Environmental Consequences of Intensive Aquaculture Practices at Moyna Purba Medinipur West Bengal India with Special Reference to Carbon Footprint and Carbon Sequestration.

Moyna of Purba Medinipur district is widely known as an aquaculture hub of West Bengal, India. Though very good production is achievable from this fish culture system, management practices are inappropriate, which could create the sustainability problem of this culture system. The present study was thus undertaken for the estimation of plankton population, water quality, carbon footprint and carbon sequestration of this intensive aquaculture practices. Information on spawn to fry, fry to fingerlings and grow-out culture were collected through the structured questionnaire from the fish farmers. The plankton density, primary productivity, carbon footprint and carbon sequestration were analyzed using standard procedures. The phytoplankton, zooplankton and primary productivity were maximum at the stocking period and minimum during the middle of culture period. The lowest feed conversion ratio (FCR) was noticed with the minimum amount of feed applied in the pond. The CO2-e emission ranged from 0.56 to 4.89 kg CO2-e/kg fish (av. 2.13) for the production levels of 5.0 to 10.7 t/ha/yr. The pond water developed salinity and ammonium-N increased from 0.01 to 0.50 mg/l. The ponds with high feed loading (28 to 32 t/ha/yr) had the highest average sediment accumulation rate (11.0 ± 3.0 cm/yr) and carbon sequestration (704 ± 30 g C/m2/yr).

Effect of dietary supplementation of fatty acids and vitamins on the breeding performance of the carp Catla catla.

Five isonitrogenous diets (approximately 33% crude protein) were fed to the brood female carp, Catla catla (weighing 3.0 to 5.5 kg), for a period of 93 days in order to observe their breeding performance in earthen ponds. Diet-I (control) contained only basic ingredients like rice bran, ground-nut oil cake, roasted soybean meal, fish meal and mineral mixture; diet-II contained added vitamins; diet-III contained added vitamins and vegetable oil (rich in n-6 polyunsaturated fatty acids, PUFA); diet-IV contained added vitamins and fish oil (rich in n-3 PUFA); and diet-V contained added vitamins and a mixture of vegetable and fish oils. The results showed that nutritional quality of the diet considerably influenced breeding performance in the species. The total number of matured females was the highest in the diet-V group and maturity was advanced by 35 days in this group compared to the control. In diet-III and diet-V groups, all the maturated females bred fully and the relative fecundity was increased significantly in diet III, IV and V. The maximum (73.4%) fertilisation rate was observed in the diet-V group, followed by 61.3%, 56.8%, 49% and 22.7% in diet-I, diet-IV, diet-III and diet-II groups respectively. Most of the eggs in the diet-II treatment group remained immature. The various data thus obtained suggest that dietary supplementation of both n-3 and n-6 PUFA, is essential to improve gonadal maturation, breeding performance and spawn recovery in the Catla female broodstock.

Ocular injuries.

A total of 800 cases of ocular injuries were studied during the period from January, 1982 to December, 1985 at the department of eye, North Bengal Medical College and Hospital, Darjeeling. Major ocular injuries (n = 248) required hospitalisation. The rest 552 cases had minor injuries and treated at outpatients' department. The incidence of age, sex, mode of injury, interval between injury and first observation, structural damage were studied in all these cases.