New study takes aim at dolphin pollution threat

PUBLISHED : Monday, 10 April, 2006, 12:00am
UPDATED : Monday, 10 April, 2006, 12:00am

Hong Kong researchers will use crossbows to take tissue samples from live Chinese white dolphins for a new study. They have, however, stressed that this will not hurt the marine mammals.

The two-year study to monitor the number of Chinese white dolphins, also known as Indo-Pacific humpback dolphins, and their distribution in Hong Kong was launched by the Agriculture, Fisheries and Conservation Department (AFCD) at the end of last year.

Using tissue samples from live dolphins, the research aims to investigate the long-term impact of environmental contaminants on the mammals' health.

AFCD's senior marine conservation officer Joseph Sham Chun-hung said the department has been studying this rare dolphin for the last 10 years to help protect them from the threat of pollution, construction work and other human activity.

In the past, however, researchers could only test tissue from dead dolphins found stranded on the beach because of limitations in the technology available.

To better gauge pollutant levels in the dolphins' bodies and understand their biology, the new study will take samples from live dolphins with a crossbow that has proved successful and effective in preliminary trials.

Researchers will use the crossbow to shoot a biopsy dart attached to a retrieval line. The dart takes a tiny core of skin and blubber from the animal.

The skin sample will help determine the dolphins' gender and the blubber can help in pollutant analysis.

Mr Sham said that the dolphins should not feel pain because the dart will only take away a little piece of skin and blubber without touching the nerves. The method has also been widely adopted by marine mammal experts worldwide.

Furthermore, the department will impose a number of strict restrictions when taking samples from the dolphins to minimise the impact on the animals. For example, researchers will not be allowed to take samples in the marine park, and no samples will be taken from dolphin parents that are still looking after their offspring.

The study is expected to collect about 30 biopsy samples in two years, and the tissue will be tested in collaboration with the City University of Hong Kong.

The results will help generate an environmental risk assessment for Chinese white dolphins in Hong Kong waters.