Eel farming. (Photo: Mahurangi Technical Institute/FIS)
Eel farming advances
Tuesday, February 14, 2012, 15:10 (GMT + 9)
A major research project being conducted at Mahurangi Technical Institute's (MTI) Warkworth facility is the breeding of NZ short fin eels.
Eel farming currently relies on wild-caught juvenile or glass eels subsequently raised to marketable size on eel farms. Over the past 20 years, water pollution, migration barriers, changing land use, overfishing and predators have been driving the natural eel population toward extinction.
Wild eel stocks are doing particularly poorly in Europe. In NZ, the three local species are doing a little bit better: the native longfin eel is classified as threatened and the shortfin and Australian longfin eels are doing just barely better, Fairfax NZ News reports.
The MTI research team is trying to develop a process to produce glass eels for supply to aquaculture farms, thereby reducing pressure on wild stocks of eel.
MTI researchers have successfully bred NZ short fin eels for the first time even though until recently very little was known about the breeding habits of the species. The current challenge is keeping the larval fish alive for 100 days, by which time they will have matured into baby or glass eels and can be transferred to aquaculture farms until they mature.
Conservation groups overseas, such the Environment Agency Wales, are becoming increasingly interested in the institute's work and hoping it will help them preserve European populations.
"Increasingly our focus is falling upon eels, given the perilous state of that species in Europe where stocks have fallen 95 percent in the last 20 years", said Environment Agency Fish Culture Manager John Taylor.
On the other hand, a valuable species in Europe is perch. As its farming is seasonal and New Zealand's breeding season is about six months later than Europe's, there is an opportunity to export “out of season” fertilised eggs to a major perch hatchery in Ireland which supplies young fry to other European countries; this supply could raise the Irish hatchery's annual output by about 25 per cent, MTI said.
The research team exported 2 million live eggs to Ireland in 2006.
Currently, MTI is successfully farming koura or freshwater crayfish, banded kokopu and inanga and is experimenting with the raising of several other native freshwater fish species for production and sale, including red-finned bully, common bully, Crans Bully and torrent fish.
- EU grants North Ireland eels special protection
By Natalia Real