"For centuries, it has been believed that selective fishing that avoids young, rare and charismatic species and focuses on older and larger individuals, is key to increased harvest and reduced impacts on the environment," says François Simard, IUCN's Senior Adviser for Fisheries. "But old individuals largely contribute to reproduction and removing them distorts the environment's structure and functioning. It can also have serious ecological and evolutionary side effects."
A group of fisheries and conservation scientists of the IUCN Commission on Ecosystem Management (CEM), introduced a fundamental change to the way fisheries have been managed so far.
The study is published in the journal Science and suggests major rethinking of fisheries management that could increase food security and minimize the negative impacts of fishing on the environment.
The new approach proposed by IUCN, called 'balanced harvesting', involves targeting all edible components of the marine environment, in proportion to their productivity.
"Balanced harvesting is a selective approach to fishing but, in line with the ecosystem approach adopted by the Convention on Biological Diversity and the Food and Agriculture Organization, this selectivity has a much broader perspective than what has been used until now," says Serge M. Garcia, Chair of the Fisheries Expert Group of IUCN's CEM.
"Instead of focusing solely on optimizing the catch taken from selected target species and sizes, it aims at maintaining the structure and productivity of the ecosystem as a whole."
The paper is based on a comparative study of various types of selectivity using 36 different models of ecosystems. Some examples of fishing strategies coming close to balanced harvesting have also been found in African inland artisanal fisheries.
"This new thinking about fisheries management may be seen as Utopian, as human capacity to manage ecosystems is limited", says Jeppe Kolding, member of the Fisheries Expert Group.
"But it's a utopia that allows energies to be focused in the right direction. We now have sufficient evidence that this new approach could make fishing much more sustainable, reducing its impact on the ecosystem and benefiting the marine environment and food security."