The Waikato’s vanishing whitebait fishery could be revived and millions of whitebait returned to the environment using artificial pond breeding, according to a Raglan-based biological consultant.
Charles Mitchell told this week’s Environment Waikato Environment Committee that opportunities existed for environmental management agencies and regional councils to help in restoring the fishery.
He said the Waikato once had a huge whitebait fishery yielding 100 tonnes a year with two canneries and the excess used as fertiliser. Agricultural development had had a huge effect on the industry as early as after the first World War, but the scope of the problem and lack of effective alternatives or funding prevented any response.
Catches had fallen dramatically since the early 1930s, but over 100 fishers a day still fished the lower Waikato River and catches fetch up to $170 a kilo. As a result of overfishing and habitat loss the fishery was in danger of collapse.
He said possible solutions included a conservation response, but this relied on sufficient habitat and, realistically, natural production from small reserves could not support any significant improvement for the present fishery.
Aquaculture based on artificial pond systems where water levels could be manipulated and feeding supplemented was a better solution.
He said he had built six tidally influenced ponds at Raglan over a hectare which mimicked a natural oxbow meander and which was achieving good results so far.
“It’s a bit like trying to start a sheep station with a pair of sheep, but after initial set up we hope it would be self sustaining.”
Producing a tonne of whitebait required a hectare of land in a tidal area, part time labour and $4000 worth of trout pellets, which produced whitebait worth $60,000 to the economy, or added 33 million whitebait to the environment and brought nutrients back to the food chain.
“Ten hectares of managed ponds in the lower Waikato could double current yields from the River and could begin a commercially viable aquatic industry. As well we have added fernbirds, crakes, branded rail and bittern flocking to the pond areas.”
He suggested regional councils, local bodies, fishing interests and Maori could provide support for whitebait restoration projects.
While regional councils were not responsible for fisheries stock management, they were responsible for protecting significant habitats of indigenous fauna. Reversing the effects of habitat loss, particularly in aquatic ecosystems such as the Lower Waikato, required cost effective methods for restoring existing habitat and, where possible, creating new habitat for species such as native inanga which made up more than 60 percent of the annual Waikato River whitebait catch.
Councillors were enthusiastic about the project, and Cr Evan Penny suggested discussions should be held with major users of the Waikato River to make use of the ideas in their mitigation programmes.