Broodstock management: an integral part of hatchery techniques

The paper presents bighead carp broodstock management, an integral part of hatchery techniques as it will determine the quality of resulting fry and fingerlings. Proper methods on the selection and management of broodstock are discussed.

Effect of replacement of fish meal with soybean meal plus supplementary enzymes on growth performance, survival rate and apparent digestibility of rainbow trout (Oncorhynchus mykiss)

This study was carried out to measure the effects of a supplementary multi enzyme on growth performance , survival rate and apparent protein digestibility of rainbow trout fed some diets containing different amounts of soy bean meal. Five exprimental diets with replacement of 25, 50, 75 and 100 percent of fish meal protein by soy bean meal protein were made and 0, 500 and 1000 ppm dosages of supplementary multi enzyme had used in each of them. By the means a diet with fish meal as the only source of protein has used as the control. So this study had 13 treatments. The trouts in 89.40±4.01 gr mean weight were stocked in 39 experimental fiberglass tanks in abundance of 30 fish per any tank. These specimens fed experimental diets for 8 weeks and ten of them in each tank fed same diets which added Cr2O3 to them for one more week to measure the apparent protein digestibility in them. The results shown that supplementary multi enzyme (Avizyme) which contains Protease , Amylase and Xylanase , caused increases in growth performance , survival rate and apparent protein digestibility in trouts which fed soybean meal. Also this study shown that using 1000 ppm of Avizyme in diets which containing soybean meal had the best results and the diet which contained 39 % soybean meal with this amount of enzymes, had no significant differences by the control in any of the studied factors.

Water budgeting studies on the hatchery and nursery rearing practices for the common carp, Cyprinus carpio (Linnaeus, 1758)

Aquaculture systems are an integral element of rural development and therefore should be environment friendly as well as socially and economically designed. From the economic standpoint, one of the major constraints for the development of sustainable aquaculture includes externalities generated by competition in access to a limited resource. This study was conducted as an investigation into the water requirement for the hatchery and nursery production phases of common carp, Cyprinus carpio (Linnaeus, 1758) at the Maharashtra State Fish Seed Farm at Khopoli in Raigad Dist. of Maharashtra during the winter months from November to February. The water budgeting study involves the quantification of water used in every stage of production in hatchery and nursery systems and aimed at becoming a foundation for the minimization of water during production without affecting the yield; thereby conserving water and upholding the theme of sustainable aquaculture. The total water used in a single operation cycle was estimated to be 11,25,040 L [sic]. Out of the total water consumed, 4.74% water was used in the pre-operational management steps, 4.48% was consumed during breeding, 62.72% was consumed in the hatching phase, 21.50% was used for hatchery rearing and 6.56% was consumed during conditioning. In the nursery ponds, the water gain was primarily the regulated inflow coming through the irrigation channel. The total quantum of water used in the nursery rearing was 31,60,800 L [sic]. The initial filling and regulated inflow formed 42.60% and 57.40% respectively of water gain, while evaporation, seepage and discharge contributed 20.71%, 36.46% and 42.82% respectively to the water loss. The total water expended for the entire operation was 1,21,61,120 L [sic]. Water expense occurred to produce a single spawn in the hatchery system was calculated and found to be 0.56 L while the water expended to produce one fry was calculated as 4.86 L. The study fulfills the hydrological equation described by Winter (1981) and Boyd (1985). It also validates the water budget simulation model that can be used for forecasting water requirements for aquaculture ponds (Nath and Bolte, 1998).