Mery Rodrigues

This study describes reproductive aspects of the Pinctada capensis (pearl oyster) and Saccostrea cucullata (rocky shore oyster) in Inhaca Island, southern Mozambique (Western Indian Ocean). Adult oysters were collected monthly over two years within seagrass banks for P. capensis and rocky shore habitats for S. cucullata. The animals were evaluated using biometric and histological analyses of the gonads. Of the total population, females were predominant among larger individuals (>55 mm) and males were more dominant among smaller individuals (Pinctada capensis and (1 M–1.6 F) for Saccostrea cucullata. Five gonad maturation stages were identified: indifferent, developing I, developing II, ripe and spent. The size at first maturity was mm and 26.2 mm for pearl oysters females and males, respectively, whereas for rocky shore oysters was 32.8 and 28.3 mm for females and males, respectively. We conclude that the reproduction of S. cucullata and P. capensis occurs mainly in summer, with a short resting period in winter, when many oysters are in the indifferent stage. These results provide valuable information to fisheries for management of both species in the area.

Water microbial contamination is one of the major threats to human health. The study focus is on Infulene River Basin, a urban catchment with mainly informal settlements, with limited water supply and sanitation. In the catchment there are two wastewater treatment plants, one hospital and beer factory located on the banks of the main stream; water from this stream is used for urban agriculture and domestic uses by some dwellers. These factors present a significant health risk from water-borne diseases. At the moment there is limited knowledge about the level of microbial contamination of the different sources of water at the disposal of the communities. Thus, a preliminary study on fecal microbial contamination was conducted targeting the Infulene River and the drainage system from the nearby Maputo city draining into the system, with additional investigation on the drinking water provided by the city water supply company. The quantification of Total Coliforms (TC) and Escherichia coli (EC) was conducted at several sampling locations. Results were compared with official drinking water standards. Eighty two percent (82%) and 61% of Infulene river water and drainage water samples were positive for TC (10⁵ to 10⁹ NPN/100 mL) and EC (10⁵ to 10⁷ NPN/100 mL), respectively. For drinking water samples, 63% and 23% were positive for TC (up to 6000 NPN/100 mL) and EC (up to 1000 NPN/100 mL), respectively. Higher microbial contamination was found in neighborhoods with the poorest sanitation and shallow groundwater, i.e., Chamanculo, Xipamanine, Mafalala, Aeroporto and Maxaquene, a situation that was more expressive during the rainy season. Overall, the study confirmed the high vulnerability to microbial contamination of all sources investigated due to poor sanitation and lack of drainage infrastructure. The risks to human health might be even higher considering that contaminated water is used for gardening of vegetable watering and domestic use.