Kamaldeep Kaur

Effect of Dissolved Oxygen on the Survival and Hatching of Eggs of Scale Carp

Abstract Eggs of scale carp (Cyprinus carpio communis) were exposed to various levels of dissolved oxygen (DO) from fertilization to completion of hatching. Survival and hatching rate increased directly with increasing concentration of DO. Dissolved oxygen levels below 6.0 mg/1 appeared inadequate for proper survival. The retarding effect of reduced DO levels was less pronounced at early than at later stages of development.

Efficacy of biogas slurry in carp, Cyprinus carpio var. communis (Linn.), culture—effects on survival and growth

Abstract Effects of biogas slurry, a by-product of biogas plants, on the survival and growth of common carp, Cyprinus carpio var. communis over 270 days of culture were determined. Growth rates of the fish (in terms of weight) were 3·54 times higher in biogas slurry-treated tanks than in controls. Supplementary feeding (with rice bran: groundnut oil-cake, 2:1 at 2% of the body weight) further increased growth rates to 5·70 times higher. Biogas slurry was a better fish pond manure than raw cowdung, for growth rates of common carp in raw cowdung-treated tanks were only 1·18 to 1·24 times higher than in the control. A strong positive correlation existed between length and weight of fish in all treatments.

Phytoplankton response to biogas slurry in carp ponds

Abstract Biogas slurry (BGS) when applied at the rate of 52 liters ha −1 day −1 (6.4% dry matter) did not result in a significant increase in total phytoplankton (TP). Application of BGS along with supplementary feeding (SF) (3:1, rice bran: groundnut oil-cake, dry w/w basis) improved phytoplankton quality by resulting in the dominance of green algae instead of diatoms as in the control and the biogas slurry-treated tanks. Blue-green algae contributed insignificantly to TP biovolume (3–6%) and did not dominate during any part of the experiment. The BGS seems to have promoted a heterotrophic food chain responsible for higher fish growth. The usefulness of BGS in the culture of benthophagic fishes is discussed.

Effect of zinc on maturation and breeding potential of Cyprinus carpio and Cirrhina mrigala

Effects of safe and sublethal concentrations of zinc were observed on ovarian maturation and breeding potential of carps. Exposure of Cyprinus carpio to 56 and 100 μg/L and Cirrhina mrigala to 560 and 1000 μg/L of zinc for 60 days during each of the preparatory and prespawning phases of reproduction revealed concentration dependent decline in gonado‐somatic index, ova diameter and absolute fecundity complemented with decline in total proteins and total lipids in the ovaries. Exposed fishes were also induced to breed except C. carpio exposed to sublethal concentration.

Toxic effects of industrial effluents on hatchability and viability of Cyprinus carpio eggs

Both field and laboratory studies have revealed that the early developmental stages of fishes are most susceptible to pollutants. Acidification of water and low concentrations of metals and pesticides reduce egg hatchability /viability and larval survival, which are of great concern for recruitment of fishes (von Westernhagen 1988). There have been studies of embryo viability and hatching success of freshwater fishes at low concentrations of single toxicants in clean water (Lockwood 1976; McCormick et ai.1984; Mayes et al. 1986; Dave et al. 1987). However,there is paucity of information on the embryo viability and hatching success of fishes in effluents containing mixtures of organic and inorganic toxicants. Recently, the toxic effects of industrial waste and domestic sewage on embryo viability of rainbow trout, Salmo gairdneri (Fraser and Clark 1984); of pulp and paper mill effluent on egg hatchability of pike, Esox lucius (Tana and Nikunen 1986) and bleached kraft mill effluent on early life stages of brown trout, Salmo trutta (Vuorinen and Vuorinen 1987), have been studied. Hence, the aim of the present study was to examine the effect of different industrial effluents on the hatchability and viability of Cyprinus carpio eggs and to determine their safe levels for discharge.

Effect of biogas slurry on ovarian maturation of common carp

Abstract Biogas slurry (BGS) applied at 52·1 litres ha −1 day −1 (6·4% dry matter) resulted in faster maturation of common carp. Fingerlings of Cyprinus carpio communis (Linn.) became fully mature at eight months old in tanks treated with BGS and supplementary feed (SF) and at the ninth month in BGS-treated tanks. The control fish became fully mature during the eleventh month. The fecundity of the fish in tanks treated with BGS+SF was also highest, although the differences among the treatments were statistically non-significant.