Counting fish at night using artificial light: transect survey of common bream Abramis brama and northern pike Esox lucius abundance as an example.

Abstract

Visual transect counting of large-bodied fish using artificial light at night in a shallow littoral zone (<1 m water depth) is introduced as a complementary survey method for fishes such as common bream Abramis brama and northern pike Esox lucius that are under-represented in standard gillnet surveys. The results suggest that transect counting at night and applying necessary corrections for environmental variables could provide a simple and repeatable method to assess the presence and abundance of large-bodied fishes in lakes with satisfactory water clarity.