Development of More Muscular Trout Could Boost Commercial Aquaculture

A 10-year effort by a University of Rhode Island scientist to develop transgenic rainbow trout with enhanced muscle growth has yielded fish with what have been described as six-pack abs and muscular shoulders that could provide a boost to the commercial aquaculture industry.Terry Bradley, a URI professor of fisheries and aquaculture, said his research into the inhibition of myostatin, a protein that slows muscle growth, has obtained "stunning results" in the last two years, with trout growing 15 to 20 percent more muscle mass than standard fish."Belgian blue cattle have a natural mutation in myostatin causing a 20 to 25 percent increase in muscle mass, and mice overexpressing myostatin exhibit a two-fold increase in skeletal muscle mass. But fish have a very different mechanism of muscle growth than mammals, so we weren't certain it was going to work," Bradley said.According to Bradley, the number of muscle fibers in mammals is limited after birth, but in fish, muscle fiber numbers increase throughout their lifespan. Since inhibition of myostatin increases the numbers of muscle fibers, it had been a mystery as to whether inhibiting myostatin would cause an increase in muscle growth in fish.Bradley and a team of graduate students spent 500 hours injecting 20,000 rainbow trout eggs with various DNA types designed to inhibit myostatin. Of the eggs that hatched, 300 carried the gene that led to increased muscle growth. After two years, most exhibited a "six-pack ab" effect, even though fish lack standard abdominal muscles. They also have increased musculature throughout, including a prominent dorsal hump that made them look like they had muscular shoulders.The first generation of transgenic trout were subsequently spawned, and offspring carrying the gene in all of their muscle cells have been produced. Studies are under way to determine if the fish grow at a faster rate as well."Our findings are quite stunning," said Bradley, who also studies salmon, flounder and tuna. "The results have significant implications for commercial aquaculture and provide completely novel information on the mechanisms of fish growth. The results also allow for comparisons between the mechanisms of growth of muscle in mammals versus fish, and it could shed light on muscle wasting diseases in humans."About 500,000 metric tons of rainbow trout are raised each year in aquaculture facilities in the United States and Europe. In the U.S., some 1,000 trout farms produce approximately $80 million of trout annually, mostly in Idaho, New York, Pennsylvania and California. Assuming Bradley's transgenic fish meet with regulatory approval, it could provide a boost to the industry by enabling aquaculturists to grow larger fish without increasing the amount of food the fish are fed."One of the advantages of this approach is that the modified genes introduced into the fish use the same mechanism and cause the same type of effect that occurs naturally in Belgian blue cattle and other 'double muscled' animals," said Bradley.While the transgenic trout may look like bodybuilders, Bradley said they exhibit normal behaviors. He will continue to study the fish to learn if the new gene affects any other genes, and to determine if new husbandry practices will aid in the raising of the trout.

Fisheries and Aquaculture Face Multiple Risks from Climate Change

A new report, published by the Food and Agriculture Organization (FAO) of the United Nations, predicts "an ocean of change" for fishers and fish farmers. It concludes that urgent adaptation measures are required in response to opportunities and threats to food and livelihood provision due to climatic variations.

The study, 'Climate change implications for fisheries and aquaculture', is one of the most comprehensive surveys to date of existing scientific knowledge on the impacts of climate change on fisheries and aquaculture. Covering some 500 scientific papers, the picture the FAO review paints is one of an already-vulnerable sector facing widespread and often profound changes.

The report includes contributions from experts from around the world, including Dr Tim Daw and Prof Katrina Brown of the School of International Development and Prof Neil Adger of the School of Environmental Sciences at UEA. Other contributors come from the WorldFish Center, Globec, Network of Aquaculture Centres in Asia-Pacific, and Fisheries and Oceans Canada.

Dr Daw and Profs Adger and Brown co-authored the chapter 'Climate change and capture fisheries: potential impacts, adaptation and mitigation', which looks at the social vulnerability of fisherfolk to climate change. "Marine and freshwater ecosystems will be profoundly affected by processes like ocean acidification, coral bleaching and altered river flows with obvious impacts on fisherfolk, but it is not just about what happens to the fish," said Dr Daw. "Fishing communities are vulnerable to sea level rise and their livelihoods are threatened by storms and extreme weather. Meanwhile, the social and economic context of fisheries will be disrupted by impacts on security, migration, transport and markets."

"Fisheries are already rapidly evolving due to overexploitation and globalisation. They will suffer from wide range of different impacts from climate change, which may be unpredictable and surprising. The poorest will be least able to adapt to these impacts. For example in Kenya poorer fishers were shown to be less likely to switch to other livelihoods if catches declined."

Prof Adger added: "Climate change is going to be a huge challenge to every sector of society and what we're learning about fisheries shows how difficult adaptation will be, particularly for the poorest parts of the world."

According to the report, marine capture fisheries already facing multiple challenges due to overfishing, habitat loss and weak management are poorly positioned to cope with new problems stemming from climate change. Small island developing states -- which depend on fisheries and aquaculture for at least 50 percent of their animal protein intake -- are in a particularly vulnerable position.

Some 520 million people depend on fisheries and aquaculture as a source of protein and income. For 400 million of the poorest of these, fish provides half or more of their animal protein and dietary minerals. Many fishing and coastal communities already subsist in precarious and vulnerable conditions because of poverty and rural underdevelopment, with their wellbeing often undermined by over-exploitation of fishery resources and degraded ecosystems.

Inland fisheries -- 90 per cent of which are found in Africa and Asia -- are also at risk, threatening the food supply and livelihoods of some of the world's poorest populations. Warming in Africa and central Asia is expected to be above the global mean, and predictions suggest that by 2100 significant negative impacts will be felt across 25 per cent of Africa's inland aquatic ecosystems.

Fish farming will also be affected. Nearly 65 per cent of aquaculture is inland and concentrated mostly in the tropical and subtropical regions of Asia, often in the delta areas of major rivers at the mid- to upper levels of tidal ranges. Sea level rise over the next decades will increase upstream salinity, affecting fish farms.

A crucial issue highlighted by the report relates to how well such communities will be able to adapt to change. For example, even if African coastal fisheries do not face huge impacts, the region's 'adaptive capacity' to respond to climate change is low, rendering communities there highly vulnerable even to minor changes in climate and temperatureAdapted from materials provided by University of East Anglia.

Marine Aquaculture Could Feed Growing World Population

Marine aquaculture could play a large role in feeding humanity in the coming decades, although substantial changes will be needed to reduce its reliance on terrestrial agriculture and other external feed subsidies.The oceans could become the source of more of humanity's food if steps are taken to expand and improve marine aquaculture, according to a study published in the December 2009 issue of BioScience.As the world's population continues to grow, lack of fresh water and space mean that terrestrial agriculture is unlikely to be able to meet food demand, according to Carlos M. Duarte of the University of the Balearic Islands, Spain, and his seven coauthors. Freshwater aquaculture, which is largely confined to the tropics, is expanding, but its reliance on fresh water may limit long-term growth. Fisheries catches have been declining globally for two decades, and although conservation measures and a shift in consumption patterns could allow some recovery, marine aquaculture holds more potential for sustained growth.Marine aquaculture is already on the rise: production has increased ten-fold over the past 30 years and is expected to exceed fisheries catches within 20 years. Yet Duarte and his colleagues argue that its continued growth will depend on adapting current techniques so that the food needed to feed marine animals is itself derived from marine aquaculture, rather than harvested from the wild or derived from agriculture. This goal is achievable, they maintain, if more animals low on the food chain are cultivated, including more plankton and algae. These could be used as food for both humans and for fish. New technology will also help, by allowing marine aquaculture operations to be expanded into more exposed, offshore locations. Although some environmental impacts can be expected from the expansion of marine aquaculture, these are modest compared to those resulting from food production on land.

Fish farms to fight back with EU help

Fish farms could solve the problem of fewer fish in the oceans The European Commission will unveil a new strategy later on Wednesday to revive the fish farming industry. At a time when stocks of some species of fish in the world's oceans are dangerously low, the authorities in Brussels are concerned that Europe's aquaculture sector has stagnated. Most of the seafood consumed within the EU is imported, but the Commissioner for Maritime Affairs and Fisheries, Joe Borg, believes that can be reduced with the right strategy to encourage the industry to grow. Among the key measures likely to be announced are plans to encourage more investment in the sector, by making it easier to open a fish farm. That, in turn, will create more jobs. The commissioner also believes that the EU should offer more support for research and development. Europe's farmed fish producers are facing increasingly tougher competition from Asia and Latin America. BIM, Ireland's state run body for fisheries, says the huge growth in imports of mussels from Chile and pangasius, a species of catfish, from Vietnam, shows how much pressure producers are under. Job creation The industry is not just focused on farming species, such as salmon, eel or trout. Production of shellfish, such as clams and oysters, also needs support. For the European Union, aquaculture is a sector that provides jobs for 65,000 people. France, the UK, Italy and Spain are the leaders, but some countries are at the forefront of producing certain species. For example, Greece is the dominant producer of farmed sea bass and sea bream, while Scotland and the Irish Republic lead the way in producing Atlantic salmon. Over time, it will be more and more accepted that fish is farmed Nutreco Long-term observers of the industry will recognise that from the European Commission's perspective, we have been here before. Seven years ago, the decision-makers in Brussels reached the same conclusions that the industry needed help to develop and they set out a new strategy for aquaculture. However, at the same time, another arm of the European Commission was setting in motion a directive that eventually undermined plans to give fish farming a boost. The Habitat Directive was aimed at protecting certain rare species of wildlife in coastal areas and rivers. The subsequent regulations introduced across the EU to abide by the directive required anyone who wanted to set up a fish farm had to prove that it would not have a harmful impact on the local environment and the protected species. That proved a tough barrier for aquaculture companies to overcome and provided a competitive advantage to fish producers in Asia, where local regulation is much more relaxed. The Irish Republic's BIM has told the BBC that the European Commission should roll back the Habitats Directive to make it easier to open a fish farm. Healthy option So now it is back to the drawing board for the European Commission, although the powers in Brussels are putting a different spin on it, saying they want to give new impetus to the 2002 strategy. There are several good reasons why the fish farming sector needs to be encouraged to develop. Fewer fish are being caught at sea The experts agree eating fish is a healthy option and as stocks are low in the world's oceans, farming the food is a good solution. Then there is the economic argument that expanding the industry will create more jobs, at a time when much of the European Union is gripped by recession. The European Commission has looked at Norway and believes lessons can be learned from the way the government in Oslo has successfully nurtured its own aquaculture industry. Norway produces 800,00 tonnes of farmed Atlantic salmon every year, a far greater level of production than Scotland's 160,000 tonnes or Ireland's annual output of 12,000 tonnes. However, EU competition rules prevent direct state aid, so an indirect way of boosting the industry will have to be adopted. Image problem Aquaculture has a battle on its hands to restore its image with some consumers. The industry has been accused of polluting rivers and of allowing disease to spread among caged fish. The Netherlands-based company Nutreco is one of Europe's leading providers of food for fish farms. One of its directors has told the BBC that the industry is hampered by too much regulation and it has to restore its image with worried consumers. "Nobody is doubting whether a chicken or a pig is farmed, but still we have the choice for fish. I think that over time, it will be more and more accepted that fish is farmed, especially when you take it into consideration with biodiversity and protecting the wild stock in the oceans," he said. As Mr Borg outlines a new strategy to reinvigorate fish farming, he is probably hoping that another remote arm of the authority in Brussels is not hatching another unrelated plan that could once again undermine aquaculture.

Futuristic Seafood: Raising Delicious Cobia And Pompano Fish -- Inland

Two saltwater superstars—cobia and Florida pompano—are regarded by connoisseurs as being some of the world's best seafood. Both cobia (pronounced COE-bee-uh) and pompano (POM-puh-no) have firm, mostly white flesh that's perfect for grilling, pan-frying or baking.

Now, Agricultural Research Service (ARS) agricultural engineer Timothy J. Pfeiffer, fish nutritionist Martin A. Riche, and fish biologist Charles R. Weirich—all based in Ft. Pierce, Fla.—are determining how to best raise cobia and pompano inland, hundreds of miles from the nearest ocean or bay, in huge tanks of fresh or only slightly salty water. The tanks are part of what's known as a "recirculating aquaculture system," or "RAS," in which water is cleaned and used again and again.
These systems offer the potential to reduce discharge of everyday fish-farm effluent to as little as 3 percent—or less—of the total amount of water used each day. Fish wastes and unused food collected in the system could be recycled as nutrient-rich compost.
But much more remains to be discovered about the needs of the saltwater fish that would be reared in the tanks. And many engineering details must be worked out. In an experiment with 2,400 juvenile pompano, the scientists showed that it's indeed possible to raise this oceanic species—from juvenile to market size—in water that's only slightly salty.
In this case, the water had a salinity of only 5 parts per thousand, as compared to the 35 parts per thousand in most oceans. Now the scientists want to make the system practical, profitable, and energy efficient for all stages of inland, low-salinity production of cobia and pompano.
Pfeiffer, Riche and Weirich work for the Arkansas-based ARS Harry K. Dupree Stuttgart National Aquaculture Research Center, and are stationed at Florida Atlantic University's Harbor Branch Oceanographic Institute in Ft. Pierce.
Adapted from materials provided by USDA/Agricultural Research Service.

Aquaculture's Growth Seen As Continuing

Aquaculture production of seafood will probably remain the most rapidly increasing food production system worldwide through 2025, according to an assessment published in the January 2009 issue of BioScience.

The assessment, by James S. Diana of the University of Michigan at Ann Arbor, notes that despite well-publicized concerns about some harmful effects of aquaculture, the technique may, when practiced well, be no more damaging to biodiversity than other food production systems. Moreover, it may be the only way to supply growing demand for seafood as the human population increases.
Diana notes that total production from capture fisheries has remained approximately constant for the past 20 years and may decline. Aquaculture, in contrast, has increased by 8.8 percent per year since 1985 and now accounts for about one-third of all aquatic harvest by weight. Finfish, mollusks, and crustaceans dominate aquaculture production; seafood exports generate more money for developing countries than meat, coffee, tea, bananas, and rice combined.
Among the most potentially harmful effects of aquaculture, according to Diana, are the escape of farmed species that then become invasive, pollution of local waters by effluent, especially from freshwater systems, and land-use change associated with shrimp aquaculture in particular. Increased demand for fish products for use in feed and transmission of disease from captive to wild stocks are also hazards.
Nonetheless, when carefully implemented, aquaculture can reduce pressure on overexploited wild stocks, enhance depleted stocks, and boost natural production of fishes as well as species diversity, according to Diana. Some harmful effects have diminished as management techniques have improved, and aquaculture has the potential to provide much-needed employment in developing countries. Diana points to the need for thorough life-cycle analyses to compare aquaculture with other food production systems. Such analyses are, however, only now being undertaken, and more comprehensive information is needed to guide the growth of this technique in sustainable ways.
Adapted from materials provided by American Institute of Biological Sciences, via EurekAlert!, a service of AAAS.