Scientists Offer New Take on Selective Fishing

A new, less selective approach to commercial fishing is needed to ensure the ongoing productivity of marine ecosystems and to maintain biodiversity, according to a paper in the Proceedings of the National Academy of Sciences.

The paper, 'Ecosystem-based fisheries management requires a change to the selective fishing philosophy', was written by a team of authors led by Shijie Zhou of the CSIRO Wealth from Oceans Flagship.

Dr Zhou says ecosystem-based fisheries management (EBFM) is broadly practiced as a means of reducing the impact of fishing on marine ecosystems while ensuring sustainable fisheries.

He says fishing methods under EBFM vary greatly in how selectively they catch fish. The common view is that highly selective methods that catch only one or a few species above a certain size limit are more environmentally responsible.

But recent advances in fishery science and ecology suggest a selective approach may exacerbate rather than reduce the impact of fishing on both fisheries and marine ecosystems.

"Selective fishing alters biodiversity, which in turn changes ecosystem functioning and may affect fisheries production, hindering rather than helping to achieve the goals of EBFM," Dr Zhou says. "These effects have been overshadowed to some extent by a focus on overharvesting."

"We believe it is time to critically rethink traditional selective fishing approaches that might not protect ecosystems and fisheries as intended, but may in fact make them more vulnerable to large changes in structure and function."

Dr Zhou and his co-authors propose a "balanced exploitation" approach combining reduced fishing effort, less selective fishing strategies, and better use of the catch to help achieve sustainable overall yields while maintaining healthy ecosystems.

"The trade-off is lower exploitation levels on currently highly targeted species against better use of more parts of the ecosystem," Dr Zhou says.

"Fisheries production could actually increase through better use of non-target species, while reducing unsustainably high catches of target species, thereby helping to meet the challenge of increasing global food demand."

Dr Zhou says the implications of such a change in approach would need to be considered by a wide range of stakeholders including fishermen, fishery managers and conservation agencies.

S. Zhou, A. D. M. Smith, A. E. Punt, A. J. Richardson, M. Gibbs, E. A. Fulton, S. Pascoe, C. Bulman, P. Bayliss, K. Sainsbury. Ecosystem-based fisheries management requires a change to the selective fishing philosophy. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073/pnas.0912771107

Skate may be fished to extinction

The most precarious marine species on the planet A species of skate could become the first marine fish driven to extinction by commercial fishing, say scientists.A study reveals that an error in the classification of the species has meant researchers have failed to see just how close to the brink it is. The French team reports its findings in the journal Aquatic Conservation. Marine biologist Nicholas Dulvy from Simon Fraser University in Canada says the skate is now "the most precarious marine species on Earth". The team's genetic studies have revealed that what is referred to as the common skate is actually two clearly distinct species - the flapper skate (Dipturus intermedia) and the blue skate (Dipturus flossada).The fish were originally categorised separately, but an influential study in 1926 recognised only one valid species - Dipturus batis. This classification has been unchallenged since. The 80-year error has ensured that fisheries have not been catching what they thought, explained Dr Dulvy, who is also co-chair of the World Conservation Union's (IUCN) shark specialist group. The result has been that catches of the smaller, more resilient blue skate has entirely masked the decline of the flapper skate. Disappearing fastThe research team, led by Samuel Iglesias from the Marine Biology Station in Concarneau on the west coast of France, paints a very bleak picture for the future of the flapper skate. Dr Iglesias and his team spent over a year working with French fisheries and taking DNA samples from the skate that was caught. His findings finally revealed that the larger D. intermedia species was indeed in serious decline. Dr Iglesias said: "The threat of extinction for European Dipturus together with mislabelling in fishery statistics highlight the need for a huge reassessment of population for the different Dipturus species in European waters. "Without revision and recognition of its distinct status the world's largest skate, D. intermedia, could soon be rendered extinct." Dr Dulvy added: "As far as we can tell, [humans have] not yet driven anything fully to extinction by over-fishing." He and many other marine scientists are now very concerned that this skate species will be the first. By Victoria Gill Science reporter, BBC News

Changing The Course Of Nature: Are Fisheries Directing The Evolution Of Fish Populations?

For many of the types of fish we buy in stores or order in restaurants, the chance that an individual dies from fishing is several times higher than dying of natural causes. This may seem obvious to most (they had to get to our table somehow), but what may not be apparent is that the relentless pursuit of consumer-friendly fish product is having a massive impact on fish populations around the world. By repeatedly choosing only the biggest fish, or only those found in certain habitats, the fisheries industry may be permanently altering the genetic composition of fish populations.

What are the long-term evolutionary implications of prolonged fishing for the fish that humans and, perhaps more importantly, diverse ecosystems so depend on? A group of concerned international scientists convened at the 2008 American Fisheries Society Annual Meeting to address this issue, and contributions to the symposium are now available online in an August 2009 special issue of Evolutionary Applications.

Several groups of scientists focused on teasing apart how much of the shift in fish morphology, development and behavior that has been documented over the years is due to genetic versus non-genetic changes. Long-term genetic changes may be more problematic since these may not be reversible and they make predicting the composition of fish stocks in the future very difficult. Equally contentious among scientists was distinguishing between changes that were caused by artificial selection due to fishing per se, versus environmental influences such as habitat destruction or climate change.

The articles in the special issue use multiple approaches to address these concerns and together come to the conclusion that in many cases, fish stocks are indeed evolving in response to the artificial selection pressure imposed by fishing. Shifts in yield-determining traits such as growth and maturation are evident, and how quickly these changes manifest depends on the type of fishing gear and the rate of harvest.

Given the uncertainty surrounding the future sustainability of wild fish stocks, fisheries evolution scientists make several key recommendations: protect a portion of the stock through the creation of non-fished marine protected areas, protect late-maturing and slow-growing individuals, and perhaps the most difficult but most effective: fish less.

This Special Issue of Evolutionary Applications, 2:3, is available free online at http://www3.interscience.wiley.com/journal/119423602/home.

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Adapted from materials provided by Wiley - Blackwell, via AlphaGalileo.

West Coast fishermen embark on new wave of fishing

The West Coast groundfish fleet has struggled to stay afloat during major cutbacks to reverse long-standing problems with overfishing and to protect the seafloor from damage caused by bottom trawling gear.They are now embarking, after years of work and negotiation, on the latest system in fisheries management, known as "catch share." Fishermen are given their own individual shares of the total catch, personal responsibility for not catching overfished species, and a promise of better prices for the fish they do haul up."In the short term it might hurt people. In the long term I think it's the way to go," said Todd Whaley, 46, part-owner and skipper of the Miss Sarah, a 102-foot trawler that he rigs for groundfish, Pacific whiting, and crab, depending on the market.NOAA Fisheries Service, the federal agency that oversees commercial fishing, is pressing regional fishery councils that set harvest limits around the country to adopt catch share programs.The agency is under a congressional mandate to end all overfishing in U.S. waters by 2011, the year that the West Coast groundfish accord goes into effect. It still has 41 fisheries to bring in line out of 244 that have been assessed."The scientific evidence is pretty clear that commercial fisheries that are managed with catch shares on balance perform better than traditionally managed fisheries," Jane Lubchenco, head of the National Oceanic and Atmospheric Administration, told The Associated Press on a recent visit to Newport."So we are encouraging every (regional fishery management) council to simply look at this tool and say, 'Is it appropriate for these fisheries, or is it not.'"Chief among candidates for switching to catch share is the New England groundfish fishery, which has been struggling for 15 years to rebuild cod and haddock stocks.The stakes are high. According to NOAA, commercial fishing contributes $28 billion a year to the economy. Meanwhile, the nation's appetite for fish outstrips domestic supply. Sixty percent of the seafood consumed comes from imports.The scientific foundation for catch share comes from studies like one examining fisheries in New Zealand and Australia published in the journal Science in 2007. The report found that fishermen who owned a share of the harvest made more money fishing less while doing a better job of conserving the resource.The idea is when they no longer have to race to fill their nets they can concentrate on quality and efficiency."There is nothing magical about catch shares rescuing overfished stocks, but they do change the incentives so that the fishermen who have a dedicated share of a stock know they will be the ones who benefit when stocks are rebuilt," said co-author Ray Hilborn, fishery sciences professor at University of Washington.West Coast groundfish have been rebuilding since 2000, when harvests were cut in half to protect overfished rockfish. Despite limiting harvests and cutting the fleet through buybacks, several groundfish species remain overfished. They are still the region's most valuable fishery, with landings worth $55 million in 2007.The classification covers 82 species, caught mostly by trawlers — also known as draggers — hauling nets along the ocean bottom. The fish are sold as sole, flounder, lingcod, black cod, snapper, and imitation crab.For five years fishermen and conservation groups have been working with the Pacific Fishery Management Council to adopt a catch share system, already in force with a dozen U.S. fisheries including Alaskan halibut, Gulf red snapper and Atlantic surf clams. The council approved the move last year. The rules go into effect Jan. 1, 2011.Catch share gets rid of the traditional race for fish, where fishermen go full-bore until they fill an overall quota, or inadvertently catch too many overfished species — known as bycatch.With their own quota, fishermen can fish when the weather and market are best. With that comes individual responsibility for not exceeding limits on bycatch. Those who do can buy shares to cover the excess. To reward captains who avoid bycatch, and penalize those who don't, each West Coast groundfish trawler will have an observer on board to count every fish hauled up in the net.The New England Fishery Management Council is headed in the same direction. In July they approved a plan giving fishermen the option of a catch share fishery, with sectors rather than individuals allocated shares. NOAA Fisheries is seeking $18.6 million from Congress to implement the switch. Among the first to feel the pain of declining cod harvests — and the first to opt for catch share — were small-boat fishermen on Cape Cod, Mass., who still fish with hooks and lines the way their forefathers did. "We were almost like the canary in the coal mine," said Eric Brazer, sector manager for the Cape Cod Commercial Hook Fishermen's Association, which went to catch share in 2004. "We'll live within the limits set by science. Other fishermen are willing to go toe-to-toe with the scientists. We're most interested in preserving our community and making sure we get through the next few years till we start seeing the fish populations come back." Not everyone in the 120-boat West Coast groundfish fleet will be a winner under the new rules. An analysis estimates 50 to 70 boats will be left with fishing permits after things sort out. The remainder will have to stop groundfishing. Don Taylor, captain of the Little Joe, has built his knowledge of where and when to find fish on decades of trial and error, and fears that now even one bad tow could shut him down if the net comes up with a single canary rockfish, an overfished species with no bycatch quota. As for Whaley, he is confident that he will be able to figure out how to succeed under the new rules. "Instead of the race for fish, lately, it's been the race for bycatch," he said. "A person who has his own bycatch quota is going to be fishing much more carefully."

New Hope For Fisheries: Overfishing Reduced In Several Regions Around The World

Scientists have joined forces in a groundbreaking assessment on the status of marine fisheries and ecosystems. The two-year study, led by Boris Worm of Dalhousie University and Ray Hilborn of the University of Washington and including an international team of 19 co-authors, shows that steps taken to curb overfishing are beginning to succeed in five of the ten large marine ecosystems that they examined.

The paper, which appears in the July 31 issue of the journal Science, provides new hope for rebuilding troubled fisheries.
The study had two goals: to examine current trends in fish abundance and exploitation rates (the proportion of fish taken out of the sea) and to identify which tools managers have applied in their efforts to rebuild depleted fish stocks. The work is a significant leap forward because it reveals that the rate of fishing has been reduced in several regions around the world, resulting in some stock recovery. Moreover, it bolsters the case that sound management can contribute to the rebuilding of fisheries elsewhere.
It's good news for several regions in the U.S., Iceland and New Zealand. "These highly managed ecosystems are improving" says Hilborn. "Yet there is still a long way to go: of all fish stocks that we examined sixty-three percent remained below target and still needed to be rebuilt."
"Across all regions we are still seeing a troubling trend of increasing stock collapse," adds Worm. "But this paper shows that our oceans are not a lost cause. The encouraging result is that exploitation rate – the ultimate driver of depletion and collapse – is decreasing in half of the ten systems we examined in detail. This means that management in those areas is setting the stage for ecological and economic recovery. It's only a start – but it gives me hope that we have the ability to bring overfishing under control."
The authors caution that their analysis was mostly confined to intensively managed fisheries in developed countries, where scientific data on fish abundance is collected. They also point out that some excess fishing effort is simply displaced to countries with weaker laws and enforcement capacity.
While most of the fisheries that showed improvement are managed by a few wealthy nations, there are some notable exceptions. In Kenya, for example, scientists, managers, and local communities have teamed up to close some key areas to fishing and restrict certain types of fishing gear. This led to an increase in the size and amount of fish available, and a consequent increase in fishers' incomes. "These successes are local - but they are inspiring others to follow suit," says Tim McClanahan of the Wildlife Conservation Society in Kenya.
"We know that more fish can be harvested with less fishing effort and less impact on the environment, if we first slow down and allow overfished populations to rebuild," adds co-author Jeremy Collie from the University of Rhode Island. "Scientists and managers in places as different as Iceland and Kenya have been able to reduce overfishing and rebuild fish populations despite serious challenges."
The authors emphasize that a range of management solutions are available to help rebuild fish stocks. They found that a combination of approaches, such as catch quotas and community management coupled with strategically placed fishing closures, ocean zoning, selective fishing gear and economic incentives, offer promise for restoring fisheries and ecosystems. However "lessons from one spot need to be applied very carefully to a new area," says coauthor Beth Fulton of the CSIRO Wealth from Oceans Flagship in Australia, since "there are no single silver bullet solutions. Management efforts must be customized to the place and the people."
According to the authors' analysis, Alaska and New Zealand have led the world in terms of management success by not waiting until drastic measures are needed to conserve, restore and rebuild marine resources. Some other regions are currently recovering from overfishing: fish abundance has recently been increasing above the long-term average in Iceland, the Northeast U.S. Shelf and the California Current.
This new study is a follow-up to a 2006 paper in Science by Worm and others that highlighted a widespread global trend toward fisheries collapse. The results of that paper led to a public disagreement between Worm and Hilborn. Through their subsequent discussions, however, the two scientists recognized a shared sense of purpose. They decided to collaborate on a more detailed assessment of the world's fisheries, and brought together many of the world's most talented fisheries scientists and ecologists for a two-year series of working groups at the National Center for Ecological Analysis and Synthesis (NCEAS) in Santa Barbara, California. The current paper is the result of those meetings.
"Prior to this study, evaluations of the status of world fish stocks and communities were based on catch records for lack of a better alternative. Results were controversial because catch trends may not give an accurate picture of the trends in fish abundance," explains Ana Parma of Centro Nacional Patagónico in Argentina. "This is the first exhaustive attempt to assemble the best-available data on the status of marine fisheries and trends in exploitation rates, a major breakthrough that has allowed scientists from different backgrounds to reach a consensus about the status of fisheries and actions needed."
The analysis includes catch data, stock assessments, scientific trawl surveys, small-scale fishery data and modeling results. The authors liken their strategy to constructing a "Russian doll", with each nested layer of data adding to the strength and value of the whole.
In looking at the tools that have been used to reduce exploitation rate, the authors note that "some of the most spectacular rebuilding efforts have involved bold experimentation with closed areas, gear and effort restrictions and new approaches to catch allocations and enforcement." Laws that explicitly forbid overexploitation and specify clear rules and targets for rebuilding were seen as an important prerequisite, for example in the U.S.
While the study suggests that these tools have long-term benefits, they also come with short-term costs to fishers. "Some places have chosen to end overfishing," says Trevor Branch, a co-author from the University of Washington. "That choice can be painful for fishermen in the short term, but in the long term it benefits fish, fishermen, and our ocean ecosystems as a whole."
Key among the group's recommendations is to fish at rates lower than those producing maximum sustainable yield (MSY), a long-standing and internationally accepted benchmark for total catch. They call for MSY to be reinterpreted as an absolute upper limit rather than a target, in line with U.N. recommendations.
The authors used ecosystem models to calculate a multi-species MSY (or MMSY) that adds up yield across all species, taking account of their interrelations. That analysis suggests that fishing below MMSY yields just as much fish as exceeding that benchmark, but has many ecological benefits including fewer species collapses, an increase in fish size and fish abundance. "Below MMSY there is a fishing-conservation sweet spot," says co-author Steven Palumbi of Stanford University, "where economic and ecosystem benefits converge."
The team also notes that in addition to reducing exploitation rates below MMSY, there are several other measures that can reduce fishing impacts on ecosystems. "Fishing at maximum yield comes at a significant cost of species collapses," explains Heike Lotze, a co-author from Dalhousie University. "But even low levels of fishing do change marine ecosystems and may collapse vulnerable species. That's why we require a combination of measures, including gear restrictions and closed areas, in order to meet both fisheries and conservation objectives."
The authors caution that much work remains to be done to end global overfishing, as a large fraction of global fisheries are not properly managed, reported or regulated. Particularly outside wealthy industrialized nations, prospects for reducing fishing mortality are often more limited unless fishers get access to alternative sources of food and income. Therefore the authors highlight the need for a more global perspective on rebuilding marine resources.
"Fisheries managers currently presiding over depleted fish stocks need to become fast followers of the successes revealed in this paper," says Pamela Mace, a co-author from the New Zealand Ministry of Fisheries. "We need to move much more rapidly towards rebuilding individual fish populations and restoring the ecosystems of which they are a part, if there is to be any hope for the long-term viability of fisheries and fishing communities."
The study was based at the National Center for Ecological Analysis and Synthesis (NCEAS), funded by the National Science Foundation and the University of California, Santa Barbara.
Adapted from materials provided by Communication Partnership for Science and the Sea, via EurekAlert!, a service of AAAS.

Overfishing And Evolution: Fish Fear Their Census-takers

Using snorkelers and SCUBA divers is not the best way to monitor fish populations, if we want to know the evolutionary effects of overfishing.

The fish population in coral reef areas is often assessed by snorkelers or SCUBA divers, but new research shows that these methods may misrepresent the number of fish.
A study from the University of Victoria shows that fish avoid the divers and snorkelers who try to count them. Not all types of fish are equally frightened by the divers, and Faculty of 1000 member Helen Yap, who recommended the study, explains that therefore "such methods may not provide an accurate picture of the actual diversity and abundance of fish communities."
Counting coral reef fish informs researchers about local ecological changes. However, accurate monitoring of fish populations in other parts of the ocean is also necessary. This is because overfishing has long-term, 'evolutionary' effects on fish population and breeding rates.
This was addressed by John Pandolfi in a recent article in Faculty of 1000 Reports. Accurate assessment of changes to fish populations depends on being able to count them. Pandolfi emphasized that fish populations must be monitored over several generations, saying "While the field is exciting and changing almost daily, we still have very little information of how species are affected by fisheries-induced evolution, and the extent to which various traits are vulnerable."
Journal references:
P. Dearden, M. Theberge and M. Yasu. Using underwater cameras to assess the effects of snorkeler and SCUBA diver presence on coral reef fish abundance, family richness, and species composition. Environmental Monitoring and Assessment, 2009; DOI: 10.1007/s10661-009-0855-3
John Pandolfi. Evolutionary impacts of fishing: overfishing's 'Darwinian debt'. F1000 Biology Reports, 2009; 1 DOI: 10.3410/B1-43
Adapted from materials provided by Faculty of 1000: Biology and Medicine, via EurekAlert!, a service of AAAS.

Banning Certain Fishing Gear Can Help Save Reefs From Climate Change

Banning or restricting the use of certain types of fishing gear could help the world's coral reefs and their fish populations survive the onslaughts of climate change according to a study by the ARC Centre of Excellence for Coral Reef Studies at James Cook University, the Wildlife Conservation Society, and other groups.

The international team of scientists has proposed that bans on fishing gear - like spear guns, fish traps, and beach seine nets – could aid in the recovery of reefs and fish populations hard hit by coral bleaching events.
Around the world corals have been dying at alarming rates, due to unusually warm water events resulting from global warming.
Research carried out in Kenya and Papua New Guinea has shown that certain types of gear are more damaging to corals, to coral-dependent fish and to the key species of fish that are needed to help reefs recover from bleaching or storm damage.
"This is creating a double jeopardy for both the corals and certain types of reef fish. They are already on the edge because of overfishing– and the additional impact caused by a bleaching can push them over" Dr Cinner explains. The result can be an accelerated decline of the reef, its fish populations – and their ability to sustain local people.
"From an ecological perspective, the best response to bleaching is to close reefs to fishing entirely. But that is not feasible everywhere and is a particularly hard sell among the impoverished fishers in developing countries" says co-author Dr. Tim McClanahan of the Wildlife Conservation Society. "In areas where fishery closures are impractical, managers don't have many options and haven't been able to do much but watch the reef die and often not recover."
"Selective gear restrictions offer reef managers and fishers alike some middle ground, reducing pressure on the reef and its fish while it is in the recovery phase, while also providing fishers with some options for their livelihood" Dr Cinner says. This middle way is also more likely to be taken up by fishers. "In other research we've found that fishers themselves prefer gear restrictions to total closures, because most fishers use several types of gear so they can still earn a living when the use of one sort of gear is banned. They are more likely to comply."
The team investigated the effects of five main types of gear on different types of fish: spear guns, traps, hook and line, beach seine nets and gill nets.
They found that spear guns were the most damaging of all – to corals themselves, to susceptible fish species and to the fish needed to help reefs recover, such as parrot, surgeon and trigger fish, which keep seaweeds and urchins in check while the coral re-grows.
"Spear guns target a high proportion of species that help maintain the resilience of coral reefs, but also can result in a surprising amount of damage to the corals themselves. When a fish is shot with a spear gun, it often hides in the reef, so some fishermen break the corals in their attempts to get it." Dr Cinner says.
But in developing countries, spear guns can be the fishing tool most used by the poorest fishers because they are cheap to make and the yield can be high, so they are an important source of income for poor fishers.
"You can't simply impose an arbitrary ban on their use – you need to consider issues like compensation, other fishing options, or alternative livelihoods for the affected fishers," says co-author Dr. Shaun Wilson of the Western Australian Department of Environment and Conservation. "One key issue may be educating fishers about the importance of reef habitat and the species that help to maintain reef quality – and the need to be selective in what they shoot. This would mean fishers could still use this cheap and effective fishing tool without necessarily damaging habitat and reef resilience."
Fish traps also targeted both the most susceptible reef fish and the ones most involved in reef recovery. Beach seine nets didn't target as many key fish species as gill nets, traps, or spear guns, but were damaging both to corals directly and took large amounts of juvenile fish.
"Where people really depend on reef resources, it may not be possible to permanently ban all of these types of gear. By creating temporary bans for specific types of gear following a coral bleaching event, reef managers could ease pressure on the reef and its fish population for a time when corals ecosystems are most sensitive without causing undue hardship to the human populations that depend on it." Dr Cinner says
"Of course, where the conditions are right, managers and fishers don't have to wait for a bleaching event- preventative gear bans are a good idea, particularly in areas that are highly susceptible to the impacts of bleaching," says co-author Dr Nick Graham. "And our new research provides managers with some ideas about the trade-offs involved in banning certain gear."
Dr Cinner says that temporary bans or imposing permanent restrictions on the use of various types of gear can apply to virtually any coral reef management – whether in the developing world or in developed countries such as on Australia's Great Barrier Reef.
"In principle, it can be used anywhere. It offers both communities and reef managers much greater flexibility. Around the world, communities are increasingly making their own decisions about how to protect their reefs and they could impose voluntary bans on certain gears.
Journal reference:
Cinner et al. Gear-based fisheries management as a potential adaptive response to climate change and coral mortality. Journal of Applied Ecology, 2009; 46 (3): 724 DOI: 10.1111/j.1365-2664.2009.01648.x
Adapted from materials provided by Wildlife Conservation Society, via EurekAlert!, a service of AAAS.

Basking Sharks: Disappearing Act Of World's Second Largest Fish Explained

Researchers have discovered where basking sharks – the world's second largest fish – hide out for half of every year, according to a report published online on May 7th in Current Biology. The discovery revises scientists' understanding of the iconic species and highlights just how little we still know about even the largest of marine animals, the researchers said."While commonly sighted in surface waters during summer and autumn months, the disappearance of basking sharks during winter has been a great source of debate ever since an article in 1954 suggested that they hibernate on the ocean floor during this time," said Gregory Skomal of Massachusetts Marine Fisheries. "Some 50 years later, we have helped to solve the mystery while completely re-defining the known distribution of this species."Using new satellite-based tagging technology and a novel geolocation technique, the researchers found that basking sharks make ocean-scale migrations through tropical waters of the Atlantic Ocean during the winter, traveling at depths of 200 to 1,000 meters. Their data show that the sharks sometimes stay at those depths for weeks or even months at a time. "In doing so, they have completely avoided detection by humans for millennia," Skomal said, emphasizing that as one of the very largest of marine animals, the sharks grow to over 10 meters and weigh as much as seven metric tons.Skomal said they were "absolutely surprised" when they first received a signal from the tagged sharks coming from the tropical waters of the western Atlantic, in the vicinity of the Caribbean and Bahamas. After all, basking sharks were always believed to be cool-water sharks, restricted to temperate regions.Several factors had made basking sharks a challenge to study. On top of the fact that they disappear for long periods of time, they also feed exclusively on plankton. That means they can't readily be captured with traditional rod-and-reel methods. And even when the sharks are found closer to the ocean surface, they spend their time in the cool-temperature, plankton-rich waters that limit underwater visibility and make diving difficult.The findings could have important implications for the conservation of basking sharks, which have shown some signs of dramatic decline in the last half century and are listed as threatened by the International Union for Conservation of Nature."Coupled with recent genetic data, our finding indicates that the Atlantic population – and perhaps the world population – are connected and may constitute a single population," Skomal said. "Hence, the global population of basking sharks may be even smaller than previously thought." Efforts to boost basking sharks' numbers will therefore need to be coordinated at a global scale.The authors include Gregory B. Skomal, Massachusetts Division of Marine Fisheries, Oak Bluffs, MA; Stephen I. Zeeman, University of New England, Biddeford, ME; John H. Chisholm, Massachusetts Division of Marine Fisheries, New Bedford, MA; Erin L. Summers, Maine Department of Marine Resources, Boothbay Harbor, ME; Harvey J. Walsh, Woods Hole Oceanographic Institution, Woods Hole, MA; Kelton W. McMahon, Woods Hole Oceanographic Institution, Woods Hole, MA; and Simon R. Thorrold, Woods Hole Oceanographic Institution, Woods Hole, MA.

EU seeks deep cuts in fishing quotas for 2010

The European Commission on Tuesday proposed substantial cuts in fishing quotas next year over concerns that current levels are too high to sustain fish stocks.EU Fisheries Commissioner Joe Borg supported allowable catch cuts of "at least 25 percent" for the most vulnerable species where the commission's own scientific committee is calling for fishing to be stopped altogether."Slow progress has been made in stock recovery since the 2002 reform" of the EU's fisheries policy, he said in a statement."One of the reasons for this is that fishing opportunities consistently have been set at levels which were too high for the fish stocks to sustain," he said.As a result, more than 80 percent of EU fish stocks are now overfished, compared with a global average of 28 percent.On the other hand, the commission is ready to adopt "a more flexible approach" for species whose stocks are not under threat, with a cut in quotas limited to 20 percent.For stocks which have been replenished, quotas could be lifted by 25 percent.Total Allowable Catches (TACs) are set annually for the Baltic Sea, the Black Sea, and the Northeast Atlantic including the North Sea.TACs for fisheries on deep sea species are fixed every two years.Fisheries in the Mediterranean are not managed through catch limits, except in the case of bluefin tuna.Haggling involving the 27 EU member states, the fishing community and environmentalists should culminate in an overall deal agreed by the end of the year ahead of next year's fishing season.

'Sobering' Decline Of Caribbean's Big Fish

Sharks, barracuda and other large predatory fishes disappear on Caribbean coral reefs as human populations rise, endangering the region's marine food web and ultimately its reefs and fisheries, according to a sweeping study by researcher Chris Stallings of The Florida State University Coastal and Marine Laboratory.While other scientists working in the Caribbean have observed the declines of large predators for decades, the comprehensive work by Stallings documents the ominous patterns in far more detail at a much greater geographic scale than any other research to date. "Seeing evidence of this ecological and economic travesty played out across the entire Caribbean is truly sobering," said Associate Professor John Bruno of the University of North Carolina at Chapel Hill, who served as the PLoS One academic editor for Stallings' new paper."I examined 20 species of predators, including sharks, groupers, snappers, jacks, trumpetfish and barracuda, from 22 Caribbean nations," said Stallings, a postdoctoral associate at the FSU Coastal and Marine Laboratory. "I found that nations with more people have reefs with far fewer large fish because as the number of people increases, so does demand for seafood. Fishermen typically go after the biggest fish first, but shift to smaller species once the bigger ones become depleted. In some areas with large human populations, my study revealed that only a few small predatory fish remain."Stallings said that although several factors -- including loss of coral reef habitats -- contributed to the general patterns, careful examination of the data suggests overfishing as the most likely reason for the disappearance of large predatory fishes across the region. He pointed to the Nassau grouper as a prime example. Once abundant throughout the Caribbean, Nassau grouper have virtually disappeared from many Caribbean nearshore areas and are endangered throughout their range."Large predatory fish such as groupers and sharks are vitally important in marine food webs," Stallings said. "However, predicting the consequence of their loss is difficult because of the complexity of predator-prey interactions. You can't replace a 10-foot shark with a one-foot grouper and expect there to be no effect on reef communities. Shifts in abundance to smaller predators could therefore have surprising and unanticipated effects. One such effect may be the ability of non-native species to invade Caribbean reefs."A case in point, said Stallings, is the ongoing invasion by Pacific lionfish, which were introduced by aquarium releases."Lionfish are minor players on their native Pacific reefs, yet they are undergoing a population explosion and overeating small fishes in the greater Caribbean region," said Professor Mark Hixon of Oregon State University, Stallings' doctoral advisor at OSU. "Preliminary evidence suggests that lionfish are less invasive where large predatory native fishes are abundant, such as in marine reserves," Hixon said.The study also demonstrates the power of volunteer and community research efforts by non-scientists. Stallings used data from the Reef Environmental Education Foundation's (REEF) online database, which contains fish sightings documented by trained volunteer SCUBA divers, including more than 38,000 surveys spanning a 15-year period."Chris was completely undaunted by the lack of fisheries data and essentially adopted the 'Audubon Christmas Bird Count' approach in a marine system to find strong evidence for a native fisheries effect," said Felicia Coleman, director of the FSU Coastal and Marine Laboratory and Stallings' postdoctoral advisor.Given that about half the world's populations live near coastlines and that the world population is growing, demands for ocean-derived protein will continue to increase, Stallings warned. He said meeting such demands while retaining healthy coral reefs may require multiple strategies, including implementation of marine reserves, finding alternative sources of protein, and increased efforts to implement family-planning strategies in densely populated areas.Journal reference:Stallings et al. Fishery-Independent Data Reveal Negative Effect of Human Population Density on Caribbean Predatory Fish Communities. PLoS ONE, 2009; 4 (5): e5333 DOI: 10.1371/journal.pone.0005333 Florida State University,

Ghost fishing' major sea threat: UN report

Lost or discarded fishing nets can continue to catch fish for years and are a growing threat to the planet's marine ecosystem, according to a United Nations report released Wednesday."The report estimates that abandoned, lost or discarded fishing gear in the oceans makes up around 10 percent, (640,000 tonnes) of all marine litter," said a statement from the UN Environment Programme.The study, co-authored by the UN's Food and Agriculture Organisation (FAO), said the problem was getting worse due to the growing scale of global fishing and the use of fishing gear made of increasingly durable materials.Among the main culprits are bottom set gill nets, which are anchored to the sea floor and fitted with floats, forming an undersea wall of netting that can stretch several thousand metres."If a gill net is abandoned or lost, it can continue to fish on its own for months -- and sometimes years -- indiscriminately killing fish and other animals," the UNEP statement said.The report also cited the case of devices such as crab traps, which in some regions are lost by hundreds of thousands with each hurricane season.The UN study listed a number of measures to curb the trend such as financial incentives for fishermen to report lost gear, marking technology, improved disposal schemes and the use of bio-degradable elements in fishing gear.The report urged leaders gathering in Indonesia on May 11-15 for the World Oceans Conference to address the problem urgently."The amount of fishing gear remaining in the marine environment will continue to accumulate and the impacts on marine ecosystems will continue to get worse if the international community doesn't take effective steps to deal with the problem of marine debris as a whole," warned Ichiro Nomura, a senior FAO official for fisheries and aquaculture.UNEP executive director Achim Steiner said ghost fishing was just one of a myriad of the other "ghosts" haunting the marine environment such as acidification linked to greenhouse gases and rising de-oxygenated "dead zones" due to run-off and land-based pollution."Abandoned and lost fishing is part of this suite of challenges that must be urgently addressed collectively if the productivity of our oceans and seas is to be maintained for this and future generations," said Steiner.

Bluefin tuna will be wiped out by overfishing: WWF

OVERFISHING will wipe out the breeding population of Atlantic bluefin tuna, one of the ocean's largest and fastest predators, in three years unless catches are dramatically reduced, conservation group WWF said today.As European fishing fleets prepare to begin the two-month Mediterranean fishing season tomorrow, WWF said its analysis showed the bluefin tuna that spawn - those aged four years and older - will have disappeared by 2012 at current rates. "For years people have been asking when the collapse of this fishery will happen, and now we have the answer," said Sergi Tudela, Head of Fisheries at WWF Mediterranean. The fish, which can weigh over half a tonne and accelerate faster than a sports car, are a favourite of sushi lovers. Demand from Japan has triggered an explosion in the size of the Mediterranean fleet over the past decade and many of those boats use illegal spotter planes to track the warm-blooded tuna. "Mediterranean (Atlantic) bluefin tuna is collapsing as we speak and yet the fishery will kick off again tomorrow for business as usual. It is absurd and inexcusable to open a fishing season when stocks of the target species are collapsing," added Tudela. Environmental groups condemned an agreement signed in November by states setting bluefin quotas - a body dominated by EU members. The groups called it "a disaster" and "a disgrace," saying the states again chose to ignore their own scientists and set quotas 47 per cent higher than recommended. Illegal fishing is also rife for the bluefin, the dried, dark red meat of which once fed Roman armies on the march. Growing numbers of restaurants and retailers including Carrefour's Italian supermarkets are boycotting it. WWF said that analysis of official data showed the average size of mature tunas had more than halved since the 1990s and that this has had a disproportionately high impact since bigger fish produced many more offspring. The bluefin can only be saved by a compete halt to fishing in May and June as the fish rush through the Straits of Gibraltar to spawn in the Mediterranean, WWF and other campaign groups say.