Updating the Master Plan for Marine Protected Areas

California’s MPA network

This year, the California Department of Fish and Wildlife (CDFW) is updating the 2008 Master Plan for Marine Protected Areas (MPAs). The updated 2015 Master Plan will be a guidance document that shifts the focus from designing and siting California’s MPA network to setting a statewide framework for MPA management. CDFW will welcome input on the updated 2015 Master Plan through a public process which starts at the Aug. 2015 meeting of the California Fish and Game Commission.

California is home to the largest scientifically designed network of MPAs in the United States. This accomplishment was the result of the State Legislature passing the Marine Life Protection Act (MLPA), which required CDFW to redesign California’s system of MPAs through a highly participatory and stakeholder-driven MPA design and siting process that spanned eight years and four coastal regions.

The MLPA also required CDFW to develop a “master plan” to guide the adoption and implementation of MPAs. This master plan framework guided the incremental development of alternative MPA proposals in the first MLPA planning region on the central coast. Following the adoption of the central coast MPAs, the Master Plan for MPAs was approved as a living document by the California Fish and Game Commission in February 2008. The 2008 Master Plan then guided the development of alternative MPA proposals in the north central, south, and north coast regions.

CDFW anticipates taking a 4-step approach to update the Master Plan by the end of the year. This approach includes:

1. Working with Tribal governments over the next couple of months
2. Presenting a first draft to the Fish and Game Commission at their August 2015 meeting
3. Providing an update at the October 2015 Commission meeting, and
4. Presenting a final draft to the Commission for consideration of approval at their December 2015 meeting

For more information about the Master Plan for Marine Protected Areas and California’s network of MPAs, please visit the California Marine Protected Area website.

Read the original post: https://cdfwmarine.wordpress.com

Trawling has “negligible” effect on soft-bottom

Petrale sole, a flatfish caught by trawling on soft-bottom seafloor. Credit: The Nature Conservancy

A groundbreaking new study recently conducted by California fishermen, The Nature Conservancy and CSU Monterey Bay indicates that bottom trawling only has a “negligible effect” on the seafloor and fish habitat in certain types of soft sea bottom.

Trawling is continually criticised by environmental advocates for the damage it causes to rocky marine habitats and the long-lived animals that occur in them. However, important questions remain about the extent of any damage to sandy and muddy environments.

During the three-year study, fishermen trawled patches of the ocean floor off Morro Bay. Those areas were analysed by underwater photos and video and compared with nearby areas that were untouched.

Their peer-reviewed work, published in the Fishery Bulletin, found that California’s largely soft-bottom seafloor saw little lasting impacts from trawling with a small-footrope trawl.

The researchers say that their study adds to a growing body of literature from around the world showing trawling impacts are context-dependent – the impacts depend on the type of gear used, the types of habitats trawled and how often trawling occurs.

The scientists point out that their study does not imply that all soft-bottom habitats should be open to trawling; but, with new research and technology, “we can fine-tune our fishery regulations to protect truly vulnerable habitats.”

One of the researchers, Dr. James Lindholm has been studying marine ecosystems for 20 years and this autumn he will conduct a similar experiment off Half Moon Bay using trawling nets of different sizes. Commercial fishermen will also be involved.

Read the original post: www.worldfishing.net

OSU and NOAA Researchers Expect Low Oxygen Waters to Expand off West Coast Affecting Fisheries

Copyright © 2015 Seafoodnews.com | Posted with permission

SEAFOODNEWS.COM [SeafoodNews] – March 12, 2015

When low-oxygen “dead zones” began appearing off the Oregon Coast in the early 2000’s, photos of the ocean floor revealed bottom-dwelling crabs that could not escape the suffocating conditions and died by the thousands.

But the question everyone asked was, “What about the fish?” recalls Oregon State University oceanographer Jack Barth. “We didn’t really know the impacts on fish. We couldn’t see them.”

Scientists from NOAA Fisheries’ Northwest Fisheries Science Center and Oregon State have begun to answer that question with a new paper published in the journal Fisheries Oceanography. The paper finds that low-oxygen waters projected to expand with climate change create winners and losers among fish, with some adapted to handle low-oxygen conditions that drive other species away.

Generally the number of fish species declines with oxygen levels as sensitive species leave the area, said Aimee Keller, a fisheries biologist at the Northwest Fisheries Science Center and lead author of the new paper. But a few species such as Dover sole and greenstriped rockfish appear largely unaffected.

“One of our main questions was, ‘Are there fewer species present in an area when the oxygen drops?’ and yes, we definitely see that,” Keller said. “As it goes lower and lower you see more and more correlation between species and oxygen levels.”

Deep waters off the West Coast have long been known to be naturally low in oxygen. But the new findings show that the spread of lower oxygen conditions, which have been documented closer to shore and off Washington and California, could redistribute fish in ways that affect fishing fleets as well as the marine food chain.

The lower the oxygen levels, for example, the more effort fishing boats will have to invest to find enough fish.

“We may see fish sensitive to oxygen levels may be pushed into habitat that’s less desirable and they may grow more slowly in those areas,” Keller said.

Researchers examined the effect of low-oxygen waters with the help of West Coast trawl surveys conducted every year by the Northwest Fisheries Science Center to assess the status of groundfish stocks. They developed a sturdy, protective housing for oxygen sensors that could be attached to the trawl nets to determine what species the nets swept up in areas of different oxygen concentrations.

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Action Taken To Protect Fish At Bottom Of Ocean Food Chain

Preface:

The Council took action to prohibit new directed fisheries on a list of  currently unmanaged, largely unfished forage species this week which brings the following species and species groups into all four of the Council’s FMPs as ecosystem component (EC) species:
• Round herring (Etrumeus teres) and thread herring (Opisthonema libertate and O. medirastre)
• Mesopelagic fishes of the families Myctophidae, Bathylagidae, Paralepididae, and Gonostomatidae
• Pacific sand lance (Ammodytes hexapterus)
• Pacific saury (Cololabis saira)
• Silversides (family Atherinopsidae)
• Smelts of the family Osmeridae
• Pelagic squids (families: Cranchiidae, Gonatidae, Histioteuthidae, Octopoteuthidae, Ommastrephidae (except Humboldt squid, Dosidicus gigas), Onychoteuthidae, and Thysanoteuthidae)

The above species would be known as “Shared EC Species,” meaning that they are shared between all of the FMPs 

A new rule prohibits new fisheries on forage fish species including silversides, shown here.
Paul Asman and Jill Lenoble/Flickr

by Cassandra Profita OPB

West Coast fishery managers adopted a new rule Tuesday that protects many species of forage fish at the bottom of the ocean food chain.

The rule prohibits commercial fishing of  herring, smelt, squid and other small fish that aren’t currently targeted by fishermen. It sets up new, more protective regulations for anyone who might want to start fishing for those species in the future.

The Pacific Fishery Management Council unanimously voted to adopt the rule at a meeting in Vancouver, Washington. The council sets ocean fishing seasons off the coasts of Washington, Oregon and California.

The idea behind the new rule is to preserve so-called forage fish so they’re available for the bigger fish, birds and whales that prey on them. It’s part of a larger push by the council to examine the entire ocean ecosystem when setting fishing seasons.

Environmentalists who have been advocating for the rule for years celebrated the approval.

“If we’re going to have a healthy ocean ecosystem in the long term, we have to protect that forage base,” said Ben Enticknap of the environmental group Oceana. “These are the backbone of a healthy ocean ecosystem.”

Enticknap said many of the forage fish subject to the new rule are already being fished elsewhere in the world. Little fish at the bottom of the food chain are used to make fish meal for aquaculture, and they’re increasingly in demand as food for people as other fish populations decline.

Previous rules only required managers to be notified of a new fishery on non-managed forage fish species. Now, the council will require a more rigorous scientific review to prove that the new fishery won’t harm the ecosystem before it is allowed.

“Really, it’s being precautionary,” said Enticknap. “It’s getting out ahead of a crisis rather than waiting for a stock to collapse and then having to have serious consequences for fisheries after the fact.”

The rule has gained broad support — even from the fishing industry, according to Steve Marx of the Pew Charitable Trusts. Valuable commercial fish such as rockfish, salmon, halibut and tuna all prey on forage fish.

“The fishing industry support has been pretty strong because everybody understands how important these small forage fish are to the fish they like, that they make a living off of,” he said.

Rod Moore, executive director of the West Coast Seafood Processors Association, congratulated the council on moving forward with the rule.

“It’s rare to get this sort of consensus support from commercial, environmental and recreational sectors, and I think you have it on this one,” he said.

Before voting, council members discussed the best way to allow existing fisheries to catch some of the forage fish species incidentally – as they’re targeting other fish.

The council directed staff to continue developing the details of the rule so that it doesn’t constrain existing fisheries, but it does discourage fishing boats from targeting forage fish.

Councilors instructed staff to hold fishing boats accountable the forage fish they catch and consider discouraging development of at-sea processing of forage fish species into fish meal.

Read original post: www.opb.org

Whale of a time being had on Monterey Bay

By Tom Stienstra | www.seattlepi.com

A humpback whale, spending the winter in Monterey Bay, breaches just a short distance from the shoreline.
Photo: Giancarlo Thomae/Sanctuary Cruis / Giancarlo Thomae/Sanctuary Cruis

Outside the mouth of the harbor at Moss Landing, a scene unfolded Thursday morning that was like nothing seen in the past 200 years there in late winter: as many as 30 humpback whales spouting, lunge-feeding and breaching.

The show just a half mile out was easy to see from the jetty.

A vast swarm of anchovies dimpled the water. Pelicans dived to scoop up the small fish. Dolphins were also feeding and jumping like hurdlers in a track meet. A gray whale emerged alongside.

“It’s unheard of,” said Dorris Welch, a marine biologist for Sanctuary Cruises. “Our historical records come from whaling ships that go back to the late 1700s. Going back more than 200 years, no whale records exist that show humpbacks wintering in Monterey Bay.

“In my entire life here, working on the bay, to see this now is a phenomenon.”

It felt like Hawaii. At 10 a.m., the air temperature was already 70 degrees, with an azure sky and calm seas extending across Monterey Bay. From a kayak or boat, with 15 to 20 feet of clarity, you could look down into the water and watch murres and dolphins feed on anchovies, and see the sun reflect off the sides of the whales.

The water was warm, too, for March — 60 degrees as the old sea continues its El Niño trend.

“From the jetty at the mouth of the harbor, you can stand and watch what hasn’t been seen this time of year in recorded history,” said Giancarlo Thomae, a marine biologist and photographer with Sanctuary Cruises. “A lot of days have been flat calm for kayaking and taking photos. A lot of us can’t believe what we’re seeing.”

As with most wildlife, a key is food. Huge numbers of anchovies, with acres of “pinheads,” or juvenile anchovies, have drawn the whales and marine birds to inshore waters.

This is a prime site because of the contours of the sea bottom. The Monterey Submarine Canyon narrows and rises from 1,400 feet a few miles offshore to 800 feet deep within a mile, and then to 100 feet at the harbor entrance. Breezes push nutrient-rich seawater into the canyon and toward land, and as the canyon narrows and rises up, the nutrients are pushed to the surface. It’s the trigger point for one of the richest marine food chains on the Pacific Coast.

Yet even in the days of Cannery Row in Monterey, with some of the largest sardine populations in the world, the events of the past two months never occurred.

One reason is the resurgence of humpback whales, once decimated by whaling. “Populations were estimated as low as 1,200 animals in the entire North Pacific,” Welch said. “Now we think there are close to 20,000.”

The other shift is the amount of food and pristine water quality.

“We think the humpback whales are staying here to replenish and store up fat, to keep feeding,” she said. “There are also immature humpback whales that aren’t ready to breed. They stay instead of migrating south to the breeding and calving grounds in Mexico. It’s part of a phenomenon.”

Last week, a migrating gray whale was also seen joining a pod of six humpbacks in a feeding frenzy, right outside the Moss Landing Harbor entrance.

“It went on for more than an hour,” Welch said. “I’ve never seen that before, a gray whale and humpbacks feeding together, and I can’t find records of that ever happening.”

Another anomaly involves large numbers of long-beaked common dolphins feeding with the whales.

“It’s very unusual to see the dolphins feeding right alongside the whales for long durations,” Welch said. “We had more common dolphins here this winter than we’ve seen in Monterey Bay in the past five years.”

Of course, it wouldn’t be Monterey Bay and Moss Landing without sea otters, many of which are feeding in the channel at the mouth of the harbor. They love eating clams, crabs and fat innkeeper worms. The latest counts showed 144 resident otters at Moss Landing channel and harbor and adjoining Elkhorn Slough.

The anticipation is that female gray whales with calves will arrive in Monterey Bay in April. In turn, orcas, or killer whales, will follow them and provide a once-a-year spring spectacle. The orcas often try to separate juvenile gray whales from their mothers, and then attack and eat them.

For now, you can see much of the action from Moss Landing jetty — bringing binoculars is recommended but not necessary to see the good stuff. On calm days, experts can kayak outside the harbor. Newcomers can rent a kayak and watch from the mouth of the harbor. Whale-watching trips are also available out of Moss Landing and other harbors on Monterey Bay.

In a powerboat or kayak, if you find whales that suddenly emerge in your vicinity, just float, or go into neutral, and enjoy the show. Do not approach closer than 100 yards or do anything that changes their behavior.

On one trip, I was paddling toward some spouts several miles away when a superpod of dolphins started vaulting on my right. A moment later, three humpbacks emerged on my left, so close I could smell their breath from their blowholes. Thousands of pinhead anchovies were suddenly all around me. I took my paddle out of the water and found myself floating amid the scene, euphoric to be so lucky to be alive on this planet.

read the original post: www.seattlepi.com

SavingSeaFood – Fishing industry takes PBS to task for misleading promotion

Dear Ms. Kerger,

We in the U.S. commercial fishing industry have for the most part become inured to the distorted, mean spirited and too often self-serving attacks on domestic fish, domestic fishing and domestic fishermen that if not encouraged are definitely facilitated by a “news” industry that seems to put a much greater premium on shock value than on journalistic integrity. However, like most of our fellow citizens, we have felt that PBS has remained above that particular fray, being fortunate enough to be the recipient of significant public support.

Speaking for our membership, which is composed of the leaders of trade organizations that represent fishermen, processors and dealers who handle well over half of the fish and shellfish landed by U.S. vessels in U.S. ports, we were shocked by a promotional spot for your new series Wild. In it researcher Jeremy Jackson indicted by implication every U.S. fisherman – recreational, commercial, or party/charter – and the federal fisheries management system that we are and have been heavily invested in making the best in the world since the passage of the Magnuson-Stevens Fishery Conservation and Management Act in 1976.

Dr. Jackson started off by displaying three photographs of anglers, boat crews and dead fish. The first showed a dozen or so very large grouper. The second showed perhaps fifty not so large grouper, snapper, jacks and porgy. The third showed seven fish, possibly bonito. He then said “there’s just no way that one can misinterpret what’s happened here, which is that we’ve eaten all of these (first picture) and we’ve eaten all of these (second picture) and now all we have left is these (third picture). These are emblematic of a panoply of gigantic creatures that used to live here.”

In fact it’s very easy to misinterpret what’s happening anywhere with anything based on an analysis of three photographs taken over a period of maybe 50 years with no information other than what’s depicted in those photos. And it’s apparent that’s what Dr. Jackson did.

The large grouper in the first photograph are goliath grouper. Their harvest and possession has been prohibited by federal and state law since 1990. Since this total moratorium was put in place the stock has recovered to such an extent that these large grouper are interfering with other fisheries and the managers are being pressured to open a restricted fishery on them. But since 1990 it would be illegal to have even one goliath grouper on a dock.

Of the four taxa of fish that predominate in the second photograph, the various species are now managed by size and possession limits and most have closed seasons as well.

A brief and easily accomplished review of the commercial and recreational catch data or of the more difficult to understand assessment data would reveal the true condition of the various stocks with significantly more accuracy than would holding three undated, undocumented photographs in front of a video camera. That’s why in the U.S. we spend tens of millions of dollars a year to collect that data.

We have not caught and eaten all of the big fish, nor have we caught and eaten all of the medium sized fish. In fact, from a resource perspective our fisheries are on the whole in much better shape than they have been in since the Magnuson-Stevens Fishery Conservation and Management Act became law in 1976 and our management system is one of the most effective in the world.

Particularly considering the fact that PBS is in large part publicly funded, we would expect you to put more reliance on fact checking and less on sensationalist hype. There are fisheries scientists and professional managers whose objectivity is accepted by fishermen, the management establishment and other researchers who we would be eager to put PBS in touch with at any point in the future.

Sincerely,
Nils E. Stolpe (for the Seafood Coalition)

Alaska Bering Sea Crabbers, American Albacore Fishing Association, Atlantic Capes Fisheries, At-sea Processors Association, Blue Water Fishermen’s Association, California Wetfish Producers Association, Coalition of Coastal Fisheries, Columbia River Crab Fishermen’s Association. Coos Bay Trawlers Association, Directed Sustainable Fisheries, Fisheries Survival Fund, Fishermen’s Dock Cooperative, Fishermen’s Marketing Association, Garden State Seafood Association, Groundfish Forum, Long Island Commercial Fishing Association, Midwater Trawlers Cooperative, Monkfish Defense Fund, National Fisheries Institute, North Carolina Fisheries Association, Oregon Trawl Commission, Organized Fishermen of Florida, Pacific Seafood Processors Association, Pacific Whiting Conservation Cooperative, South Carolina Seafood Alliance, Southeastern Fisheries Association, United Catcher Boats, Washington Dungeness Crab Fishermen’s Association, Washington Trollers Association, West Coast Seafood Processors Association, Western Fishboat Owners Association

http://www.savingseafood.org/

NBCNews.com Replaces Reality, Regulation and History with Hyperbole

Original post: AboutSeafood.com | © 2015 National Fisheries Institute | Published with permission.

A story this week on NBCnews.com about the state of the seafood industry is packed with sensationalism and hyperbole, yet absent much of the real science, facts and figures that drive actual sustainability.

To begin, U.S. fisheries are among the world’s best managed and most sustainable. Though not referenced by name a single time in this article, the National Oceanic and Atmospheric Administration, NOAA, regulates U.S. seafood with headquarters in Washington D.C., five regional offices, six science centers and more than 20 laboratories around the country and U.S. territories.

Author John Roach, however, perpetuates doom and gloom throughout this piece, asserting “voids” left by cod, halibut and salmon that need to be filled by other fish. We’re guessing Mr. Roach isn’t aware that salmon shattered modern-day records in 2014, returning to the Columbia River Basin in the highest numbers since fish counting began at Bonneville Dam more than 75 years ago. Could you tell us again about that void?

Mr. Roach also intones a narrative of sustainability disaster for popular predators like tuna but forgot to mention groups like the International Seafood Sustainability Foundation (ISSF), a coalition created through a partnership between WWF, the world’s leading conservation organization, and canned tuna companies from across the globe to insure the long-term conservation and sustainable use of tuna stocks. In an article that claims the sky is falling for species like tuna it’s odd that ISSF gets nary a nod or even a mention.

Switching gears, Mr. Roach goes on to blame giant trawlers “armed” with technology and massive nets as part of the reason we’re “running low” on fish. As in any industry, technology gets better by the day, creating more efficient ways to do business. However, new technology is by no means exempt from standing national and global fishery regulations, such as catch-limits, by-catch laws, compliance, and so forth. To suggest that enhanced technology or “bigger or faster” boats are causing our fish supplies to dwindle ignores the impact of technology on sustainability and even regulatory oversight. There are pros and cons to every catch-method and there is no one-size-fits all solution to sustainability challenges but to blame technology without recognizing its contribution to solutions is folly.

Hyperbolic rhetoric about sustainability continues to be discounted by legitimate fisheries experts in the scientific community. In fact, one “report” forecasting empty oceans by 2048 was challenged by a number of independent researchers who described the study that promoted the statistics as, “flawed and full of errors.” Including Ray Hilborn, a professor of aquatic and fishery sciences at the University of Washington in Seattle whose research into the study lead him to say, “this particular prediction has zero credibility within the scientific community.” After Hilborn’ s analysis the author of the original study himself explained that his research was not in fact predicting worldwide fish stock collapse at all but merely examining trends. Articles like this track along precisely with the discounted, overblown storyline that gave birth to the empty oceans by 2048 nonsense.

Whether you’re a “natural optimist” or not, there is no question that seafood harvested from U.S. fisheries is inherently sustainable as a result of NOAA’s fishery management process and global fisheries management is far from the wild west scenario bandied about.  Things aren’t perfect and there’s work to be done but the “game” is not “almost over” and those who suggest it is, willfully propagate that narrative not because it’s accurate but because bad news sells.

Bottom trawling gets a bum rap, CSUMB study finds.

Nic Coury
Local petrale sole, like this dish at the former Alvarado Fish & Steakhouse, may be a more sustainable fish than we thought.

Bottom trawling—dragging nets along the sea floor to catch species like halibut and sanddabs—isn’t always the destructive fishing method it’s made out to be, according to a collaborative study by fishermen, The Nature Conservancy and CSU Monterey Bay.

The study, published in National Marine Fisheries Service’s Fishery Bulletin, found that not all sea floors are created equal. The “soft” sea floor (mostly mud and sand) that comprises up to 85 percent of the continental shelf off the California coast may be able to recover quickly from small footrope trawl gear, the study concludes. Yet most of the state waters and much of the federal waters are closed to bottom trawling.

“Our study adds to a growing body of literature from around the world showing trawling impacts are context dependent—they depend on the type of gear used, the types of habitats trawled and how often trawling occurs,” a press release states. “Trawling in rocky areas with long-lived corals will likely have more long-lasting impacts than trawling in soft-bottom habitats that may be less vulnerable and can recover more quickly.”

Monterey Bay Aquarium’s Seafood Watch guide, which has long shunned much of Monterey Bay’s own local catch because it viewed bottom trawling as environmentally unfriendly, is now picking up on that more nuanced approach. The updated Seafood Watch guide upgraded 21 species of West Coast groundfish from red (avoid) to yellow (good alternative) or green (best choice) rankings, as the Weekly reported last fall.

Also promising: next-generation light-trawl gear that floats just above the sea floor instead of dragging. Environmental Defense Fund consultants Huff McGonigal and David Crabbe developed the technology to allow fishermen to “fish a wider area, travel faster, reduce fuel costs by a quarter and preserve bottom-dwelling fauna,” as the Weekly reported in 2013.

Read the original post: MontereyCountyWeekly.com | by Kera Abraham

California salmon dodge drought bullet for another year

A fall-run salmon jumps at the Coleman National Fish Hatchery near Anderson, Calif., on Oct. 2, 1996. (Rollin Banderbob / Associated Press)

Apparently the California salmon has dodged the drought bullet for another year: The annual forecast for the fishery predicts that the population this year will be slightly bigger than last.
The initial results of the 2015 National Marine Fisheries Service survey forecasts an adult ocean population of California salmon that’s about 2.7% higher than last year.

That translates to about 650,000 fish — up from about 630,000 last year but substantially less than 2013 total of more than 800,000. Still, that’s far healthier than 2008 and 2009, when the fishery was closed completely.

The most recent figures are much better than many observers had predicted, given the devastating four-year drought the state is still enduring. With reduced water flow in the Sacramento River, some observers had feared a collapse in the population of young salmon heading out to sea.

“There’s a pretty good chance we’ll see that in the future, maybe as early as next year,” says Michael O’Farrell, a National Oceanic and Atmospheric Administration research fisheries biologist specializing in salmon.

“But we make abundance forecasts based on 2-year-old fish, and while California was certainly dry two years ago, it certainly wasn’t like it is now.”

In January, the U.S. Fish and Wildlife Service began a huge release of stocked juvenile salmon after warm temperatures and shallow waters killed an estimated 95% of the eggs laid in some tributaries. “But we make abundance forecasts based on 2-year-old fish, and while California was certainly dry two years ago, it certainly wasn’t like it is now.”

In January, the U.S. Fish and Wildlife Service began a huge release of stocked juvenile salmon after warm temperatures and shallow waters killed an estimated 95% of the eggs laid in some tributaries.

The salmon forecast is a preliminary report that will be used to set catch limits and seasons for fishermen, both commercial and recreational.

The Pacific Fisheries Management Council is scheduled to meet to make a final decision on those in April, but predictions are that the commercial season will likely begin around May 1, and that the fish will start showing up in markets shortly after.

“There have been various indicators about poor survival of fish in [the Sacramento River basin] that could indicate down the road we could have trouble,” O’Farrell said. “But we make these forecasts on a year-to-year basis, and this year our science is telling what the right thing to do is. Next year we’ll take another look and we’ll do the whole thing again.”

Read original post: LATimes.com

Sardines swim into northern waters to keep cool

Sardines, mackerel, anchovies and other staples of the Mediterranean diet are moving north – to as far as the Baltic Sea – to escape warming ocean temperatures. The commercial fishery is suffering. Above, a purse seiner off the coast of Italy hauls in a net full of fish. Photo courtesy Prigalla/flickr.

A staple of the Mediterranean diet is migrating north to escape warming seas – leaving fishermen with empty nets.

LONDON – Several important fish species that for centuries have been a staple of the Mediterranean diet are abandoning sub-tropical seas because the water is too warm.

Sardines, for generations have been the most abundant commercial fish species in Portugal, are moving North. They are now established in the North Sea and are being caught in the Baltic – a sea that until recently was normally frozen over in the winter.

Sardines, anchovies and mackerel – three important species in the diet of many southern European and North African countries – have been studied by scientists trying to discover how climate change and warming seas are affecting their distribution.

Crucial for the food chain

As well as the affect on the fishing industry, the abundance or disappearance of these species is crucial for many other marine species that rely on them for food.

A pioneering study, published in Global Change Biology, analyzed 57,000 fish censuses conducted over 40 years and has tracked the movement of these fish during this period.

It confirms that the continued increase in water temperature has altered the structure and functioning of marine ecosystems across the world. But it also shows that the effect has been greater in the North Atlantic, with increases of up to 1.3 degrees Celsius in the average temperature over the last 30 years.

This variation in temperature directly affects the frequency and range of pelagic fish, which live in the middle of the water column and are directly influenced by temperature rather than habitat. It includes the sardine (Sardina pilchardus), anchovy (Engraulis encrasicolus), horse mackerel (Trachurus trachurus) and mackerel (Scomber scombrus), among others.

They feed off phytoplankton and zooplankton and are themselves the staple diet of large predators, such as cetaceans, large fish and marine birds. These fish occur off the shores of many coastal countries in the world and are important sources of protein.

Response to changing temperatures

Scientists have known that fish were moving to new areas, but they did not know whether it was in response to their main food supply plankton moving first or whether it was a simple response to changing temperatures.

The new study has developed statistical models for the North Sea area, and confirms the great importance of sea temperatures.

“Time series of zooplankton and sea surface temperature data have been included to determine the factor causing these patterns,” Ignasi Montero-Serra, lead author of the study and researcher in the department of Ecology at the University of Barcelona, explains to the Scientific Information and News Service.

To demonstrate the consequences of the warming of the seas, the research team analyzed fish censuses from commercial fishing performed independently along the European continental shelf between 1965 and 2012, extracted from data provided by the International Council for the Exploration of the Sea.

Rapid ocean warming

The study, the first to be carried out on such a large timescale and area, allows for the dynamics of this species to be understood in relation to the rapid warming of the oceans observed since the 1980s.

The results reveal that sardines and other fish with fast life cycles, planktonic larval stage and low habitat dependence are highly vulnerable to changes in ocean temperature, and therefore represent, Montero-Serra says, “an exceptional bio-indicator to measure the direction and speed of climate change expected in the near future.”

Montero-Serra says that accelerated increase in temperature of the continental seas has resulted in sardines and anchovies – with a typically subtropical distribution – increasing their presence in the North Sea and “even venturing into the Baltic Sea.” And the presence of species with a more northern distribution, such as the herring and the sprat, has decreased.

A clear sign

The analysis is therefore a clear sign that species in the North Sea and Baltic Sea are “becoming subtropical.”

This is due to the pelagic fish being highly dependent on environmental temperatures at different stages of their life cycle – from reproductive migrations and egg-laying, to development and survival of larvae.

According to the researchers, the changes in such an important ecological group “will have an effect on the structure and functioning of the whole ecosystem,” although they still do not know the scale of the socio-economic and ecological repercussions.

Read the original post: DailyClimate.org