A record of Probopyrus bithynis (Richardson, 1904) in Macrobrachium rosenbergii (De Man) from coastal Andhra Pradesh, India, with special reference to host-parasite relationship

An incidence of bopyrid isopod infestation was observed in giant freshwater prawn, Macrobrachium rosenbergii (de Man) juveniles (40-60 mm/0.9-1.5 g) in a scampi culture farm in East Godavari district of Andhra Pradesh. The presence of parasite was observed by conspicuous boil like swelling of the branchial chamber where the parasite was found lodged on the gills. The infested gill was highly compressed and necrosed. Only one branchial chamber was infested by the parasite while the other gill was normal. The infested prawns were thin and emaciated and showed retarded growth. The parasite was identified as Probopyrus bithynis (Richardson, 1904) which caused inhibition of ventilation due to its permanent lodging in the branchial chamber and impaired the gaseous exchange by gills. It was also observed that this parasite caused parasitic castration in the infested prawns.

River fisheries in Africa: their relationship to flow regimes

River fisheries in Africa are important because of their contribution of animal protein to human diets. Such fisheries are highly dependent on hydrological regimes and show considerable year-to-year variation in response to natural climatic events. River flow regimes are being increasingly altered by withdrawals by man, principally for agriculture. The modification of hydrological regimes is leading to diminishing catches of fish and changes in the number and size of the species caught. Given that the trend to remove water from rivers for agriculture and power generation will continue, better appraisals of the impacts of such withdrawals are urgently needed so the policies for water allocation can be better defined. The development of tools to aid in such decision-making is equally important.