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NZ's native long-finned eel population may soon be unsustainable as a commercial fishery, a scientist believes.
South Island eels were put into the Government's quota management system in October 2000, but researcher Don Jellyman said there was increasing evidence that current levels of commercial fishing and habitat loss could wreck the long-finned eel fishery.
The North Island commercial eel fishery is not yet regulated, but is due to be taken into the quota system next year. Recreational fishing rules introduced in 1994 allow a daily bag limit of six eels.
Dr Jellyman, freshwater fisheries principal scientist at the National Institute of Water and Atmospheric Research, said long-finned eels were "chronically threatened" because their numbers are expected to decline by 5 to 30 per cent in the next decade.
They were once the nation's most commonly encountered fish. Native long-fins live only in New Zealand.
Dr Jellyman said the eels were particularly vulnerable to over-fishing because they took a long time to grow, usually only between 1cm and 2cm a year.
"This means female eels can be very old - up to 80 years old - by the time they migrate out to sea to spawn.
"Because of their slow growth they're vulnerable to commercial capture for many years before they eventually spawn."
Eels were difficult to manage because they spawned once and then died.
Sustainable harvesting of eels is among topics covered at the Third International Wildlife Management Congress, which opened in Christchurch on Monday.
Herald Feature: Conservation and Environment