Forest & Bird are saddened to hear that the necropsy of a Hector’s dolphin – which was killed in a net off the Otago Coast at the end of April – has been identified as a female of the 'nationally vulnerable’ species.
“This death is a catastrophic blow for Otago’s Hector’s dolphin subpopulation,” says Chelsea McGaw, Forest & Bird’s regional conservation manager for Otago. “A loss like this puts the Otago Hector's dolphin pod one step closer to local extinction.”
The Otago coast Hector’s dolphin subpopulation, found in the area around Blueskin Bay near Dunedin, is discrete. Estimated at just 41 individuals, the Otago population doesn’t appear to interact with other pods from further afield.
The population has not increased since the last official count in 2008, despite the introduction of restrictions on fishing measures within dolphin habitat.
“This unnecessary death clearly shows that voluntary measures for fisheries don’t go far enough to protect this taonga species,” says McGaw.
The female was caught outside the Hector’s dolphin protection zone, where fishing methods such as set netting are prohibited. But under the South Island Hector’s Dolphin Bycatch Reduction Plan, one Hector's dolphin death falls below the allowed mortality limit.
Launched in November 2022, the plan outlines a suite of regulatory and voluntary measures designed to reduce Hector’s dolphin bycatch towards zero. In Otago, the mortality limit is set at two deaths per year.
“The fisheries-related mortality limit of two deaths per year will quickly devastate this local population,” says McGaw.
“While larger populations, like the 900 or so Hector’s dolphins around Banks Peninsula, can withstand small deviations, every individual in Otago – especially a precious breeding female – is essential for the pod’s survival. This latest death represents a 10% drop in breeding females for this population.
“Two Hector’s dolphin deaths every year is simply too high. The number should be zero.
“MPI and DOC need to review the rules to make sure that dolphin-friendly methods of catching fish are required over the entire habitat of Otago's Hector's dolphins.”
This is the first reported death of a Hector’s dolphin on the Otago coast in ten years. The vessel that reported the death was accompanied by an independent observer. However, observer coverage in the fishery has been consistently falling below targets. Fishers are more likely to report bycatch when independent observers are onboard.
The roll-out of cameras across 300 inshore vessels, expected to be complete by the end of 2024, will help ensure all bycatch is reported.
Four dead Hector's dolphins. Note: this is not the deceased Hector's dolphin from Otago referenced in the release. Image credit: Department of Conservation.