Throw back the big fish and keep the small ones

(PhysOrg.com) -- Scientists at the University of Toronto analysed Canadian fisheries data to determine the effect of the "keep the large ones" policy that is typical of fisheries. What they found is that the effect of this policy is an unsustainable fishery.

In fact, the opposite policy (keep the small young ones and throw back the large old ones) would result in a more sustainable fishery. In short -- a big fish in the water is worth two in the net.

Put simply, a fish population will produce more young -- and therefore sustain more fishing -- if it is made up of big, old fish.

The team of scientists used a simple population model, as well as evaluating data from 25 marine fish species. They also tailored their methods to allow for other possible causes for the results, such as the effect of climate.

Finding ways to replenish fishery stocks and improve management provides both ecological and financial benefits.