For years, Japan has argued that reducing the number of baleen whales in the oceans would improve fisheries because whales eat fish that are caught for human consumption. However, a new study recently published in the journal Science found that even a complete eradication of whale populations in tropical waters would not lead to any significant increase in fish populations.

Many countries in Western Africa and the Caribbean have been persuaded by Japan to join the International Whaling Commission (IWC) and vote in favour of resuming commercial whaling with the understanding that culling whales would result in increased fisheries catches.

Dr. Leah Gerber, lead author and associate professor of Ecology, Evolution and Environmental Science at Arizona State University said that their models unequivocally show that removing whales would not significantly increase the amount of commercially valuable fish and that when whales were more abundant before World War II, the fisheries were in good shape. The authors constructed ecosystem models, which account for feeding interactions between whales and fish, to understand the role that baleen whales play in tropical marine ecosystems in Western Africa and the Caribbean, where baleen whales are known to breed.

The researchers suggest these results underscore the important role of science in policy decisions about whales and fisheries interactions. They also emphasize that the goal of ecosystem-based management should not be to manipulate individual components of food webs in an attempt to maximise the amount of fish to catch, but to manage the whole system for long-term sustainability.

The scientists used global and regional data, validated through scientific workshops in Senegal and Barbados, to determine whether competition was occurring.