Ovarian maturity, egg development, and offspring generation of the deepwater shrimp Plesionika edwardsii (Decapoda, Pandalidae) from three isolated populations in the eastern Atlantic

Abstract

For the first time, ovarian maturity, egg development and brood size were analysed in three isolated populations (the Madeira, Canary and Cape Verde Islands) of Plesionika edwardsii (Decapoda, Panndalidae) in the eastern Atlantic. Multiple different colour patterns were observed in the same ovarian maturity stage, which was verified histologically, invalidating the extensive use of ovarian colour as a maturity stage criterion. The physiological length at sexual maturity, based on the maturity of the ovaries, was higher in Madeira (caarapace length of 19.73 mm) and decreased to Cape Verdes (16.39 mm). Synchronic ovarian maturation was observed during the embryo incubation process, and ovigerous females bearing embryos in the final stage of development were observed throughout the year. Females are multiple spawners during the reproductive season, after which the reproductive process ends and a rest period begins. The absence of females larger than the size–aat-sexual-maturity with ovaries in stage I, the incubation of embryos in the final developmental stages, suggests that the resting period begins with a process that reabsorbs the energy located in the ovaries and that thee resting period occurs asynchronously in females in each of the studied populations. A potential relationship was found between brood size and female body size, and the number of eggs increased significantly with female size in the three study areas. The same egg mass colour pattern can correspond with different embryo developmental stages, thus invalidating the use of egg mass colour as a criterion for developmental stage.