Abstract:

Episesarma mederi (H. Milne Edwards, 1853) belongs to the dominant crab groups in estuarine and mangrove areas that play vital roles in the nutrient cycling and substrate biochemistry of tropical ecosystems. It is a traditional coastal resource in Asia, but its status remains unassessed and unmonitored. The foremost constraint in managing this crab species is the lack of knowledge on its reproductive biology. Hence, this study analysed the gonadal maturation stages of E. mederi from President Roxas, Capiz, Philippines. Morphometric analysis and sexual determination were performed. Staging of gonad development was established by complementing morphological features (i.e. colour, volume) with histological analysis (i.e. cell type and size). A total of 448 crabs (264 females, 184 males) were collected. Results showed that males were larger and heavier than females. The smallest recorded sexually mature individuals had a carapace width of 28.6 mm in females and 26.0 mm in males. Ovarian histology showed five stages of development: immature, developing/redeveloping, maturing, mature (two substages - early mature and late mature), and spent. In males, only two stages of gonad development were identifiable: immature and mature. The gonadal morphology and histology suggest that E. mederi has a continuous reproductive strategy. This is supported by the presence of post-spawning ovigerous females with redeveloping ovaries and the occurrence of mature males throughout the study period. The present study provides preliminary information on the reproductive aspects of E. mederi that may be essential for its sustainable utilisation.

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Date 2020/09/30

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