Mar 1

IUCN have proposed a new method of fishing called ‘balanced harvesting’, where all edible components of the marine ecosystem are targeted in proportion to their productivity.

Atlantic cod image

The Atlantic cod - a commonly fished species

Balanced harvesting

The study by IUCN, to be published in the journal Science, suggests a fundamental change in the way fisheries are managed. By targeting a higher diversity of species and sizes rather than selectively fishing certain species, it is hoped that full use can be made of the productivity of the marine ecosystem. The suggested changes will improve food security for people while reducing the impact that fishing has on the marine ecosystem.

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.”

Yellowfin tuna image

The yellowfin tuna is a popular and important target for commercial fisheries

Selective fishing

Conventional selective fishing methods currently result in certain species and certain sizes of fish being removed from the ecosystem disproportionately to the numbers they occur in. In some areas, such as the North Sea, selective fishing has led to a shift from large to smaller species, thus altering the ecosystem. Balanced harvesting will address this issue by targeting all edible components of the marine environment in proportion to their productivity.

Balanced harvesting is a selective approach to fishing, but 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 Commission on Ecosystem Management (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.”

Bigeye tuna image

Bigeye tuna at Tsukiji fish market

A more sustainable approach for the future

Examples of fishing methods that resemble a balanced harvesting method already exist in some countries, where a wide range of fishing methods and net mesh sizes leads to a broad distribution of fishing pressure across the ecosystem. This not only results in a high yield for people, but also maintains the ecosystem structure.

Jeppe Kolding, member of the Fisheries Expert Group, says “We now have sufficient evidence that this new approach could make fishing much more sustainable, reducing its impact on the ecosystem and benefitting the marine environment and food security.

For more information on balanced harvesting, read the report by IUCN: Selective Fishing and Balanced Harvest in Relation to Fisheries and Ecosystem Sustainability.

View images and videos of fish species on ARKive.

Becky Moran, ARKive Species Text Author

  • Neil MacDonald (April 23rd, 2012 at 3:50 am):

    For years fishers in the South Australian Lakes & Coorong Fishery (a multi species, multi method fishery) which operates within freshwater, estuarine and marine enviornments has argued that its diversity and adaptablity to changing conditions has ensured sustainability. This has had little impact on the regulatory environment that has sought to look at the parts not the whole and largely diregarded the ecological variability within the fishery’s operating area.

    The basis for this approach is refreshing and timely.