Diel feeding patterns, rate of gastric evacuation and foods of Indian sandwhiting, Sillago sihama in Mulki estuary, west coast of India

Diel feeding chronology of sandwhiting, Sillago sihama was examined from stomach collections taken during the months of April, July and December'99 in Mulki estuary along Dakshina Kannada coast, India. Significant differences in mean stomach content weight were found between several consecutive 3 hour periods with peak fullness occurring in early morning and evening hours. The rate of gastric evacuation of natural food (crustacea, polychaetes and fish) was measured in the field was best described by an exponential model, with an estimated evacuation time of 8.0 h at a temperature of 28.5 ± 1.2°C. Stomach content analysis indicated that this species is a carnivore on a wide range of benthic, epibenthic and planktonic prey. The principal food items of S. sihama were crustaceans, polychaetes and fish. Fishes less than 100 mm TL preferred mainly crustaceans while larger ones depends on polychaetes, crustaceans and fish. The feeding activity of S. sihama was influenced by tidal cycle.

Hydrography of the Bay of Bengal during south west monsoon and its significance on oil sardine fishery

Hydrographic data collected from east coast of India during 1994 monsoon period revealed that these waters are highly characterized by upwelling especially in the coastal waters with more intensity in the southern part of the region. However, the near surface salinity stratification consequent to high fresh water inflow into the bay was absent in the present study. Oil sardines are directly influenced by hydrographic parameters such as salinity and temperature and stratification of these parameters are the major reasons for non-availability/migration of oil sardine from this region in the earlier years. Considering the recent topographical change in the east coast coupled with hydrological stability an attempt has been made in this paper to give reasonable justification to the reported bumper catches of oil sardines from 1994 on wards in the east coast of India.

Performance of genetically improved farmed tilapia (GIFT) under mono and mixed cui ture with silver barb (Barbodes gonionotus) in south-west Bangladesh

A participatory on-farm trial was carried out to evaluate the production performance of GIFT (genetically improved farmed tilapia) strain of Oreochmis sp., either alone or with silver barb (Barbodes gonionotus), in six rain-fed freshwater ponds of coastal area. There vvere two treatments; (i) GIFT alone at a stocking density of 24,700/ha (T1) and (ii) 1:1 combination of GIFT and silver barb (T1). Each of the treatments had three replications. A significantly (pwest coastal areas.

Effect of stocking density on the production of common carp (Cyprinus carpio Lin.) in cages at Kaptai lake, Bangladesh

Growth, survival and food conversion ratio (FCR) of Cyprinus carpio in cages at different stocking density were studied in Kaptai lake. Fingerlings of common carp (12.47 ± 4.29 g) were stocked at 25/m2 , 50/m2 and 75/m2 each with replication in six floating net cages each of Sm x Sm x 4m and reared for 240 days. The growth rate was inversely related to the stocking density with the mean weights of 325.5 ± 11.74 g, 268.99± 8.44 g and 167.0 ± 11.66 g at low, medium and high densities, respectively. At harvest, standing crop biomass averaged 7 .82, 12.83 and 11.58 kg with the survival of 98.9%, 97.6% and 94.4% and food conversion ratios of 4.51, 3.82 and 4.21 for the above three densities, respectively. Weight gain and production at density 25 fish/m 2 were significantly different (p< 0.01) from other two densities. Water quality was not affected in the cages having different stocking densities.

Ecology of phytoplankton in the coastal waters of Mangalore, west coast of India

Phytoplankton cell count, percentage composition and species diversity at 4 locations of different depth contours in the coastal waters of Mangalore, west coast of India were studied for a period of 8 months. A total of 27 genera of phytoplankton were recorded from the area of which 20 belonged to diatoms, 6 /dinoflagellates and 1 blue-green algae. On an average the population density was higher at 4 m depth contour (280.48xl04 cells/m3 ) than 8m depth contour (97.79xl04 cells/m3 ). The plankton cell density in the present study is much higher than the earlier observations made elsewhere which might be due to intense blooming of Chaetoceros, Cosctnodiscus, Ceratium, Dinophysis and blue-green algae along this coast during the study period.

Some socio-economic aspects of the fishermen of twin pronged floodplain wetlands in West Bengal

A socio-economic investigation was carried out in two fishermen cooperative societies namely Purba Helatala Fishermen Co-operative Society (E-1), Barhal Fishermen Co-operative Society (E-2), under Maldah district, West Bengal to which the beels (flood plains) under study belong. A total of 132 member fishermen, which constituted the sample, were personally interviewed. The age group of the fishermen of the sample in E-1 varied between 20 and 66 years whereas in E-2 it was 22 and 61 years. All the members of the sample belonged to Scheduled Caste (SC) community. The primary occupation of all the respondents of both the beels was observed to be fishing (100%). Maximum number of illiterate respondents was observed to 56% in E-2 and 35% in E-1. It has been observed that as many as 38.3% of fishermen were having fishing experience which ranging from 16 to 20 years in E-1 whereas it was 6 - 10 years (36.1%) in E-2. Maximum number of fishermen lived in thatched houses (41.66%) in E-1 whereas in E-2 most of them lived in houses made of corrugated tin/tile shed (41.66%). As many as 41.55% of E-1 and 30.55% of E-2 used dug-out canoes for their fishing. Maximum number of fishermen used cast net with individualistic approach (100%) followed by Gill net (E-1:41.56% and E-2:55.55%). Most of the fishermen of the sample participated in fishing activities for 241 to 270 days (41.66%) in E-2 whereas it was 211 to 240 days (33.33 %) in E-1 in a year. During fishing season as many as 40.0% of the respondents of E-1 earned on an average Rs. 801.00 to Rs. 900.00 per month whereas it was Rs. 901.00 to Rs.1,000.00 (43.05%) in case of E-2. A section of fishermen of the sample borrowed money often (51.6%) E-1 whereas it was most often (27.27%) of E-2. The respondents of E-2 made regular repayment of the loan to the maximum extent (79.48%) whereas it was 57.44% in E-1. Higher fish production vis-a-vis higher income for the fishermen was observed in the beel (E2) having close characteristic.

Bacillus solisalsi sp nov., a halotolerant, alkaliphilic bacterium isolated from soil around a salt lake

A novel Gram-positive, motile, rod-shaped bacterium isolated from a saline soil in China was characterized by a polyphasic taxonomic approach. The strain, designated YC1(T), was halotolerant [tolerating up to 15 % (w/v) NaCl] and alkaliphilic (growing at