A record drop in the number of New Zealand sea lion pups means the Fisheries Minister must cut the number of sea lions killed in the southern squid fishery, Forest & Bird says.
Department of Conservation researchers on New Zealand’s sub-Antarctic islands have recorded a 31% fall in the number of NZ sea lion pups born this season.
In December Fisheries Minister Phil Heatley set the number of sea lions which the squid fishery around the islands is permitted to kill as “by-catch” at 113 – up from 81 the previous year.
Forest & Bird marine advocate Kirstie Knowles says the fall in the number of sea lion births means that the high kill quota in the squid fishery seriously threatens the ability of sea lion populations to recover.
“The model used by the minister to calculate how many sea lions could be killed without threatening the sea lion population did not factor in such a low birth rate. There are hundreds fewer sea lions being born than was predicted by the model,” Kirstie Knowles says.
“With so few sea lions being born, the potential for the squid fishery to kill so many sea lions could have a catastrophic effect on the future survival of sea lion populations.”
Forest & Bird is calling on the minister to urgently review his decision to increase the kill quota by 40%.
“That number of sea lion deaths in the squid fishery risks reducing the sea lion population to a level from which it cannot recover. In the light of this new information, the minister should set a much lower kill quota so this endemic marine mammal is not put at risk.”
Once found right around the mainland New Zealand coastline, NZ sea lions now breed in just a few colonies in the sub-Antarctic islands, where they are highly vulnerable to disease epidemics and genetic “bottle-necks”.
Researchers are not sure why fewer sea lions have been born this season, but have observed far fewer females coming ashore to breed. The sea lions are killed when they get caught and drown in the trawl nets used to catch squid. More than 80 per cent of sea lions killed by the squid fishery are female, many of which are pregnant and also have a pup on shore, which will then starve to death, so by-catch deaths have a direct impact on sea lion reproduction.
NZ sea lions are found only in New Zealand waters and have been classified as a threatened species since 1997. Last year the World Conservation Union (IUCN) elevated their threat status by listing them as being in decline.
• Ministry of Fisheries and DOC data.