Posted by Jim Kerr - 13/08/2015 12:22:00
Seastar recently collaborated with Medins Biologi during a long term electric fishing campaign to assess the abundance of juvenile salmonids in Swedish Rivers. The project formed part of a long term contract to estimate the population of juvenile Atlantic salmon, Salmo salar, and brown trout, Salmo trutta, (0+ and 1+) at select sites in several Swedish River systems to assess the effects of acidification on riverine fish.
The current survey data will be fed into a long term data set that has been on-going since the 1980's allowing temporal changes in population characteristics to be assessed. The yearly catch data are used to produce biological indices that help scientists to assess the ecological status of the river system as well as assess the population status of these commercially and ecologically important species.
Three consecutive sweeps of a predetermined river area were undertaken and species specific equations used to estimate the total number of fish per 100 m2 . Between each sweep fish were weighed, measured and identified and logged into pre-prepared site-specific spreadsheets.