KiEco Ecology: Freshwater Fish

A strict methodology is applied when sampling for freshwater river fish. There is a core network of sites which are monitored on an annual basis, and also catchment-wide surveys on a six-year rolling programme. These sites are located in habitat types suitable for the respective fish species. In addition, sites may be sampled for investigative work, or on an ad hoc basis. Sampling areas are commonly 50 metres long and the full width of the river and may embrace different flow types and substrate. Electric fishing is the most commonly used sampling method, although alternative methods are available for different strategies, such as netting and trapping. Once a sample of fish is collected, they are immediately identified in the field, measured and counted and then released alive into the same section of river from where they were captured. Freshwater fish survey data is available from 1974 to present. A caveat being that historical data are sporadic until 2001. This is because fish survey data collected before 2001 were often saved in local databases and not the national ones (KiEco and formerly NFPD).