In Conservation Magazine’s recent good read, “Point of No Return: Why Aren’t Fish Populations Recovering?” author Natasha Loder examines why fishery management policies may have resulted in an insurmountable “Darwinian Debt.”
In the 1940s, cod in the northeast Arctic had an average size of 95 cm. Today they average only 65 cm. And average size and age of fish at maturation have been decreasing for decades in many commercially exploited fish stocks. Size limits may be the culprit.
A controlled, peer-reviewed study published in the journal Science in 2002, turned conventional thinking about fisheries management on its head.
“In most commercial fisheries, fish are removed on the basis of size. There are minimum, not maximum, size limits. But the study’s results show that this approach may have results that are exactly the opposite of what is intended. Within only four generations, taking out larger fish produced a smaller and less fertile population that also converted food into flesh less efficiently,” writes Loder.
