.

The Pacific sardine fishery continues to be a significant part of California’s economy at times. At the recent fishery’s peak in 2007, 80,000 metric tons (mt) of Pacific sardine was landed resulting in an export value of more than $40 million. The majority of California commercial sardine landings occur in the ports of San Pedro/Terminal Island and Monterey/Moss Landing.

The Pacific sardine resource is assessed annually, and the status information is used by the Council during its annual management and quota setting process. The Council adopted the 2015 stock assessment, including the biomass projection of 96,688 mt, as the best available science. Current harvest control rules prohibit large-volume sardine fishing when the biomass falls below 150,000 mt. The Council recommended a seasonal catch limit that allows for only incidental commercial landings and fish caught as live bait or recreationally during the 2015-16 season.

The decrease in biomass has been attributed, in part, to changes in ocean temperatures, which has been negatively impacting the species’ production. While the estimated population size is relatively low, the stock is not considered to be overfished. The early closure of the 2014-15 fishing season and the prohibition of directed fishing during the 2015-16 season are intended to help prevent the stock from entering an overfished state.

“Hard-working fishermen take pride in the precautionary fishery management that’s been in place for more than a decade,” said Diane Pleschner-Steele, Executive Director of the California Wetfish Producers Association. “Thankfully the Pacific Fishery Management Council recognized the need to maintain a small harvest of sardines caught incidentally in other coastal pelagic fisheries. A total prohibition on sardine fishing would curtail California’s wetfish industry and seriously harm numerous harbors as well as the state’s fishing economy.”

Pacific sardine is considered to be an important forage fish in the Pacific Ocean ecosystem and is also utilized recreationally and for live bait in small volumes. CDFW protects this resource by being an active participant in this co-management process. CDFW has representatives on the Council’s advisory bodies, works closely with the industry to track Pacific sardine landings in California and runs a sampling program that collects biological information, such as size, sex and age of Pacific sardine and other coastal pelagic species that are landed in California’s ports. These landings and biological data are used by CDFW in monitoring efforts and are also used by NMFS in annual stock assessments.

For more information about Pacific sardine history, research and management in California, please visit CDFW’s Pacific sardine webpage at www.dfg.ca.gov/marine/cpshms/.

School of sardines, Channel Islands CDFW file photo

# # #

Researchers, Managers, and Industry Saw This Coming: Boom-Bust Cycle Is Not a New Scenario for Pacific Sardines

A Message from Eileen Sobeck, Head of NOAA Fisheries

Pacific sardines have a long and storied history in the United States. These pint-size powerhouses of the ocean have been — on and off — one of our most abundant fisheries. They support the larger ecosystem as a food source for other marine creatures, and they support a valuable commercial fishery. When conditions are good, this small, highly productive species multiplies quickly. It can also decline sharply at other times, even in the absence of fishing. So it is known for wide swings in its population.

Recently, NOAA Fisheries and the Pacific Fishery Management Council received scientific information as a part of the ongoing study and annual assessment of this species. This information showed the sardine population had continued to decline. It was not a surprise. Scientists, the Council, NOAA, and the industry were all aware of the downward trend over the past several years and have been following it carefully. Last week, the Council urged us to close the directed fishery on sardines for the 2015 fishing season.  NOAA Fisheries is also closing the fishery now for the remainder of the current fishing season to ensure the quota is not exceeded.

While these closures affect the fishing community, they also provide an example of our effective, dynamic fishery management process in action. Sardine fisheries management is designed around the natural variability of the species and its role in the ecosystem as forage for other species. It is driven by science and data, and catch levels are set far below levels needed to prevent overfishing.  In addition, a precautionary measure is built into sardine management to stop directed fishing when the population falls below 150,000 metric tons. The 2015 stock assessment resulted in a population estimate of 97,000 metric tons, below the fishing cutoff, thereby triggering the Council action.

The sardine population is presently not overfished and overfishing is not occurring. However, the continued lack of recruitment of young fish into the stock in the past few years would have decreased the population, even without fishing pressure. So, these closures were a “controlled landing”. We saw where this stock was heading several years ago and everyone was monitoring the situation closely.

This decline is a part of the natural cycle in the marine environment. And if there is a new piece to this puzzle — such as climate change — we will continue to work closely with our partners in the scientific and management communities, the industry, and fishermen to address it.

To learn more about this amazing fish, go to these websites:

FishWatch

NOAA Southwest Fishery Science Center

NOAA Fisheries West Coast Region

Pacific Fishery Management Council

Read the original post: www.nmfs.noaa.gov

Another View: Sardine population isn’t crashing

Freshly caught sardines awaiting sorting at West Bay Marketing in Astoria, Ore. On April 15, federal regulators approved an early closure of commercial sardine fishing off Oregon, Washington and California to prevent overfishing. Alex Pajunas Associated Press file

By D.B. Pleschner | Special to The Bee

Environmental groups such as Oceana complain that the sardine population is collapsing just as it did in the mid-1940s. They blame “overfishing” as the reason and maintain that the fishery should be shut down completely (“Starving sea lions spotlight overfishing,” Viewpoints, April 14).

In truth, Pacific sardines are perhaps the best-managed fishery in the world. The current rule – established in 2000 and updated last year with more accurate science – sets a strict harvest guideline. If the water temperature is cold, the harvest rate is low. And if the population size decreases, both the harvest rate and the allowable catch automatically decrease.

It’s inaccurate and disingenuous to compare today’s fishery management with the historic sardine fishery collapse that devastated Monterey’s Cannery Row. During the 1940s and ’50s, the fishery harvest averaged more than 43 percent of the standing sardine stock. Plus, there was little regulatory oversight and no limit on the annual catch.

Since the return of federal management in 2000, the harvest rate has averaged about 11 percent, ranging as low as 6 percent. Scientists recognize two sardine stocks on the West Coast: the northern stock ranges from northern Baja California to Canada during warm-water oceanic cycles and retracts during cold-water cycles. A southern or “temperate” stock ranges from southern Baja to San Pedro in Southern California. The federal Pacific Fishery Management Council manages only the northern stock.

Doing the math, our current fishery harvest is less than a quarter of the rate during the historical sardine collapse. The so-called “sardine crash due to overfishing” mantra now peddled by Oceana isn’t anything of the sort. It’s simply natural fluctuations that follow the changing conditions of the ocean, reflected in part by water temperature.

California’s wetfish industry relies on a complex of coastal species including mackerel, anchovy and squid, as well as sardines. Sardines typically school with all these species, so a small allowance of sardine caught incidentally in these other fisheries will be necessary to keep wetfish boats fishing and processors’ doors open.

Sardines are critically important to California’s historic wetfish industry. This industry produces on average 80 percent of total fishery catches, and close to 40 percent of dockside value. A total prohibition on sardine harvests could curtail the wetfish industry and seriously harm California’s fishing economy.

Sardines are gone, long live the mackerel, with six recipes

Mackerel baked with bay and lemon | Gary Friedman / Los Angeles Times

 *corrected figures of jack mackerel catch

There will be no California sardines in the market this summer. But, as much as we’ll miss them, that’s probably a good thing.

Monday the Pacific Fishery Management Council, the group responsible for setting catch limits for California fishermen, closed the sardine fishery completely, citing a 91% drop in sardine population. Beginning July 1, there will be no sardines caught from Mexico to British Columbia.

Although this may conjure up visions of Cannery Row and earlier sardine collapses, this closure could actually be a blessing in disguise. So rather than mourning it as a disaster, use it as an opportunity to expand your fishy horizons.

Unlike many fisheries, which remain relatively steady from year to year if managed properly, sardines have always been extremely cyclical — even before fishermen started catching them. Scientists analyzing ocean bed sediment have found evidence of sardine population collapses dating at least 1,700 years.

The most famous of these, of course, came in the 1940s and 1950s and drove the many Monterey Bay sardine canners out of business (inadvertently paving the way decades later for a terrific aquarium and tourist enclave).

In the 1930s, California fishermen caught as much as 700,000 tons of sardines; by the mid 1960s that had plummeted to only 1,000 tons. But just as people began talking about possible extinction, the fish came roaring back. As recently as 2012, there were nearly 100,000 tons caught.

The difference between then and now is that today there is a strong enough fisheries management program to at least minimize the human influence on this natural cycle. Sardines may come and go, but if fishermen keep catching them, they can turn a downturn into a disaster — as happened in Monterey. Closing the fishery is a way to let the population recover.

If you’re a sardine lover, though, what are you to do? First, you may still see imported sardines at Japanese fish markets such as Mitsuwa and Marukai, though they’ll probably be a little more expensive.

Perhaps a better solution is to swing with the cycle. Fish folk have long known that sardine and mackerel populations ebb and flow complementarily — when sardines are plentiful, mackerel tend to be scarce, and vice versa.

And sure enough, just as the jack mackerel catch off California crashed a couple of years ago (in 2011, only 60 tons were caught), the last few years have seen a tremendous rebound. In 2013, the last year for which statistics are available, almost 900 tons were caught.

Mourn the sardine, certainly, but take this opportunity to embrace the mackerel. Here’s six recipes to get you started.

Read the original post: www.latimes.com

Ray Hilborn: Analysis Shows California Sardine Decline Not Caused by Too High Harvest Rate

Posted with permission from SEAFOODNEWS — Please do not repost without permission.

SEAFOODNEWS.COM [SeafoodNews]  (Commentary) by  Ray Hilborn April 22, 2015

Two items in the last weeks fisheries news have again caused a lot of media and NGO interest forage fish. First was publication in the Proceedings of the National Academy of Sciences of a paper entitled “Fishing amplifies forage fish population collapses” and the second was the closure of the fishery for California sardine.  Oceana in particular argued that overfishing is part of the cause of the sardine decline and the take home message from the PNAS paper seems to support this because it showed that in the years preceding a “collapse” fishing pressure was unusually high.

However what the PNAS paper failed to highlight was the real cause of forage fish declines.  Forage fish abundance is driven primarily by the birth and survival of juvenile fish producing what is called “recruitment”.  Forage fish declines are almost always caused by declines in recruitment,  declines that often happen when stocks are large and fishing pressure low.  The typical scenario for a stock collapse is (1) recruitment declines at a time of high abundance, (2) abundance then begins to decline as fewer young fish enters the population, (3)  the catch declines more slowly than abundance so the harvest rate increases, and then (4) the population reaches a critical level that was called “collapsed” in the PNAS paper.

Looking back at the years preceding collapse it appears that the collapse was caused by high fishing pressure, when in reality it was caused by a natural decline in recruitment that occurred several years earlier and was not caused by fishing.

The decline of California sardines did not follow this pattern, because the harvest control rule has reduced harvest as the stock declined,  and as fisheries management practices have improved this is now standard practice.  The average harvest rate for California sardines has only been 10% per year for the last 10 years, compared to a natural mortality rate of over 30% per year.  Even if there had been no fishing the decline in California sardine would have been almost exactly the same.

In many historical forage fish declines fishing pressure was much higher, often well over 50% of the population was taken each year and as the PNAS paper highlighted, this kind of fishing pressure does amplify the decline.  However many fisheries agencies have learned from this experience and not only keep fishing pressure much lower than in the past, but reduce it more rapidly when recruitment declines.

So the lesson from the most recent decline of California sardine is we have to adapt to the natural fluctuations that nature provides.  Yes, sea lions and birds will suffer when their food declines, but this has been happening for thousands of years long before industrial fishing.  With good fisheries management as is now practiced in the U.S. and elsewhere forage fish declines will not be caused by fishing.

Ray Hilborn is a Professor in the School of Aquatic and Fishery Sciences, University of Washington specializing in natural resource management and conservation.  He is one of the most respected experts on marine fishery population dynamics in the world.

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Environmental changes stress West Coast sea lions

Sardine Assessment Shows Cyclic Decline in Population

Pacific sardines are known for wide swings in their population: the small, highly productive species multiplies quickly in good conditions and can decline sharply at other times, even in the absence of fishing. Scientists have worked for decades to understand those swings, including a decline in the last few years that led to the Pacific Fishery Management Council‘s recommendation on April 13th to suspend commercial sardine fishing off the West Coast for the first time in decades..

An updated stock assessment by NOAA Fisheries’ Southwest Fisheries Science Center (SWFSC) was the basis for the Council’s action. Stock assessments are research tools that estimate the status and size of the sardine population. The Council uses the assessments to set fishing quotas.

Models that support the sardine assessment combine NOAA data on past and current abundance of sardine eggs, larvae and mature fish with other data on sardine biology and fishery catches. The data on sardine abundance come from two SWFSC research vessel surveys conducted off the West Coast each year.

These surveys employ two methods to estimate the current size of the sardine population. They use underwater acoustic equipment (like sonar) to estimate the size of fish schools, followed by the use of trawl nets to verify the species comprising the schools. Additionally, the surveys employ devices that measure the density of sardine eggs in the water as a gauge of sardine spawning. Scientists can then calculate how large the spawning population must be to produce the measured density of sardine eggs.

These data feed a computer model to estimate sardine population trends and provide the foundation for projections of the total population of sardines off the West Coast in the next fishing year.

“The assessment produced this year suggests that cool ocean water temperatures off the West Coast beginning around 2007 may have reduced the survival of juvenile sardine resulting in a population decline”, said Kevin Hill, a fisheries biologist who oversees the stock assessment for the SWFSC. The number of surviving young fish appears to have dropped to the lowest levels in recent history and has likely remained low in 2014. This has led to a steady decline in the fishable sardine stock biomass, which is defined as the total volume of sardines at least one year old. This is the measure the Council relies on when setting fishing quotas.

“The environment is a very strong driver of stock productivity. If ocean conditions are not favorable, there may be successful spawning, but fewer young fish survive to actually join the population,” Hill said. “Small pelagic fish like sardine and anchovy undergo large natural fluctuations even in the absence of fishing. You can have the best harvest controls in the world but you’re not going to prevent the population from declining when ocean conditions change in an unfavorable way.”

The current decline adds to a series of ups and downs that illustrate the boom-and-bust nature of sardine populations. The sardine biomass rose from about 300,000 metric tons in 2004 to a high point of more than 1 million in 2008 and is predicted to decrease to an estimated 97,000 metric tons by this coming July.

Because of these swings in sardine populations, the Council’s management framework for sardines includes built-in mitigation measures and safeguards to exponentially reduce fishing pressure as the stock declines.  One of these Council measures is a cessation in directed fishing on sardines when the biomass falls below 150,000 metric tons. “The fishing cutoff point is included in the guidelines adopted by the Council and is designed to maintain a stable core population of sardines that can jump-start a new cycle of population growth when oceanic conditions turn around,” Hill said.

In the course of reviewing the 2015 updated assessment, it became evident that the final model used in the 2014 assessment did not correspond to the best fit to the data. The data were reanalyzed and a better fit to the 2014 model was achieved. This re-examination resulted in a lower 2014 biomass estimate of 275,705 metric tons, down from the previous estimate of 369,506 metric tons, which is still above the fishing cutoff value of 150,000 metric tons.

The revised model applied to the 2015 assessment resulted in a biomass estimate of 97,000 metric tons, which is below the fishing cutoff.  As a result, the Council decided to close the 2015-2016 sardine fishing season and requested that NOAA Fisheries close the remainder of the 2014-2015 sardine fishing season. The sardine population is presently not overfished and overfishing is not occurring; however, the continued lack of recruitment observed in the past few years could decrease the population, even without fishing pressure.

The NOAA Ship Bell M. Shimada is currently conducting a new sardine survey off the West Coast to collect updated information on the size and location of the sardine stock. In addition, a large-scale 80-day survey this summer will collect data on sardine and whiting (hake) populations from the Mexican border to Canada. This new information will support the next stock assessment SWFSC prepares for the Council and NOAA fisheries managers.

Learn more:

Pacific sardine stock assessment
Executive summary
Full report 

In the Field: Spring Sardine Survey 2015
Pacific Fishery Management Council Coastal Pelagic Species
California Cooperative Oceanic Fisheries Investigations (CalCOFI)
Video – Coastwide Sardine Survey

Green Seas Blue Seas – Interactive Guide to the California Current 

For more information, please contact: Michael.Milstein@noaa.gov or Jim.Milbury@Noaa.gov (West Coast Regional Office Public Affairs), Dale.Sweetnam@noaa.gov (Southwest Fisheries Science Center) and Joshua.Lindsay@noaa.gov (West Coast Regional Office)

Read the original post https://swfsc.noaa.gov