Friday, September 27, 2013

27/09/13: Salmon special: Cooke Aquaculture escape update; feed limits put salmon at risk; understanding the life cycle of sea lice

Today we round up the most importnat salmon stories from around the world.

Salmon farming in Canada is a controversial issue so it is not a surprise to hear that the recent escape at a Cooke Aquaculture facility in Heritage Bay, Newfoundland, has become a political issue.

Jim Bennett, Liberal Critic for the Department of Fisheries and Aquaculture and the Department of Education, has raised his concerns about the incident in a letter to Fisheries and Oceans Canada

Bennett claims that the number is escapees in closer to 50,000 rather than the 20,000 reported by Cooke Aquaculture. If this is true, the escape would be the largest of salmon in Canada since 1999.

He also writes about the potential danger of interbreeding and the spread of disease.

In a statement on its website from September 24, 2013, Cooke Aquaculture does not mention how many fish escaped.

However, the CBC Fisheries Broadcast spoke to Nell Halse, vice president communications at Cooke Aquaculture, about the escape. Halse explains how the incident happened and estimates that between 10,000-20,000 fish escaped. 

The plan now is to try and capture as many of the salmon as possible. However, fishing regulations mean that the company cannot simply go out in boats to try and fish for salmon.

Addressing the question of dangers to wild populations, Halse says that the fish not an invasive species and she believes they will not be a threat.

Feed limits put salmon at risk according to Grant Rosewarne, chief executive  New Zealand King Salmon.

The company is asking for urgent action on its application to the Marlborough District Council to lift feed limits at its Clay Point fish farm in Tory Channel. 

Unless they can use more pellets at Clay Point from October to December they will have to starve fish, cull fish or harvest them too small for the market. 

Rosewarne said the fish need more feed because they are bigger than usual this season and there are greater numbers of fish.

News that sea lice go through various larval stages before reaching adulthood could affect how the pest is treated in salmon.

New results from the Institute of Marine Research, Norway have shown that the salmon louse has seven larval stages before it develops into an adult. Previously, nine larval stages have been described.

For the aquaculture industry, understanding the life cycle and the number of molts, is important because some of the compounds that can be used against salmon lice infestation are inhibitors of the molting process.
Salmon louse. From top: 1. Mature female with ...
Salmon louse. From top: 1. Mature female with egg strings. 2. Mature female without eggstings. 3. Immature louse. Picture taken at Norwegian Aquaculture Center, Brønnøy, Norway ‪Norsk (bokmål)‬: Lakselus. Øverst: Voksen hunn med eggstrenger. I midten: Voksen hunn uten eggstrenger. Nederst: Ung lus. Bilde tatt på Norsk Havbrukssenter, Brønnøy (Photo credit: Wikipedia)

 

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