Rebuilding the Stock of Northeast Arctic Greenland Halibut (Reinhardtius hippoglossoides)

Abstract

After the absence of 1989–1994 year classes of Northeast Arctic Greenland halibut (Reinhardtius hippoglossoides) in regular surveys, an annual survey programme was initiated in 1996 to map juveniles in previously unsurveyed waters north and east of Svalbard. After rather stable juvenile indices in the first years, the recruitment indices have increased tenfold from 2001 to 2006. The increase in juvenile Northeast Arctic (NEA) Greenland halibut corresponded with an increase in spawning stock biomass. The swept area abundance estimates of spawning females (i.e., females >60 cm), has nearly tripled since 1996 having achieved 29 000 t in recent years. This improvement occurred after years of strong regulations, introduced in 1992, by enforcing a moratorium on the targeted offshore fishery and strict bycatch regulations for the species. Regulations were introduced after a dramatic change in stock status for the NEA Greenland halibut during the 1980s. Females >75 cm contributed more to the stock’s total egg production (TEP) in more recent years. The contribution from these larger females increased from 10% of the TEP estimate in 1996 to 21% in 2006. The results from the present study indicate that rebuilding Greenland halibut stocks takes time, and that at least 12–15 years with restrictions are needed to recover from the low levels observed in the Barents Sea in the beginning of the 1990s.