Liz Slooten: Inconvenient Truths About Dolphins

Plans to protect Hector’s and Maui’s dolphins have led to some unusual claims in the media in the last week or two. Having studied these dolphins since 1984, we thought we should answer some of these claims.

“The number of dolphin deaths has been exagerated”

A repeated claim is that published estimates of dolphin bycatch must be wrong because the DOC database of voluntary reports includes far fewer dolphin deaths. The bycatch record for Canterbury shows why these statements are misleading. Voluntary reports of dolphin entanglements average 2 dolphins per year. However, using data from independent observers on fishing boats NIWA estimate that around 30 dolphins a year are caught in the Canterbury gillnet fishery alone. That’s 15 times the average voluntary reporting rate, and does not include bycatch by trawlers or amateur gillnets.

“Research showing that dolphin populations are declining is wrong”

This would mean that scientists at Otago University, NIWA and the fishing industry are all wrong, as their work indicates that Hector's dolphin populations numbered 21,000-29,000 in the early 1970s compared to fewer than 8,000 now. In the next 50 years, they are expected to decline to below 6,000 if nothing more is done, or recover to around 15,000 individuals if fishing deaths are reduced to zero.

“Maui’s dolphins don’t enter harbours and haven’t been studied since 1987”

Since 1987 research by Auckland University, Otago University and DOC has included boat surveys, genetic sampling, aerial surveys (one is happening right now) and monitoring with acoustic data loggers (starting in 2004 and ongoing). There have been several sightings and acoustic detections in the Manukau Harbour, beyond the protected area. The other harbours have not yet been studied in detail, but reliable sightings have been made in 3 of the 5 harbours.

“We need more information”

This is a standard catch-cry from industries causing health and environmental impacts, and sometimes echoed by management agencies responsible for managing those impacts. We heard the same from tobacco companies long after smoking had been proven to cause lung cancer and from oil industry scientists challenging the International Panel on Climate Change.

In fact, much more information is available for Hector’s dolphin than for most other dolphin species. e.g. Hector's dolphin is one of only two species of dolphins in the world for which there is a robust estimate of total population size and one of three species for which there is an estimate of adult survival rate.

About 2 years ago, as part of the development of the Threat Reduction Plan, DOC and MFish set up an Advisory Group and an Expert Panel. Both groups included representatives from the fishing industry, recreational fishers, tourism industry, conservation groups, iwi and independent scientists. These groups agreed without difficulty that the most serious threat to the species is entanglements in gillnet and trawl fisheries.

We know exactly what the problem is and how to solve it. Hector’s dolphins have been killed in fisheries for more than 35 years now, and studied in detail for nearly 25 years. It's just not credible to keep saying "we need more information".

“The economic cost is too high”

Fishing industry lobbyists argue that saving Hector’s dolphin will cost hundreds of jobs and millions of dollars. These claims are simply unfounded. First, setnetting is not very important to the NZ economy, contributing a fraction of one percent of total income from fishing. Secondly, the claim assumes that all these fishers would have to stop fishing. The more relevant figure would be how much less would they make if they change to fishing methods that don't catch dolphins. There is no need to stop fishing.

Moreover the change could be relatively painless. Most fishing boats in NZ that use gillnets already use other methods as well, including trawling, craypots, longlines. Fish an chips will certainly continue to be a popular meal. For example, ling caught on longlines and blue cod caught in fish traps is often used in fish & chips.

What needs to be done

The Department of Conservation (DOC) and Ministry of Fisheries (MFish) have recently released for public consultation a draft Threat Management Plan for the species. The public has been invited to comment on the plan by 24 October 2007. Option 3 is the only option in the draft Plan that comes close to meeting national and international standards for marine mammal conservation, that is to ensure population recovery

Fishermen themselves will benefit from using selective, sustainable fishing methods

Changing to selective, sustainable fishing methods would have many benefits, not just for Hector’s dolphin and other dolphin species but for a wide range of other species including non-traget fish species and seabirds. And in addition, there will be long-term economic benefits. Using selective, sustainable fishing methods is an inherently good idea.

Dolphins: Worth more alive than dead

Another important consideration is that these dolphins are worth millions of dollars to the NZ tourism industry. But the emphasis on the details of the biological and economic facts and figures obscures an important consideration. What is it worth for New Zealand to be seen internationally as a clean and green country that makes conservation decisions based on peer reviewed and published scientific data rather than hearsay and political pressures. How much would it cost us if we lost that image?

ENDS

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