Appendage regeneration in southern king crab females: effects on growth and egg production

Abstract

Regeneration of the lost appendages determines an extra energy demand, limiting energy allocation to other functions, including reproduction, growth and maintenance. In decapod species, injuries and appendage loss may increase due to fishing practices. The southern king crab (SKC) Lithodes santolla supports commercial fisheries in southern Argentina and Chile. Little is known about the impact of appendage regeneration on SKC biology and population dynamics. The main goal of this study was to assess the effects of appendage regeneration on the growth and egg production of SKC females to better understand its impact on the population. The frequency of appendages loss was estimated, and the effect of injuries on growth and egg production was assessed. Molt increments, fecundity, and egg dry mass (EDM) of non-injured and injured females were compared using a general linear model approach. The frequency of SKC females with appendage loss was 8.2%. No differences were found in molt increments when comparing between non-injured and injured females. Regenerating females were 38.6% less fecund than non-regenerating females, while no effects on EDM were observed. As the theory predicts, at maturity, the energy allocated to egg production increases, leading to reduced growth in SKC females. Therefore, it is expected that energy allocation to reproduction may be more affected by the extra energy required for appendage regeneration. Our results indicate that appendage regeneration has a detrimental effect on SKC fecundity. This limitation affects the reproductive potential of the SKC and their population replacement rate.