Ovarian development in relation to changes in the external genitalia in captive Penaeus monodon

Hatchery-reared Penaeus monodon postlarvae were cultured in ponds until they attained adult size. Thereafter, the shrimps were transferred to concrete broodstock tanks for maturation. During the culture period, the morphological changes of the ovary in relation to the development of the external genitalia and other quantitative parameters were examined. Based on histology, primordial germ cell and chromatin nucleolus in the early stages of ovarian development were reported in addition to the stages that have been described earlier on adult specimens, thus completing the description of ovarian development on P. monodon. Females with ovaries at the perinucleolus stage can be impregnated as long as the thelycum is structurally developed to receive the spermatophores. Females with cortical rod stage ovaries either spawned or resorbed their eggs before molting, indicating that the molting cycle overrides reproductive activity in first-maturing females

Collection of the clam Anodontia edentula in mangrove habitats in Panay and Guimaras, central Philippines

The mangrove clam Anodontia edentula is highly prized in the Philippines for its flavor and large size. Because this infaunal species is found down to one meter deep in mangrove areas, harvesting the clam reportedly damages mangrove stands. To evaluate such reports, a survey of collection methods was undertaken in Panay and Guimaras, central Philippines in August 1997-December 1999. Host to chemosynthetic bacterial symbionts that utilize sulfide as energy source, A. edentula are strategically situated in sulfide-rich anoxic substrates but also gain access to oxygenated seawater through a ventilation burrow or tube. By locating the opening of this burrow, collectors can detect the presence of a buried clam and harvest it nondestructively with a blade or bare hands. In contrast, the indiscriminate tilling of wide mangrove areas can damage mangrove plants. Most collectors were 40-45 years old with 22-30 years collection experience, married with 5-7 children, and had low educational attainment. They sold clams directly in the local markets or through middlemen (to restaurants and beach resorts); sales provided from 10% to 100% of daily family income. Collectors complained of decreasing clam sizes and numbers and the physically strenuous work of collecting