Methodology to survey and monitor New Zealand mudfish species

Abstract

Standard methods to survey and monitor NZ mudfish species involve Gee minnow traps for adults and hand nets for earlier life stages, although a range of methods have been used. A basic assessment of fish abundance can be gained from one night of trapping, however, estimates of fish density and sub-population size require repeated identical sampling events. In developing a study the objective neds to be well considered in order that the information collected addresses the particular research question. Study design and sampling effort are usually individualised to the type of habitat being sampled and resources available. Catching fish and measuring their length and weight is straightforward and uses relatively simple equipment. More detailed examination and marking of fish may be required in some studies. From information collected in the field a range of further calculations and analyses are usually done to assess the state of health of the sub-population. Capture data should be submitted to the NZ freshwater Fish Database and habitat assessed using the Handbook for Monitoring Wetland Condition. The Department of Conservation Mudfish Recovery Group plans to regularly collate survey and monitoring information.