Swept area variation with depth and its influence on stratified trawl surveys indices on Arcto-Norwegian cod

• Main Authors: Engås, Arill, Godø, Olav Rune
• Format: Report
• Language: English
• Published: ICES 1986
• Subjects: trawl; trål; sampling; prøvetaking; VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497; VDP::Mathematics and natural science: 400::Geosciences: 450::Oceanography: 452; Svalbard; Barents Sea
• Online Access: http://hdl.handle.net/11250/104141

Stratified trawl surveys have been carried out in the Barents Sea and the Svalbard areas since 1981. Based on the assumption of a constant area swept by the trawl during a standard trawl haul at any depth, swept area abundance indices have been presented for both areas. The results have been used in the management of the Arcto-Norwegian cod stock. In this paper results from measurements of trawl geometry during trawling operation during a standard stratified trawl survey in the Svalbard area in September-October 1985 are presented and the implication on the trawl indices of these results are discussed.