Published online 26 April 2010 | Nature | doi:10.1038/news.2010.203


Proposal sets whaling limits

Conservative hunting quotas require more scientific data.

Limited hunting of the minke whale will be allowed.NOAA

For the first time in a quarter of a century, commercial whaling on the open seas could be condoned — and scientists are working to figure out exactly how much should be allowed.

The International Whaling Commission (IWC) released a controversial proposal on 22 April which would allow limited hunting in the hope of achieving an enforceable, consensus agreement that would include Japan, Iceland and Norway, which have caught more than 33,000 whales since the 1986 IWC moratorium on commercial whaling. If adopted in June at the IWC annual meeting in Agadir, Morocco, the proposal would set 10 years of "scientifically determined" catch limits for the whaling nations. But the scientists involved in recommending the caps for the proposal say that there is still considerable uncertainty in both the estimation of existing whale populations and what constitutes a safe or sustainable target. Four populations lack a scientifically determined management plan altogether, yet allowable catch limits for these have been included in the proposal.

Put simply, two parameters are needed to produce a catch limit: current abundance and knowledge of past and present catches. But in most cases, abundance estimates have uncertainties of at least 20%, says mathematician Doug Butterworth of the University of Cape Town in South Africa and a member of the IWC scientific committee. As a result, the committee has embedded a conservatism in its recommendations, prescribing annual catch limits lower than 1% of current population sizes. "This is a very risk-averse formula," says Butterworth, who says that there has been debate within the scientific committee as to whether they were being too precautionary for whale populations that are thriving. "These things require goodwill to reach scientific consensus, let alone political consensus."


Catch-limit models have been run for several of the whale populations currently being hunted — such as the western North Pacific Bryde's whales and the North Atlantic common minke whales. But the scientific committee has not done enough work yet to complete management plans for four populations: the western North Pacific common minke, Antarctic minke, sei, and Southern Ocean fin whales.

Yet the proposal currently includes "example" catch limits for these populations, even though some of the scientists are uncomfortable with the IWC political delegates including catch limits before researchers have finished their assessments. "It seems a little backward to do it that way," says Andy Read, a biologist at the Duke University Marine Laboratory in Beaufort, North Carolina and a member of the scientific committee. The scientists say they will need several years before they can complete their surveys and come up with a credible management plan for all the whale populations currently being targeted. 

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