Deer farmer Shelley Trotter, near Warkworth, wants to release 1000 three-year-old fish to restock a stretch of Duck Creek in her farm, a tributary of the Mahurangi River.
Juvenile kokopu are one of the species which contribute to endemic whitebait and are classified by the department as “at risk, declining”.
Giant kokopu are bred in captivity by the Mangakura fish hatchery in the Kaipara district only 20km cross-country from Solway deer farm, which has won awards for environmental achievements, including waterway restoration.
The licenced fish farm owner Jerry Rees-Webbe says he is frustrated by the delays in processing and the reasons given by DOC for declining release permission.
The Ministry for Primary Industries, which must also approve a transfer and release of captive fish, and Fish & Game have supported the planned release.
Similar releases of fish from captivity were made two years ago in the Nukumea Stream in the Auckland district of Orewa and giant kokopu have also been released in the Tawharanui Regional Park, both approved by the department.
Rees-Webbe says the department should be harnessing the concerns of New Zealanders over native flora and fauna and encouraging landowners who are making ecological efforts.
“Farmers are restoring waterways at considerable cost and effort and we are trying to restock these with native endangered fish,” Rees-Webbe said.
“DOC appears to put legislative blocks in our way, which seem to be nonsense and outdated.”
He says it seemed the Duck Creek planned release seemed to be welcomed by the department until advice was sought from its in-house freshwater ecologist Marine Richardson.
In an email to the applicants, Lynette Trewavas of the permissions group in Waikato, says an application to release indigenous fish was not as straightforward as it looks initially.
Richardson had advised that release of captive animals carried the potential for introducing diseases, pathogens and parasites not present in the wild.
Conversely, the immune systems of aquaculture fish might not be adapted to pathogens in the natural environment.
She says the release of 1000 giant kokopu in one creek could destabilise the food web in that location.
Without an estimate of the fish population in the location, there was no indication if the freshwater system was suitably large for that number.
Native fish were largely diadromous – using marine waters in their life cycle – and could naturally repopulate the Mahurangi/Duck Creek system.
Rees-Webbe says DOC now required an Environmental Impact Assessment, which could be very costly on top of the $2300 fee the department charged, plus the requirement to advertise the planned release in local media.
“Introduced captive fish are being released all the time by Fish & Game and our indigenous kokopu have been kept in pristine disease-free conditions and have already been conditioned for life in the wild,” he said.
He says the fish need acclimatisation before spawning in late winter and release should ideally occur before mid-April.
In a recent freshwater fish study done for the Auckland Council, it was stated that the Nukumea and Tawharanui waterways were the only two in the mainland region containing giant kokopu, and that was because of restocking.
Trotter has written to the Minister for Conservation Kiri Allan asking her to intervene.
