Reproductive biology aspects with a specific focus on histological analysis of oogenesis in Heterocarpus woodmasoni Alcock, 1901 from Southeastern Arabian Sea, Indian Ocean

Abstract

The expansion of deep-sea fisheries in India has underscored the necessity for comprehensive data on the reproductive characteristics of targeted species to facilitate effective resource management. Heterocarpus woodmasoni Alcock, 1901 plays a pivotal role in supporting India’s deep-sea shrimp fishery sector. In this pioneering study, we provide novel insights into the reproductive dynamics of H. woodmasoni, utilizing specimens collected from 2019 to 2022 at the primary deep-sea shrimp landings site of Sakthikulangara fisheries harbour, Kerala, India. The research revealed that H. woodmasoni exhibits a continuous breeding pattern characterized by three prominent spawning peaks: two occurring in January and April with an additional extended peak observed in September. Moreover, the study observed a consistently high proportion of ovigerous females throughout all seasons, suggesting year-round reproductive activity in H. woodmasoni. Size (CL) at the onset of sexual maturity (SOM) for males and females measured 16 mm and 17 mm, respectively. In terms of brood size, the mean absolute brood size estimated in H. woodmasoni was 5438 ± 2687. Interestingly, while brood size increased as a power function of carapace length, the correlation between reproductive output and carapace length was found to be statistically not significant. Embryo volume varied significantly between the three developmental stages (Stage I: 0.03 ± 0.02 mm3, stage II: 0.05 ± 0.04 mm3 and stage III: 0.11 ± 0.03 mm3). The gonadosomatic index showed increasing trend corresponding ovary maturation. However, the index declined in the final maturity stage characterized by a black coloured ovary. The vivid colour changes observed in mature ovaries, spanning early vitellogenesis, late vitellogenesis and maturation phases offer valuable insights into the dynamic cellular transformations occurring during ovarian development. The present study regarding the various reproductive traits of H. woodmasoni with histological examination of oogenesis will help to facilitate sustainable exploitation and adequate conservation management of this species.