Dr. Simon Muncaster controlling kingfish farming conditions. (Photo: www.waikato.ac.nz)
Less sex helps kingfish growth
Tuesday, September 18, 2012, 02:40 (GMT + 9)
Scientists at the University of Waikato and Bay of Plenty Polytechnic are working on a project to have kingfish commercially farmed in New Zealand.
Dr Steven Bird, a molecular biologist from Scotland, and Dr Simon Muncaster, a specialist in fish reproductive physiology who completed his doctorate in Norway, are collaborating to discover how to successfully breed kingfish in captivity.
Although kingfish are already farmed in Australia and Japan, Bird said, a lot of issues around deformity and disease in the farming environment remain to be solved.
“So we’re trying to find out the ideal conditions for breeding – things like water temperature, diet and how the fish respond to stress,” he explained.
Muncaster has obtained fertilised eggs for research from the National Institute of Water and Atmospheric Research (NIWA).
“Kingfish grow quickly, which is good for commercial farming, but there are usually a few challenges associated with developing new aquaculture species and this is where we are interested in focusing our research efforts,” he said.
One challenge is slower growth. This happens in farmed fish because they reach maturity early under farmed conditions, such that a lot of their energy is then spent on reproduction rather than growth before harvesting.
Muncaster said that this slowed growth is often more evident in one sex of fish than in the other.
“One of our interests is to investigate the process of sexual differentiation in kingfish to see when and how they start developing either male or female characteristics. This could help us to produce fish of the same sex to maximise growth and to stop unwanted breeding, which can be important from an environmental point of view,” he commented.
To achieve this, he and Bird will need to rear more kingfish in the Tauranga facilities and produce two different types of zooplankton to feed the larvae, while carefully caring for the fish’s environmental conditions so they can successfully metamorphise into juvenile kingfish.
At Waikato University, Bird is using biomarkers and testing genetic level responses to external environment changes. The University has provided preliminary funding to obtain the biomarkers.
“With this technology we can get results in months, not years,” said Bird. “The information we get allows us to monitor responses to environmental changes and in turn fine tune farming practices during the different growth phases.”
Bird added that if New Zealand wants to grow its commercial aquaculture base, it will need to boost the number of species it farms.
By Natalia Real