What’s Killing Farmed Salmon? New Virus May Also Pose Risk to Wild Salmon

Farmed fish are an increasingly important food source, with a global harvest now at 110 million tons and growing at more than 8 percent a year. But epidemics of infectious disease threaten this vital industry, including one of its most popular products: farmed Atlantic salmon. Perhaps even more worrisome: these infections can spread to wild fish coming in close proximity to marine pens and fish escaping from them.

Heart and skeletal muscle inflammation (HSMI), an often fatal disease, was first detected in salmon on a farm in Norway in 1999, and has now been reported in 417 fish farms in Norway as well as in the United Kingdom. The disease destroys heart and muscle tissue and kills up to 20 percent of infected fish. Although studies have indicated an infectious basis, recent efforts to identify the pathogen causing the disease have been unsuccessful. Now, using cutting-edge molecular techniques, an international team led by W. Ian Lipkin, MD, the John Snow Professor of Epidemiology and director of the Center for Infection and Immunity at Columbia University's Mailman School of Public Health, has found evidence that the disease may be caused by a previously unknown virus. The newly identified virus is related but distinct from previously known reoviruses, which are double-stranded RNA viruses that infect a wide range of vertebrates.

The full study findings are published online in the publication PLoS ONE.

"Our data provide compelling evidence that HSMI is associated with infection with a new reovirus," says Gustavo Palacios, first author of the study and assistant professor of Epidemiology in the Center.

"While there is no evidence that this could spread to humans, it is a threat to aquaculture and it has the potential to spread to wild salmon," added Dr. Lipkin.

To identify the virus, the Columbia University investigators used 454 high throughput DNA sequencing and bioinformatics, including a new tool called Frequency Analysis of Sequence Data (FASD), pioneered by Raul Rabadan of Columbia's Department of Biomedical Informatics. Investigators in Norway and the U.S. then looked for viral sequences in heart and kidney samples from 29 salmon representing three different HSMI outbreaks and 10 samples from healthy farmed fish. Twenty-eight of the 29 (96.5%) known HSMI samples and none of the 10 healthy salmon samples were positive. The investigators also tested 66 samples obtained from wild salmon living in nine coastal rivers in Norway. The virus was detected in sixteen of these samples (24.2%), though generally in lower concentrations than found in ailing farmed fish.

"The speed of this process, and the enthusiasm on both sides of the Atlantic created a very fruitful collaboration," says Espen Rimstad, a professor at the Norwegian School of Veterinary Science in Oslo. "Using the expertise of our colleagues at Columbia in high throughput sequencing and advanced bioinformatics, we had within a few weeks the whole genome sequence of a hitherto unknown virus."

Additional research will be needed to confirm that the reovirus is the cause of HSMI. Meanwhile work has already begun in Norway to develop a vaccine to protect farmed Atlantic salmon. Columbia University's Mailman School of Public Health (2010, July 12). What’s killing farmed salmon? New virus may also pose risk to wild salmon. ScienceDaily. Retrieved July 13, 2010, from http://www.sciencedaily.com­ /releases/2010/07/100709210823.htm

Impacts of Chilean Salmon Farms on Coastal Ecosystem Discovered Accidentally

Until recently, the disastrous scale of the threat posed by salmon farms to the fauna and National Park of the Aysén region of southern Chile was entirely unknown. The unexpected discovery was made by researchers from the Max Planck Institute for Dynamics and Self-Organization and the University of Göttingen, who were studying acoustic communication among the native whales in the region. The researchers not only discovered that the salmon industry is rapidly spreading to the hitherto largely unspoiled south of the region; they also documented the previously unknown threat to the region's native sea lions.

International environmental organisations have expressed their surprise at this accidental discovery.

The Göttingen researchers report their observations in the "Correspondence" section of the current edition of the journal Nature.

With an export volume in excess of two billion US dollars, Chile is one of the world's main producers of farmed salmon. The aquaculture, which is carried out on a massive scale, is mainly concentrated on the ramified fjords of the province of Aysén in Patagonia. While parts of the province are classified as a National Park, the protection does not extend to the surrounding sea. The salmon farms, which are entirely legal from the government's perspective, have, in part, devastating impacts on the region's entire ecosystem -- not least because Atlantic salmon is an alien species in Chile, introduces diseases and therefore poses an additional risk to already threatened native species. Moreover, the use of medication on the farms and the waste they produce also burden the ecosystem.

The ISA (infectious salmon anaemia) virus, which causes anaemia and death in salmon, has forced many aquaculture operators to close down their farms in northern Chile in recent years. "The farms, however, are now spreading further south," reports Heike Vester from the Norwegian research institute Ocean Sounds, who is currently completing her doctorate at the Max Planck Institute for Dynamics and Self-Organization and the University of Göttingen. Because the region's ramified fjords are difficult to access from land, the full scale of the impact of this development only became clear to her when she was carrying out research from the water. Vester's photographs document, among other things, the threat posed to the South American sea lion. The animals get caught in the protective nets surrounding the salmon farms when young and, even if they manage to free themselves, parts of the nets often remain stuck to the sea lions and suffocate them as they grow (Image 1).

The salmon farms also incur other negative effects on the ecosystem: large volumes of excess feed for the farmed fish and their faeces can be seen floating in the water, and the crowded conditions under which the salmon are kept necessitate the use of medication and pesticides. Measurements taken by other participants in the Göttingen researcher's expedition prove that no forms of life now exist in direct proximity to the farms. "The air there smells like bleach," says Vester.

Acoustic measurements carried out in the field by the biologist also reveal the existence of another invisible threat: the ships that supply the farms and the generators of the feeding machines generate constant noise. "This noise can drive the threatened marine mammals, for example blue, humpback and sei whales and Peale's dolphins and Chilean dolphins, away and disrupt their communication in the ramified fjords and channels," explains Marc Timme from the Max Planck Institute for Dynamics and Self-Organization, who is co-supervising Heike Vester's doctoral thesis.

The north of the province of Aysén, where many salmon farms were shut down and abandoned due to the virus, also presents a bleak picture. "The diseased fish were obviously not disposed of properly and, in some cases, simply sunk in the water in plastic bags," reports Vester. Her photographs show discarded, dead and partly eaten salmon. "It would appear that this is how the virus managed to enter the ecosystem," concludes the biologist. It is not possible to quantify the effects of this infestation on the native flora and fauna.

In their report published in the journal Nature, the Göttingen researchers suggest that the salmon industry, local fishermen and environmental protection organisations join forces in seeking a solution to this problem. A joint approach of this kind has already been tested in countries like Italy, Australia and the USA. The aim must be to ensure that, in addition to those of the salmon farms, the rights of the local fishermen and the environment are asserted. This is the only way that sustainable tourism can be established as a new sector with good prospects in the region.

The Max Planck Institute for Dynamics and Self-Organization in Göttingen researches complex systems from very wide-ranging areas in physics, information technology and biology. Heike Vester's research project involves the study of the complex communication between social whales, such as pilot and killer whales. As part of her study, the biologist has collected and compared sound recordings and behavioural studies from northern Norway and southern Chile with a view to identifying variations in the sound patterns of the two geographically divided populations. The aim of the study is to gain a better understanding of the composition and structure of the sounds and their use. This could contribute to the identification of important steps in the evolution and development of the formation of sounds by these animals. Heike Vester has visited Chile every year since 2008 on the invitation of the Chilean Center for Scientific Tourism to study how sustainable tourism could be developed there. Max-Planck-Gesellschaft (2010, June 23). Impacts of Chilean salmon farms on coastal ecosystem discovered accidentally.ScienceDaily. Retrieved June 25, 2010, from http://www.sciencedaily.com/releases/2010/06/100622112558.htm

New System Helps Explain Salmon Migration

A new acoustic telemetry system tracks the migration of juvenile salmon using one-tenth as many fish as comparable methods, suggests a paper published in the January edition of the American Fisheries Society journal Fisheries. The paper also explains how the system is best suited for deep, fast-moving rivers and can detect fish movement in more places than other tracking methods.

The Juvenile Salmon Acoustic Telemetry System (JSATS) estimated the survival of young, ocean-bound salmon more precisely than the widely used Passive Integrated Transponder (PIT) tags during a 2008 study on the Columbia and Snake rivers, according to the results of a case study discussed in the paper. The paper also concludes that fish behavior is affected least by light-weight JSATS tags compared to larger acoustic tags.
"Fisheries managers and researchers have many technologies to choose from when they study fish migration and survival," said lead author Geoff McMichael of the Department of Energy's Pacific Northwest National Laboratory.
"JSATS was specifically designed to understand juvenile salmon passage and survival through the swift currents and noisy hydroelectric dams on the Columbia River," McMichael continued. "But other systems might work better in different circumstances. This paper demonstrates JSATS' strengths and helps researchers weigh the pros and cons of the different fish tracking methods available today."
Scientists at PNNL and the U.S. Army Corps of Engineers' Portland District co-authored the paper. PNNL and NOAA Fisheries began developing JSATS for the Corps in 2001.
JSATS is an acoustic telemetry system that includes the smallest available acoustic transmitting tag, which weighs 0.43 grams. Its battery-powered tags are surgically implanted into juvenile salmon and send a uniquely coded signal every few seconds. Receivers are strategically placed in waterways to record the signal and track when and where tagged fish travel. A computer system also calculates the precise 3-D position of tagged fish using data gathered by the receivers.
PIT tags are also implanted into juvenile salmon for migration and survival studies, but don't use batteries to actively transmit signals. Instead, PIT tags send signals when they become energized while passing by PIT transceiver antennas.
For the paper's case study, researchers implanted 4,140 juvenile Chinook salmon with both JSATS and PIT tags. They also placed just PIT tags inside another 48,433 juveniles. All of the case study's tagged fish were released downstream of Lower Granite Dam on the Snake River in April and May 2008.
A significantly greater percentage of JSATS tags were detected than PIT tags, the case study demonstrated. For example, about 98 percent of JSATS-tagged fish were detected at Ice Harbor Dam on the Snake River. About 13 percent of PIT-tagged fish were detected in the same stretch of river. As a result, studies using JSATS require using roughly one-tenth as many fish as those employing PIT tags, which helps further conserve the salmon population.
Survival estimates were similar between JSATS and PIT tags. Forty-eight percent of the JSATS-tagged fish were estimated to have survived migration between Lower Granite Dam and Bonneville Dam, which is the last dam on the Columbia before the Pacific Ocean. For PIT-tagged fish, 43 percent were estimated to have reached the same area.
Having flexibility in where receivers can be placed is advantageous, the authors reported. JSATS receivers can be located in both rivers and dams, while PIT antennas usually can only go inside fish bypasses at dams. Researchers can estimate fish survival for an entire river system when receivers are placed in more locations, the paper explains.
The team also compared JSATS' technical features with those of another acoustic telemetry system, the VEMCO system being used for the Pacific Ocean Shelf Tracking (POST) project along North America's West Coast. The VEMCO system is best suited for use in the slow-moving, open ocean when observing small numbers of large fish, the authors wrote. In contrast, JSATS was developed to study the migration of larger quantities of small juvenile fish in fast-moving rivers.
A key difference between the JSATS and VEMCO systems is dry tag weight. JSATS tags weigh 0.43 grams and are the smallest acoustic tags available. VEMCO tags that have been used in Columbia River juvenile salmon weighed 3.1 grams. Previous research shows fish can bear a tag that weighs up to 6.7 percent of their body weight without significant adverse survival effects. That means JSATS tags can be implanted into fish as light as 6.5 grams, while VEMCO tags should be used in fish that weigh no less than 46.3 grams.
Another advantage of JSATS is that it is non-proprietary and available for anyone to manufacture or use. Because several companies have been able to competitively bid for the opportunity to produce the system's components, its cost has dropped in recent years. JSATS tags, for example, have gone from $300 per tag in 2005 to $215 in 2008. And JSATS tags cost $40 to $135 less than other commercially available acoustic tags in 2008. Proprietary interests have hindered the development of acoustic telemetry equipment in certain areas, the team wrote.
"JSATS has helped us get a clearer, more complete picture of how salmon migrate and survive through the Columbia and Snake rivers to the Pacific Ocean," McMichael said. "But we're continuing to develop JSATS and hope others will find it useful in studies of other aquatic animals. There's an opportunity for all aquatic telemetry technologies to be improved."

Poor Sacramento River salmon runs a bad sign for Oregon's fishing fleet

What remains of the Oregon coast's salmon fishing fleet is largely dependent on chinook salmon that are born and spawn in California's Sacramento River but mature in the ocean.

Poor runs in the Sacramento have led to the repeated shutdown of the salmon fishing here, and the signs are pointing to another nonexistent commercial fishing season this year.
The Sacramento Bee's Matt Weiser reported this week on the state of the fall chinook runs in the Sacramento River:

The run as a whole seems likely to turn out the same or slightly smaller than in 2008, which was the smallest year ever recorded.

"We are really upset," said Dick Pool, president of Pro-Troll Fishing Products, a Bay Area manufacturer of salmon fishing tackle. "Every appearance is the fall run returns this year (2009) may set a new record low."

Weiser reports the cause of the poor runs is two-fold: poor ocean conditions, and environmental degradation and water withdrawals for irrigation in the Sacramento-San Joaquin Delta.

Those poor returns contrast with relatively strong runs in the Columbia Basin and on coastal river further north.

The fishing seasons are set by the Pacific Fisheries Management Council.

Weiser's article goes on to say that the fall chinook run could eventually be listed under the Endangered Species Act, leading to further fishing and farming restrictions.

In a related story in Redding's Record Searchlight, Dylan Darling reports on the effect the disappointing run is having on the system's biggest salmon-producing hatchery:

Normally, the hatchery's biologists choose the biggest, strongest and healthiest fish to supply eggs and sperm for the following spring's young.
This year, Darling reported, they aren't being so picky.

Roe of Marine Animals Is Best Natural Source of Omega-3

The roe of hake, lumpsucker and salmon is the best dietary source of Omega 3, according to a study carried out by researchers at the University of Almería (UAL). The scientists analysed the eggs, or roe, of 15 marine animals, and found all of these contained high levels of these fatty acids, which are essential to the human body.

Until now there had been no precise understanding of the nutritional potential of the roe of marine animals, but a team of researchers from the UAL has now shown that this is one of the best natural sources of Omega 3 fatty acids, which are essential for ensuring the correct development of a wide variety of metabolic functions in the human body.

"We have classified these eggs as unequivocal sources of Omega 3, and have proven that this appears at high concentrations in all the species studies," José Luis Guil Guerrero, director of this study and a researcher in the Food Technology Department of the UAL, said.

The results, published in the European Journal of Lipid Science and Technology, show that Omega 3 fatty acids are present in all fish roe, but especially in the eggs of Atlantic bonito (Sarda sarda), mackerel (Scomber scombrus), squid (Loligo vulgaris), cuttlefish (Sepia sp.), lumpsucker (Cyclopterus lumpus), hake (Merluccius merluccius) and salmon (Salmo salar).

The team studied the fatty acid content in the eggs of 15 marine animals, focusing their research on two types of Omega 3 -- eicosapentaenoic acids (EPA) and docosahexaenoic acids (DHA). More than 30% of the fatty acids found in these eggs were EPA and DHA.

The conclusions of the study also show that minimal consumption of lumpsucker, hake or salmon roe satisfies the human body's Omega 3 essential fatty acid requirements, because of its levels of EPA y DHA. A lack of these compounds is associated with cardiovascular disease, hypertension, depression, diabetes, poor development of the nervous and reproductive systems, and inflammatory diseases, such as Crohn's disease.

"Aside from their nutritional importance, we could also make use of roe to extract its oil, which is rich in PUFAs (polyunsaturated fatty acids) and can be used as a dietary supplement, since it has a higher Omega 3 content than regular oils, for example salmon and tuna oil," explains Guil Guerrero.

Hatchery-Raised Salmon Too Crowded

Every year, large numbers of hatchery-raised young salmonids are released into Swedish rivers and streams to compensate for losses in natural production. Butthese fish generally survive poorly in the wild.. Researchers at the University of Gothenburg have discovered why: the young fish are too crowded at the hatchery.

Raised fish face problems

Salmonids constitute an important natural resource in Scandinavia. Large amounts of young salmon , smolts, are therefore released into rivers and streams. However, conventionally raised fish seem to have problems adapting to their natural environment. The reason for this has not been clear, but researchers at the University of Gothenburg have recently been able to show that one key factor is that the young fish do not get their due personal space at the hatcheries.

Increased survival

Sofia Brockmark, researcher at the Department of Zoology, has studied how the hatchery environment can be improved to increase the survival of the released fish. Her thesis, which will be publicly defended on 18 December, shows that young salmon fish that are less crowded in the hatchery manage the transition more successfully. 'The combination of high density and lots of food affects their development. Our experiments show that salmon fish raised in a more spacious environment, meaning it is more similar to nature, are better at adapting to life in rivers and streams,' says Brockmark.

Millions to salmon research

The research will now be developed further in the SMOLTPRO project, which recently received 20 million SEK from the Swedish Research Council Formas. The project is led by Professor Jörgen Johnsson at the Department of Zoology and is coordinated from the University of Gothenburg, and involves researchers from Sweden, Denmark, Norway and Canada.

Natural hatching

The researchers will use full-scale models in the different climate zones in the Baltic Sea, the Kattegat and the North Sea to investigate the effects of different modifications of the hatchery environment. In addition to experimenting with density, the team is striving to make the hatching environment more natural: 'Today, salmon eggs are put in crates. Our research suggests that the presence of structures on the bottom, such as rocks, stimulates brain development in young salmon,' says Johnsson.

Sustainable practices

An additional hypothesis is that hatchery-raised salmon are fed too much and that their diet is too high in fat. This may make them too fat to be able to adjust successfully. The results of the project will, following a dialogue with several public actors, be used to develop new recommendations on how to make the production of hatchery-raised smolts more ecologically sustainable and ethical. The project is directly linked to the strategic efforts of Formas and the Swedish Government to develop aquaculture practices and attain sustainable management of natural resources.

The Swedish Research Council Formas is now granting 20 million SEK to a Swedish/Nordic research project. The goal is to find out how the hatcheries can be made more effective. Adapted from materials provided by University of Gothenburg.

Forty Years of Farmed Salmon and One Genetic Mystery

It's known that escaped fish from Norwegian salmon farms can interbreed with wild salmon, and thus must have changed the genetic and physical makeup of the country's famed wild salmon stocks. But how much? Biologists at the Norwegian University of Science and Technology (NTNU) are trying to answer this question by breeding special fish families to determine the exact genetic differences between farmed and wild salmon stocks.

Scientists at the Norwegian University of Science and Technology are trying to determine the genetic differences between farmed and wild salmon -- and the effects of those differences -- as a way to help protect the country's unique wild salmon stocks.

Beginning in 1971, aquaculture researchers combed 40 of Norway's best wild salmon rivers to find the soundest genetic stock they could. These fish, selected for their ability to grow rapidly and use food efficiently, formed the breeding lines for Norway's wildly successful salmon aquaculture industry. Nearly 40 years and 10 salmon generations later, the industry has grown by a factor of more than 600, and had a turnover of roughly $3 billion US in 2007.

But producing more than 170 million farmed salmon results in at least some escapees -- according to Statistics Norway, the official government statistics office, roughly 450,000 farmed salmon and trout escaped from Norwegian fish farms in 2007. In comparison, an estimated 470,000 wild Atlantic salmon approached the Norwegian coast in 2007 to spawn in one of Norway's salmon rivers. It's known that escaped farmed fish can interbreed with wild salmon, and thus must have changed the genetic and physical makeup of today's wild salmon stocks. But how much? Biologists at the Norwegian University of Science and Technology (NTNU) are trying to answer this question by breeding special fish families to determine the exact genetic differences between farmed and wild salmon stocks.

130 different salmon "families"

Led by Ole Kristian Berg and Sigurd Einum, professors at NTNU's Department of Biology, researchers including have established 130 different salmon "families," where the father's contribution comes from sperm taken from Norway's first generation of farmed salmon (stored in a sperm bank), and the mother comes from a selection of Norwegian salmon rivers as well as from farmed stock.

The result is a combination of specially bred fish that can be compared to today's stocks of wild fish. When the specially bred fish are five centimeters long, they will have grown enough so that their physical characteristics, as well as their genetic makeup, can be compared to wild salmon of today.

Wild salmon under siege

Norway is home to the world's most genetically varied wild salmon stocks on the planet, with genetically distinct groups found in the country's 452 different wild salmon rivers. But since 1970, wild salmon stocks have been reduced by roughly 80 per cent. Fully 10 percent of the country's salmon rivers have lost their populations, with another 32 rivers severely threatened because of the effects of hydropower development, acid rain, sea lice and the invasion of the parasite Gyrodactylus salaris.

In 2008, scientists from the Norwegian Institute for Nature Research, a government research institute, determined that fully 35 per cent of all salmon in the Surna River, one of Norway's most important wild salmon rivers, were in fact farmed fish "That is very high for such a big salmon river," says Kjetil Hindar, a senior researcher at NINA.

"In rivers that have been affected by diseases or by parasites like Gyrodactylus, wild salmon stocks are weakened and are particularly vulnerable," says NTNU's Berg. "It is easy for these stocks to be affected by wild salmon whose genes have been diluted by farmed fish."

Adapted from materials provided by The Norwegian University of Science and Technology (NTNU), viaAlphaGalileo

Global Study of Salmon Shows: 'Sustainable' Food Isn't So Sustainable

Popular thinking about how to improve food systems for the better often misses the point, according to the results of a three-year global study of salmon production systems. Rather than pushing for organic or land-based production, or worrying about simple metrics such as "food miles," the study finds that the world can achieve greater environmental benefits by focusing on improvements to key aspects of production and distribution.

For example, what farmed salmon are fed, how wild salmon are caught and the choice to buy frozen over fresh matters more than organic vs. conventional or wild vs. farmed when considering global scale environmental impacts such as climate change, ozone depletion, loss of critical habitat, and ocean acidification.
The study is the world's first comprehensive global-scale look at a major food commodity from a full life cycle perspective, and the researchers examined everything -- how salmon are caught in the wild, what they're fed when farmed, how they're transported, how they're consumed, and how all of this contributes to both environmental degradation and socioeconomic benefits.
The researchers behind the study sought to understand how the world can develop truly sustainable food systems through the lens of understanding the complexities associated with wild and farmed salmon production, processing and distribution. They found that decision-making for food must learn to fully account for the life cycle socioeconomic and environmental costs of food production. How we weight the importance of such impacts is ultimately subjective and in the realm of policy and culture, but using a comprehensive approach provides a more nuanced process for informed decision-making. Even food has a lifecycle, and the world must learn to comprehend the full costs of it in order to design reliable, resilient food systems to feed a world population that's forecast to grow to 9 billion in less than 40 years.
The researchers chose salmon as their focus as it exemplifies important characteristics of modern food systems, yet offers unique opportunities for comparison. It is available around the world at any time and in any location, regardless of season or local ecosystem, it is available in numerous product forms, and it is distributed using a variety of transport modes. Unlike many other food systems, however, it is available from both wild sources and a range of farmed production systems.
While it isn't easy to balance people, profit and planet, the world must do much better. Food production, in aggregate, is the single largest source of environmental degradation globally. Impacts vary dramatically depending on what, where and how food is produced. For example, early results of the study found that growing salmon in land-based farms can increase total greenhouse gas emissions ten-fold over conventional farming depending on how and where the farming is conducted. Similarly, while organic farming of many crops offers benefits over conventional production, organic salmon production gives rise to impacts very similar to conventional farming due to the use of resource intensive fish meals and oils. Beyond the farm, it's important to also consider the total impact of food preparation. Driving to the store alone and then cooking alone at home has a big environmental impact. Going out to dinner more, or just eating more frequently with friends and family at home, has huge benefit.
For concerned consumers, it's important to think about how food was produced and transported -- not just where it was produced -- when making food choices.
Initial Findings from the Study (More Due with the Final Report in 2010):
Fish should swim, not fly. Air-freighting salmon, and any food, results in substantial increases in environmental impacts. If more frozen food were consumed, more container ships would be used to ship food. Container ships are by far the most efficient and carbon-friendly way to transport food. Globally, the majority of salmon fillets are currently consumed fresh and never frozen. In fish-loving Japan, which gets much of its fish by air, switching to 75 percent frozen salmon would have more benefit than all of Europe eating locally farmed salmon.
The choice to buy frozen matters more than organic vs. conventional or wild vs. farmed.
A full life cycle assessment approach to research provides a more nuanced process for informed decision-making. Even food has a lifecycle, and we must comprehend the full impact to make meaningful improvements to food systems. Tradeoffs may be inevitable.
Contrary to what is widely perceived, the vast majority of broad-scale resource use and environmental impacts (energy inputs, GHG emissions, etc) from conventional salmon farming result from the feeds used to produce them. What happens at or around a farm site may be important for local ecological reasons but contributes very little to global scale concerns such as global warming.
Across the globe, what is used to feed salmon and the amounts of feeds used vary widely. As a result, impacts are very different. Norwegian salmon farming resulted in generally lower overall impacts while farmed salmon production in the UK resulted in the greatest impacts.
Reducing the amount of animal-derived inputs to feeds (e.g. fish meals and oils along with livestock derived meals) in favor of plant-based feed inputs can markedly reduce environmental impacts.
Growing organic salmon using fish meals and oils from very resource intensive fisheries results in impacts very similar to conventional farmed salmon production.
If not planned carefully, technological fixes aimed at addressing local environmental challenges associated with conventional salmon farming can result in substantial increases in global-scale environmental impacts. In general, salmon fisheries result in relatively low global-scale environmental impacts. However, substantial differences exist between how salmon are caught. Catching salmon in large nets as they school together has one tenth the impact of catching them in small numbers using baited hooks and lures.
Across salmon production systems -- and all food systems -- the world is often swimming against the tide. Instead of working with nature, people work against it, chasing fish in the open ocean with big diesel engines or substituting energy demanding pumping and water treatment for free ecosystem services in salmon farming. We can and must do better than this and start to swim with the tide.

A different kind of fish toss: Planting dead salmon to enrich a watershed

Humans aren't the only ones who benefit when large runs of salmon return to rivers and streams. Joel Davis/The OregonianThe nutrients and organic matter deposited by salmon carcasses are critical to the health of Pacific Northwest watersheds.For the watersheds of the Pacific Northwest, dead salmon -- rotting, stinky, gross -- provide crucial nutrients to support diverse, complex freshwater environments. Pacific salmon complete almost all of their growth while living in the ocean. When they migrate back to natal streams and die, decomposition releases calcium, phosphorous and nitrogen into the water, enriching streams with nutrients that feed algae, aquatic insects and juvenile salmon. The salmon goodness spreads to plants and wildlife. Studies of some old confer trees growing near rivers have revealed marine nitrogen isotopes that could only have come from rotting salmon. But recent declining salmon runs have raised concerns about the health of watersheds as they lose those nutrients. Researchers believe that nutrient deficiencies -- because of fewer decomposing salmon -- actually hinder the recovery of salmon and steelhead populations. That's where the annual Sandy River Basin Watershed Council "salmon toss" comes in. Thousands of salmon carcasses from the Sandy Fish Hatchery on Cedar Creek are "planted" in and along tributaries of the Sandy River in the late fall. The work is dirty -- organizers joke that they should try out for Discovery Channel's popular "Dirty Jobs" show. But it always draws lots of volunteers. On Saturday, crews from the Oregon Department of Fish and Wildlife and the Mount Hood National Forest will join with about 40 students from Sam Barlow High School to dump fish carcasses near Lost Creek Campground. Sam Barlow teens have helped with the salmon toss the past four years. The six-year-old program aims to increase the production of naturally spawning populations of salmon and steelhead in the Sandy River basin, to increase the production of other native fish, to provide nutritional benefits for plants and wildlife, and to encourage community watershed stewardship.The salmon carcasses come from the Sandy Fish Hatchery. Early in the season, the returning coho salmon were harvested, flash-frozen and donated to the Oregon Food Bank. But later arrivals, often used for the breeding program, have been stored in a 40-foot-long refrigerated trailer to become food for the watershed ecosystem. The salmon have their tails cut off so they aren't included in stream counts of spawning salmon. Volunteers distributed almost 40,000 pounds of salmon carcasses along streams in 2006 and 2007.

Salmon Migration Mystery Explored On Idaho's Clearwater River

Temperature differences and slow-moving water at the confluence of the Clearwater and Snake rivers in Idaho might delay the migration of threatened juvenile salmon and allow them to grow larger before reaching the Pacific Ocean.

A team of Northwest researchers are examining the unusual life cycle of the Clearwater's fall Chinook salmon to find out why some of them spend extra time in the cool Clearwater before braving the warm Snake. The Clearwater averages about 53 degrees Fahrenheit in the summer, while the Snake averages about 71. The confluence is part of the Lower Granite Reservoir -- one of several sections of slow water that are backed up behind lower Snake and Columbia river dams -- that could reduce fish's cues to swim downstream.
The delayed migration could also mean Clearwater salmon are more robust and survive better when they finish their ocean-bound trek, said Billy Connor, a fish biologist with the U.S. Fish & Wildlife Service.
"It may seem counterintuitive, but the stalled migration of some salmon could actually help them survive better," Connor said. "Juvenile salmon may gamble on being able to dodge predators in reservoirs so they can feast on the reservoirs' rich food, which allows them to grow fast. By the time they swim toward the ocean the next spring, they're bigger and more likely to survive predator attacks and dam passage."
Scientists from the U.S. Geological Survey, the U.S. Fish & Wildlife Service, the Department of Energy's Pacific Northwest National Laboratory and the University of Washington are wrapping up field studies this fall to determine if water temperature or speed encourage salmon to overwinter in the confluence and in other reservoirs downstream. The Bonneville Power Administration is funding the research to help understand how Snake and Columbia River dams may affect fish.
USGS and USFWS are tracking fish movement by implanting juveniles with radio tags, which are more effective in shallow water. PNNL is complementing that effort with acoustic tags, which work better in deeper water. PNNL is also contributing its hydrology expertise to measure the Clearwater and Snake rivers' physical conditions. UW is providing the statistical analysis of the tagging.
"Fall Chinook salmon on the Clearwater River have a fascinating early life history that may contribute to their successful return as adults," said PNNL fish biologist Brian Bellgraph. "If we can support the viability of such migration patterns in this salmon subpopulation, we will be one step closer to recovering the larger fall Chinook salmon population in the Snake River Basin."
Scientists used to think all juvenile fall Chinook salmon in the Clearwater River migrated to the ocean during the summer and fall after hatching in the spring. But researchers from USGS, USFWS and the Nez Perce Tribe began learning in the early 1990s that some stick around until the next spring. Similar delays have also been found in a select number of other rivers, but this is still the exception rather than the rule. The Clearwater is unique because a high number -- as much as 80 percent in some years -- of its fall Chinook salmon don't enter the ocean before they're a year old.
To better understand how fish react to the river's physical conditions, scientists are implanting juvenile salmon with the two types of small transmitters that emit different signals. The transmitters -- commonly called tags -- are pencil eraser-sized devices that are surgically implanted into young fish 3.5 to 6 inches in length. Specially designed receivers record the tags' signals, which researchers use to track fish as they swim. The gathered data helps scientists measure how migration is delayed through the confluence.
Radio tags release radio waves, which are ideal to travel through shallow water and air. And acoustic tags emit higher-frequency sounds, or "pings," that more easily move through deeper water. The acoustic tags being used are part of the Juvenile Salmon Acoustic Telemetry System, which PNNL and NOAA Fisheries developed for the U.S. Army Corps of Engineers.
Together, fish tagged with both acoustic and radio transmitters help create a more comprehensive picture of how the river affects fish travel. The location data can also indicate how well fish fare. If a tag's signal stops moving for an extended period, the fish in which it was implanted might have died. Researchers examine the circumstances of each case to determine the fish's fate.
This study is a unique example of how both tag technologies can jointly determine the survival and migration patterns of the relatively small juvenile fall Chinook salmon. The size of transmitters has decreased considerably in recent years; further size reductions would allow researchers to study even smaller fall Chinook salmon. This could provide further insight into this mysterious migration pattern.
Beyond the fish themselves, researchers will also examine water temperature and flow to determine what correlation the river's physical conditions may have with the fish movement. Salmon use water velocity and temperature as cues to guide them toward the ocean. But the Lower Granite Dam's reservoir, which extends about 39 miles upriver from the dam to Lewiston, makes the water in the Clearwater River's mouth move slowly. Researchers suspect the slow water may encourage some fall juvenile Chinook salmon to delay their journey and spend the winter in the confluence.
To test this hypothesis, PNNL scientists take periodic velocity measurements in the confluence from their research boat. Submerged sensors have recorded water temperatures every few minutes between about June and January since 2007. Both sets of information will be combined to create a computational model of the fish's river habitat.
This study's results could be used to modify river water flow to improve fish survival. The Clearwater's Dworshak Dam already helps manage water temperature by strategically releasing cool water toward the Snake. The waters form thermal layers -- with the Snake's warm water on top and the Clearwater's cool liquid below -- that fish move through to regulate their body temperatures.
The Nez Perce Tribe began studying fall Chinook salmon in the lower Clearwater River in 1987. USGS and USFWS joined the effort in 1991, when the Snake River Basin's fall Chinook salmon were first listed under the Endangered Species Act. PNNL and UW joined the study in 2007. The Bonneville Power Administration is paying for the study.
Adapted from materials provided by DOE/Pacific Northwest National Laboratory.

New Chemical Method For Distinguishing Between Farmed And Wild Salmon

Wild salmon and farmed salmon can now be distinguished from each other by a technique that examines the chemistry of their scales.Dr Clive Trueman, who is based at the National Oceanography Centre, Southampton said: "Salmon farming is a big, intensive business. In 2006, around 130,000 tonnes of salmon were farmed in Scotland for the table. Wild populations of Atlantic salmon are in serious decline across their whole range and the total wild population returning to Scottish rivers in the same year is estimated at less than 5000 tonnes. Wild fish are rare and expensive so there is a strong incentive for fraudulent labelling. Farmed fish also escape into rivers, harming the wild population. Unfortunately, it can be difficult to distinguish between farmed and wild fish."The new work which was done in collaboration with the Scottish Association for Marine Science (SAMS), Oban, will help crack this problem.Fish scales are formed from the same chemicals as bones and teeth and grow like tree rings, preserving a chemical record of the water the fish lived in throughout its whole life. Scales are easy to collect, and can be removed from fish without harming them – which is important when studying an endangered population. The team discovered that levels of the trace metal manganese were always much higher in fish of farmed origin."This is probably caused by manganese supplements in fish food, and also because conditions underneath the fish cages promote recycling of manganese in the water column," says Dr Elizabeth Adey from SAMS, lead author on the research.Using relatively simple techniques, the team was able to distinguish between farmed and wild fish with 98% accuracy."Because of its non-destructive nature, this technique could be used to assess the proportion of farm escape salmon present in any river, and therefore identify where additional conservation and wildlife protection measures are needed," says Dr Trueman, a geochemist with the University of Southampton's School of Ocean and Earth Science, based at that National Oceanography Centre.Concern over declining numbers of wild Atlantic salmon has led to the closure of most fisheries, and the growth of salmon farms has been implicated in the decline of the wild fish. In 2000, more than 400,000 fish escaped from farms in Scotland. This is a problem as farmed salmon are not adapted to the local environment, and if they breed with the wild stock, the resulting offspring are less likely to survive to adulthood. In some years, the number of fish that escape from farms in Scotland exceeds the total number of wild fish, and in some Norwegian rivers more than half of all fish are of farmed origin.It is particularly difficult to distinguish between a farm origin and wild origin fish if some time has passed after the fish escaped, and that is why the new method should prove valuable.The team also found differences in the chemistry of scales between fish farms, which might allow researchers to identify individual farms responsible for the release of wild fish – although this would require additional work.The research was supported by the UHI Millennium Institute.Journal reference:Adey et al. Scale microchemistry as a tool to investigate the origin of wild and farmed Salmo salar. Marine Ecology Progress Series, 2009; 390225 DOI: 10.3354/meps08161National Oceanography Centre, Southampton (UK)

Millions of salmon go missing on Canada's Pacific Coast

Millions of sockeye salmon expected to reach the Fraser River on Canada's Pacific Coast this month have vanished, devastating the local fishery, officials said Thursday.According to the Department of Fisheries and Oceans, between six to 10 million sockeye were projected to return to the river this month.But the official count is now just 600,000 for the "summer run" -- by far the largest of four salmon groupings that return to area lakes and rivers each year from June to late August.Where the other fish went remains a mystery.The daily Globe and Mail cited fishermen who said the situation was "shocking," a "catastrophe" and a "crisis," while public broadcaster CBC said this could end up being the worst year ever for the Pacific salmon fishery.A record number of smolts were born in the Fraser watershed in 2005 and migrated to the ocean, and were expected this month to return en masse to spawn."It's a bit of a mystery," Watershed Watch Salmon Society fish biologist Stan Proboszcz told AFP.Officials and ecologists speculated they could have been affected by warmer ocean temperatures, fewer food sources, or more prey.Others suggested juvenile salmon may have contracted sea lice or other infections from some 30 fish farms in the Straight of Georgia as they migrated out to sea.Fisheries officials may have also erred in their complex forecasting calculations, or the fish could just be late arriving, although the latter is very unlikely, said Proboszcz."Honestly, we don't know what happens to them when they go out into the ocean," he said. "There's a myriad of factors that could explain what's going on."Regardless, this outcome is "quite shocking," he said.Department of Fisheries and Oceans spokeswoman Lara Sloan said the Fraser River commercial sockeye fishery has not opened as a result of the drop in fish stocks, and a parallel aboriginal fishery scaled back its catch this season to just five percent of its usual take.Moreover, no recreational fishing has been allowed allowed.Sloan also declined to try to pinpoint the specific reason for the collapse in sockeye salmon stocks."There are a lot of variations in the ocean," she said. "They're all interconnected, so it's impossible to point to one reason for this happening.""So far, they're not coming back in the numbers we expected, but we will continue to look for them," she said.Meanwhile, pink and Chum salmon are still due to arrive around the end of August through October. So far there is no indication they have been affected. Chinook salmon are also returning to spawn in the region, but they have been a "conservation concern" for several years, and their numbers remain low.

Atlantic Salmon returns to Seine

After an absence of nearly a century, Atlantic salmon have returned to France's Seine River, with hundreds swimming past the Eiffel Tower and Notre Dame cathedral this year alone, researchers told AFP.The reappearance of salmon and other species chased from these waters by dams and pollution is all the more remarkable because no efforts have been made to reintroduce them.They came back on their own."There are more and more fish swimming up the Seine," said Bernard Breton, a top official at France's National Federation for Fishing."This year the numbers have exceeded anything we could have imagined: I would not be surprised if we had passed the 1,000 mark," he told AFP by phone.2008 was already a record-breaking year, with at least 260 tallied on a video system in the fish passage of the Poses dam above Rouen, a city roughly half way between Paris and the Atlantic Ocean.Historically, the Seine hosted a flourishing population of salmon, a migratory species that return from the sea between December and June to their freshwater birth place to reproduce.But the construction of dams, and especially the fouling of the Seine with chemical runoff from industry and agriculture along with organic pollution, led to their local extinction sometime between WWI and WWII.Today, Salmo salar, or Atlantic salmon, is listed as a threatened species throughout Europe.Imagine the surprise, then, of the weekend angler who reeled a six-kilo (13-pound) specimen just downstream from Paris at the end of last month.Or the dozing fisherman in Suresnes, also downstream from the city gates, who snagged an even bigger one last October, the first such catch in over seven decades.Salmon are not the only fish in the Seine making a comeback.In 1995, only four species were known to swim its waters -- eels, redeye, bream and carp -- and at least one of these is invasive.Today there are at least 32, according to the water purification authority for the larger Paris region. The lamprey eel, sea trout and shad have all joined salmon in the Seine over the last few years.The reason, say scientists, is simple: cleaner water.In the mid-1990s, "between 300 and 500 tonnes of fish died in the Seine up river from Paris every year because of pollution," said Breton.But massive efforts over the last 15 years, including a new water purification plant, have removed much of the river's pollutants.The results suggest that when it comes to conservation, restoring an ecosystem is probably a better strategy than restocking depleted waters, notes Breton. Scientists at France's National Institute for Agricultural Research who track salmon say it is a "bellwether species", a living indicator of their habitat's state of health. To find out more about how Atlantic salmon are recolonising their ancient river haunt, they recently captured and released seven adults in the Seine. Four had spent less than two years at sea before returning to fresh waters, two had returned in the Spring after two years in open waters, and one had waited three years before leaving the ocean. DNA analysis showed that the fish came from several different rivers, in France and elsewhere in Europe. It also suggested that a new "embryo" population specific to the Seine might be forming, probably southeast of Paris at the headwaters of the Yonne River in the region of Morvan. Atlantic salmon were once abundant throughout the north Atlantic, from Quebec to New England in the west, and from the Arctic Circle to Portugal to the east. But over the last three decades, their populations have plummeted, with commercial catches declining by more than 80 percent. Adults spend most of their lives in small groups roaming vast distances at sea in search of food, mainly squid, shrimp and small fish such as herring. Salmon fast during the arduous, upstream journey to their birth place, where females lay eggs and males fertilise them before dying.

King salmon vanishing in Alaska, smokehouses empty

Yukon River smokehouses should be filled this summer with oil-rich strips of king salmon — long used by Alaska Natives as a high-energy food to get through the long Alaska winters. But they're mostly empty.The kings failed to show up, and not just in the Yukon.One Alaska river after another has been closed to king fishing this summer because significant numbers of fish failed to return to spawn. The dismally weak return follows weak runs last summer and poor runs in 2007, which also resulted in emergency fishing closures."It is going to be a tough winter, no two ways about it," said Leslie Hunter, a 67-year-old store owner and commercial fisherman from the Yup'ik Eskimo village of Marshall in western Alaska.Federal and state fisheries biologists are looking into the mystery.King salmon spend years in the Bering Sea before returning as adults to rivers where they were born to spawn and die. Biologists speculate that the mostly likely cause was a shift in Pacific Ocean currents, but food availability, changing river conditions and predator-prey relationships could be affecting the fish.People living along the Yukon River think they know what is to blame — pollock fishery. The fishery — the nation's largest — removes about 1 million metric tons of pollock each year from the eastern Bering Sea. Its wholesale value is nearly $1 billion.King salmon get caught in the huge pollock trawl nets, and the dead kings are counted and most are thrown back into the ocean. Some are donated to the needy."We do know for a fact that the pollock fishery is slaughtering wholesale and wiping out the king salmon stocks out there that are coming into all the major tributaries," said Nick Andrew Jr., executive director of the Ohagamuit Traditional Council. "The pollock fishery is taking away our way of living."Since 2000, the incidental number of king salmon caught has skyrocketed, reaching over 120,000 kings in 2007. A substantial portion of those fish were bound for western Alaska rivers. If those fish had lived, an estimated 78,000 adult fish would have returned to rivers from the Pacific Northwest to Western Alaska.Efforts to reduce bycatch are not new. In 2006, bycatch rules were adopted allowing the pollock fleet to move from areas where lots of kings were being inadvertently caught, thereby avoiding large-scale fishing closures. Then, 2007 happaned, and it was back to the drawing board.Last April, the North Pacific Fishery Management Council, the organization that manages ocean fish, passed a hard cap on the pollock fishery. Beginning in 2011, the portion of the fleet that participates in the program is allowed 60,000 kings a year. If the cap is reached, the fishery shuts down. Those who don't participate have a lower cap — 47,591 fish.The loss of the kings is devastating village economies. These are the same Yukon River villages where spring floods swept away homes, as well as boats, nets and smokehouses. There's no money to buy anything, Andrew said."It is crippling the economy in all of the rivers where we depend on commercial fishing for income," he said.Bycatch plays a role but is not the only reason for the vanishing kings, said Diana Stram, a fishery management plan coordinator at the council.Herman Savikko, an Alaska Department of Fish and Game biologist, agreed. He pointed to changing ocean currents, plankton blooms and even the carnivorous nature of salmon. River conditions could be changing, too, he said.A lot isn't known about what happens to king salmon in the ocean, Savikko said. "Once the fish enter the marine environment it just is a big black box," he said.In a good year, Kwik'pak Fisheries L.L.C. in Emmonak on the lower Yukon employs between 200 and 300 people. This summer, only about 30 people have been hired. Kwik'pak is the largest employer in the region. General manager Jack Schultheis said when the king fishery was shut down, the summer chum salmon run was curtailed as well, even though a good number of chums were returning to the river. The lower Yukon villages are economically devastated, he said. Fishermen used to get between $5 million and $10 million from the fishery. Last year, it was $1.1 million. That means instead of making between $20,000 and $30,000 in the 1970s, fishermen are making just a few thousand dollars now, and that in villages where fuel costs $8 a gallon, milk is $15 a gallon and a T-bone steak costs $25, he said. It's hard to see the villages in such economic hardship but the Yukon should be managed conservatively until the problem of the disappearing kings is better understood, Schultheis said. "For 50 years, it was an extremely stable fishery," he said.

Sockeye salmon numbers crash as bust replaces anticipated bounty on B.C. coast

What was supposed to be a bountiful year for the Fraser River sockeye salmon fishery -- the height of the four-year cycle -- is beginning to look like a bust.Returns are so low for early Stuart sockeye, the first run of the season, that the Pacific Salmon Commission has lowered its estimate by 48 per cent.Instead of the 165,000 projected before the season started, the commission now expects 85,000, after just 83,484 fish had shown up as of Friday.The commission has also downgraded its pre-season projection of 739,000 early summer sockeye by 64 per cent to 264,000.But the big question is what will happen to the summer sockeye, which are supposed to make up 83 per cent of the 10.5 million salmon the Pacific Salmon Commission had predicted would make their way up the Fraser River this year.The summer sockeye run so far has been "well below expectations," said a fishery notice released by Fisheries and Oceans Canada on Friday.The summer sockeye are supposed to make their way to the Fraser River between now and the end of August. So far, just 7,160 have shown up, but it's still early.The Fisheries and Oceans Canada report is not optimistic, noting: "Fraser River water temperatures are forecast to reach approximately 21 C by Aug. 1. Water temperatures exceeding 20 C may cause high en route mortality of Fraser River sockeye."As a result of the low returns, the sockeye fishery on the Fraser River has been closed until further notice, raising concerns that first nations may not be able to catch enough for their food fishery."Most Indians who live in the Fraser watershed are low-income or poor," said Ernie Crey, an adviser to the Sto:lo Tribal Council. "The fishery is their principal source of dietary protein."First nations have first priority on the sockeye fishery. It is opened to commercial fishing and sport fishing only if there are enough fish. In June, federal salmon resource manager Jeff Grout said all three groups were expected to be able to participate in this year's fishery.Last year's sockeye salmon catch was 1.7 million fish, Fisheries and Oceans Canada salmon team leader Paul Ryall said last September. That was well below the average return of 4.4 million fish.In October, the International Union for the Conservation of Nature went so far as to label B.C.'s sockeye salmon a threatened species. David Karp, VANCOUVER SUN

Health-related Loss In Salmon Farming

Norwegian veterinary scientist Arnfinn Aunsmo showed in his doctorate that health-related loss in modern salmon farming may be systematically monitored and quantified, both in biological and economical terms.

The salmon farming industry is characterised both nationally and internationally by large swings in profitability, a large part of which is due to health-related challenges. However, in order to address health-related problems and use resources optimally, it is first necessary to find out how health status influences biological production. This has now been down, thanks to Aunsmo's own field studies and analyses of selected private and public databases.
The doctorate describes biological and economic models for quantification of health-related loss in salmon farming. It further describes how health-related loss may be monitored systematically both at farm level and by the industry as a whole. The statistical methods used in these analyses of information from salmon farming are innovative and world-class.
Specific causes of death were investigated in a study of 10 localities from Rogaland to Troms. The study forms a basis for a description of methods of quantitative monitoring of causes of death in aquaculture.
Better methods of mapping side-effects
In two studies, vaccines were found to be risk factors for spinal deformities in salmon. Fish with spinal deformities had in addition a significant growth rate reduction. In addition, it was shown in one study that the use of oil-based vaccines leads to a weight loss of 0.5kg in slaughter-weight salmon. The work describes better methods of mapping the side-effects of fish vaccines.
The expense of an outbreak of pancreas disease (PD) on the Norwegian west coast was in one economic model calculated to be NOK 14,400,000 for a typical farm with some 500,000 smolts. This economic model can be used for general economic evaluations of health effects and in coast-benefit analyses of counter-measures.
This doctoral work was carried out at the Centre of Epidemiology and Biostatistics of the Norwegian School of Veterinary Science, in close collaboration with private companies such as Marine Harvest, SalMar, Pharmaq, AquaGen, and others, and regulatory bodies such as the National Veterinary Institute and the Norwegian Food Safety Authority.
Arnfinn Aunsmo defended his Ph.D. thesis, entitled "Health related losses in sea farmed Atlantic salmon - quantification, risk factors and economic impact", at the Norwegian School of Veterinary Science, on May 12, 2009.
Adapted from materials provided by Norwegian School of Veterinary Science.

Deadly Parasite Could Endanger Salmon And Trout Populations In U.K.

Stocks of the UK’s Atlantic salmon along with varieties of domestic brown trout could be under threat from a deadly parasite according to research led by Bournemouth University (BU) and published in the International Journal of Parasitology.

Lead author of the paper Dr Rodolphe Gozlan believes the disease is a rosette agent or parasite first identified in the UK in 2005. The agent - Sphaerothecum destruens – was originally found in the US and is closely associated with ‘invasive’ fish species including topmouth gudgeon and could prove deadly to native salmonids (Atlantic salmon, brown trout).
Dr Gozlan and his colleagues from the University of California-Davis, State University of New York, the UK’s Centre for Ecology and Hydrology and Cardiff University have found the first record of the new infective parasite rosette agent outside North America.
In his previous research (Nature, 2005), Dr Gozlan initially found that the parasite poses a severe threat to some freshwater fish species in Europe. The latest findings have serious implications in understanding the potential risk posed by the association in the UK of this disease, the rosette agent, with invasive fish species.
North American isolates of the rosette agent have been shown to cause both high morbidity and mortality in various salmonid species including Atlantic salmon, brown and rainbow trout. Analysis of the European strain indicates a degree of isolation between European and North American rosette agent populations.
“Unlike in the US, the occurrence of this agent in invasive fish presents a major risk of spread from wild invasive populations to sympatric populations of susceptible native fish,” said Dr Gozlan, an Associate Professor in Conservation Ecology within BU’s School of Conservation Sciences. “As such it represents a risk for fisheries and commercial aquaculture, as movement of fish for stocking purposes is common practice.”
Dr Gozlan and his colleagues say more work is required to determine the extent of the threat to UK and European fish diversity. They have already observed the rapid demise of the sunbleak (Leucaspius delineatus) in parts of Europe in the last forty years following the spread of a healthy carrier – the Asian topmouth gudgeon - the most invasive fish species in Europe. As a result, the sunbleak species is now on the European list of threatened freshwater fishes.
Scientists at Bournemouth University have so far found 26 populations of topmouth gudgeon across England and Wales in rivers, enclosed lakes and sites connected to the river network. Catchments at risk from invasion include the Kent, Yorkshire Ouse, Trent, Thames, Medway, Itchen, Test and Severn.
“The new parasite has also been shown to affect other UK freshwater fish such as bream, carp and roach so there is an urgent need to develop more sensitive detection tools of the rosette agent if responsible authorities want a chance to control its spread and limit future outbreaks,” concluded Dr. Gozlan.
Journal reference:
Rodolphe E. Gozlana, Christopher M. Whippsb, Demetra Andreouc and Kristen D. Arkushe. Identification of a rosette-like agent as Sphaerothecum destruens, a multi-host fish pathogenstar, open. International Journal of Parasitology, DOI: 10.1016/j.ijpara.2009.04.012
Adapted from materials provided by University of Bournemouth, via AlphaGalileo.

Hatchery fish may hurt efforts to sustain wild salmon runs

Steelhead trout that are originally bred in hatcheries are so genetically impaired that, even if they survive and reproduce in the wild, their offspring will also be significantly less successful at reproducing, according to a new study published today by researchers from Oregon State University.The poor reproductive fitness - the ability to survive and reproduce - of the wild-born offspring of hatchery fish means that adding hatchery fish to wild populations may ultimately be hurting efforts to sustain those wild runs, scientists said.The study found that a fish born in the wild as the offspring of two hatchery-reared steelhead averaged only 37 percent the reproductive fitness of a fish with two wild parents, and 87 percent the fitness if one parent was wild and one was from a hatchery. Most importantly, these differences were still detectable after a full generation of natural selection in the wild.The effect of hatcheries on reproductive fitness in succeeding generations had been predicted in theory, experts say, but until now had never been demonstrated in actual field experiments."If anyone ever had any doubts about the genetic differences between hatchery and wild fish, the data are now pretty clear," said Michael Blouin, an OSU professor of zoology. "The effect is so strong that it carries over into the first wild-born generation. Even if fish are born in the wild and survive to reproduce, those adults that had hatchery parents still produce substantially fewer surviving offspring than those with wild parents. That's pretty remarkable."An earlier report, published in 2007 in the journal Science, had already shown that hatchery fish that migrate to the ocean and return to spawn leave far fewer offspring than their wild relatives. The newest findings suggest the problem does not end there, but carries over into their wild-born descendants.The implication, Blouin said, is that hatchery salmonids - many of which do survive to reproduce in the wild- could be gradually reducing the fitness of the wild populations with which they interbreed. Those hatchery fish provide one more hurdle to overcome in the goal of sustaining wild runs, along with problems caused by dams, loss or degradation of habitat, pollution, overfishing and other causes.Aside from weakening the wild gene pool, the release of captive-bred fish also raises the risk of introducing diseases and increasing competition for limited resources, the report noted.This research, which was just published in Biology Letters, was supported by grants from the Bonneville Power Administration and the Oregon Department of Fish and Wildlife. It was based on years of genetic analysis of thousands of steelhead trout in Oregon's Hood River, in field work dating back to 1991. Scientists have been able to genetically "fingerprint" three generations of returning fish to determine who their parents were, and whether or not they were wild or hatchery fish.The underlying problem, experts say, is Darwinian natural selection.Fish that do well in the safe, quiet world of the hatcheries are selected to be different than those that do well in a much more hostile and predatory real-world environment. Using wild fish as brood stock each year should lessen the problem, but it was just that type of hatchery fish that were used in the Hood River study. This demonstrates that even a single generation of hatchery culture can still have strong effects.Although this study was done with steelhead trout, it would be reasonable to extrapolate its results to other salmonids, researchers said. It's less clear what the findings mean to the many other species that are now being bred in captivity in efforts to help wild populations recover, Blouin said, but it's possible that similar effects could be found.Captive breeding is now a cornerstone of recovery efforts by conservation programs for many threatened or endangered species, the researchers noted in their report. Thousands of species may require captive breeding to prevent their extinction in the next 200 years - which makes it particularly important to find out if such programs will ultimately work. This study raises doubts."The message should be clear," the researchers wrote in their report's conclusion. "Captive breeding for reintroduction or supplementation can have a serious, long-term downside in some taxa, and so should not be considered as a panacea for the recovery of all endangered populations."Oregon State University

Scientist discovers beavers building prime salmon habitat in Skagit Delta

A scientist goes looking for a shrub and discovers a nearly lost world of tidal beavers thriving in a rare habitat in the Skagit Delta. His discovery raises questions for salmon-recovery projects based on incomplete information — likened to a kind of ecological amnesia about what was here before.By Lynda V. MapesSeattle Times staff reporterALAN BERNER / THE SEATTLE TIMESIn a pool behind a beaver dam, Greg Hood, a senior research scientist with the Skagit River System Cooperative, nets fish to see what's in this tidal wetland. These dams help provide safe havens for young fish, increasing their chance of survival. Fish he netted were released. SKAGIT COUNTY — As sometimes happens with science, Greg Hood went looking for one thing, and found something else:Tidal beavers.Just about everyone knows about freshwater beavers, damming streams and gnawing down the forested uplands like furry chain-saw gangs. But what Hood found in the Skagit River Delta was something else. Not a different species of beaver, genetically speaking. But one thriving in a different place — the tidal scrub shrub zone.Once, they must have been as abundant as the habitat they claim as their niche. An almost unheard of habitat today, these tidal wetlands were among the first to be diked, drained and filled nearly out of existence in Puget Sound country as the region developed. But as recently as the 1800s, these wetlands were just about everywhere in the deltas where rivers twine and spill into Puget Sound.Today, only about 6 percent of the tidal scrub shrub habitat is left in the Skagit River Delta, and that's better than a lot of places where it's gone altogether.So it was here that Greg Hood, a senior research scientist with the Skagit River System Cooperative in La Conner, came to do his research on sweetgale, a shrub that thrives in tidal scrub shrub wetlands.But the beavers provided the exciting discovery. Searching scientific literature, Hood could find not a single reference on tidal beavers in the United States. What he discovered, too, was the beavers were, well, busily creating nearly ideal rearing habitat for Puget Sound chinook, a threatened species.In that, Hood found a cautionary tale, about forging ahead with salmon-restoration plans without finding out what was here before."Recovery to what, what is your historical baseline?" Hood said. "We don't know as much as we think we do about what was here before. It's a kind of ecological amnesia."About 95 percent of the tidal shrub wetlands are lost; most people have never even heard of them. You come here, and get a sense of what used to be everywhere. And the next generation that never experienced it, they don't even miss it."Sometimes seals watched, lounging on the banks of the Skagit, as Hood motored in an open skiff through the river delta, then tied up to bushwhack on foot up the tidal channels. He'd come here mostly alone, just him and the swish of the wind in the cattails, willows and sweetgale, and the sound of the red wing blackbirds and swallows' aerial ballet accompanying his work.He mapped where he found beaver dams, and where he didn't. He mapped where he found their lodges, and netted channels for fish counts, both where he found the beavers' pools, and where he didn't.What Hood learned surprised him. Like a puzzle, there were many pieces, and they all fit together.When Hood went looking for sweetgale, a signature plant of the remnants of intact tidal scrub shrub habitat, he usually found the telltale signature of beavers just about everywhere.Dams. Pools. Lodges. Tiny toe-pad prints. Even, sometimes, the slap of a tail. Everything but the beavers, which are nocturnal.The beavers, he discovered, relied on the sweetgale for the building material for their dams.Ever the efficient engineers, they built the dams to create pools in the brackish water, so they could swim at low tide, rather than walk, to their favorite food on the banks: willows.Hood only found the beaver dams where he found sweetgale. And he only found sweetgale in certain spots in scrub shrub habitat. There, nurse logs washed downriver and left by the tides provided the platform to raise the sweetgale into the high-tide zone, just wet enough and just dry enough for the plant to thrive.Next, by netting the tidal channels and beaver pools, he learned through fish surveys that chinook density was five times higher in pools created by the beavers. The pools also were loaded with detritus that fed invertebrates; in turn fed on by fish, including chinook, coho, chum and stickleback.In the coupe de grâce, he discovered the shrubby uplands of the pools also defeated heron that prey on the young fish, because they don't have enough space to land, and the pools are too deep for wading."It's a great way for them to get away from the heron," Hood said."It's a system. Everything is connected. You start looking at one thread, and you find out it is connected to something else."

Lummi ceremony marks return of salmon, concern for the future

About 600 Lummi Indian Tribe members and guests gathered Thursday, May 14, at Lummi Nation School to celebrate the arrival of the first salmon - a celebration marked by both hope and fear for the future of the fish that defines tribal identity."When I was a young boy, I heard my grandfather say, when he was eating a salmon, 'This is good medicine,'" said Merle Jefferson, the tribe's natural resources director.The First Salmon Ceremony is a key cultural observance for the Lummi and other Coast Salish tribes. For generations, the tribes have conducted these ceremonies to honor the salmon and assure their return. KATIE BARNES THE BELLINGHAM HERALD Lummi's First Salmon Ceremony Jefferson noted that the first local salmon run, the spring chinook that return to the Nooksack River, is listed as threatened under federal law."Our first salmon is in trouble," Jefferson said. "The spring chinook is in trouble. ... The habitat is going to take many years to fix."Each year at about this time, the tribe has been conducting a limited harvest of the spring chinook for use in the traditional first salmon ceremony and feast. This year, Jefferson said, Lummi fishers netted 27 fish in just three hours, giving possible evidence that the beleaguered run may be strengthening.Meanwhile, the late summer harvest of Fraser River sockeye that once provided a decent living for both tribal and non-tribal fishers of Whatcom County has dwindled to near nothing, partly due to environmental factors and partly because of changes in the way the fish harvest is divided between U.S. and Canadian fishers."I used to gross probably $40,000, $50,000 a year on sockeye," said Richard Finkbonner, 79, a Lummi gillnetter. "I got one last year."The collapse of the sockeye fishery received an official disaster declaration from the federal government in 2008, and the tribe is now seeking $24.4 million in federal disaster aid to help in a variety of ways. Some of the money would be made available to help individual fishermen with grants or loans. About $17 million would be invested in salmon and shellfish hatchery improvements.But economic and political concerns faded Thursday as Lummi elder Jack Cagey beat his drum and led a procession of red-and-black-costumed youngsters into the school auditorium, escorting a wheeled cart carrying the roasted first salmon. It was covered with feathery green cedar fronds and wrapped in aluminum foil. Everyone at the ceremony got a morsel of the first salmon in a small plastic cup, but every bit of bone was saved for the final portion of the ceremony, in which the uneaten remains of the fish were returned to the waters off Lummi Peninsula.After the ceremonial consumption of the first fish, tribal cooks rolled out a lavish feast that included not only alder-roasted salmon but fried halibut, prawns, clam fritters, fry bread, rice and potato salad.Heather Leighton, school principal, took the microphone to get her young charges organized for food service. They trooped out of the bleachers to pile plates with food for the elders and guests seated at long tables on the auditorium floor."I don't want to see any food in your hands until all the elders have been served," Leighton said.Finkbonner said he expects to be out on the salt water off Sandy Point again this year, hoping to net enough silver salmon to get him through another season. But he doesn't recommend that Lummi youth try to follow in his footsteps."Tell the young people to get out of it," Finkbonner said. "There's nothing left anymore. Go to school and learn a trade."But Lorraine Loomis, the Swinomish Tribe's fisheries manager who attended as a ceremonial witness, struck a different note."If we didn't believe that our salmon would come back, we would not be here today," Loomis said. "We're not going to give up."