Performance and Biological Implications of a Multi-gear Fishery for Greenland Halibut (Reinhardtius hippoglossoides)

Abstract

Simultaneous full-scale fishing operations using bottom trawl, gillnet and longline for Greenland halibut (Reinhardtius hippoglossoides, Walbaum) were performed in the Barents Sea (ICES Divisions IIa and IIb) for two weeks in October 1992. The mesh size of the trawl codend was 135 mm, and that of the gillnets 220 mm. Additionally, seven gillnet fleets of 180 mm mesh size were set for selectivity comparison. The catch rates and the length distributions of the Greenland halibut in the catches taken by trawl, longline and gillnet were different. Gillnets almost exclusively caught fish between 60 and 70 cm, mostly mature females (about 90%). The size distribution taken by longline was wider than that taken by gillnet. Two thirds of the longline catches were females, and the proportion of immature individuals was larger (14-30%) than in the gillnet catches. The trawls, however, caught large amounts of fish between 40 and 60 cm, consisting of almost equal amounts of males and females, and 30-40% immature fish. Gear-specific selection properties were the main reasons for the observed differences.Yield-per-recruit and spawning-stock-biomass-per-recruit analyses showed that fixed gears captured proportionally fewer immature fish, and thus indicated they would provide greater spawning biomass and yield-per-recruit than would trawl gear, for an equivalent reference fishing mortality rate.

Population Structure of Greenland Halibut (Reinhardtius hippoglossoides) in the Northeast Arctic, 1992-2000

“…Trawl catches had a wider size spectrum than catches from gillnets and longlines and also caught more fish of smaller sizes. The differences between gillnet and trawl catches may be explained by the mesh selection properties of the gillnet (Nedreaas et al, 1996) and that the trawl is an active gear catching more or less all in its path. The trawls may better reflect the true size composition in the stock, but the catch is also affected by avoidance reactions to the approaching gear, which may bias the length frequency composition in these catches (Ona and Godø, 1990).…”

“…In addition some publications have used parts of the available data from the time series analyzing selectivity, fecundity and distribution of Greenland halibut (i.e. Nedreaas et al, 1996;Huse et al, 1999;Gundersen et al, 1999;Bowering and Nedreaas, 2000).…”

“…length, age and sex composition changes with different gear. Longline and gillnet catch larger fish than trawl (Nedreaas et al, 1996). The present study therefore used data from all three gear types with the objective to describe how the population structure of the Greenland halibut stock varied between years, areas and gears along the slope area between Norway and Svalbard in the period 1992 2000.…”

Gill net and long-line catch comparisons in a hake fishery: the case of southern Portugal

“…Despite the fact that several studies have been conducted on multi-gear fisheries, namely on the comparison of static gear selectivity (Erzini et al 1996;Huse et al, 1996Huse et al, , 1999Huse et al, , 2000 and on their performance (Aldebert et al, 1993;Nedreaas et al, 1993;Walsh, 1997), the present study constitutes an additional attempt to improve the available information on a set gear deep-water hake fishery within European waters. The main objective of this study was to compare long-line and gill net catches.…”

Competition between static gear of the small-scale fisheries in Algarve waters (southern Portugal)

“…Several comparative fishing studies have been carried out in a number of fisheries, but in most cases the studies have focused on one or two species (ENGAS et al, 1993;ELLIOTT & BEAMESDERFER, 1990;NEDREAAS et al, 1993;ROLLEFSEN, 1953;RUSSELL et al, 1988;YANG & GONG, 1988) with a few examples of a multi-species assemblage (STERGIOU et al, 1996;2002;ERZINI et al 1996b). ERZINI et al (1996b) compared small hook Medit.…”