New Standards for Reliable Fisheries: Preserving Population Diversity Stabilizes Fisheries, Ecosystems, and Economies

The many populations of sockeye salmon in Bristol Bay, Alaska act like a diversified portfolio of investments, buffering fisheries and incomes from the ups and downs of particular stocks. Sockeye salmon are one of the most valuable fisheries in the U.S., and since 1950, more than 60% of that value has come from Bristol Bay.

A new study in the June 3 issue of Nature quantifies, for the first time, just how much depends on this "portfolio effect." Without its current population diversity, the Bristol Bay sockeye fishery would close ten times more frequently -- once every two to three years rather than once every 25 years.
The study, by scientists at the University of Washington, draws on five decades of data and provides the first solid evidence that population diversity within a species plays a key role in maintaining stable fisheries.
"We believe this new evidence is a game-changer for managing species and entire ecosystems," says lead author Daniel Schindler, an ecologist at the University of Washington. "Population diversity of species is often overlooked by managers and conservationists. Yet in general, current rates of population loss are probably a thousand times higher than species loss."
The authors argue that, in order to maintain the steady flow of fish and other ecosystem services people depend upon, managers will need to put an explicit priority on preserving population diversity within species. Such strategies require aggressive protection of the habitat networks that ultimately generate and maintain population diversity. Both approaches will become increasingly important as a first line of defense against climate change.
"Part of it is understanding history and having the discipline not to chase the hottest stock of the day," says co-author Ray Hilborn, also at the University of Washington. "We have to maintain a range of productive elements -- a broad range of stocks."
With a landed value of more than $120 million in 2009, the Bristol Bay sockeye fishery has provided a reliable source of income and food year after year. This is because sockeye salmon are finely tuned to the individual streams and lakes in which they were born, and are thus incredibly diverse. Some populations do better in cold, wet years -- others thrive when it's hot or dry. Each population experiences its own boom and bust cycles based on environmental conditions and pure chance. But given sufficient diversity, there should be enough winners to make up for the losers every year for the species overall.
"Mother Nature does a pretty good job dealing with uncertainties -- climate change, for instance -- by producing a diversity of populations," explains Schindler. "In terms of fisheries, we need to have a longer- term vision for the viability of populations; the populations that are strong now are not necessarily going to be strong in coming years, so we need to protect weaker populations too, as insurance for the future."
Protecting weaker populations is a challenge- not only in salmon, but also in other species like tuna and cod. Managers must reduce fishing pressure below the levels that the stronger populations can tolerate, or distribute fishing pressure to protect diversity within stocks. The authors argue that in addition to protecting existing population diversity, we must also preserve and protect the variety of habitats that generate population diversity in the first place.
Many salmon rivers, including the Sacramento River in California and the Columbia in Washington, once enjoyed a high degree of population diversity and productivity. However, decades of heavy fishing, habitat degradation and reliance on hatcheries have dramatically simplified populations in these rivers. This has resulted in intense boom-and-bust cycles and frequent fishery closures. In British Columbia, major salmon rivers like the Skeena and Fraser have some populations that are highly depressed and show symptoms of decreased portfolio performance and increased vulnerability.
Hatcheries are frequently used to bolster wild salmon populations. But over time, hatchery fish can become closely related to one another, and can contribute to declines in unique wild populations. Eventually, hatchery-dominated areas can resemble one giant population. Just as intensive monoculture practices make food crops more vulnerable to disease or bad weather, a dependence on hatcheries can leave a fishery open to huge swings in fortune.
"The first lesson [of this paper] is that a wild multi-stock fishery can function very well on its own -- better than we've ever done with any kind of hatcheries," says Jack Stanford, an ecosystem scientist at the University of Montana who was not involved with the research. "Hatcheries are counterproductive if the goal is to sustain very healthy wild fisheries, especially in light of climate change."
Beyond hatcheries, the study results hold other important implications for wildlife management strategies in the US and beyond. In terms of habitat protection, for example, California is currently working on lessening the blow to Chinook salmon, delta smelt, Central Valley steelhead, and green sturgeon in the Sacramento and San Joaquin delta. A March 2010 report by the National Research Council supported recommendations by the Fish and Wildlife Service and the National Marine Fisheries Service to reduce the number of engineered diversions, such as dams and water diversion channels, in these river systems, on the grounds that they have negative consequences for these endangered species.
"In the Sacramento River, we have a history of exploitation and degradation going back to the gold rush," says Steve Lindley, a research ecologist with the National Marine Fisheries Service in Santa Cruz, CA, who was not involved with the research. "It's radically simplified the habitats that salmon depend on in the valley. In California, people have managed ecosystems with concrete. We build dams, line channels, and build flood control structures. Rivers need room to work, and they make salmon habitat if you let them. This research shows that sustainability depends on a healthy ecosystem, but our technological fixes to ecosystem problems usually have unintended consequences that make matters worse for salmon."
Salmon population loss is not confined to places with lots of people. The same activities that started eroding salmon diversity in the Columbia and Sacramento rivers a hundred years ago are spreading northward quickly.
"Bristol Bay, the most productive salmon ecosystem in the world, is facing decisions about major development proposals such as the giant Pebble Mine copper and gold mining facility, as well as hydroelectric dams," explains Stanford. "This research shows that the choices made in Bristol Bay today will help determine whether the fishery remains reliable for the next hundred years and beyond."
Hilborn adds, "Offshore drilling has also been proposed in Bristol Bay, and a spill similar to what we're seeing in the Gulf of Mexico could devastate this productive fishery. However the diversity in timing of migration to the ocean and age at maturation among different sockeye populations -- that is, the portfolio effect -- could afford them protection. In essence, protecting diversity is a form of insurance against the unexpected."
The lessons from Bristol Bay will be important for communities that rely on sustainable ecosystems, as well as the decision makers charged with managing them.
"This is a ground-breaking piece of work," says Jeff Hutchings, a professor of biology at Dalhousie University in Canada and former chair of the Committee on the Status of Endangered Wildlife in Canada, who was not involved with the study. "It's the strongest evidence to date that there's a financial benefit to maintaining population diversity -- and a greater chance that species can withstand environmental and human induced change. It's not done in a lab or in a tank. These are real rivers and a strong data set for a major fishery. If managers ignore this, they do so at their own peril."

Daniel E. Schindler, Ray Hilborn, Brandon Chasco, Christopher P. Boatright, Thomas P. Quinn, Lauren A. Rogers, Michael S. Webster. Population diversity and the portfolio effect in an exploited species. Nature, 2010; 465 (7298): 609 DOI: 10.1038/nature09060

Do Fish Feel Pain? Norwegian Research Suggests They Can

Norwegian School of Veterinary Science doctoral student Janicke Nordgreen has studied nociception and pain in teleost fish. Her conclusion is that it is very likely the fish can feel pain.
In her dissertation, Nordgreen studied the response to potentially painful stimuli in groups of cells and at the individual. As consciousness is essential to feel pain, Nordgreen tested as well whether fish can be taught to solve a task as in humans requires conscious attention.
The research on pain and nociception (physiological detection of stimuli that can cause tissue damage) in fish is important primarily because pain is a serious threat to animal welfare. In addition, the research may increase our understanding of the evolution of consciousness and the nociceptive system.
In her project, Nordgreen used Atlantic salmon (Salmo salar), goldfish (Carassius auratus) and rainbow trout (Oncorhynchus mykiss). Her research showed that noxious galvanic stimulation elicited activity in the Atlantic salmon telecephalon, and that the response was graded with stimulus intensity. In another experiment, the goldfish showed escape responses when the temperature exceeded 38 degrees C, which is within the temperature range that is deadly to goldfish. This suggests that the ability to respond to harmful point heat is a conserved feature among vertebrates.
The third experiment mapped the metabolism of morphine in Atlantic salmon and goldfish. It was found that they metabolize and secrete morphine more slowly than humans, and that the morphine in small extent reaches the brain of the fish. It was shown that the elimination half life of morphine was approximately one order of magnitude higher than in humans for both species.
The last experiment showed that rainbow trout could learn by trace classical condition. By using reinforcer devaluation, it was also found that the underlying association was most likely of a stimulus-stimulus nature.
No single experiment can unequivocally answer the question of whether fish can feel pain, but the current findings, seen in the context of existing literature strongly indicates that fish are not only capable of nociception but also of conscious perception of pain.
Janicke Nordgreen defended her PhD-thesis, entitled "Nociception and pain in teleost fish," at the Norwegian School of Veterinary Science on October 28, 2009.

Catch Shares Improve Consistency, Not Health, of Fisheries

Catch share programs result in more consistent and predictable fisheries but do not necessarily improve ecological conditions, according to a new study published online the week of December 22 by the journal Proceedings of the National Academy of Sciences.

Employed by nations around the world, catch shares -- a management system that divides up and allocates percentages, or shares, of the total allowable catch to individual fishermen or fishing groups -- have generated controversy as to whether they lead to better environmental stewardship than other fishery management options. The study, funded by the Lenfest Ocean Program, concludes that these programs help to eliminate erratic swings in fishing rates, catch landings and fish population sizes, among other factors, but may not necessarily lead to larger fish populations. This research is the most in-depth and comprehensive study of the ecological impacts of catch share programs in North America.
Publication of this research coincides with the public-comment period for the U. S. National Oceanic and Atmospheric Administration's (NOAA) draft catch share policy, which evaluates catch share programs under the Magnuson-Stevens Act, the nation's primary fisheries law. NOAA's draft policy "encourages the consideration and adoption of catch shares wherever appropriate in fishery management and ecosystem plans and amendments and will support the design, implementation, and monitoring of catch share programs."
"Many proponents of catch share programs presume that they improve the health of fisheries, but our research indicates a much different expectation: They work very well to avoid erratic swings. They generally do not lead to more fish to catch," said author Dr. Tim Essington of the School of Aquatic and Fishery Sciences at the University of Washington in Seattle, Washington. "Catch shares are one potential method for improving fisheries management, but we shouldn't expect these programs to be a panacea."
Participants in a catch share program may fish for their shares of the fishery at their discretion until their quotas are filled. This management method is often contrasted with a "race-for-fish" management option, where fishermen compete with others in the fishery during a set time frame.
The increase in predictability found to accompany catch share programs may result from greater incentives for fishermen to comply with rules and regulations. The study's findings also suggest that catch share fisheries may have lower rates of discarded fish.
Essington studied 15 catch share programs in the United States and Canada and looked at a range of measurements for each fishery, including population status, catch landings and fishing rate. He compared fisheries with catch shares to fisheries without them and also evaluated fisheries before and after the implementation of a catch share program. The research analyzed both the average value and the year-to-year variability of the measurements.
Essington cited a need to assess a larger number of fisheries globally.
"We have sufficient data to quantitatively evaluate many pros and cons of catch share programs, but as of now we still don't know how much they help to end overfishing," said Essington. "Analysis of a larger set of catch share programs could also help identify fishery and program-design characteristics that make these programs more effective in achieving better ecological outcomes."
The Lenfest Ocean Program supports scientific research aimed at forging solutions to the challenges facing the global marine environment. Adapted from materials provided by Pew Environment Group

Giant tuna fetches $177,000 at Japan fish auction

A giant bluefin tuna fetched 16.3 million yen ($177,000) in an auction Tuesday at the world's largest wholesale fish market in Japan.
The 513-pound (233-kilogram) fish was the priciest since 2001 when a 440-pound (200 kilogram) tuna sold for a record 20.2 million yen ($220,000) at Tokyo's Tsukiji market.
The gargantuan tuna was bought and shared by the owners of two Japanese sushi restaurants and one Hong Kong-based sushi establishment, said a market representative on condition of anonymity because he was not authorized to disclose the information.
Caught off the coast of northern Japan, the big tuna was among 570 put up for auction Tuesday. About 40 percent of the auctioned fish came from abroad, including from Indonesia and Mexico, the representative said.
Japan is the world's biggest consumer of seafood with Japanese eating 80 percent of the Atlantic and Pacific bluefins caught. The two tuna species are the most sought after by sushi lovers.
However, tuna consumption in Japan has declined because of a prolonged economic slump as the world's second-largest economy struggles to shake off its worst recession since World War II.
"Consumers are shying away from eating tuna ... We are very worried about the trend," the market representative said.
Apart from falling demand for tuna, wholesalers are worried about growing calls for tighter fishing rules amid declining tuna stocks.
The International Commission for the Conservation of Atlantic Tunas in November slashed the quota for the 2010 catch by about one-third to 13,500 tons (12,250 metric tons) — a move criticized by environmentalists as not going far enough.

Fish With Attitude: Some Like It Hot

Coral reef fish can undergo a personality change in warmer water, according to an intriguing new study suggesting that climate change may make some species more aggressive.

Experiments with two species of young damselfish on Australia's Great Barrier Reef have shown for the first time that some reef fish are either consistently timid, or consistently bold, and that these individual differences are even more marked as water temperatures rise.

A slight lift of just one or two degrees may have only a small effect on some fish but the behaviour of others can be transformed -- leading them to become up to 30 times more active and aggressive.

"The idea that fish have personalities may seem surprising at first, but we now know that personality is common in animal populations, and that this phenomenon may have far-reaching implications for understanding how animals respond to ecological and environmental challenges," says Dr Peter Biro, of the UNSW School of Biological, Earth and Environmental Sciences, who led the study with colleagues Christa Beckmann and Judy A. Stamps. It is published in the journal Proceedings of the Royal Society B.

"Our results also suggest that temperature variations are much more significant than we thought in the way they affect the behaviours of individual animals. This needs to be taken into account for scientific studies of other cold-blooded animals, or ectotherms, such as reptiles and amphibians.

"For instance, individual variations in activity and boldness can affect food acquisition, encounter rates with predators and even the likelihood of an individual being captured by sampling or harvesting gear.

"We observed that most of the individuals in our experiments were very responsive to changes in temperature, dramatically increasing their levels of activity, boldness and aggressiveness as a function of increases of only a few degrees of temperature. Fish would experience such temperature fluctuations during the course of a normal day."

The scientists used fish that were captured just as they were ending their larval stage in open water and had not yet settled onto the reef, and so were naive to social hustle and bustle of reef fish life. They then directly manipulated water temperatures in laboratory tanks at Lizard Island Research station.

Placed by themselves in tanks, the fish were free to explore or to take refuge in a short piece of plastic pipe. The scientists observed how far and how often the fish ventured from the pipe. In cooler water, individual fish differed greatly in their activity levels. They all became more active to varying degrees when the water was warmed, with some becoming up to 30 times more active, bold and aggressive.

Fishery Impact Test Developed

Aspects of the 'ecological risk assessment' (ERA) method have been adopted in the US, Canada, Ecuador, and the Western and Central Pacific, and by the international eco-labelling organisation the Marine Stewardship Council.

The method was developed in research led by Dr Tony Smith and Dr Alistair Hobday from CSIRO's Wealth from Oceans Flagship in association with the Australian Fisheries Management Authority (AFMA).
"AFMA needed a tool for assessing the ecological risk associated with a diverse range of fishing practices: from the hand-selection of rock lobsters in the Coral Sea, to the trawling of Patagonian Toothfish deep in the Southern Ocean," Dr Smith says.
"We met the challenge with a three-step method that considers targeted and incidentally caught species, as well as threatened, endangered and protected species. Ongoing research is further developing the method for habitats and ecological communities.
"Each level of analysis potentially screens out issues of low concern and directs attention to higher risk issues. This helps fishery managers to guard against unacceptable changes to the ecosystem, while being strategic about where to focus dollars and time," Dr Smith says.
Dr Hobday says the completion of ERA reports for more than 30 AFMA-managed fishing sectors has been a mammoth undertaking involving many years of work by a large research team.
"Our ERA reports document the most comprehensive assessment of the ecological impacts of fishing in Australia's commercial fisheries and for any large set of fisheries in the world," he says.
"More than 1200 species have been assessed, highlighting the diversity of Australian fisheries and pointing to risks requiring analysis and management, both for individual fisheries, and on a cumulative scale."
The ERA process contributes to the strategic assessment of fisheries under the Environment Protection and Biodiversity Conservation Act 1999 and flags priorities for research, data collection, monitoring and management.
AFMA is responding with environmental risk management strategies for each fishery and other initiatives such as a guide for fishery managers to help manage shark bycatch. (Sharks and rays come out repeatedly as high-risk species across many fisheries.)
The research has also yielded a database of information on more than 1000 species of mammals, seabirds, reptiles, scalefish, and sharks and rays
Adapted from materials provided by CSIRO Australia.

Tropical Regions To Be Hardest Hit By Fisheries Shifts Caused By Climate Change

Major shifts in fisheries distribution due to climate change will affect food security in tropical regions most adversely, according to a study led by the Sea Around Us Project at The University of British Columbia.

In the first major study to examine the effects of climate change on ocean fisheries, a team of researchers from UBC and Princeton University finds that climate change will produce major shifts in productivity of the world's fisheries, affecting ocean food supply throughout the world. The study is published October 7 in the journal Global Change Biology.

"Our projections show that climate change may lead to a 30 to 70 per cent increase in catch potential in high-latitude regions and a drop of up to 40 per cent in the tropics," says lead author William Cheung, a researcher at the University of East Anglia in the UK who conducted the study while at UBC.

"Many tropical island residents rely heavily on the oceans for their daily meals. These new findings suggest there's a good chance this important food source will be greatly diminished due to climate change."

Previous studies have looked at how climate change affects global food supply but were limited to land-based food sources. These studies have also predicted that tropical areas will see a decline in land productivity.

The team, led by UBC Fisheries professor Daniel Pauly, also found that regions with the highest increase in catch potential by 2055 include Norway, Greenland, Alaska and the east coast of Russia. Meanwhile, regions with the biggest loss in catch potential include Indonesia, the United States (excluding Alaska and Hawaii), Chile and China.

While greater catch potential in colder regions might appear beneficial, the authors caution that more research is needed to account for the multitude of dynamic factors that affect every ecosystem.

"We need to keep the big picture in mind when looking at the 'winners' and 'losers' of climate change," says Pauly. "Major shifts in fish populations will create a host of changes in ocean ecosystems likely resulting in species loss and problems for the people who now catch them."

"While warmer waters might attract new species to colder regions, the rise in temperature might make the environment inhospitable to current species in the region that cannot move to even higher latitudes. Often these species are important to the diets and culture of native subsistence fishermen."

The team's projections also show that Canada's overall catch potential will remain approximately the same. The west coast may see a decrease of almost 20 per cent from 2005 to 2055 while the east coast may get a 10 per cent boost.

The study analyzed 1,066 species ranging from krill to sharks that constitute roughly 70 per cent of the world's catch. The authors used models that include a large number of environmental and biological factors that affect fisheries. They ran these models through two climate change scenarios, one more conservative than the other, and measured the impact of the scenarios on fish distribution from the years 2005 to 2055. The authors did not include the highest emission level scenario considered by the Intergovernmental Panel on Climate Change, which would have produced even more dramatic results.

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Adapted from materials provided by University of British Columbia, via EurekAlert!, a service of AAAS.

Fish Fend Off Invading Germs With An Initial Response Similar To One Found In Humans

Since the human response to infection is highly complex, research to understand how people fight infection is facilitated by studying how similar processes occur in simpler organisms. Zebrafish are becoming an important model for human disease, since they are easily handled, maintained and manipulated and many fundamental processes between zebrafish and humans are conserved. In addition, the small zebrafish embryo is highly amenable to drug screening assays.

The functional similarity between the initial responses of zebrafish embryo and humans to infection suggests that the zebrafish embryo may be a valuable model for understanding early immune responses and identifying potential therapeutics for infection or immune mediated disease. However, the initial response of zebrafish to infection and how it compares to the human response is not well understood.
When humans first encounter germs, like viruses or bacteria, the first stage of a two-part inflammatory response is triggered, which is termed the innate immune response. During this early phase, proteins are made around the site of infection to initiate the body's defense system and to recruit circulating immune cells, which begins the inflammatory process. A family of proteins that are critical to instigating the immune response are the interferons (IFN), particularly IFN-γ.
Scientists now report that IFN-γ is also produced in zebrafish embryos when they are exposed to bacteria that cause disease in fish. These studies use developing zebrafish embryos whose response to infection is isolated to the innate immune response. Since the zebrafish embryo only demonstrates innate immunity, it allows for specific study of the effects of IFN-γ on these early events. This study demonstrates that both zebrafish and human IFN-γ proteins function in much the same way, despite having very distinct protein structures. In both zebrafish and humans, IFN-γ triggers the production of an array of proteins that rally the defense mechanisms of the infected cell and activate the immune system. They also found that compromising the ability of the zebrafish embryos to produce IFN-γ impairs the fish's ability to survive infection. Thus, the zebrafish embryo may provide a very simple model to understand the innate immune response.
Interestingly, large quantities of bacteria, which would cause septic shock -- a potentially fatal condition -- in humans, do not elicit the same response in zebrafish. This suggests that some key differences between the immune systems of zebrafish and humans may also provide insight into harmful events associated with inflammation.
The characterization of IFN-γ function in zebrafish is presented in an article appearing in the November/December 2009 issue of the new research journal, Disease Models & Mechanisms (DMM), published by The Company of Biologists, a non-profit based in Cambridge, UK.
Journal reference:
Dirk Sieger, Cornelia, David Neifer, Maria Leptin, Astrid van der Sar. The role of gamma interferon in innate immunity in the zebrafish embryo. Disease Models & Mechanisms, November/December 2009 DOI: http://dmm.biologists.org/
Adapted from materials provided by The Company of Biologists, via EurekAlert!, a service of AAAS.

Oceanographers Examine Mercury Levels Of Pelagic Fish In Hawaii

In the open ocean, species of large predatory fish will swim and hunt for food at various depths, which leads to unique diets in these fish. Oceanographers and geologists in the School of Ocean and Earth Science and Technology (SOEST) at the University of Hawaiʻi at Mānoa (UHM) and colleagues have found that those fish that hunt deeper in the open ocean have higher mercury concentrations than those that feed near the surface of the ocean because their deep water food has higher mercury.

This research was detailed in the August 18th early edition of the prestigous journal the Proceedings of the National Academy of Sciences.
Mercury is a naturally-occurring trace element distributed throughout the Earth's oceans, land and air. The general public is interested in mercury levels in fish because the organic form, methylmercury, can be toxic at elevated levels if ingested by humans and animals.Mercury enters open ocean food webs, where it bioaccumulates, leading to higher levels in large predatory animals.
Researchers looking at mercury levels in the open ocean have indicated that deeper waters have elevated levels relative to the surface waters. "Bu! ilding o n this information, we thought that deeper-dwelling open ocean animals might have more mercury, as well as the predatory fishes that feed on them," says Anela Choy, a Department of Oceanography Graduate Student at UHM and lead author in this study. This was indeed the case, and the results of their work show that large pelagic fish like bigeye tuna and swordfish that feed deeper in the ocean have elevated total mercury levels relative to their shallower-dwelling counterparts like yellowfin tuna and mahi-mahi. "We show that this is because the food items that they eat also have varying levels of mercury", continues Choy. "Deeper-living micronekton prey (small fishes, squids, and crustaceans) have higher mercury levels relative to more surface-dwelling prey animals. This is important knowledge for scientists studying animals in the open ocean because it helps them to understand how energy and matter cycle, as well as show who is eating who in the vast, blue water environment. Although not the focus of this study, the results may also help provide information to the fish-consuming public on mercury levels in popular commercial species."
To study the mechanisms governing bioaccumulation in open ocean fish, the researchers, who also included Brian N. Popp and Jeffrey C. Drazen, also from UHM, and John Kaneko from the Honolulu company PacMar Inc, collected nine predatory pelagic fish species with different diets in waters surrounding Hawaiʻi, along with a representation of the types of prey these fishes eat. The predatory fish collected represented a wide variety of depths at which they search for food, varying from shallow-ranging predators (0 – 300 meters) to deep-ranging predators (up to 1000 meters). Total mercury levels of these fish were measured, along with an analysis of animals in their stomachs. The authors found that while the sex of a fish and the location where a fish was caught d! id not a ffect mercury concentrations, the size, age and species of fish did. However, for similar sized fish of different species, deeper-ranging predators still had more mercury than shallow-ranging ones. This study shows for the first time, that in addition to the size and age of a fish, or where it swims/lives, that the depth at which a fish feeds influences the amount of mercury it has in it's tissues.
"After looking more closely at these different mid-water prey organisms, a number of interesting questions have opened up," says Choy. "As these organisms are the primary food items for large pelagic fishes that humans like to eat, we need to understand more about how they fit into the open ocean ecosystem in order to sustainably manage our fish populations."
It is important to understand that ocean biology is connected across depths by the movements and hunting behaviors of animals. "The deep sea is remote, hard to study, and often ignored but our results clearly show how its biology is directly connected to human interests, both fishing and health," says Drazen. "Some of the fishes we enjoy at the dinner table grew on a diet of strange and exotic creatures from 1000s of feet deep in the ocean."
The original research was funded by University of Hawaiʻi Sea Grant College Program at UHM, the State of Hawaiʻi, JIMAR (Pelagic Fisheries Research Program (PFRP)), and the National Oceanographic and Atmospheric Administration. The need for a detailed study came after Popp attended a PFRP meeting on the UHM campus and he saw a data table from the State Department of Health of mercury concentrations in Hawaiian pelagic fishes that was published in the newspaper The Honolulu Advertiser. "The table was very crude showing only the average and range of mercury contents in each fish," says Popp." The fishes were listed from lowest m! ercury a t the top and highest mercury at the bottom -- it hit me that the order in the list roughly followed the depth the fish are typically caught in the ocean." Fortunately for Popp and Drazen, Choy, who had completed her undergraduate degree and was doing consulting work within the local seafood industry, and was also interested in this topic. Says Choy, "after interacting with the public, I found that many people were concerned with mercury levels in fish, and I eventually became interested in the oceanographic/ecological aspect of it."
The researchers have recently received funding from the Pelagic Fisheries Research Program, within the Joint Institute for Marine and Atmospheric Research (JIMAR) at UHM to continue using mercury, along with other chemical tracers to elucidate the structure and function of the open ocean food web in Hawaiian waters. Concludes Choy, "We hope this will provide crucial information for ecosystem-based fishery managers and ecosystem modelers."
Journal reference:
Choy et al. The influence of depth on mercury levels in pelagic fishes and their prey. Proceedings of the National Academy of Sciences, 2009; DOI: 10.1073/pnas.0900711106
Adapted from materials provided by University of Hawaii at Manoa.

To Manage A Fishery, You Must Know How The Fish Die

Recreational anglers and commercial fishermen understand you need good fishery management to make sure there will be healthy populations of fish for generations to come. And making good management decisions rests in large part on understanding the mortality of fish species – how many fish die each year as a result of natural causes and recreational and commercial fishing.

Now researchers at North Carolina State University have utilized a new research method that can give fishery managers a better idea of how fish are dying, so they can make informed decisions on how to ensure a healthy fish population.
Fisheries scientists from NC State have, for the first time, implemented a research strategy that uses both "conventional" tags and ultrasonic telemetry tags (transmitters) to estimate mortality rates. The approach was used in a study on mortality rates of "sub-adult" red drum, which are red drum that are close to adult in size but have not yet begun to reproduce. However, the research methods pioneered in this study could be applied to many other species, including popular fish such as striped bass. Red drum are popular among recreational anglers in many parts of the country, and are also important to commercial fishermen in North Carolina.
The conventional tags offer rewards to recreational and commercial fishermen who catch the tagged fish, creating an incentive for them to contact researchers. This approach lets researchers know how many of the tagged fish have been caught and how many of the fish were subsequently released or harvested, explains Dr. Jeff Buckel, an associate professor of biology at NC State and co-author of the study. This approach provides particularly good data on mortality resulting from commercial and recreational fishing, Buckel says.
The telemetry tags transmit uniquely coded sounds to receivers, allowing researchers to track fish movement in a given area. In this instance, the researchers were using both stationary receivers and mobile hydrophones to track tagged fish in the Neuse River estuary in eastern North Carolina, Buckel says. Telemetry tags provide excellent data on natural mortality, because the tags stop moving once the fish has died. These tags can also detect that a fish has been caught by commercial or recreational fishermen, because the tag will disappear from the study area without swimming past any of the receivers.
"The methodology we used in this study combined good natural mortality data from the telemetry tags with good recreational and commercial fishing mortality data from the conventional tags to give us a more precise estimate of overall mortality for sub-adult red drum," Buckel says. "This is important because, if you have a good understanding of mortality rates, you can make informed decisions about how to manage a fishery in order to ensure its long-term health." For example, the information generated by this study contributed to state and regional assessments of the red drum population.
"This is the first time this approach, using both kinds of tags, has been used in the field," Buckel says, "and it could have significant applications for other species, such as striped bass." One limitation is that the telemetry tags are only useful in relatively confined areas, such as lakes, estuaries or reservoirs – where researchers can place listening devices near exits to determine if a fish has left the waterbody on its own, rather than being caught by a fisherman.
The researchers, led by then-NC State Ph.D. student Nathan Bacheler, focused on sub-adult red drum because North Carolina only allows recreational and commercial fishermen to keep drum that are between 18 inches and 27 inches long. These fish are generally not old enough to reproduce. So researchers wanted to determine whether natural mortality and fishing mortality were limiting the long-term viability of the fishery. Good news fish fans: "Natural mortality was much lower than we previously assumed," Bacheler says, "and the fishing mortality was similar to previous estimates."
The research, "A combined telemetry – tag return approach to estimate fishing and natural mortality rates of an estuarine fish," was funded by North Carolina Sea Grant and is published in the August issue of the Canadian Journal of Fisheries and Aquatic Sciences. The study was co-authored by Bacheler, Buckel, NC State biology professors Dr. Joseph Hightower and Dr. Kenneth Pollock, and Lee Paramore of the North Carolina Division of Marine Fisheries.
Adapted from materials provided by North Carolina State University, via EurekAlert!, a service of AAAS.

How Can The World's Fisheries Be Sustainable?

According to the most recent report on the status of the world's fisheries by the United Nations Food and Agriculture Organization, fisheries supply at least 15% of the animal protein consumed by humans, provide direct and indirect employment for nearly 200 million people worldwide and generate $US85 billion annually. This same report indicates that 28% of the world's fisheries stocks are currently being overexploited or have collapsed and 52% are fully exploited.

A new study published in PLoS Biology provides the first global evaluation of how management practices influence fisheries' sustainability. The study assessed the effectiveness of the world's fisheries management regimes using evaluations from nearly 1,200 fisheries experts, analyzing these in combination with data on the sustainability of fisheries catches. The results indicate that most fisheries management regimes are lagging far behind standards set by international organizations, and that the conversion of scientific advice into policy, through a participatory and transparent process, plays the most critical role in determining the sustainability of fisheries.
"The world's fisheries are one of the most important natural assets to humankind," says lead author Camilo Mora, a Colombian researcher at Dalhousie University and the University of California San Diego. "Unfortunately, our use of the world's fisheries has been excessive and has led to the decline or collapse of many stocks."
"The consequences of overexploiting the world's fisheries are a concern not only for food security and socio-economic development but for ocean ecosystems," says Boris Worm, a professor at Dalhousie University and co-author of the paper. "We now recognize that overfishing can also lead to the erosion of biodiversity and ecosystem productivity."
"The different socioeconomic and ecological consequences associated with declining fish stocks are an international concern and several initiatives have been put forward to ensure that countries improve the way they use their marine resources," explains Mora. "Some of these initiatives include the United Nations Code of Conduct for Responsible Fisheries, the Convention on Biological Diversity, and the Millennium Ecosystem Assessment. Although these initiatives have been endorsed by most governments, a global assessment on the extent to which these ideals are actually implemented and effective remains lacking."
Mora and his colleagues analyzed a set of attributes upon which country-level fisheries could be evaluated. They pinpointed six parameters, including the scientific quality of management recommendations, the transparency of converting recommendations into policy, the enforcement of policies, the influence of subsidies, fishing effort, and the extent of fishing by foreign entities.
To quantify those attributes the researchers developed a questionnaire designed to elicit worst- to best-case answers. The survey was translated into five languages and distributed to over 13,000 fisheries experts around the world. Nearly 1,200 evaluations were used in the study. The responses of the surveyed experts were compared to, and found to be in accordance with, empirical data, supporting the validity of the data obtained in the study.
The results of this global survey showed that 7% of all coastal states carry out rigorous scientific assessment for the generation of management policies, 1.4% also have a participatory and transparent process to convert scientific recommendations into policy, and less than 1% also implement mechanisms to ensure the compliance with regulations. No one country was additionally free of the effects of excess fishing capacity, subsidies or access to foreign fishing.
"Perhaps the most striking result of our survey was that not a single country in the world was consistently good with respect to all these management attributes. So which countries are doing well and which are not is a question whose answer depends on the specific attribute you are looking at," says Mora.
The results of the study show that wealthier countries, though they have predominantly better science and enforcement capabilities, face the negative repercussions of excessive subsidies and larger fishing capacity, which have resulted largely from increased modernization of national fleets. In contrast, poorer countries largely lacked robust science and enforcement capabilities and although these nations have less fishing capacity nationally, they disproportionally sold fishing rights to nations that did. The study showed that in 33% of the coastal states classified as low-income (commonly countries in Africa and Oceania) most fishing is carried out by foreign fleets from either the European Union, South Korea, Japan, China, Taiwan or the United States.
The only attribute in which poorer and wealthier countries overlapped significantly was their limited ability to convert scientific recommendations into policy. The mechanism for this pattern, however, was different. Poor countries reportedly struggle with the effects of corruption while wealthier countries often encounter more political or economical pressures.
For the second part of the study, Mora and his colleagues combined the database on management effectiveness with a recently developed index to assess the probability that the catch of a particular country is sustainable or not. This part of the study showed that out of several attributes analysed, the transparency with which scientific recommendations are turned into policy plays the strongest role in the fate of fisheries sustainability.
"Transparent policy-making is at the centre of the entire process," explains co-author Marta Coll, at the Institut de Ciènces del Mar in Spain. "If this is heavily influenced by political pressures or corruption, it is unlikely that good scientific advice will ever be translated into proper regulations. Similarly, authoritarianism in this process is likely to reduce compliance with the resulting policies."
"This study provided us with a look at both sides of the coin," says Andrew Rosenberg at the University of New Hampshire, who was not involved in the study. "On one hand, it reminds us of the difficult challenges facing fisheries management globally in protecting critical natural resources from overexploitation. On the other hand it delivers a message of hope that when policy-making is transparent, participatory, and based on science, things can improve."
Funding to CM, RAM, and BW was provided by the Sloan Foundation through the Future of Marine Animal Populations Project. KJG holds a Royal Society-Wolfson Research Merit Award. Funding to RUS was provided by the Pew Fellowship for Marine Conservation. Funding to DZ, RUS, and RW was provided by the Pew Charitable Trust, Philadelphia through the Sea Around Us Project. Funding to MC was provided by the European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement #GA-2008-219265 for the implementation of ECOFUN Project. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Journal reference:
Mora C, Myers RA, Coll M, Libralato S, Pitcher TJ, et al. Management Effectiveness of the World's Marine Fisheries. PLoS Biol, 7(6): e1000131 DOI: 10.1371/journal.pbio.1000131
Adapted from materials provided by Public Library of Science, via EurekAlert!, a service of AAAS.Public Library of Science (2009, July 7). How Can The World's Fisheries Be Sustainable?. ScienceDaily. Retrieved July 8, 2009, from http://www.sciencedaily.com­ /releases/2009/06/090622201918.htm

Did The North Atlantic Fisheries Collapse Due To Fisheries-induced Evolution?

The Atlantic cod has, for many centuries, sustained major fisheries on both sides of the Atlantic. However, the North American fisheries have now largely collapsed. A new article from scientists at the University of Iceland and Marine Research Institute in Reykjavik provides insights into possible mechanisms of the collapse of fisheries, due to fisheries-induced evolution.

Cod fishing is of highest intensity in shallow water in Iceland and it selects against genotypes of cod adapted to shallow water. The new PLoS One article reports a significant difference in Darwinian fitness (relative survival rate) between shallow-water and deep-water adapted cod. The shallow-water fish have only 8% of the fitness of deep-water fish. This difference can lead to rapid elimination of shallow-water fish in only a few generations with drastic effects on the population and the fishery.
Using molecular population genetics, the authors reports steep changes in the frequency of genotypes at a single genetic locus with depth: a gradient of nearly one half percent drop in frequency per meter. The genotypes at the locus are directly related to behavioral types that select deep vs shallow water habitat by genotype.
"There is no direct targeting of specific genotypes. Instead the intense selection results from the interaction of fish that select their habitat by genotype and fishermen choosing to fish in the preferred habitat of the fish," said Einar Arnason, professor of population genetics and lead author.
In addition to the molecular results, the study also demonstrates that the length and age at which the fish become mature have decreased. So-called "probabilistic maturation reaction norms" show that the length at which there is a 50% probability of becoming mature, has, on average, decreased nearly one centimeter per year. The changes observed very likely are evolutionary genetic changes and not simply plastic phenotypic responses to the environment. They are comparable to changes that preceded the collapse of northern cod at Newfoundland.
This finding further supports the hypothesis of an imminent collapse of Icelandic cod due to the intense fisheries-induced selection. The cod fishery at Iceland is one of the world's few remaining cod fisheries. The study appears to have met all criteria for concern that this fishery is threatened.
"Can anything be done to avert collapse?" the authors ask. A strategy that would remove selection pressures against shallow-water adapted fish would seem to be the answer. The authors speculate that immediate establishment of large no-take reserves might be the right strategy by relieving selection pressures on all genotypes.
The findings provide general lessons for population and conservation genetics that anthropogenic changes in habitat can lead to intense selection even if the mortality is non-selective in the habitat in which it occurs. The study highlights the importance of applying Darwinian principles and evolutionary thinking to fisheries and conservation science.
The study was funded by grants from the Icelandic Research Fund and resources from the Marine Research Institute and the University of Iceland. Specimens were obtained during Marine Research Institute Surveys. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Journal reference:
Árnason et al. Intense Habitat-Specific Fisheries-Induced Selection at the Molecular Pan I Locus Predicts Imminent Collapse of a Major Cod Fishery. PLoS ONE, 2009; 4 (5): e5529 DOI: 10.1371/journal.pone.0005529
Adapted from materials provided by Public Library of Science, via EurekAlert!, a service of AAAS

Bonefish Census Reveals Population Holding Steady

If you're looking for bonefish from Miami down to the Marquesas Islands, you have about 321,000 to choose from, and that is down slightly from the average of previous censuses—mostly due to increased participation among those who are counting, researchers speculate.

The University of Miami's Rosenstiel School of Marine and Atmospheric Science held the sixth annual Florida Keys bonefish census, in conjunction with the conservation group Bonefish & Tarpon Unlimited (BTU), which involved 64 professional fishing guides, scientists and graduate students split up among 19 zones, covering 1,575 square miles.
"It's true the numbers are down slightly," said Dr. Jerry Ault, Rosenstiel School professor of marine biology and fisheries and co-founder of the census along with Sandy Moret of BTU, "However, I wouldn't read too much into that change. Statistically there is no significant difference year over year. The decrease could be due to variations in where the bonefish showed up this year, the weather on census day, or the fact that we had more guides scouring the Lower Keys than in previous years. A Spring 2008 census to calibrate the Fall census showed pretty much the same thing --we're getting a generally consistent count from year to year, which helps to validate our research process and confirm our estimates."
Ault and BTU started the annual census in 2003 to determine a baseline for scientifically evaluating changes in the Florida Keys bonefish population. With help from flats guides and their customers to poll the flats looking for bonefish, they counted the quantities of bonefish observed and caught. This year, the boats set out on October 29, to visually and methodically count bonefish throughout the day. The volunteers, who ranged from fisherman to scientists and graduate students, covered well-known, popular bonefish territory, which ultimately resulted in a population estimate this year of 320,961 bonefish (+/- 41,091 for a 12.8 percent coefficient of variation) or about 204 bonefish per square mile.
Bonefish are valuable for several reasons. Because of their large size, bonefish obviously rely on smaller creatures in the ecosystem whose populations aren't as easy to assess. Bonefish are fairly easy to count on the flats and can be seen as an indicator of the overall ecosystem's general health—researchers will observe changes here much sooner than within a smaller creature whose numbers are in the millions. Long-time bonefish anglers often remark on the dramatic decreases they've observed in this popular sportfish's population.
"Bonefish are a great indicator of ecological change," Ault said. "I would be concerned if the population drops from 300,000 to 200,000."
These fish also bring South Florida a significant amount of tourism. Bonefish sportfishing contributes approximately $1.0 billion annually to the Florida economy, making sportfishing more valuable than commercial fishing in today's market.
"This estimate of the 'visible' population makes each bonefish in the water worth about $3,500 per year to the industry, and about $75,000 per fish over its lifetime," Ault said.
Adapted from materials provided by University of Miami Rosenstiel School of Marine & Atmospheric Science.

Fishing Ban Protects Largest Coral Reef In The Philippines

Reef fish and other marine species can breathe easier with the introduction of a fishing ban around Apo Reef, the largest coral reef in the Philippines and the second largest contiguous reef in the world after the Great Barrier Reef।

Under the ban, all extractive activities, such as fishing, and coral collection and harvesting, will be completely forbidden.
“This ‘no-take’ zone will allow the reef and its residents ample time to recover from years of fishing,” stressed John Manul of WWF-Philippines.
The 27,469-hectare Apo Reef off the coast of Mindoro Island is surrounded by mangrove forest, which serves as a source of food, nursery and spawning ground of several coastal fish and marine species, including sharks, manta rays, sperm whales and several sea turtles.
In 1996, the reef was declared a national park, but enforcement proved lax and illegal fishing methods persisted.
The park was once one of the world’s premier diving destinations, but years of fishing — including by unsustainable fishing practices such as using dynamite and cyanide — took its toll.
“You would hear 25 to 30 dynamite blasts daily,” said Robert Duquil, a former protected area assistant superintendent. “The international diving community lost interest in the area and destructive activities prevailed.”
Adding to the reef’s troubles, the El Niño phenomenon in 1998 raised ocean temperatures, prompting a massive bleaching episode and the death of countless corals, and an explosion of coral-eating crown-of-thorns starfish।

“Unfortunately, Apo is plagued by millions of these starfish, probably due to a lack of natural predators like the giant triton, napoleon wrasse and harlequin shrimp,” said Gregg Yan of WWF-Philippines. “We hope that the ban will ensure protection of these predators and the many other reef species.”
WWF has been working towards sustainable coastal practices for the Apo Reef Natural Park since 2003. The marine park will be opened for tourists to help generate funds for its protection, as well as provide an alternative livelihood for hundreds of fishermen in the area.
Note: This story has been adapted from material provided by World Wildlife Fund.

Killing Only A Few Animals Won't Do Any Harm. Or Will It?

Sometimes killing even a few individuals can have dramatic consequences, causing populations to fluctuate wildly। The regulation of populations is usually determined by the properties of one specific size class of individuals. When such a crucial size class is the target of mortality, unexpected things may happen. In harvested cannibalistic fish populations, individuals may reach "giant" sizes, more than double the size of those in unharvested population in heavily fished lakes.

Using advanced mathematical modeling, researchers from Sweden and The Netherlands show in an article in the August issue of the American Naturalist that this statement is sometimes true. Sometimes though, killing even a few individuals can have dramatic consequences, causing populations to fluctuate wildly. "The important question is: who gets killed" The effects of killing individuals crucially depend on the size of the victims," says Tobias van Kooten, assistant professor at Umeå University in Sweden.
The regulation of populations is usually determined by the properties of one specific size class of individuals. In some species, this "crucial stage" consists of small individuals that can monopolize the available food, denying it to all other individuals.Alternatively, especially in fish populations, large individuals can limit the abundance of smaller individuals through cannibalism. It is when such a crucial size class is the target of mortality that unexpected things may happen.
Van Kooten and co-workers predict for example that in harvested cannibalistic fish populations, individuals may reach "giant" sizes, more than double the size of those in unharvested population। Indeed, such "giant cannibals" seem to occur frequently in heavily fished lakes। "Our results are directly applicable to conservation and management, since almost all human-induced mortality is size-selective," van Kooten states. "Fishermen select gear to catch large fish, while deer hunters prefer the tender meat of calves."

Unexpected effects of mortality have been reported before, but this systematic study, to be published in The American Naturalist, unravels the mechanisms behind the effects. Such "deep" understanding makes it possible to predict effects of size-dependent mortality for a wide range of species.
Reference: Tobias van Kooten, Lennart Persson, and André M. de Roos, "Size-dependent mortality induces life history changes mediated through population dynamical feedbacks" The American Naturalist (2007) 170:258--270. DOI: 10.1086/518947
Note: This story has been adapted from a news release issued by University of Chicago Press Journals.

Game fishing Sustainability

NSW Department of Primary Industries (DPI) fisheries scientists are investigating ways to boost the survival rates of several more species of fish caught and then released by anglers।

Some guidelines designed to improve fish survival were recently developed for released line-caught snapper, silver trevally, mulloway, sand whiting, yellowfin bream and dusky flathead.
The research, costing more than $1.5 million and funded by NSW DPI and the Recreational Fishing Trust (using money from licence fees), is developing protocols designed to maximise fish survival via subtle changes to management practices.
Owing to bag limits, legal sizes and non-consumptive angling, between 30 and 50% of the total recreational catch is released each year in Australia. This amounts to more than 47 million fish being caught and released annually.
New research is now seeking to maximise the post-release survival of other commonly-caught species including luderick, sand mullet, garfish, tailor, Australian bass, Murray cod and golden perch.
NSW DPI scientists Matt Broadhurst and Paul Butcher have shown that mortality rates can be significantly improved through changed practices.
Key recommendations from an initial two-year project are that fishers should:
Cut the line on fish that swallow hooks
Remove hooks caught in the fish’s mouth
Minimise air exposure
Use landing nets without knotted mesh
Maintain water quality in on-boat holding tanks, and
Use the right rig for the fish species being targeting.
Dr Broadhurst said some of these actions were found to massively boost fish survival.
“Simply cutting the line rather than attempting to remove hooks swallowed by mulloway and yellowfin bream increased their survival from 12 percent to more than 85 percent.
“Up to 76 percent of the released line-cut, gut-hooked yellowfin bream then shed their hooks over an average of three weeks”, he said।Note: This story has been adapted from a news release issued by New South Wales Department of Primary Industries.

Fish Growth Changes Enhanced By Climate Change

Changes in growth rates in some coastal and long-lived deep-ocean fish species in the south west Pacific are consistent with shifts in wind systems and water temperatures, according to new Australian research।

“We have drawn correlations between the growth of fish species related to their environmental conditions – faster growth in waters above a depth of 250 metres and slower rates of growth below 1,000 metres,” says lead author, Dr Ron Thresher.
“These observations suggest that global climate change has enhanced some elements of productivity of shallow-water stocks but at the same time reduced the productivity and possibly the resilience of deep water stocks,” he says.
A biological oceanographer with CSIRO’s Wealth from Oceans Research Flagship, Dr Thresher said the research – published in the latest edition of the US science journal, Proceedings of the National Academy of Sciences – is based on the examination of fish earbones, or otoliths, which show similar characteristics to the growth rings used to date the age of trees. The work was done in collaboration with the Victorian Marine and Aquatic Fisheries Research Institute, which has specialist skills in analysing otoliths.
Water temperatures have been obtained from a 60-year-long record at Maria Island on the Tasmanian east coast, and using 400-year-old deep-ocean corals to measure temperate at depth.
Dr Thresher said populations of large marine species are widely subject to two major stressors – commercial fishing and climate change. Heavy exploitation increases the sensitivity of species to environmental effects and could be magnifying the effects of long-term climate change and short-term climate variability on the viability of some species.
“Dr Thresher said slower growth in fishes has been correlated with a variety of life history traits – from higher mortality to reduced food availability and increased age or smaller size at sexual maturity.”
He said correlations for long-lived shallow and deep-water species suggest that water temperatures have been a primary factor in determining juvenile growth rates in the species examined – Banded morwong, redfish, Jackass Morwong, Spiky, black, smooth and Warty Oreo and Orange roughy. Because of the pervasive effect of temperature on the physiology and growth of marine animals, it was likely that similar effects would be seen in many other species.
The science team examined 555 specimens ranging in age from two to 128 years, with birth years from 1861 to 1993. Growth rates of a coastal species, juvenile morwong, in the 1990s were 28.5 per cent faster than at the beginning of the period under assessment in the mid-1950s. By comparison, juvenile oreos, a species found at depths of around 1,000 metres, were growing 27.9 per cent slower than in the 1860s. There was no or little change in the growth rates of species found between 500 and 1,000 metres.
Growth rates of the juveniles of the deep-water species all began decreasing well before the onset of commercial fishing. Dr Thresher said slower growth in fishes has been correlated with a variety of life history traits – from higher mortality to reduced food availability and increased age or smaller size at sexual maturity.
He said comparisons of historical and modern oceanographic data indicate temperature trends very similar to the apparent changes in growth rates. In the south west Pacific east of Tasmania sea surface temperatures have risen nearly two degrees, based on the results of a monitoring program at Maria Island. Coinciding with this has been a southward shift in South Pacific zonal winds which has strengthened the warm, poleward-flowing East Australian Current.
“Modelling suggests that, with increasing global warming, temperatures at intermediate depths are likely to rise near-globally,” Dr Thresher said. “This could mean that over the course of time, the decrease in growth rates for the deep-water species could slow or even be reversed,” Dr Thresher said.
Article: Depth-mediated reversal of the effects of climate change on long-term growth rates of exploited marine fish, was authored by Dr Thresher, Dr Tony Koslow, now of the Scripps Institute of Oceanography, Dr A.K. Morison, now at the Bureau of Resource Sciences, and Dr David Smith, now of CSIRO.
Note: This story has been adapted from a news release issued by CSIRO Australia.

Ocean Fisheries Maxed Out

BROOKLIN, Canada, Mar 5 (IPS) - Two-thirds of fish stocks in the world's high seas are overfished, while most of those closer to shore are failing or fished to the maximum, a new U.N. report said Monday. More and stronger regional fisheries management organisations are needed to rebuild depleted stocks and prevent the collapse of other stocks, warned the FAO's latest "State of World Fisheries and Aquaculture" (SOFIA) report. Ocean fisheries have "most likely" reached their zenith, said FAO Assistant Director-General for Fisheries Ichiro Nomura. In fact, that peak may have been reached some time ago. The annual world fish catch since the late 1980s has been stalled at between 85 million and 95 million tonnes. The SOFIA 2006 report records marine fisheries catch at 85.8 millions tonnes and notes that 25 percent of marine stocks are overexploited or depleted while 52 percent are "fully exploited". Full story at

The rape of Tubbataha Reef

There is one thing that sets us apart as a winner among our globalneighbors. We may be losing out on economic gains, on political maturity andon being a choice destination for tourists and investors, but we undoubtedlyhave the richest and most diverse marine life in the world. There is,however, something here that scares me. We are a people prone to shootingour own feet. How much longer can we hang on to the one remaining asset wehave, which our neighbors in the region lust after? Just before Christmas, particularly on Dec. 21, a Chinese fishing vesselwith 30 Chinese fishermen on board were caught red-handed poaching or takingrare and endangered species of fish in our area of jurisdiction, just 1.5miles from the Tubbataha Reef which was declared by no less than UnitedNations as a World Heritage Site. Tubbataha's reef form the core of theSulu-Sulawesi Marine Eco-Region, hailed as one of the world's mostproductive ecosystems. The 30 Chinese poachers were caught with tons of high-value fish including359 napoleon wrasses-locally known as mameng-an endangered species, as wellas groupers and other rare fish varieties. The collection, possession,transport or trade of the napoleon wrasse is illegal and carries with it afine of $2,400 for each fish as well as a prison term of up to 20 years. Thewrasse is prized as a delicacy and may sell for as much as $100 for everykilogram. Of the fishes poached, 59 napoleon wrasses and a large number ofother varieties have died as they were kept in dark holding tanks in thevessel with no food to nourish them. The Bureau of Fisheries and AquaticResources in Puerto Princesa is now temporarily holding the fish in sea pensto nourish them back to health before they are released back to the reefs.

Fish Follow Their Noses Back to Tropical Reefs

WASHINGTON - Baby tropical fish, drifting at the mercy of ocean currents,
probably follow their noses back to their home reefs when they grow large
enough to swim, researchers said on Monday.

Fish that dwell on Australia's Great Barrier Reef generally like to stick
close to home, where they know where to find food and hide from predators.

But in their first few weeks of life, lacking the ability to swim, larval
fish can drift up to 20 miles (30 km) from where they were born. They likely
rely on their sense of smell to make their way back home, according to
scientists at the Marine Biological Laboratory in Woods Hole, Massachusetts.

Much as subway riders look for signs to make sure they are on the right
train, the fish use smell to find an ocean current, several of the
facility's biologists found.

"Fish have as good a nose as anybody," said Jelle Atema, a professor at
Boston University and Woods Hole who took part in the research. "You think
of dogs and rats as super smellers but eels and catfish and hammerhead
sharks are at least as good."

Full story at