Eel farming could be the way ahead
Commercial eel farm research at Warkworth is offering hope for endangered wild populations in Britain.
Eel populations having plummeted worldwide over the past 20 years and New Zealand eel research and management strategies are coming into the international spotlight.
Overfishing, pollution and a host of other threats have hit populations around the world.
Our three species are still not in great shape but in better shape than wild eel populations elsewhere.
The native longfin eel is classified as threatened and the shortfin and Australian longfin eels are only marginally better.
The work at Mahurangi Technical Institute in Warkworth on developing methods to commercially farm eels is attracting serious interest as conservation groups overseas grapple with how to save their own populations.
Last month Welsh fish culture manager John Taylor visited Warkworth to see their research into the breeding of shortfin eels and their work with native freshwater fish for conservation and education.
Dr Taylor manages the fish hatchery and farm at Brecon for the Environment Agency Wales where threatened British native fish are produced for re-stocking projects across the UK.
"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," Dr Taylor says.
"The work at MTI has achieved international recognition and I am very pleased to have received support from the Winston Churchill Memorial Trust which has enabled me to visit MTI and learn from their advances."
He spent the day touring the MTI aquaculture research and educational facility in Woodcocks Rd and discussing methods of artificially maturing, spawning and rearing New Zealand shortfin eels.
Preparing hatchery bred native fish for transition to the wild was also discussed including training captive bred fish and others like koura (freshwater crayfish) to recognise predators in an effort to help improve their chances of survival when released.
Efforts to commercially farm eels in New Zealand were made in the 1970s but the industry struggled with high costs and low returns.
Eels are slow-growing, long-lived and unlike any other exploited fish species only breed once at the end of their lives which can be as long as 100 years.
They also swim a vast distance to New Caledonia and Vanuatu to spawn and then die. Larvae, are carried back on ocean currents, taking up to 18 months to return to the New Zealand coastline. By the time eels came under Fisheries quota management system in 2004 the local populations had been over-fished and were in a poor state.
The $6 million industry exports most of its catch often to countries whose own eel populations have been seriously depleted.
While conservation groups and some scientists have been scathing of the commercial eeling industry, questioning its sustainablility, Mr Decker is more forgiving.
"If we only rely on the quota management system to save the eels we'll still loose them. Stopping commercial catches will only buy us an extra 15 years. We have to look at water quality and hydrodams," he says.
While young eels can still enter the hydro lakes, they are chewed up in the turbines when they try to leave to spawn, he says.
The $3 billion international industry relies entirely on growing-on young eels taken from the wild.
Researchers at MTI now believe they are much closer to being able to produce eels in a closed loop – to farm using artificially bred stock.
- Rodney Times
Are our classrooms becoming overcrowded?