New cod? Quick-growing tropical cobia could replace dwindling species

Species has high oil content, white flesh, and grows three times as fast salmon, and 'could be next big farmed fish'
Alexandra Topping
guardian.co.uk, Wednesday 5 May 2010 20.06 BST
A new fast-growing tropical fish that could provide an alternative to popular species for environmentally-conscious fish-lovers is being imported to the UK.
With recent studies revealing that UK's fish stocks have fallen by 94% in the past 100 years, Marine Farms argues that cobia, which has white flesh and a high oil content, could be the next big farmed fish species. The fish grows three times faster than Atlantic salmon and has good taste and consistency according to Bjørn Myrseth, the chief executive of Marine Farms, based in Norway.
"For us it is a very attractive fish because of the rate of growth. It can grow from about 1g to 5kg -6kg in a year, when it takes salmon around 30 to 36 months to reach the same size. It also has good eating qualities with very firm flesh and high oil content. It is easy to prepare and has a nice mild flavour," he said.
In the wild, cobia can grow up to 60kg, but it is very uncommon for the fish to be caught commercially, he said.
Marine Farms expects to produce 1,500 tonnes of the fish this year for export. There are plans to expand the site, which has the capacity to produce up to 6,000 tonnes a year, depending on demand.
"The challenge will be to introduce the fish and convince people to eat it – we have to make it known to people," he said.
The fish could also provide a viable alternative for other fish species that are under strain.
Said Myrseth: "With a high oil content, it is also great raw for sushi or sashimi. It can also be used as a replacement for fish such as tuna, if people are looking for an environmentally sustainable alternative, as the texture and flavour are quite similar."
The fish is currently placed at the more expensive end of the market and costs slightly more than Atlantic salmon, said Myrseth. "But we hope that as demand grows the cost of the fish will go down, and if demand is high enough it could become a relatively inexpensive fish in the future," he said.
Cobia has been commercially produced in Asia, particularly in Taiwan where it is stocked in about 80% of ocean cages, according to the Marine Farms website.
It has operated a cobia farm in Florida since 2002 and has opened operations in Belize and Vietnam.
The Monterey Bay Aquarium Seafood Watch, which publishes guides for sustainable seafood purchasing, recommends US-farmed cobia as it is farmed inland with closed recirculating systems that help prevent diseases and pollutants.
However, it advises against buying cobia from outside the US as it is often farmed in floating or submerged cages and pens in nearshore and open ocean waters. "This creates a risk of disease transfer, escapes and pollution impacts on surrounding ecosystems and species," according to the Seafood Watch website.
Myrseth said all Marine Farm cobia was sustainably farmed in low-density ocean cages with site rotation to prevent disease and damage to the environment. "This is very important to us, because if the environment is impacted we are the first to feel that," he said. The company's cobia is fed on fish oil, fishmeal and vegetable protein but it aims to feed the fish on vegetable protein in the future, he added.
Dawn Purchase, aquaculture officer at the Marine Conservation Society, said: "With 50% of global seafood now being farmed it is essential that all current and new farmed species coming into the UK market is produced in the most environmentally sustainable way possible, which ensures the health and diversity of the environment on which it depends."
Charles Clover, creator of The End of the Line – an exposé of the fishing industry – declined to comment on cobia specifically but said the farming of carnivorous fish posed significant environmental problems because of the shortage of smaller fish to provide food.
"Without that it is difficult to see how the aquaculture industry is going to continue to grow, unless they find some way of creating synthetic fish food," he said. "And as fish have been eating other fish for millions of years, that is not going to be easy."