1/27/16 1/27/16

DANIEL PAULY FEEDS MEDIA THE WRONG STORY ABOUT GLOBAL FISHERIES DECLINE; OTHER SCIENTISTS OBJECT

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

SEAFOODNEWS.COM by John Sackton – January 25, 2016 — Last week the media was full of a new round of global fishery disaster stories, prompted by an article in Nature Communications by Daniel Pauly & Dirk Zeller affiliated with the Sea Around Us project.Pauly and Zeller state that FAO global fisheries data has underestimated prior catch, and that therefore if this is taken into account, the decline in fish catch from the peak in the late 1990’s is not 400,000 tons per year, but 1.2 million tons per year.“Our results indicate that the decline is very strong and is not due to countries fishing less. It is due to countries having fished too much and having exhausted one fishery after another,” said Pauly to the Guardian newspaper. As a result, a new round of handwringing ensued about global overfishing.But, the facts don’t support Pauly’s interpretation. Catch rates are simply not a suitable measure of fisheries abundance. In fact, declines in catch rates often are due to improvement in fisheries management, not declines in abundance.Over at cfood, a number of scientists specifically rebutted the premise of Pauly’s article.Ray Hilborn of the University of Washington says:This paper tells us nothing fundamentally new about world catch, and absolutely nothing new about the status of fish stocks.It has long been recognized that by-catch, illegal catch and artisanal catch were underrepresented in the FAO catch database, and that by-catch has declined dramatically.What the authors claim, and the numerous media have taken up, is the cry that their results show that world fish stocks are in worse shape than we thought. This is absolutely wrong. We know that fish stocks are stable in some places, increasing in others and declining in yet others.Most of the major fish stocks of the world, constituting 40% of the total catch are scientifically assessed using a mixture of data sources including data on the trends in abundance of the fish stocks, size and age data of the fish caught and other information as available. This paper really adds nothing to our understanding of these major fish stocks.Another group of stocks, constituting about 20% of global catch, are assessed using expert knowledge by the FAO. These experts use their personal knowledge of these fish stocks to provide an assessment of their status. Estimating the historical unreported catch for these stocks adds nothing to our understanding of these stocks.For many of the most important stocks that are not assessed by scientific organizations or by expert opinion, we often know a lot about their status. For example; abundance of fish throughout almost all of South and Southeast Asia has declined significantly. This is based on the catch per unit of fishing effort and the size of the individuals being caught. Estimating the amount of other unreported catches does not change our perspective on the status of these stocks.In the remaining fisheries where we know little about their status, does the fact that catches have declined at a faster rate than reported in the FAO catch data tell us that global fisheries are in worse shape than we thought? The answer is not really. We would have to believe that the catch is a good index of the abundance.Figure 1 of the Pauly and Zeller paper shows that a number of major fishing regions have not seen declines in catch in the last 10 years. These areas include the Mediterranean and Black Sea, the Eastern Central Atlantic, the Eastern Indian Ocean, the Northwest Pacific and the Western Indian Ocean. Does this mean that the stocks in these areas are in good shape, while areas that have seen significant declines in catch like the Northeast Atlantic, and the Northeast Pacific are in worse shape?We know from scientific assessments that stocks in the Mediterranean and Eastern Central Atlantic are often heavily overfished – yet catches have not declined.We know that stocks in the Northeast Pacific are abundant, stable and not overfished, and in the Northeast Atlantic are increasing in abundance. Yet their catch has declined.Total catch, and declines in catch, are not a good index of the trends in fish stock abundance.Michael Kaiser of Bangor University commented:Catch and stock status are two distinct measurement tools for evaluating a fishery, and suggesting inconsistent catch data is a definitive gauge of fishery health is an unreasonable indictment of the stock assessment process. Pauly and Zeller surmise that declining catches since 1996 could be a sign of fishery collapse. While they do acknowledge management changes as another possible factor, the context is misleading and important management efforts are not represented. The moratorium on cod landings is a good example – zero cod landings in the Northwest Atlantic does not mean there are zero cod in the water. Such distinctions are not apparent in the analysis.Also David Agnew, director of standards for the Marine Stewardship Council, said:It is noteworthy that the peak of the industrial catches – in the late 1990s/early 2000s – coincidentally aligns with the start of the recovery of many well managed stocks. This point of recovery has been documented previously and particularly relates to the recovery of large numbers of stocks in the north Pacific, the north Atlantic and around Australia and New Zealand, and mostly to stocks that are assessed by analytical models. For stocks that need to begin recovery plans to achieve sustainability, this most often entails an overall reduction in fishing effort, which would be reflected in the reductions in catches seen here. So, one could attribute some of the decline in industrial catch in these regions to a correct management response to rebuild stocks to a sustainable status, although I have not directly analyzed the evidence for this. This is therefore a positive outcome worth reporting.This opinion piece originally appeared on SeafoodNews.com, a subscription site. It has been reprinted with permission.

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5/14/15 5/14/15

Demystifying Ecosystem-Based Fisheries Management

Ecosystem-based fisheries management (EBFM) became a major initiative of resource managers around the world beginning in the 1990s. Unlike traditional management approaches that focused solely on the biology of a particular stock, EBFM provides a more holistic approach to fisheries management – one that takes into account the complex suite of biological, physical, economic, and social factors associated with managing living marine resources.EBFM has continued to evolve over the past 20 years and is now a cornerstone of NOAA Fisheries’ efforts to sustainably manage the nation’s marine resources. But despite substantial progress in the science behind and application of EBFM, a perception remains that the science and governance structures to implement EBFM are lacking, when in fact they have already been resolved in the United States and other developed countries. An April 2015 article in Fisheries took on the important challenge of identifying some of the most common myths that can impede the implementation of EBFM. Here’s a look at some of them.

Myth 1: Marine ecosystem-based management lacks universal terminology, making it difficult to implement.

FALSE

The scientific literature provides clear and consistent definitions of marine ecosystem-based management and associated terminology. There are three primary levels of ecosystem-based management in relation to marine fisheries that differ by focus area. Full definitions can be found in the paper. From most comprehensive to least comprehensive, the three levels differ by their key focus:

Ecosystem approaches to fisheries management (EAFM) focus on a single fisheries stock and include other factors that can influence a stock.
Ecosystem-based fisheries management (EBFM) focuses on the fisheries sector (multiple fisheries).
Ecosystem-based management (EBM) focuses on multiple sectors, such as fisheries, ecotourism, and oil and gas exploration.

Myth 2: There's no clear mandate for EBFM.

FALSE

For the past 20 years, the Magnuson-Stevens Fishery Conservation and Management Act, combined with more than 90 separate federal legislative mandates, either implicitly or explicitly have given NOAA authority to implement an ecosystem-based approach to management. NOAA Fisheries specifically has been fully engaged during this period to implement EBFM, in order to more efficiently and effectively fulfill its key mandate – stewardship of the nation’s living marine resources and their habitats, interactions, and ecosystems. Rather than waiting for the perfect mandate to move forward with EBFM, managers, scientists, and policymakers can and should move forward within current authorities.

Myth 3: EBFM requires extensive data and complicated models.

FALSE

A common misconception is that EBFM requires comprehensive data and complex models, and can only be applied in exceptional, data-rich circumstances. The reality is that EBFM begins with what is known about the ecosystem. It provides a framework to use all available knowledge, whether it’s a detailed time series of species abundance or more descriptive local knowledge of the ecosystem. When data are limited, approaches such as risk, portfolio, or loop analysis can be applied to work with available information. These techniques provide managers with a tool to assess whether a fish population or the ecosystem is likely to reach a tipping point.The key point here is that EBFM allows managers to work with the information available to best manage the resources in an ecosystem, aware of all the parts of the system simultaneously.

Myth 4: EBFM results will always be conservative and restrictive.

FALSE

There is an existing perception that applying EBFM will always result in a more precautionary approach to management and reduced catch limits. The rationale is that accounting for more uncertainty as well as focusing on conserving protected or non-target species will lead to more restrictive management measures that further reduce catches below maximum sustainable yield (MSY) levels. A better question might be, why would stakeholders ignore the best available science and jeopardize the resiliency of the stocks and ecosystem? Fisheries scientists over the past half century have criticized the concept of maximum sustainable yield for single species because of the impossibility of achieving MSY for all species simultaneously.Furthermore, some studies show that when management applies EBFM and focuses on the combined landings and value of all targeted species in an ecosystem, the landings are comparable to the amounts under single-species management. Plus, there may be long-term economic benefits for multiple fisheries when the system is managed as a whole.

Myth 5: EBFM is a naïve attempt to describe a complex system.

FALSE

Proponents see EBFM as a solution, whereas critics see it as an approach that falls short of addressing the many socioeconomic, political, and other challenges inherent in marine resource management. Scientific agencies worldwide have traditionally given fishery management advice on a stock-by-stock basis rather than consider multiple fisheries and multiple user groups. But ignoring the trade-offs, or the existence of multiple objectives, does not make them go away. Different stakeholders often have competing interests, and it is important to acknowledge these differences and identify management options that optimize the full range of interests. Strategies can often meet multiple objectives, such that no one stock, fishery, sector, economy, or community is unknowingly depleted at the expense of another. Ultimately, EBFM is about trade-off analysis – examining which options meet the most objectives as a collective system.

Myth 6: There aren't enough resources to do EBFM.

FALSE

A final myth is that it will take substantially more resources – more funding, staff, data, and sophisticated models – to implement EBFM. But EBFM implementation actually has the potential to increase efficiencies. Many national and international working groups currently exist to support single-species management efforts. A transition to EBFM allows multiple species to be addressed through a more integrated assessment process, thus requiring fewer working groups. This has the potential to reduce staff workloads and consolidate modeling efforts. In addition, applying EBFM has been shown to improve the stability of marine ecosystems, which translates into improved regulatory and economic stability and better business planning.

Dispelling the myths and taking action

These myths have discouraged some managers from even trying EBFM and have prevented them from getting the best available information needed for resource management. Instead of viewing EBFM as a complex management process that requires an overabundance of information, it should be viewed as a framework to help managers work with the information they have and address competing objectives. To learn more about EBFM and how NOAA is implementing it, click here.

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

4/8/15 4/8/15

Oceans might take 1,000 years to recover from climate change, study suggests

Sea urchins disappeared for thousands of years during ancient warming periods that could be a model of future climate change, a new study shows. Here, the shells of modern sea urchins lie in a tide pool in Corona del Mar. (Glenn Koenig / Los Angeles Times)

By Geoffrey Mohan Naturally occurring climate change lowered oxygen levels in the deep ocean, decimating a broad spectrum of seafloor life that took some 1,000 years to recover, according to a study that offers a potential window into the effects of modern warming.Earth's recovery from the last glacial period, in fact, was slower and more brutal than previously thought, according to the study, published online Monday in the journal Proceedings of the National Academy of Sciences.Researchers deciphered that plotline from a 30-foot core of sea sediments drilled from the Santa Barbara Basin containing more than 5,000 fossils spanning nearly 13,000 years."The recovery does not happen on a century scale; it's a commitment to a millennial-scale recovery," said Sarah Moffitt, a marine ecologist at UC Davis' Bodega Marine Laboratory and lead author of the study. "If we see dramatic oxygen loss in the deep sea in my lifetime, we will not see a recovery of that for many hundreds of years, if not thousands or more."Studies already have chronicled declines in dissolved oxygen in some areas of Earth's oceans. Such hypoxic conditions can expand when ocean temperatures rise and cycles that carry oxygen to deeper areas are interrupted.As North American glaciers retreated during a warming period 14,700 years ago, an oxygen-sensitive community of seafloor invertebrates that included sea stars, urchins, clams and snails nearly vanished from the fossil record within about 130 years, the researchers found."We found incredible sensitivity across all of these taxonomic groups, across organisms that you would recognize, that you could hold in your hand, organisms that build and create ecosystems that are really fundamental to the way ecosystems function," Moffitt said. "They were just dramatically wiped out by the abrupt loss of oxygen.”That highly diverse community soon was replaced with a relatively narrow suite of bizarre and extreme organisms similar to those found near deep-ocean vents and methane seeps in modern oceans, Moffitt said.Evidence of that transition was confined to such a narrow band of sediments that the turnover could have been "nearly instantaneous," the study concluded.Then, beginning around 13,500 years ago, the seafloor community began a slow recovery with the rise of grazers that fed on bacterial mats. Recovery eventually was driven by a fluctuation back toward glaciation during the Younger Dryas period, a cooling sometimes called the Big Freeze."The biological community takes 1,000 years to truly recover to the same ecological level of functioning," Moffitt said. "And the community progresses through really interesting and bizarre states before it recovers the kind of biodiversity that was seen prior to the warming.”That relatively brief freeze also ended abruptly around 11,700 years ago, virtually wiping out all the seafloor metazoans, the study found. They were gone within 170 years and did not appear again for more than 4,000 years, according to the study.The climate changes chronicled in the study arose from natural cycles involving Earth's orbit of the sun, and the oxygen declines that ensued were more extreme than those that have occurred in modern times, the study noted.Still, the abrupt fluctuations offer a glimpse at the duration of the effects of climate change driven by human activity pumping more planet-warming gases into Earth's atmosphere, Moffitt said."What this shows us is that there are major biomes on this planet that are on the table, that are on the chopping block for a future of abrupt climate warming and unchecked greenhouse gas emissions," Moffitt said. "We as a society and civilization have to come to terms with the things that we are going to sacrifice if we do not reduce our greenhouse gas footprint."

Read original post: http://www.latimes.com

11/21/14 11/21/14

Surrogate sushi: Japan biotech for bluefin tuna

By ELAINE KURTENBACHAP Business WriterTATEYAMA, Japan (AP) - Of all the overfished fish in the seas, luscious, fatty bluefin tuna are among the most threatened. Marine scientist Goro Yamazaki, who is known in this seaside community as "Young Mr. Fish," is working to ensure the species survives.Yamazaki is fine-tuning a technology to use mackerel surrogates to spawn the bluefin, a process he hopes will enable fisheries to raise the huge, torpedo-shaped fish more quickly and at lower cost than conventional aquaculture. The aim: to relieve pressure on wild fish stocks while preserving vital genetic diversity.Yamazaki, 48, grew up south of Tokyo in the ancient Buddhist capital of Kamakura, fishing and swimming at nearby beaches. His inspiration hit 15 years ago while he was out at sea during graduate studies at the Tokyo University of Marine Science and Technology, and a school of bluefin tuna streaked by."They swam just under the boat, and they were shining metallic blue. A beautiful animal," Yamazaki said. "Before that, tuna was just an ingredient in sushi or sashimi, but that experience changed bluefin tuna into a wild animal to me."An animal, that like so many other species, is endangered due to soaring consumption and aggressive modern harvesting methods that have transformed the bluefin, also known as "honmaguro" and "kuromaguro," from a delicacy into a commonly available, if pricey, option at any sushi bar.This month, experts in charge of managing Atlantic bluefin met in Italy and raised the quota for catches of Atlantic bluefin tuna by 20 percent over three years. Stocks have recovered somewhat after a severe decline over the past two decades as fishermen harvested more to meet soaring demand, especially in Japan.But virtually in tandem with that, the International Union for Conservation of Nature put Pacific bluefin tuna on its "Red List," designating it as a species threatened by extinction.About a quarter of all tuna are consumed by the Japanese, according to the United Nations Food and Agricultural Organization. They gobble up most - between 60 percent and 80 percent - of all bluefin. Rosy, fatty "chu-toro" from the upper part of bluefin bellies, is especially prized for sushi and sashimi.Out at his seaside lab in Tateyama, on the far northern rim of Tokyo Bay, Yamazaki and other researchers are hoping their latest attempt to get mackerel to spawn bluefin will prove a success. An earlier attempt failed due to what he thinks was a problem with the water temperature.Yamazaki's technique involves extracting reproductive stem cells from the discarded guts of tuna shipped by cold delivery from fish farms and inserting them into mackerel fry so tiny they are barely visible.The baby fish are put in an anesthetic solution and then transferred by dropper onto a slide under the microscope. Researcher Ryosuke Yazawa deftly inserts a minute glass needle into one's body cavity to demonstrate.Under the right conditions, the tuna stem cells migrate into the ovaries and testes of the mackerel. The team is now waiting to see if the mackerel, when mature, will spawn tuna, and if the tuna will survive. Following that, they could be released into the sea or farmed.The research team has already succeeded in using surrogate technology to produce tiger puffer fish, the poisonous "fugu" used in sashimi and hotpot, using smaller grass puffer fish. It has produced trout spawned by salmon. Companies that import rare and tropical fish also are interested in the technology.The method could help reduce pressure on wild populations, Yamazaki hopes, and also help ensure the greater genetic diversity needed to preserve various species.Though he started out working in the field of genetic modification, Yamazaki emphasizes that his techniques involve only surrogate reproduction, not GM.The main "tricks," as he calls them, are using baby fish as future surrogates, because their immature immune systems will not reject the tuna cells, and relying on the natural tendency of the reproductive stem cells to mature and produce viable offspring. To simplify matters, the lab is using triploid, or sterile hybrid fish commonly bred at fish farms, that will not develop eggs or sperm of their own species.Yamazaki expects his research to be useful for commercial purposes. Though researchers elsewhere have succeeded in breeding tuna in captivity, the process is costly and survival rates are low. Mackerel, less than a foot long when caught, are much easier to handle and keep in land-based tanks than tuna, which can grow to nearly the size of a small car and require far more food per fish. The mackerel also mature more quickly and spawn more frequently, if they are well fed and kept at the right temperature.Not all experts favor such high-tech solutions for the bluefin.Amanda Nickson, director of global tuna conservation for The Pew Charitable Trusts, said the partial recovery of Atlantic bluefin stocks shows that enforcement of catch limits, backed by threats of trade bans, can work.Earlier this year, the multi-nation fisheries body that monitors most of the Pacific Ocean recommended limiting the catch of juvenile bluefin tuna to half the average level of 2002-2004. Scientists found that stocks of the species had dwindled to less than 4 percent of their original size. It also found that most fish caught were juveniles less than 3 years old, before they reach reproductive maturity.The group set a 10-year target of rebuilding the population to 8 percent of its original size."As long as you don't take too many, those populations can rebuild and rebuild fairly effectively," she said.Perhaps so, said Yamazaki, but over the centuries, humans have repeatedly over consumed resources, sometimes past the point of no return."Japanese people eat tuna from all over the world. We have to do something. That is the motivation for my research."

(AP Photo/Tokyo University of Marine Science and Technology, Goro Yamazaki)

(AP Photo/Elaine Kurtenbach)

(AP Photo/Shizuo Kambayashi, File). FILE - In this Jan. 5, 2014 file photo, people watch a bluefin tuna laid in front of a sushi restaurant near Tsukiji fish market after the year's celebratory first auction in Tokyo.

(AP Photo/Elaine Kurtenbach)

Read original post: http://www.news10.com/

11/1/14 11/1/14

Eastern Pacific bluefin tuna catch to be cut 40 percent to 3,300 tons

SEAFOODNEWS.COM [Jiji Press] - October 31, 2014 — posted with permission of Seafood News.The Inter-American Tropical Tuna Commission, comprising a total of 21 countries and regions, has decided to tighten controls on bluefin tuna fishing in the eastern Pacific.The decision was made at a special session of the commission in La Jolla, Calif., on Wednesday, according to Japanese officials.Bluefin tuna catches in the ocean region will be reduced by 40 percent from the 2014 level to 3,300 tons in both 2015 and 2016.The commission also set a nonbinding goal of cutting the proportion of young tuna weighing less than 30 kilograms in total catches to 50 percent.The nonbinding goal was set as a compromise after Mexico opposed a Japanese proposal for halving annual catches of young tuna in and after 2015 from the average level between 2002 and 2004. In the central and western Pacific, including waters around Japan, the halving of young tuna catches has already been agreed.Mexico has developed a tuna ranching sector dependent on capture of juvenile tuna used for growout.

Read original article: SeafoodNews.com

10/28/14 10/28/14

FDA finds wholesale seafood products are labeled correctly 85% of the time

Posted by permission of SEAFOODNEWS.COM [SCOM] October 27, 2014

A two-year long investigation by the FDA into seafood mislabeling among wholesaler distributors found that fish products are labeling correctly 85 percent of the time.The FDA's study (the report can be found here) tested seven hundred DNA samples collected from wholesalers in 14 states, prior to restaurant or retail sale. Part of the study had the FDA target seafood that is most often suspected to be mislabeled including cod, haddock, catfish, basa, swai, snapper and grouper. Of that group, the FDA said a majority of the mislabeling was found in two species, snappers and groupers, which represent less than two percent of total seafood sales.“This extensive federal analysis brings the challenge of mislabeling into a much clearer focus,” said John Connelly, President of the National Fisheries Institute (NFI.) “While at the same time calling into question other mislabeling ‘studies’ that suggest the issue is widespread and in need of a legislative fix.”The NFI has previously called for more enforcement of federal and state labeling laws, rather than new legislation, noting that multiple anti-fraud laws already exist.“What the FDA found reinforces the need for implementation of rules already on the books,” said Lisa Weddig, Secretary of the Better Seafood Board (BSB.) “We don’t need more regulations and rhetoric, we need more enforcement.”Along with releasing the findings, the FDA also released its first-ever online seafood labeling training module designed to instruct industry participants, retailers and state regulators how to properly label seafood items throughout the supply chain."Proper identification of seafood is important throughout the seafood supply chain to ensure that appropriate food safety controls are implemented and that consumers are getting the type of seafood they expect and for which they are paying," the FDA said.Meanwhile, the BSB and the National Restaurant Association will work together on the labeling issue through a memorandum of understanding that includes educational outreach and even menu audits.“Eighty-five percent of seafood was labeled correctly and the mislabeling was focused on two species,” said Connelly. “Our job is to work with companies and focus on those problem areas.” He continued, “This type of information gives regulators important insights and helps them focus their resources. New laws don’t do that.”Photo Credit: FDA

8/7/14 8/7/14

Russian ban hits US exports of hake, surimi, pink salmon and salmon roe; canned products excluded

SEAFOODNEWS.COM by John Sackton - Aug 7, 2014

Russia's announcement early today of the food commodity imports it will ban covers most frozen fish and seafood products. However canned products under custom codes 1604 and 1605 will not be included.

The list of banned products covers all fresh and frozen fish, molluscs, and crustaceans.

The most immediate impacts for US producers will be felt on the West Coast, with hake, surimi, frozen pink salmon and salmon roe all significant export products to Russia. All are now subject to the import ban.

For whiting/hake, US exports to Russia through June were worth about $4 million, and for all of 2013, the total export value was nearly $8 million.

For pollock surimi, shipments through June to Russia were worth $3.5 million, and for all of 2013 $8.2 million.

Salmon roe is where the most direct market impact might be felt because Russian imports of salmon roe represent a larger share of total production than they do for hake or surimi. In 2013, total salmon roe exports to Russia were valued at $45.9 million, with a volume of over 7 million pounds. Through June, shipments of salmon roe out of inventory from last year were worth $8.5 million, with a total volume of 1.1 million pounds.

The imposition of the import ban on salmon roe at the height of the roe production season is going to have a market impact, since the roe not shipped to Russia will have to be sold in Eastern Europe and Japan. As a result, these markets will have to absorb greater supply, with a corresponding decline in price.

Frozen pink salmon will also be affected. In 2013, virtually no frozen pinks were sold to Russia, but in 2014, that jumped from less than $250,000 to $3.3 million, making frozen pink salmon the second most valuable US export in the first half of the year, after whiting.

Canned pink salmon and other canned seafoods are not part of the ban. However, Russia is not an export market for canned salmon from the US, and the exemption will have little impact.

The Russian sanctions on fresh and frozen fish and seafood were applied to the EU, Canada and Australia as well. The biggest impact will be in Norway, where an immediate fall in salmon prices is expected.

Russia imported 6.6 billion NOK worth of seafood from Norway last year, of which 4.2 billion NOK was salmon.

Analysts who have modeled the impact of a Russian ban see an immediate price drop of more than 10-12%, and then a near term market settling about 10-12% below current levels for fresh Norwegian salmon.

Long term, if these sanctions continue in place for a year or longer, these same analysts from the Bergen firm Optimeering expect the impact to be minimal, as new markets will be found and trade patterns adjusted.

One of the 'winners' on salmon is likely to be Chile, whose exports are not affected. Ironically, the same Norwegian firms cut out of the market via Norway, will be expanding their sales in Russia through their Chilean subsidiaries. However, the Chilean shipments will be frozen Atlantic salmon, which has had nowhere near the growth experienced in fresh.

Russia is likely to expand its imports from Asia, including black market channels through China. China already imports Norwegian and other farmed salmon, and it would not take much for some of this salmon to find its way to Russia.

7/15/14 7/15/14

More Big Whales in Ocean Could Mean More Fish, Scientists Find

New study reveals how scientists and fisheries managers underestimated the massive mammals.The return of large whales—such as sperm (pictured), blue, right, and gray—could help ocean fish populations recover.Photograph by Stephen Frink, CorbisBrian Clark HowardNational GeographicPublished July 10, 2014Scientists and fisheries managers have long underestimated the valuable role large whales play in healthy ocean ecosystems, a new study suggests. And, scientists add, those commercial fishermen who complain that whales steal fish from their nets have it wrong.An increase in the number of large whales—like blue, sperm, right, and gray—around the world could lead to a healthier ocean and more fish, a team of scientists report in a review study published this month in the journal Frontiers in Ecology and the Environment.The underestimation occurred because "when oceanographic studies were started, large whales were largely absent from the ecosystem—because we had killed most of them," says the study's lead author, Joe Roman, a biologist at the University of Vermont in Burlington.Large whales were heavily hunted until the 1970s. At that point an estimated 66 to 90 percent of the animals had been removed from ocean waters.But since then, great whales have been slowly recovering. There are now more than a million sperm whales, and tens of thousands of gray whales.Yet blue whales—the largest animal ever known to have lived on the planet—have been slower to rebound. In fact, they remain at about one percent of their historic range in the Southern Hemisphere. Roman says scientists think their absence may have altered the ecosystem in a way that made it harder for all life to survive there.In recent years, as whale numbers have increased and technology has advanced—especially the ability to tag and track seafaring animals—we've begun to gain a better understanding of how important cetaceans are, says Roman."Whale Pumps and Conveyor Belts"The scientists report that when whales feed, often at great depths, and then return to the surface to breathe, they mix up the water column. That spreads nutrients and microorganisms through different marine zones, which can lead to feeding bonanzas for other creatures. And the materials in whale urine and excrement, especially iron and nitrogen, serve as effective fertilizers for plankton.Many great whales migrate long distances to mate, during which time they bring those nutrients with them. When they breed in far latitudes, they make important nutrient contributions to waters that are often poor in resources. Even their placentas can be rich sources of feedstocks for other organisms, says Roman, who calls whale migration a "conveyor belt" of nutrients around the ocean.Whale deaths can be helpful too. When one of the massive mammals dies, its body sinks to the sea bottom, where it nourishes unique ecosystems of scavengers, from hagfishes to crabs to worms. Dozens of those scavenger species are found nowhere else, says Roman."Because [humans] took out so many whales, there were probably extinctions in the deep sea before we knew those [scavenger] species existed," says Roman, who adds that he's working on a new study to estimate how many of those scavenger species were lost.Maddalena Bearzi, a marine biologist and president of the California-based Ocean Conservation Society who was not affiliated with the study, calls the paper "a great and interesting piece" that could help us better understand the role marine mammals play in the ocean ecosystem.Fishers vs. WhalesFor decades some commercial fishermen have complained that whales eat the fish that they're trying to catch. Japan's government has been particularly vocal, going as far as to say that whaling is necessary because "whales are threatening our fisheries." (See "Japan's Commercial Whaling Efforts Should Resume, Says Prime Minister.")Masayuki Komatsu, one of Japan's international whaling negotiators, famously told the Australian Broadcasting Corporation in 2001 that "there are too many" minke whales, calling them "the cockroach of the ocean."Roman disagrees."It's far more complicated than that," he says, referring to the whale pump and the conveyor belt. "Our new review points to several studies that show you have more fish in an ecosystem by having these large predators there."The next step, he says, is to conduct more field studies on those processes. That could help scientists better understand exactly how plankton and other organisms respond to the presence of whales.

Read original post and view the videos at: news.nationalgeographic.com

Dispelling the myths and taking action

REPRESENTING CALIFORNIA’S HISTORIC FISHERY