An experimental study was carried out to evaluate the efficacy of three commercially available probiotics P1, P2 and P3 consisting of mainly Bacillus spp. and nitrifying bacteria against Vibrio loads in mass culture tanks of the rotifer Brachionus plicatilis. Triplicate tanks were maintained for each of the probiotic treatment as well as for control group. All the tanks were inoculated with 50 rotifers ml -1 and were fed with Nannochloropsis oculata at a density of 1 x 10 7 cells ml -1 . Every alternate day, all the experimental tanks were treated with probiotics at a concentration of 1 x 10 4 cfu ml -1 and the experiment was carried out for one week. The study showed a significant increase in rotifer density (p<0.05) in all the tanks treated with the probiotics and a maximum density of 400 nos. ml -1 was observed in the tanks treated with P3. After 5 th and 6 th day of culture, total elimination of Vibrios was also recorded in the tanks treated with P3 and P2 respectively. The study revealed that P3, with a combination of Bacillus, Thiobacillus, Acetobacter and Paracoccus supplemented with enzymes, was found to be most effective in the enhancement of rotifer density and also in the elimination of Vibrios in rotifer mass culture tanks.

(Linnaeus, 1766) in relation to the water and sediment quality of marine farm at Karwar for two consecutive crops (2012-13 and 2013-14) were analysed. No significant variation was observed in the specific growth rate (SGR) of both the species between the crops. But within a crop, variations were observed in the SGR and absolute growth rate (AGR) of both the species (p<0.05). Specific growth rate of cobia was 0.75 and 0.78 % day -1 in 210 days of culture for the years 2012-13 and 2013-14 respectively. Physico-chemical parameters of water at cage and reference sites did not vary significantly, except for ammonia-nitrogen and nitrate-nitrogen levels at cage site between and within the crops. No significant variation was observed in total bacterial and Vibrio loads of water in cage site between the crops but significant variation was observed within the crop. The results revealed that temperature (r = +0.61 for 2012-13 and +0.63 for 2013-14) and salinity (r = +0.6 for 2012-13 and +0.5 for 2013-14) played a major role on SGR of cobia during both the crops with higher AGR recorded during summer months. In case of Asian seabass, no significant impact of temperature and salinity on SGR was noticed during the experimental period.

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Effect of marine microalgal diet on filtration and ingestion rates of Brachionus plicatilis was studied. Marine microalgae viz., Nannochloropsis oculata, Isochrysis galbana, Chaetoceros calcitrans and a combination of N. oculata and I. galbana (Nanno+Iso) at different cell concentrations were selected for the experiment and triplicates were maintained for each feed. Significant difference (p<0.05) was observed in the filtration and ingestion rates of B. plicatilis, between the treatments. Peak filtration rate of 12.2x10-5 cells ml -1 ind -1 min -1 was recorded in B. plicatilis fed with Nanno+Iso, followed by I. galbana. Ingestion rate was found to be significantly high (p<0.05) for those fed with C. calcitrans, followed by Nanno+Iso. Filtration rate was significantly high (p<0.05) in rotifers stocked at an initial density of 50 nos. ml -1 fed with Nanno+Iso. The results indicated that a combination of Nanno and Iso is the best suitable microalgal diet for rotifer with peak filtration (12.2x10 -5 cells ml -1 ind -1 min -1 ) and ingestion (5.4x10 -3 cells ml -1 ind -1 min -1 ) rates during the first 60 min.

Broodstock development, induced maturation and breeding of the newly described seabream, Sparidentex jamalensis collected from Kali estuary, Karnataka, India were achieved successfully for the first time. Taxonomy of the fish was confirmed employing morphological and molecular tools. Majority of the brooders collected were in the 20–30 cm length class (140–510 g) and were ideal for developing matured broodstock. Periodic microscopic observation of ovarian biopsy indicated progressive gonadal development in the broodstock. The broodstock developed for this protandrous hermaphrodite consisted of females having maturing oocytes and males with oozing milt during the breeding season. Final maturation and spawning of the females (520 ± 8 g; ova diameter above 400 µm) was achieved using cholesterol‐based LHRH analogue pellets (50 µg/kg fish) and the males (450 ± 54 g) were not treated with hormones. Pelagic fertilized eggs (720 ± 8 µm) with a single oil globule were obtained with an absolute fecundity of 0.42 ± 0.06 million/kg fish and a fertilization rate of 82 ± 2.4%. Major embryological stages were recorded and the fertilized eggs hatched after 18–20 hours with 80 ± 4.6% hatching rate at 28°C. The newly hatched planktonic larvae measured 1.8 ± 0.12 mm in total length. Mouth opening of the larvae was observed on second day post hatch (dph). Resorption of the yolk sac was observed on third dph. These results will act as a baseline for developing a breeding programme for this species.