Seasonal Variation in Length-weight Relationship, Condition Factor and Biological Indices of Snow Trout, Schizothorax esocinus (Heckel, 1838) Inhabiting River Jhelum of Kashmir Himalaya (original) (raw)
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Journal of Environmental Biology
Schizothorax labiatus is one of the economically valuable food fish among indigenous schizothoracids (snow trouts), inhabiting the Jhelum River system in Kashmir along with other snow trouts of family Cyprinidae. The present study was conducted to understand and bring forward various reproductive traits of S. labiatus inhabiting River Jhelum. The investigation was carried on 310 samples (221 males and 89 females) with total length and total weight ranging between 143 to 350 mm and 62 to 449 g, respectively, for a period twelve months. Gonadosomatic index (GSI) was recorded maximum during April for both males (6.19) and females (11.12), indicating that the fish fully matures during this month and spawns during coming months i.e., May when the GSI values start decreasing abruptly. The average values of absolute and relative fecundity in the fish were recorded per gm body weight as 10323 and 42, respectively. Sex ratio was found in 1:0.41 ratio, indicating a significant dominance of males over opposite sex and L , i.e., length at first maturity was m estimated to be 196 mm and the corresponding age at this length was 2+ years. The fish breeds once in a year in natural/wild habitat. These findings on reproductive biology of the endemic snow trout, and the influence of environmental conditions on breeding biology will serve as a baseline data towards planning seed production and conservation strategies.
Current World Environment, 2009
Fecundity of a fish can be defined as the number of eggs that are likely to be laid during one spawning period or the capacity of the fish in terms of egg production (Bagenal, 1968). It differs in different races of the same species. The measure of fecundity in fishes is a basic determinant of productivity and hence, contributes to fish culture and population dynamics. Important contributions to the study of fecundity in relation to the other parameters of body are made by Das & Koul (1965);
2018
The food and feeding habits of Schizothorax plagiostomus in river Lidder was studied by examining 500 guts collected throughout the year. The fish samples used in the present study was within the range of 25.5cm to 40.33cm in total length and weight ranging from 250g to 580g in weight and the sampling duration was from July, 2013 to June, 2014. During the analysis of food and feeding habits of S. plagiostomus it was concluded that the fish is benthic herbivorous. Its food mainly consists of plant matter 62.02%. A good amount of miscellaneous food items i.e. mud, sand and detritus 31.01% was also present in the gut of fish along with small quantity of animal food 6.97%. Overall it was concluded that diatoms formed an important constituent of food of S. plagiostomus in all months of the year and the presence of detritus, mud and sand indicates that the fish is a detrivorous, bottom feeder. The gastrosomatic index in case of females ranged from 3.88±0.30 to 7.30±2.128 with minimum in J...
Environmental Biology of Fishes, 2022
The controlled breeding program of Schizothorax labiatus requires in-depth knowledge of its reproductive features, which were studied for 2 years (October 2017 to September 2019). The study revealed four maturity phases in S. labiatus differing morphologically as well as histologically. Overall gonadosomatic index (GSI) followed the same trend in both the sexes (p>0.05; t-test), but a significant difference in GSI was observed in March with females having a higher GSI than males (p<0.05; t-test). The peak values of GSI in both sexes were observed during April and May with an abrupt decrease in June. The minimum ova diameter (0.3 mm) showed high frequency during the regressing phase, whereas the maximum ova diameter (2.4 mm) showed high frequency during the spawning capable phase. Absolute and relative fecundity ranged from 2754±1388 to 13465±7508 ova and 14±10 to 45±12 ova/g body weight, respectively. Absolute fecundity showed a highly significant positive correlation (p<0.01) with ovary weight as compared to ovary length, total length, and the total weight of the fish. Length at first maturity (Lm) for males and females was estimated to be 23.6 cm and 27.6 cm, respectively, indicating that males mature earlier than females. GSI of both sexes was found to increase significantly with the water temperature from December to April (rs = 1.0 for males and rs = 0.9 for females; p<0.05). The unimodal distribution of oocytes revealed that all oocytes are released in a short period (total spawner) from the late spring to summer season.
International Journal of Fisheries and Aquatic Studies, 2019
Present work was carried out in order to find out some seasonal variables on some blood parameters of Schizothorax plagiostomus caught from the world-famous River lidder (Pahalgam Kashmir, India). Effects of the independent variables e.g., sex, weight and length values were determined seasonally. Analysis revealed that highest number of leukocytes was found in spring and lowest number was found in winter. Hemoglobin and Haematocrit values were highest during the months of summer and lowest during winter. It was also seen that Males were having greater values for hemoglobin and Haematocrit than females, whereas total leukocyte count in females was higher than males. It was also found that there was a positive correlation between Length/weight and Hemoglobin and Haematocrit values where as a negative correlation between length or weight and Total leukocyte counts.
This study examines the relationship between morphological traits related to body size and fin morphology and the environment in snow trout, Schizothorax richardsonii, a widespread species from the upper Ganga river basin, India. Three body shape traits (index of compression, index of trunk shape and relative body depth) and three fin traits (relative area of dorsal fin, relative area of pectoral fin and pectoral fin aspect ratio) were related to five environmental variables (water temperature, flow, depth, conductivity and substrate diversity) across eight study streams. Principal components analysis (PCA) of the environmental variables showed that water temperature, conductivity and substrate diversity were highly variable across the sampled sites. A significant negative correlation (r = -0.676) between composite morphological traits (principal components) related to body size and fin morphology. Further the body size and fin morphology from PCA were strongly correlated (r = 0.861...
University of Sindh Journal of Animal Sciences (USJAS)
In this study, the relationship of total body length (TBL) and total body weight (TBW), Fulton’s condition factor (FCF), gonado somatic index (GSI) and absolute fecundity were determined in snow trout (Schizothorax plagiostomus) from river Indus at district Kohistan, Northern Pakistan. A total of 540 matured specimens (male=277, female= 263) were collected between January and December 2016 by using a gill net. A curvilinear relationship of fecundity and GSI with TBL and TBW were investigated by the quadratic model fit. The study revealed the fact that S. plagiostomus spawned twice in a year, during spring and autumn. The growth coefficient b value and mean condition factor were estimated at 3.42 and 1.75 in both sexes respectively. The GSI in males and females was found 4.4% and 10.96% respectively. In females mean absolute fecundity was 4578.16 eggs. The present study has significance in providing baseline information for the management and conservation of this species of economic ...
International Journal of Fisheries and Aquatic Studies, 2017
A total of 253 brown trout (Salmo trutta fario L.) (130 males and 123 females) were examined for the study of fecundity, spawning season and sex ratio. The length ranged in between 26.15 to 44.15 cm, while, weight from 235 to 1140 gms. The fecundity of brown trout (S. trutta fario L.) was in between 454 to 1052 eggs per female. It was positively co-related with the total fish length (r=0.859), fish weight (r=0.653), ovary length (r=0.828) and ovary weight (r=0.996). Gonadosomatic index (GSI) confirmed that spawning lasted from October to January. The sex ratio of male and female was 1: 0.95.