Wednesday, 26 November 2008

Larger Fish Produce Hardier Offspring

Research published in the Royal Society's Biology Letters journal suggests that fisheries management must consider population demography.

Modeling the life history demographics of 25 different marine fish species, Canadian scientists have found that larger, older female fish produce tougher offspring than their younger counterparts.

In efforts to make fisheries more sustainable, conserving the elder female fish could help sustain populations. Currently the findings of the research are out of sync with real-life fisheries practice, where the largest fish are sought. Overfishing results from this practice because of the two-fold effect of removing the best breeders, and subsequently reducing the rate of recruitment in the local population.

It is suggested that by enforcing size regulations, altering the size of fishing gear and how it's used could protect the bigger older individuals. The practicality of implementing these measures on the ground are not explored explicitly however, and targeting large female fish within populations could be very difficult to implement.

Do blog readers believe that European fisheries practices are sustainable? Does the Common Fisheries Policy need re-evaluating?

Blog readers are invited to comment on this article

1 comment:

Anonymous said...

Thanks for a great post.

Yes, I have often wondered at the wisdom of catching the larger fish when it's been known for a while that they're often the most fecund.

I wonder if this is a case of mis-applying scientific knowledge from a different area?

It would be a sweeping generalisation to state either way on European fishing practices.

The CFP needs to be overhauled on the basis of scientific evidence, but I think us scientists would do well to increase our work with people whose livelihoods depend on fisheries, in order to build a consensus which governments and the large fishing companies can't argue out of.