Lake Peipsi fishery data 1986 and 1990-2007 (test trawling samples)

For Lake Peipsi, experimental trawling has been conducted since 1986. Test trawling was conducted in the Estonian side of Lake Peipsi s.s. in autumn 1986 and from 1990 to 2007 using the bottom trawl (height 2 m, width 12 m, knot-to-knot mesh size at the cod-end 10 to 12 mm). The trawl was towed by a ship for 15-30 min per haul at speed of 5.5–6.2 km h–1. Test trawling was carried out monthly at noon from August until November in the pelagic zone of the Estonian side of Lake Peipsi s.s. On each sampling occasion, several hauls were made at multiple locations of the lake. All fish were identified, and their standard lengt (SL) was measured to the nearest mm. Moreover, the catches per unit effort (CPUE, individual per trawl-hour and kg per trawl-hour) of trawl samples taken in autumn were calculated for the main fish species (i.e., lake (dwarf) smelt (Osmerus eperlanus), vendace (Coregonus albula), Peipsi whitefish (Coregonus lavaretus maraenoides), Northern pike (Esox lucius), roach (Rutilus rutilus), common bleak (Alburnus alburnus), common bream (Abramis brama), burbot (Lota lota), Eurasian perch (Perca fluviatilis), pike-perch (Sander lucioperca), ruffe (Gymnocephalus cernuus) and total catch.