Bremerhaven, 17 April 2013. Researchers have known for some years that the Atlantic cod beats the retreat in the direction of the Arctic when the waters in its traditional habitat become too warm. In summer, shoals from the Atlantic Ocean, for example, are now moving up as far as Spitsbergen into the waters the Arctic cod calls its own. In the next two and a half years, biologists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, together with scientists from Kiel, Bremen, Dsseldorf and Mnster, will be seeking to discover the consequences of this climate-related migration on the stocks of these two commercial fish species, how the fish are responding to the water becoming warmer and more acidic and at which stages of life the changes are most dangerous to them. The first investigations are already in progress as part of the joint project BIOACID with focus placed on the early life stages.
Until recently, Flemming Dahlke, fishery biologist at the Alfred Wegener Institute (AWI), could not have imagined that he would one day have to resort to the fishing rod to pursue his doctorate. But after several fruitless attempts at getting hold of an Atlantic cod ready to spawn, a fishing trip proved to be the most profitable method. Flemming Dahlke stripped off the eggs from his catch, fertilised these with Atlantic cod sperm and was finally able to start on his actual research work.
At the Swedish research station of Kristineberg, the AWI fishery biologist observes, documents and measures how the cod eggs develop at different water temperatures. He would like to know whether as many larvae hatch from eggs which have matured in sea water at a temperature of 12 degrees as from eggs which have been kept in water at a temperature of six degrees, and how the quantity of dissolved carbon dioxide in water impairs the survival chance of the fish spawn.
These two questions are among the focal research topics of the BIOA
|Contact: Sina Loeschke|
Helmholtz Association of German Research Centres