Female reproductive output and potential recruitment of three fished southern king crab stocks from the Southern Atlantic Ocean

Abstract

The female reproductive output and potential recruitment (PR) were studied in three Argentinean southern king crab (Lithodes santolla and Lithodes confundens) stocks: in the Beagle Channel (BC), under an artisanal fishery pressure since 1930; in the San Jorge Gulf (SJG), under 10-years industrial fishing exploitation; and off the Atlantic coast of Isla Grande de Tierra del Fuego (TDF), under current exploratory regime. After evaluating their reproductive parameters, we suggest that these fisheries pass through at least two detectable phases. The first phase, in the SJG stock, is sperm limitation evidenced by a high proportion of ovigerous females but a decreased female fecundity. A second phase, in the BC stock, shows a sustained low proportion of ovigerous females which were the largest females of this stock, along with a decreased relative abundance, which in lithodids are indicators of recruitment overfishing. Contrastingly, the TDF stock showed healthy population parameters before the opening of the exploratory fishery. The extremely low value of PR (2.6%) in the bc stock further reinforces that this stock is experiencing or has experienced recruitment overfishing, as a small proportion of the offspring would reach sexual maturity or achieve legal sizes.

Size at Sexual Maturity of Deep-Sea Unexploited Caribbean Metanephrops binghami (Boone, 1927) and Overexploited Mediterranean Nephrops norvegicus (Linnaeus, 1758) Using Morphometric and Gonadal Staging Approaches

“…Marković et al [47] suggested that overfishing was the cause of the decreased size at 50% maturity (25.7 mm CL) observed for N. norvegicus in the South Adriatic Sea, the same size as the one found in the NW Mediterranean. Indeed, the abrupt decline in population abundances, which is observed in the NW Mediterranean Sea, caused by overfishing [4], can be followed by shifts in size and age at first maturity [48][49][50]. The current estimates of size at sexual maturity using the gonadal maturity of N. norvegicus (26.0 CL) confirm a decline in size at sexual maturity of about 4 mm CL in two decades, consistent with that reported by Vigo et al [20], and probably linked to relatively high fishing pressure [12].…”

Trophic Ecology of Juvenile Southern King Crab Associated with Kelp Forest: Evidence of Cannibalism

“…Southern king crab stocks demonstrate signs of overfishing in Chile and Argentina [67,68] probably due to male-only fishery management [69,70]. Therefore, stock enhancement, a feasible strategy to restore natural king crab populations [71], seems a management alternative for the near future.…”