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Ten successful trials on induced breeding of the striped murrel Channa striata (Bloch, 1793) under indoor conditions were carried out during July-August 2019. Brooders reared in cement tanks,(males weighing in the range of 290-700 g and females 220-600 g), were used in a set of 2:2 male to female ratio for induced breeding with salmon gonadotropin releasing hormone anologue (sGnRHa) and dopamine antagonist commercial formulation. Each brooder set was kept in an FRP tank (13’x3’x14’’) along with submerged macrophyte Hydrilla verticillata, which was sparsely spread all around the tank. Maturity of brooders was screened on the basis of secondary sexual traits. The brooders were given hormonal injection after 6 h of acclimatisation under indoor conditions @ 1 ml kg-1 body weight (containing sGnRHa 20 µg ml-1 and domperidone 10 µg ml-1) to both the sexes. Natural spawning occurred in all ten sets within 21.5+3.2 h (17-26 h) of injection. In all the tanks, two separate egg masses were observed with 30-95% fertilisation. Approximately 0.14 million eggs were scooped out from the tanks and reared in round plastic tanks (70 l) for hatching, where hatching occurred within 17-26 h post-fertilisation (hpf) with hatching rates of 50.76 to 93.18% at 28+2oC. The embryonic development was recorded under a stereo-zoom microscope in live condition under controlled temperature conditions and described with digital images. The study revealed that induced breeding of C. striata can be undertaken in FRP tanks under indoor conditions for mass-scale seed production, which will provide a platform for diversification of this high valued fish species for large scale farming practices in ponds as well a new species for culture in recirculatory aquaculture system (RAS) and biofloc technology (BFT).

A study was conducted to observe the breeding and larval rearing of Asian Catfish, Clarias batrachus fed with live and/or artificial feed for 21 days in an indoor hatchery. The brooders of C. batrachus (Av. wt of female 160 ± 10.5 g; Av. wt of male 120 ± 6.75 g) were procured from outside ponds and stocked in a pond near the experiment site 2-months prior to spawning. The fishes were successfully induced bred using ovaprim @ 1.0-2.0 ml/kg body weight (bw) to females and 0.5-1.0 ml/kg bw to males. Fertilization, hatching and survival percentages at spawn stage were respectively recorded 70.6 -72.8, 60.7 -55.3 and 54.3 -56.2. After yolk-sac absorption, fry of three age groups 7, 14 and 21 days were subjected to feed trial using Artemia nauplii followed by laboratory made feed for 21 days. Weekly sampling indicated that higher age groups constantly maintained higher lengths and weights with highest survival in the age group of 14-days old fry and SGR in 7-days old. The quality of hatchery water was recorded for temperature 29 ± 1°C, pH 7.2 ± 0.2, DO 7.1 ± 0.3 mgL -1 and total alkalinity 132 ± 4.0 mgL -1 respectively.

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Survival and growth of tiger shrimp (Penaeus monodon) at three salinity levels, 5, 10 and 15 g/L were investigated in potassium deficient natural inland saline water (PD-ISW) and potassium supplemented inland saline water (PS-ISW). Shrimps reared in PS-ISW survived well, whereas total mortality occurred in PD-ISW. The survival at 45 and 60 days at the salinities of 5, 10 and 15 g/L was assessed in PS-ISW. The supplementation of potassium showed significant effect on the survival rates at different salinities. Length-weight studies at different salinities and periods of time in PS-ISW showed significant differences in the linear component, but there was no significant difference in respect to interaction of salinity and rearing periods in a two-way ANOVA repeated measures. Growth parameters indicated that a salinity of 10 g/L was best for the survival and growth of shrimps in inland saline water of the site with potassium supplementation. Individual cations and ratios between other cations were found to be equally important for survival and growth. The results of the present study will be useful in utilizing degraded ISW sites for the culture of tiger shrimp.