Students Staff

13 October 2014

When less is more: the key to sustainability?

Colchester Campus

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Less really could turn out to be more when it comes to how we make our fishing stocks sustainable for the future, according to new research from the University.

The study could help to improve the understanding and management of animal populations whether for conservation, pest control or harvesting, such as in fish populations.

Traditional harvesting methods focus on getting the maximum catch and this easily leads to over-exploitation, including the collapse of certain fished or hunted species around the world.

An international group of scientists undertook a review of experiments that detailed how animal populations respond to experimental harvesting. Their results show that by switching the emphasis away from getting maximum catches to looking for novel responses at lower mortality rates, positive effects on population growth occur - benefitting both fishermen and fish populations alike.

“We have found a counterintuitive ‘sweet spot’ where if you harvest at a lower rate the total population size or biomass will increase,” explained Dr Tom Cameron from Essex. “This means that for potentially the same yield you harvest a lower percentage of a higher amount of individuals rather than a higher percentage of a lower amount of individuals.”

The study, which also involved scientists in the Leibniz-Institute for Freshwater Ecology and Inland Fisheries in Germany and Princeton University in the United States, is published in the Trends in Ecology and Evolution journal.

The international research team compared the results from laboratory and field studies across many different animal species and the positive effects of mortality found in the review are themselves not new.

“However, this research hints that we may be able to continue to harvest populations in a way that is a win-win situation where less really is more,” added Dr Cameron. “But only if we take population structure into account, and cease to make predictions about animals using models that assume all individuals in a population grow or reproduce at the same rates or are equally sized.

“We are always going to depend on the environment for our resources, but we have to find a way to do so sustainably and therefore to find this counterintuitive effect is promising.”


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