Fisheries-related variations in the fecundity of the southern king crab in Patagonia

Abstract

The southern king crab (SKC) Lithodes santolla has supported a profitable fishery in the San Jorge Gulf (SJG) and adjacent area, Argentina, since 2004. This fishery allows landings only of males larger than 110 mm carapace length. Since large-male-only harvests have had a detrimental effect on the egg production of other king crab populations, here, we compared the SKC fecundity before the start of the industrial fishery (1994–1996) with that of the fully harvested population (2014–2018), and analyzed the variation in fecundity related to fishery policies, to areas with different levels of fishing effort, and to different times of the fishing season. During 2014–2016, SKC fecundity was 25% lower than that during the pre-fishery period (1994–1996). However, fecundity in 2017–2018 was 11% lower than that during the pre-fishery period. Results also revealed that fecundity was greater in coastal areas (where an artisanal fleet operates) than in offshore areas (where the industrial fleet operates) and that it was similar throughout the fishing season. We concluded that: 1) SKC fecundity decreased after 10 years of fishing, 2) fishing during the mating period affected SKC fecundity, and 3) there is no significant egg loss during the fishing season. Recent changes in SKC fishery management, including the mandatory use of escape rings and the implementation of a closure during mating, seem to have had a positive effect on SKC fecundity.