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ThesisItem Open Access Production of sterile trout (Triploids) using thermal shock treatment in Oncorhynchus mykiss and Salmo trutta fario(SKUAST Kashmir, 2022) Bazaz, Asim Iqbal; Shah, Tasaduq HussainTriploidy refers to the occurrence of three sets of homologous chromosomes in an organism or a cell. Triploidy can occur naturally and can also be induced artificially by different methods. Artificial induction of triploidy in fishes is an accepted method for producing sterile fish for aquaculture and fisheries management as gonadal development and gamete production negatively affect somatic growth and feed conversion ratios. The present work was undertaken to produce sterile triploids of Oncorhynchus mykiss (rainbow trout) and Salmo trutta fario (brown trout) using thermal shock treatment. Dry stripping method was adopted for obtaining eggs in both the trouts. Four heat shock treatments and a control group in three replicates were investigated. Heat shock was applied to eggs at 26oC and 28oC for 10 minutes duration, 15 and 20 minutes after fertilization using a water bath. In rainbow trout, the highest fertilization rate of 90.393±0.37% among all the treatment groups was observed in group T1, heat shocked at 26oC, 15 minutes after fertilization, while as in brown trout, the highest fertilization rate of 87.55±0.54% was observed in group S2, heat shocked at 26oC, 20 minutes after fertilization. The highest hatching rate (81.843±0.88%) in rainbow trout among the treatment groups was observed in group T2 heat shocked at 26oC after 20 minutes of fertilization,while as in brown trout the highest hatching rate (78.72±1.30%) was observed in group S2 at 26oC, 20 minutes after fertilization. The maximum (Mean±SE) rate for complete yolk sac absorption in case of rainbow trout was estimated at 83.94±0.52% and for brown trout at 85.57± 0.71% in group T2 and S2 respectively. The maximum triploidy rates (Mean±S.E) in case of rainbow trout (76.66±3.33%) and brown trout (63.33±3.33%) were observed in groups T4 and S4 heat shocked at 28oC, 20 minutes after fertilization process. Among the experimental groups, the survival rates at fertilization, hatching and complete yolk sac absorption were recorded higher in the control group compared to heat shocked groups.The diploid chromosome number (2n) in case of rainbow trout was estimated at 60 and the triploid chromosome number (3n) at 91, while as in case of brown trout, the diploid and triploid chromosome numbers were estimated at 80and 120 respectively. A significant (P<0.05) positive correlation between triploidy rate with temperature intensity and time after fertilization in rainbow trout and brown trout was recorded in the study indicating that with an increase in the heat shock temperature intensity and time after fertilization, the triploidy rates also increased. At both the heat shock intensities (26 and 28°C), it was found that heat shock applied 20 minutes after fertilization resulted in higher triploidy rates in both the fish. However, the maximum survival rate at hatching and yolk sac absorption were observed at temperature intensity of 26oC applied 20 minutes after fertilization.ThesisItem Open Access Studies on histomorphology of alimentary canal and some digestive enzymes in rainbow trout, Oncorhynchus mykiss(SKUAST Kashmir, 2022) Asifa Wali; Shah, Tasaduq HussainThe study includes the collection of about 200 samples of O. mykiss from the national trout fish farm Kokernag to analyze the histomorphology, digestive enzyme evaluation, and gut metrics of the alimentary canal of fish from fry to brood size stages. The microscopical investigations of the alimentary canal showed that the epithelial cells lining both the gastric mucosa and pits contain mucosubstances with more numbers in the proximal intestine from fry to brood size stage. The findings of the intraepithelial lymphocytes (IEL) with the epithelial cells and mucus-producing cells from the fingerling stage onwards indicate an active role in the teleost gut immune response. The thickness of lamina propria from the fingerling stage onwards indicates that the trout alimentary canal is driven by immunity aspects as well. Also, the highest luminal diameter in the proximal and middle portions of intestines from fry to brood size stages indicates the accumulation of the feed in the intestinal lumen. The micrographs of the alimentary canal of table size fish showed complex and more advanced branching of the intestine with the numerous pinocytic vacuoles and mucus-secreting cells lining the gut with the tunica muscularis present at the junctions of its branchings, and the tunica submucosa reduced to a thin layer of connective tissue without the compactum or granulosum layers. The study shows that there is a wide variation of villi length observed in the proximal intestine; at table sizes, only the long villi increased their average length, while the number of short villi diminished. Based on our observations, we conclude that branching may be accompanied by or due to the short villi fusing into the long ones suggesting possible functional differences between the two villi types. Further, our study revealed that there is no linearity in terms of digestion and absorption within the alimentary canal of trout in each stage as the number of mucous cells, gastric glands, pits, etc. vary along the proximal, distal, and pyloric sections with pyloric caeca showing food retentive function rather than food absorptive one. Villus branching was not observed at any stage in the pyloric caeca, but the tract revealed supranuclear pinocytotic vacuolization which became more visible in enterocytes of large individuals and which could be related to lipid accumulation. The goblet cells and mucous secreting cells are distributed all along the intestinal length, but the size is comparatively lesser than early stages. A comparison of digestive enzymes revealed the highest values of alkaline phosphates (85.16U/mg) and lipase activity (273.16U/L) in the gut of the table size stage, while the highest value of trypsin activity was recorded in the fry (95U/mg) and yearling stage (80U/mg). The highest amylase was recorded in yearling stage (208.24U/L). A significant amylase enzyme activity was seen in broods (1.73 U/L). Analysis of data combined for all stages revealed that the characters in the PC1 were more likely to be associated with intestinal coefficient, relative length of gut, gastrosomatic index, relative gut mass, Zihlers index, amylase, lipase, gut weight, gut length, intestinal length, ALP and weight. The highest gut weight (64.27g), intestinal length (335mm), and liver weight (16.81g) were observed in the brood stage of the fish. The highest intestinal coefficient (1.2) and Zihler's index (5.56) were found in the fry stage, whereas gut length (310mm) and relative gut length (1.2) was found to be the highest in table sized fish. The digestive somatic index (0.24), hepatosomatic index (4.14%), and gastrosomatic index (24.13%) was found to be highest for the fingerling stage.ThesisItem Open Access Biology, fishery and population dynamics of Cyprinus carpio var. communis in Manasbal lake, Kashmir(SKUAST Kashmir, 2021) Syed, Nimat; Shah, Dr. Tasaduq HussainThe present study was carried to study the fishery, biology and population dynamics of Cyprinus carpio var. communis from Manasbal lake. A total of 360 specimens of Cyprinus carpio var. Communis were collected during July, 2018 to June, 2019. During the present study, maximum total length of C. carpio var. communis was recorded as 319.6 mm in the month of March, while minimum length recorded was 110 mm in the month of September. Similarly, the minimum and maximum weight ranged from 22g to 470g respectively. The correlation coefficient (r) value was recorded highest between total length and standard length (0.92%) and least between head length and snout length (0.61%). The study indicated negative allometric growth for Cyprinus carpio var. communis. The growth parameters of C. carpio var. communis was determined and the value of ‘L∞’ was estimated to be 342.21 mm and that of ‘K’ was estimated to be 0.105 month-1 respectively. The value of ‘W∞’ was estimated to be 522 g and that of ‘K’ was estimated to be 0.068 month-1 respectively. The peak breeding season was observed in the month of April and May for males and females.The condition factor (K) of C. carpio var. communis was highest in the month of October (1.88) and lowest in the month of March (1.23) in females and in case of males, it was highest in the month of September (1.84) and lowest in the month of March (1.31). The estimated absolute fecundity ranged from 7250 and 93,000 with a mean of 25,159. The relative fecundity ranged from 56 to 258 ova per gram of ovary weight with a mean of 119.6. The length at first maturity (LM50), was estimated at 250 mm TL for the females. The month wise sex ratio for the entire period of study was 1.23:0.81 (Male:Female) indicating a significant dominance of males. In the present study, the annual reproductive cycle of males and females of Cyprinus carpio were observed and five maturity stages were identified in both the sexes. These were Immature phase, early maturing phase, advanced maturing phase, mature phase and spent phase. During the present study, five traditional gears were found to be operated by fishers in the Manasbal lake viz., cast net, long line, pole and line, multiple head spear and double pronged spear with cast net being used dominantly. The design, construction and operation of fishing gears were recorded forming a baseline information for the technological modifications the gear may undergo in the coming years.ThesisItem Open Access Study on the efficacy of synthetic hormones - Ovatide and Wova-FH on the breeding performance and Gonadotropin levels of Cyprinus carpio var. communis in Kashmir waters(SKUAST Kashmir, 2021) Ishrat Mohd; Bhat, Dr. Farooz AhmadA global call for foods of aquatic origin has heightened due to the zooming population growth. As the global aquaculture expands, increasing efforts are focusing on induced breeding techniques. Induced breeding is entailed to meet the rising demand of fish. Cyprinus carpio is considered the most desirable species to meet the challenge through induced breeding techniques. Cyprinus carpio var. communis brooders were treated with two synthetic hormones; Wova-FH and Ovatide and the resulting changes in Gonadotropins (GtH-I and GtH-II) and steroid hormones (estradoil and progesterone) were studied. The changes in the breeding performance due to hormone injections were studied. Efficacy of Wova-FH and Ovatide at different graded dosages (Control, T1, T2 and T3) were tested to see the breeding performance in Common carp, Cyprinus carpio var. communis. The ability of these treatments to elicit the response was further examined by stimulation of GtH-I and GtH-II and steroids (estradiol and progesterone). Females in the Control group showed lower ovulation rate compared to other treatment groups of both the injections. Female latency period decreased with increased dosage of both the hormones. Ovulation rate, spawning fecundity and relative fecundity were recorded highest in T2 group (0.5 ml/kg) of both the injections. In males, sperm volume and sperm density significantly varied with hormone type and with different hormonal treatment groups of both the injections. Sperm volume increased with hormone dosages and sperm density decreased with dosage in both the hormone injections. Fertilization and hatching rate were not impacted by hormonal type and hormonal treatments. GtH-I, GtH-II, Estradoil and Progesterone were significantly impacted by hormone type and hormonal treatments. The level of these hormones (GtH-I, GtH II, estradoil and progesterone) also varied significantly with post injection durations (6 hr, 24hr, 36 hr and 48 hr). Efficacy of Ovatide was found higher than Wova-FH in terms of breeding success and eliciting the gonadotropin and steroidal release. Biochemical parameters (glucose, total protein, triglyceride, cholesterol and urea) also showed the significant change with hormone type; Wova-FH and Ovatide and their different treatment groups. Gonadal development e.g. Gonadosomatic index, related hormone, Gonadotropin levels and steroid levels (estradoil and progesterone) were studied to determine the spawning season of the fish and to establish the optimum season for the artificial propagation. Results showed marked annual cyclical changes in GSI. The GSI in both the sexes was low in late summer (August to November) and started increasing from December month and remained high in the month of May. GtH–I hormone was found very low and did not varied throughout the year. Compared to the GtH-I, GtH-II varied considerably throughout the year in both the sexes, highest value was observed in the month of May, indicating the spawning season/month of the fish. Estradoil level in males was found highest in March and in females in February suggesting the spermatogenic stage in males and vitellogenic phase in females in respective months. Likewise, progesterone in males was found highest in May and in females in March. Relationship of GSI with gonadotropins and steroid hormones indicated that the GSI has a positive relation with gonadotropins and steroids (E2 and P4). GSI showed the strong significant positive correlation with GtH-II in both the sexes. GSI also showed a significant positive correlation with Estradoil in females, however, non significant positive correlation was found between the two in males. GSI showed the significant positive correlation with progesterone in males but in females a non significant positive correlation was found.ThesisItem Open Access Comparative studies on abundance, food, feeding habits and reproductive biology of Cyprinus carpio var. communis and Schizothorax niger in Dal Lake, Kashmir(SKUAST Kashmir, 2021) Wani, Iqra Farooq; Shah, Dr. Tasaduq HussainThe present investigation was carried out to study abundance, food, feeding habits and reproductive biology of Cyprinus carpio var. communis and Schizothorax niger in Dal Lake, Kashmir. A total of 360 samples each of C. carpio and S. niger were collected from Dal Lake from August 2018 to July 2019. The present study revealed an overall higher abundance index of exotic Cyprinus carpio var. communis (57.54%) in the fishery as compared to native Schizothorax niger (11.69%). Length-weight relationship of C. carpio var. communis and S. niger both indicates negative allometric growth. The value of growth coefficient (b) for pooled data was found to be greater for C. carpio (2.615) than that of S. niger (2.399) which indicates better growth in C. carpio as compared to S. niger. The analysis of gut content of C. carpio revealed that the fish is omnivorous with 55.99% of plant matter, 32.71% of animal matter while as sand and unidentified matter contributed the rest. While as the analysis of gut content of S. niger revealed that the fish was herbi-omnivorous in feeding with 67.53% of plant matter and 23.43% of animal matter, with green algae as dominant food. Relative Length of Gut (RLG) values in C. carpio (1.53) and S. niger (1.68) indicate that the fishes are omnivorous in feeding habit. In both the species, low feeding intensity was observed during extreme winters, however, an improving trend was observed on the approach of spring and summer months. Feeding intensity also recorded low values during peak breeding season. In C. carpio, sex ratio for the entire period of study was estimated at 2.05:0.49 (Male: Female) indicating a significant dominance of males. In S. niger, sex ratio for the entire period of study was 0.48:2.07 (Male: Female) indicating a significant dominance of females. The value of the condition factor (K) of the common carp ranged from 1.151 (December) to 1.928 (March) while as in case of S. niger it ranged from 0.966 (November) to 1.32 (March) which indicates good condition of C. carpio. Based on Gonadosomatic index (GSI) values, peak spawning was observed in March in both C. carpio and S. niger. Absolute fecundity of C. carpio varied from 6325 to 33,066 and relative fecundity (per gram of body weight) varied from 66 to 211 ova in C. carpio, while as in case of S. niger absolute fecundity varied from 2700 to 16,758 and relative fecundity varied from 28 to 89 ova per gram of body weight. It was found that C. carpio is more fecund fish as compared to S. niger. An increase in pH values was found during summer months (8) and decrease in pH values was found during the winter months (7.29). Dissolved oxygen recorded lower values during the summer months (5.28mg/L) while higher values were recorded in winter months (8.3 mg/L). Free carbon dioxide recorded higher values during spring (14.44 mg/L) while lower values were recorded in winter months (10.07mg/L). Nitrate nitrogen recorded higher values during summer months (518.49μg/L) while as lower values were recorded during winter (306.63μg/L). Ammonical nitrogen recorded higher values during summer months (243.13μg/L) while lower values were found during winter (110.55μg/L). Total phosphorous recorded higher values during summer months (635.67µg/L) while as lower values were recorded during winter (392.87µg/L).
