Guardian: Sea surface temperatures are coldest at this time of year as cod are spawning in the Channel and southern North Sea. This is the southerly point of this hunted fish, and there is a lot of research into how long cod can remain in the current breeding grounds as the climate warms.
Cod has been exploited for 2000 years, and until the invention of sonars, the stock was thought to be inexhaustible. However, fishermen have long known that the cod's range and numbers changed with temperature. In the...