Relationship between ovary maturation and various physiological indices in the slipper lobster Ibacus novemdentatus Gibbes, 1850 (Decapoda: Pleocyemata: Scyllaridae)

Abstract

The reproductive biology of the slipper lobsters, including Ibacus novemdentatus Gibbes, 1850, remains underexplored, particularly in northern Taiwan, which supports a major portion of local lobster fisheries. We aimed to establish a comprehensive staging system for ovarian maturation in I. novemdentatus based on both external and histological characteristics. Nine distinct stages were defined, ranging from immature to complete post-spawning recovery. Physiological indicators such as gonadosomatic index, hepatopancreatic index, and hemolymph composition were analyzed to improve our understanding of the reproductive status of the species. Hemolymph parameters, including Brix values, an indirect indicator of nutritional and physiological status, and absorbance at 334 nm and 480 nm, which are associated with carotenoid pigments involved in reproductive development, showed changes associated with ovarian development, providing a potential non-destructive indicator of maturity. Two patterns of ovarian resorption were identified: partial post-spawning resorption and complete resorption without spawning, highlighting the need for ecological assessments beyond visible egg-carrying and offering improved insights for broodstock management in aquaculture.