North Sea cod 'doomed by climate change'

By Simon de Bruxelles Cod are doomed to disappear from the North Sea because of climate change and not just as a result of over-fishing, researchers have discovered. In the past 40 years the average temperature of the North Sea has increased by one degree centigrade with catastrophic effects on its delicate eco-systems. Species of plankton, on which cod larvae feed, have moved away in search of cooler waters. The decline in cod stocks has led to an explosion in the populations of crabs and jellyfish, on which the adult fish feed. The shortage of predators at the top of the food chain has had a knock-on effect on flat fish, such as plaice and sole, whose offspring are eaten by crabs. The cumulative consequences of warming for the North Sea have been spelt out in detail in the study published in the Proceedings of the Royal Society Biological Sciences journal today. Dr Richard Kirby, a Royal Society Research Fellow at the University of Plymouth, and Dr Gregory Beaugrand, from France’s Centre National de la Recherche Scientifique, warn that stricter quotas or a ban on fishing would not be enough to save the North Sea’s cod. … Dr Kirkby said: “The plankton that young cod usually eat during March, April and May, a species of copepod that is the size of a grain of rice, prefer cold water and so they have become much less frequent as the North Sea has warmed. … “The increase in temperature has affected the whole food chain from the plankton to fish and jellyfish, including animals that live on the sea bed such as crabs, sea urchins and bivalves, animals like mussels and scallops. … “And on the seabed the adult crabs and shrimps eat newly settled bivalves and young flatfish such as plaice and sole, which now also appear to be declining in abundance.” …  North Sea cod ‘doomed by climate change’ via Apocadocs