The number of Hectors dolphins being mutilated on New Zealand's coastlines is growing, according to figures obtained from the NZ Department of Conservation.

Records show there have been 36 cases of dolphins found mutilated since 1980, with 17 examples occurring in the last 8 years.

Five dolphins had their bellies slit open, one in 2004 had its head cut off and had been hit with a blunt instrument, eight had their tails or tail flukes cut off, two had fins cut off, two had been filleted, one was gutted and another nine dolphin carcasses had knife marks on them. In 15 cases the dolphins were known to have been killed in set nets or had set net marks on their bodies. The maimed bodies were found on beaches around the country, and post mortems were done by Massey University pathologists.

It is feared that many of the mutilations were inflicted by fishermen who had accidentally caught Hector's dolphins in their nets and were trying to hide the evidence. In May 2008 the NZ Government announced measures to protect Hector's and Maui's dolphins, including the creation of marine mammal sanctuaries and bans on set netting in the coastal waters where the dolphins are most often found. However, five commercial fishing companies have legally challenged the fishing measures, and the High Court will hear the case in April 2009.

Hector's dolphins are an endangered species. A sub-species, Maui's dolphin, numbers just 111 individuals, and is critically endangered.

Image copyright: Forest and Bird