How temperature affects kingfish larval quality
A kingfish larva, approximately 5 mm long. (Photo: Damian Moran, NIWA)
Although commercial-scale production of kingfish fingerlings is now a reality, researchers at NIWA’s Bream Bay Aquaculture Park continue to investigate how production techniques can be improved to benefit the industry. One such study aims to find out how different egg incubation temperatures affect the quality of kingfish larvae; higher quality larvae in turn become higher quality fingerlings, which subsequently benefit commercial operations growing these on to marketable kingfish.
The size of fish larvae at hatching is often used as an indicator of larval quality by scientists, both in the wild and in aquaculture. Temperature greatly modifies the development of fish eggs and larvae, and it is important to optimise the temperature range for incubation to maximise larval survival and fitness.
The work at Bream Bay shows that while higher incubation temperatures result in smaller kingfish larvae at hatching, the larvae reach similar sizes at first feeding irrespective of incubation temperature. The practical implication of this is that, between 17–21 °C, there is little effect of incubation temperature on larval fitness. Higher temperatures probably result in smaller larvae at hatching because the formation of hatching glands is accelerated, and there is increased activity of hatching enzymes and embryo movement, causing the egg shells to break earlier. This work has been published in the prestigious industry journal Aquaculture, a summary of which is available at http://tinyurl.com/2mlc9m