Radio-tagging risks infecting dolphins
It is with grave concern that I read in the South China Morning Post ('Pact agreed to help save dolphins', June 3) of a plan to capture and radio-tag humpback (or Chinese white) dolphins in the Pearl River.
Several years ago, proposals were tabled by a scientist working on behalf of the Hong Kong government to conduct a biopsy sampling project (involving firing darts at dolphins to collect a few millimetres of skin and some underlying blubber tissue). These proposals were rejected, with opponents saying that the research would be too invasive, that dolphins would be exposed to a risk of infection from contaminated seawater and that it would add stress to an already strained population of dolphins. The proposals were criticised by the World Wide Fund for Nature in Hong Kong.
It surprises me, therefore, that WWF-HK now plans an even more invasive research project, which would require the chasing, netting and manhandling of dolphins, and ultimately punching holes in their dorsal fins through which a radio tag is bolted.
Studies into the stress effects of capturing and sampling dolphins in the US have shown that it causes an increase in 'stress hormones' and a depression of the immune system. In the Pearl River, the information could be gained using non-invasive techniques or at the very least tags with non-injurious suction cups.
WWF should perhaps concentrate its conservation efforts to reduce the impacts of pollution, collisions among boat traffic and entanglement in fishing gear (which are actually killing dolphins).
E. C. M. PARSONS, humpback dolphin researcher, Gaithersburg, Maryland, US