Saving Seafood

Ray Hilborn study disputes previous findings on forage fish

April 3, 2017 — A new study has been published today by a scientific group led by University of Washington fisheries researcher Ray Hilborn that disputes previous findings on the impact of human and natural predation on forage fish such as anchovies, sardines and herring.

The study, published in the scientific journal Fisheries Research, found that human fishing for forage fish does not have as great an impact on the food chain as previously thought, given that humans typically catch fish of much larger size than those typically hunted and eaten by non-human species. The study also decouples the link between the size of forage fish populations and the populations of species that predate on forage fish.

“What we found is that there is essentially no relationship between how many forage fish there are in the ocean and how well predators do in terms of whether the populations increase or decrease,” Hilborn said in a video explaining the study’s findings.

The study was co-authored by the University of Washington’s Ricardo O. Amoroso and Eugenia Bogazzi, Olaf P. Jensen of Rutgers University, Ana M. Parma of the Centro Nacional Patagónico, Cody Szuwalski of the University of California Santa-Barbara and Carl J. Walters of the University of British Columbia. It was funded in part by the National Coalition for Fishing Communities and was supported by the IFFO, the marine ingredients trade group.

It takes particular fault with the methods used by a 2012 study on forage fish by the Lenfest Ocean Program, which is managed by the Pew Charitable Trusts.

“The Lenfest conclusion that predators rise and fall with their prey populations is simply not true. It’s not empirically true,” Walters, one of the authors of the original Lenfest study, said. “One of the things we did in this study was collect together a lot of time-series patterns of predator abundances and forage-fish abundances, and we just didn’t see the correlation, nor have other scientists who have looked at this objectively.”

Predators “have developed some strategy of how to cope with the natural variability” of forage fish populations, according to Amoroso, the study’s second author.

Read the full story at Seafood Source

Predators may be less affected by catch of small fish than previously thought, new study says

WASHINGTON (NCFC) – April 3, 2017 – New research published today in the journal Fisheries Research finds that fishing of forage species likely has a lower impact on predators than previously thought, challenging previous studies that argued forage fish are more valuable left in the ocean.

A team of seven respected fisheries scientists, led by Prof. Ray Hilborn, Ph.D., of the University of Washington, found that predator populations are less dependent on specific forage fish species than assumed in previous studies, most prominently in a 2012 study commissioned by the Lenfest Ocean Program, which is managed by The Pew Charitable Trusts. The Lenfest Forage Fish Task Force argued that forage fish are twice as valuable when left in the water to be eaten by predators, and recommended slashing forage fish catch rates by 50 to 80 percent.

For fisheries management, such a precautionary approach would have a large impact on the productivity of forage fisheries. As groups such as IFFO (The Marine Ingredients Organisation) have noted, these stocks contribute strongly to global food security, as well as local and regional social and economic sustainability.

However, the new research found multiple omissions in the methodology of the Lenfest study. “When you review the actual models that were used [by Lenfest], there are a few key elements on the biology of these animals that were not represented,” said Dr. Ricardo Amoroso, one of the study’s co-authors. He added that one of the authors’ approaches was to “look for empirical evidence of what is actually happening in the field.” Previous studies relied on models which took for granted that there should be a strong link between predators and prey.

Specifically, the Lenfest study and another study using ecosystem models ignored the natural variability of forage fish, which often fluctuate greatly in abundance from year to year. It also failed to account for the fact that predators tend to eat smaller forage fish that are largely untouched by fishermen. Because of these oversights, the new study concluded that the Lenfest recommendations were overly broad, and that fisheries managers should consider forage species on a case-by-case basis to ensure sound management.

“It is vital that we manage our fisheries to balance the needs of the ecosystem, human nutrition and coastal communities,” said Andrew Mallison, IFFO Director General. “These findings give fishery managers guidance based on science, and update some of the inaccurate conclusions of previous reports.”

The Lenfest findings were largely based on a model called EcoSim, developed by Dr. Carl J. Walters, one of the co-authors of the new paper. Dr. Walters found that the EcoSim models used in earlier studies had omitted important factors, including natural variability, recruitment limitations and efficient foraging of predators.

Dr. Walters noted that there were “very specific” issues with previous uses of the EcoSim model. “It was predicting much higher sensitivity of creatures at the top of the food webs to fishing down at the bottom than we could see in historical data,” he said.

This is not the first time ecosystem models used in earlier studies have been questioned. One year after the Lenfest study was completed, two of its authors, Dr. Tim Essington and Dr. Éva Plagányi, published a paper in the ICES Journal of Marine Science where they said, “We find that the depth and breadth with which predator species are represented are commonly insufficient for evaluating sensitivities of predator populations to forage fish depletion.” The new study reaffirmed this finding, noting “several reasons to concur with the conclusion that the models used in previous analysis were insufficient.”

In addition to its critiques of previous research, the researchers found further evidence of the lack of fishing impact on forage fish. Their research indicated that environmental factors are often much more important drivers of forage fish abundance. They also found that the distribution of forage fish has a greater impact on predators than simply the raw abundance of forage fish.

The authors concluded by noting the importance of forage fish as a part of human food supply chains, praising their high nutritional value, both through direct human consumption and as food in aquaculture, as well as the low environmental impact of forage fishing. Cutting forage fishing, as recommended by the Lenfest group, would force people to look elsewhere for the healthy protein and micronutrients provided by forage fish – likely at much greater environmental cost, the authors wrote.

“Forage fish provide some of the lowest environmental cost food in the world – low carbon footprint, no water use,” Dr. Hilborn said. “[There are] lots of reasons that forage fish are a really environmentally friendly form of food.”

It is also well-established that forage fisheries provide substantial health benefits to human populations through the supply of long chain omega-3 fatty acids, both directly through consumption in the form of fish oil capsules, and indirectly through animal feed for farmed fish and land animals.

The paper was authored by Dr. Ray Hilborn, Dr. Ricardo O. Amoroso, and Dr. Eugenia Bogazzi from the University of Washington; Dr. Olaf P. Jensen from Rutgers University; Dr. Ana M. Parma from Center for the Study of Marine Systems -CONICET, Argentina; Dr. Cody Szuwalski from the University of California Santa Barbara; and Dr. Carl J. Walters from the University of British Columbia.

Read the full study here

Watch a video about the study here

Read an infographic about the study here

Predators may be less affected by catch of small fish than previously thought, new study says

April 3, 2017 — WASHINGTON — The following was released by the National Coalition for Fishing Communities and IFFO: 

New research published today in the journal Fisheries Research finds that fishing of forage species likely has a lower impact on predators than previously thought, challenging previous studies that argued forage fish are more valuable left in the ocean.

A team of seven respected fisheries scientists, led by Prof. Ray Hilborn, Ph.D., of the University of Washington, found that predator populations are less dependent on specific forage fish species than assumed in previous studies, most prominently in a 2012 study commissioned by the Lenfest Ocean Program, which is managed by The Pew Charitable Trusts. The Lenfest Forage Fish Task Force argued that forage fish are twice as valuable when left in the water to be eaten by predators, and recommended slashing forage fish catch rates by 50 to 80 percent.

 For fisheries management, such a precautionary approach would have a large impact on the productivity of forage fisheries. As groups such as IFFO (The Marine Ingredients Organisation) have noted, these stocks contribute strongly to global food security, as well as local and regional social and economic sustainability.

 However, the new research found multiple omissions in the methodology of the Lenfest study. “When you review the actual models that were used [by Lenfest], there are a few key elements on the biology of these animals that were not represented,” said Dr. Ricardo Amoroso, one of the study’s co-authors. He added that one of the authors’ approaches was to “look for empirical evidence of what is actually happening in the field.” Previous studies relied on models which took for granted that there should be a strong link between predators and prey.

 Specifically, the Lenfest study and another study using ecosystem models ignored the natural variability of forage fish, which often fluctuate greatly in abundance from year to year. It also failed to account for the fact that predators tend to eat smaller forage fish that are largely untouched by fishermen. Because of these oversights, the new study concluded that the Lenfest recommendations were overly broad, and that fisheries managers should consider forage species on a case-by-case basis to ensure sound management.

 “It is vital that we manage our fisheries to balance the needs of the ecosystem, human nutrition and coastal communities,” said Andrew Mallison, IFFO Director General. “These findings give fishery managers guidance based on science, and update some of the inaccurate conclusions of previous reports.”

 The Lenfest findings were largely based on a model called EcoSim, developed by Dr. Carl J. Walters, one of the co-authors of the new paper. Dr. Walters found that the EcoSim models used in earlier studies had omitted important factors, including natural variability, recruitment limitations and efficient foraging of predators.

Dr. Walters noted that there were “very specific” issues with previous uses of the EcoSim model. “It was predicting much higher sensitivity of creatures at the top of the food webs to fishing down at the bottom than we could see in historical data,” he said.

This is not the first time ecosystem models used in earlier studies have been questioned. One year after the Lenfest study was completed, two of its authors, Dr. Tim Essington and Dr. Éva Plagányi, published a paper in the ICES Journal of Marine Science where they said, “We find that the depth and breadth with which predator species are represented are commonly insufficient for evaluating sensitivities of predator populations to forage fish depletion.” The new study reaffirmed this finding, noting “several reasons to concur with the conclusion that the models used in previous analysis were insufficient.”

In addition to its critiques of previous research, the researchers found further evidence of the lack of fishing impact on forage fish. Their research indicated that environmental factors are often much more important drivers of forage fish abundance. They also found that the distribution of forage fish has a greater impact on predators than simply the raw abundance of forage fish. 

The authors concluded by noting the importance of forage fish as a part of human food supply chains, praising their high nutritional value, both through direct human consumption and as food in aquaculture, as well as the low environmental impact of forage fishing. Cutting forage fishing, as recommended by the Lenfest group, would force people to look elsewhere for the healthy protein and micronutrients provided by forage fish – likely at much greater environmental cost, the authors wrote.

“Forage fish provide some of the lowest environmental cost food in the world – low carbon footprint, no water use,” Dr. Hilborn said. “[There are] lots of reasons that forage fish are a really environmentally friendly form of food.”

It is also well-established that forage fisheries provide substantial health benefits to human populations through the supply of long chain omega-3 fatty acids, both directly through consumption in the form of fish oil capsules, and indirectly through animal feed for farmed fish and land animals. 

The paper was authored by Dr. Ray Hilborn, Dr. Ricardo O. Amoroso, and Dr. Eugenia Bogazzi from the University of Washington; Dr. Olaf P. Jensen from Rutgers University; Dr. Ana M. Parma from Center for the Study of Marine Systems -CONICET, Argentina; Dr. Cody Szuwalski from the University of California Santa Barbara; and Dr. Carl J. Walters from the University of British Columbia.

Read the full study here

Watch a video about the study here

Read an infographic about the study here

About the NCFC

The National Coalition for Fishing Communities provides a national voice and a consistent, reliable presence for fisheries in the nation’s capital and in national media. Comprised of fishing organizations, associations, and businesses from around the country, the NCFC helps ensure sound fisheries policies by integrating community needs with conservation values, leading with the best science, and connecting coalition members to issues and events of importance. For more, visit www.fisheriescoalition.org.

About IFFO

IFFO represents the marine ingredients industry worldwide. IFFO’s members reside in more than 50 countries, account for over 50% of world production and 75% of the fishmeal and fish oil traded worldwide. Approximately 5 million tonnes of fishmeal are produced each year globally, together with 1 million tonnes of fish oil. IFFO’s headquarters are located in London in the United Kingdom and it also has offices in Lima, Peru, and in Beijing, China. IFFO is an accredited Observer to the UN Food and Agriculture Organisation (FAO). To find out more, visit www.iffo.net.

PRESS CONTACT

Robert Vanasse

National Coalition for Fishing Communities

Washington

+1 (202) 333-2628

bob@savingseafood.org

Georgie Harris

IFFO, The Marine Ingredients Organisation

London

+44 (0) 2030 539 195

gharris@iffo.net

DAVE FRULLA & ANNE HAWKINS: Whither the Lenfest report?

May 20, 2016 — The following is an op-ed by Dave Frulla and Anne Hawkins, published in the June 2016 issue of National Fisherman:

In 2012, the Lenfest Ocean Program commissioned a report entitled “Little Fish, Big Impact,” regarding management of lower trophic level fisheries. Lenfest and other environmental groups followed the report’s publication with a major domestic and international media campaign. If Lenfest wanted to spark scientific debate and inquiry regarding forage fish management, it did a good job. If, however, its plan was to drive a “one- size-fits-all” solution to a complex problem, the results are far less constructive.

The report consisted of a literature review and basic computer modeling to “quantify” the value of forage fish to their predators. It concluded these fish were twice as valuable to other animals as for human nutritional, agricultural and aquaculture uses. The report thus recommended cutting forage fish catch rates between 50 and 80 percent across the board, to double the amount of forage fish left for fish, seabirds and other predators. It also recommended closures for spawning and around seabirds that rely on forage fish, and instructed no additional forage fish fisheries be authorized.

At release, the Lenfest report was received relatively uncritically, despite its far-reaching conclusions and recommendations. Since then, globally preeminent fishery scientists, including some of the Lenfest report’s own authors, have begun to examine the report’s assumptions and conclusions. Despite the report’s confident tone, there is no consensus on whether special management measures will provide any benefit to forage stocks.

Criticism of the Lenfest report can be divided into two main categories: its application to specific forage species, and its general methodology. Regarding application to specific species, it is important first to highlight there is no common definition of “forage fish.” It is, rather, a loosely formed concept, given how many marine organisms (and not just finfish) can be labeled important prey species for a given ecosystem or even for just one species.

Further, not all low trophic species fit the Lenfest report’s biological archetype. For instance, in April 2015, the Atlantic States Marine Fisheries Commission’s Biological Ecological Reference Points Workgroup presented a Memorandum to the Commission’s Menhaden Management Board stating that, “Ultimately, the BERP WG does not feel that the management actions recommended in [the Lenfest report]… are appropriate for Atlantic menhaden specific management,” in part because menhaden do not exhibit the stock-recruit relationship assumed in the Lenfest paradigm. (That is, menhaden recruitment is driven by environmental factors, rather than spawning stock size.)

As to methodology, the Lenfest report largely drew conclusions from ecosystem models that were not designed to evaluate management strategy impacts on low trophic level fisheries. The Lenfest report admits this shortcoming. Indeed, after its publication, Lenfest report authors Tim Essington and Eva Plaganyi co-authored their own follow-up paper showing that among the most common features absent from most of these ecosystem models were natural variability of forage fish stocks, important aspects of spatial structure, and the extent of overlap in size of predator and prey stocks. Regarding the last factor, a predator may eat smaller-sized year classes of prey fish than a fishery targets. Accordingly, humans and the predator fish aren’t competing; the forage species ran the predation gauntlet before being subject to fishing. Overall, Essington and Plaganyi concluded that “most of [the existing] models were not developed to specifically address questions about forage fish fisheries and the evaluation of fishing management.” Model suitability is but one element of the post-Lenfest report work on the scientific agenda for further consideration.

The ultimate question is whether the public, press and fisheries managers will pay attention as fisheries scientists pursue the important questions the Lenfest report raised, but did not resolve. The situation is reminiscent of the debate that occurred following publication by Dr. Boris Worm and other scientists of a 2006 report in Science suggesting all fisheries could collapse by 2048. That report received the same sort of PR roll-out as the Lenfest forage fish report. (We understand Dr. Worm’s work also received Pew Charitable Trusts/Lenfest funding.)

In 2009, Drs. Worm, Ray Hilborn (not a co-author of the initial report), and 19 other scientists collaborated on a subsequent report in Science concluding that existing fishery management tools were reversing the claimed global trend of depletion for individual stocks, and the situation was not so dire as Dr. Worm originally forecast. To this day, though, Dr. Worm’s original report is presented in press and policy debates without mention of his even more significant subsequent collaborative work. We hope the Lenfest report on forage fish management represents one early element — but not the final word — in consideration of the important topic it addresses.

Read the op-ed at National Fisherman

Fisheries scientists to address flaws in past forage fish research

WASHINGTON (Saving Seafood) – May 2, 2016 – Dr. Ray Hilborn, a marine biologist and fisheries scientist at the University of Washington, has launched a new initiative aimed at addressing key issues surrounding forage fish science and the impacts of forage fishing on predator species. Dr. Hilborn’s Forage Fish Project is one of several scientific efforts occurring in the next few months to expand the existing body of scientific research on forage fish.

Comprised of 14 renowned fisheries scientists from around the globe, the Forage Fish Project held its inaugural conference last month in Hobart, Australia, where it identified shortcomings in the existing forage fish research. Specifically, it found several issues with work produced by the Lenfest Forage Fish Task Force, whose April 2012 report, “Little Fish, Big Impact,” concluded forage fish are vulnerable to overfishing, among other findings.

The Forage Fish Project, which includes two members of the Lenfest Task Force, began work to address these flaws, with the goal of producing an accompanying study later this year.

In Hobart, Project members found that most of the models used in previous forage fish studies, like the Lenfest Task Force report, left out factors such as the natural variability of forage fish stocks, and the extent of size overlap between fisheries and predators. The group also found multiple indications that the Lenfest study greatly overstated the negative impact of forage fishing on predator species.

“Most [food web] models were not built with the explicit intention of evaluating forage fish fisheries, so unsurprisingly many models did not include features of forage fish population biology or food web structure that are relevant for evaluating all fishery impacts,” according to minutes from the Hobart meeting.

Two upcoming fishery management workshops will also evaluate forage species on the East and West Coasts of the U.S., the first organized by the Southwest Fisheries Science Center and the Pacific Fishery Management Council. The workshop, which will be held in La Jolla, Calif., from May 2-5, will focus on how to improve stock assessment methods for northern anchovy and other coastal pelagic species. Attendees will evaluate model-based assessment approaches based on routinely assessed pelagic species from around the world, consider non-assessment approaches to estimate fish stocks, and develop recommendations for how the SWFSC should evaluate coastal pelagic fish stocks in the future.

A similar forage fish workshop will be held May 16-17 in Portland, Maine. This workshop will focus on Atlantic herring, with the goal of establishing a rule to specify its acceptable biological catch (ABC), the recommended catch level for any given fish species. An effective ABC rule will consider the role of Atlantic herring in the ecosystem, stabilize the fishery at a level that will achieve optimum yield, and address localized depletion in inshore waters.

Ultimately, these various forage fish workshops and projects are striving to use the best available science to update previous research and determine sound management practices for forage species.

Read the full minutes from the Forage Fish Project conference in Hobart, Australia

Learn more about the upcoming coastal pelagic species workshop in La Jolla, Calif.

Learn more about the upcoming Atlantic herring workshop in Portland, Maine

Climate cycle could determine the reproductive success of menhaden

February 19, 2016 — Scientists have long puzzled over what drives the reproductive success of Atlantic menhaden, a tiny but critical East Coast fish.

A new study, published in the ICES Journal of Marine Science and supported by the Lenfest Ocean Program, provides a partial answer: An oceanic climate cycle known as the Atlantic Multidecadal Oscillation, or AMO.

The finding is likely to be useful in improving the way scientists assess the species and the way managers set catch limits.

Menhaden is a small, oily fish that provides food for striped bass, bluefish, and several other species, as well as bait for fishermen.

It also is the target of the largest fishery on the East Coast, which is centred in Virginia and catches menhaden for use in nutritional supplements, animal feed, and fertilizer.

Setting catch limits has proved challenging, in part because no one has been able to say what drives recruitment—a technical term for how many young fish are produced. Recruitment largely determines how much fishing a population can sustain.

Tom Miller of the University of Maryland, and one of the authors of the study, explained that it is very difficult to understand and manage this stock.

To address this, the researchers used a statistical model designed for disorderly data like those on the abundance of young menhaden. They considered 16 factors that might be driving that abundance, including climatic cycles, intensity of fishing, temperature, salinity, and predator abundance.

Read the full story at FIS