Invasive fish research
Invasive fish research programme
The invasive fish research programme focuses on investigations into the distribution and abundance of pest fish such as koi carp (Cyprinus carpio), goldfish (Carassius auratus), and brown bullhead catfish (Ameiurus nebulosus). It also includes studies on the ecological effects of pest fish and on methods to improve capture efficiency and biosurveillance. Key equipment in this programme is a highly successful electrofishing boat.
The University of Waikato's electrofishing boat on Lake Karapiro with (left to right) Dudley Bell driving, and David Hamilton and Brendan Hicks fishing.
Fish sampling in non-wadeable habitats
Brendan Hicks and Dudley Bell have developed New Zealand's first successful electrofishing boat specifically to fish non-wadeable habitats. The ability to catch pest fish in fresh water that is too deep for wading (1-3 m) is the key to determining the abundance, impacts, and biological effects of pest fish. Another major advantage of boat electrofishing is its time efficiency, with the ability to fish kilometres of habitat in a single day without the need for repeat visits. Further, quantitative fish capture is possible. With our on-board GPS unit we estimate the distance and area fished. We can then calculate density and biomass per unit area. Since its launch in July 2003 we have was used in over 100 locations in the North Island of New Zealand to catch over 20,000 fish (total weight over 5 tonnes). We have developed multiple-pass boat electrofishing to give removal population estimates (Hicks et al. 2006). Using this method, we have found that koi carp biomass in the Waikato region can reach 2,060 kg/ha.
