Are we moving in the right direction?
The size of several fish stocks in the North Sea is low. Among these are cod and mackerel. The number of stocks within and outside safe biological limits is to some extent constant during the period. However, which species fall into the three categories does vary. Some of this variation may be explained by naturally occurring cycles, though it is likely that many of the spawning stocks are highly influenced by fishing.
Two of the stocks (mackerel and blue whiting) have been harvested at a higher level than the safety limits, which means that there is high probability that fishing has caused a decline in these stocks´ ability to reproduce.