Size at sexual maturity of male Lucensosergia lucens (Decapoda: Sergestidae) in Suruga Bay, Japan

Abstract

This study investigated size at sexual maturity of the male sergestid shrimp Lucensosergia lucens (“Sakura-ebi” in Japanese). The shrimps were captured in the inner part of Suruga Bay, Japan in August 2013 using experimental trawls. Carapace length (CL), body length (BL), development of petasma, and presence of spermatophores in the terminal ampoule were documented. Probabilities of maturity as a function of CL were modeled using general linear models with a binomial and logit link function and predicted the CL at which 50% of individuals were mature (CL₅₀). Morphologically mature males had a petasma connected with the pars astringens, and the basal part of the pars media was developed. In physiologically mature males, chambers in terminal ampoules were filled with spermatophores, including spermatozoa and appendages. CL₅₀ (mm) was estimated to be 8.87 (=27.86 mm BL) and 7.84 (=24.65 mm BL) based on the morphological and physiological criteria, respectively. It is believed that most of the age-0 males attain sexual maturity within the first year and mature males are exploited in the autumn fishing season (October–December).