Fecundity and Gonadosomatic Index of Sucker Throat Catfish, Pseudecheneis sulcata (McClelland, 1842) from the Snow-fed Tamor River in Eastern Nepal

In comparison to other nations, the Nepalese information on the reproductive biology of hill-stream fish is limited. So, the purpose of the present study was to provide information related to reproductive biology of a hill-stream sucker throat catfish Pseudecheneis sulcata from the snow-fed Tamor River, Nepal. The study was carried out from June 2018 to May 2019. A total of 57 female fish was collected. The fecundity of 22 females was assessed, while the gonadosomatic index was determined using all the collected samples. The absolute fecundity ranged from 2,316 to 7,597 eggs, with an average of 3,660 ± 210. This range of absolute fecundity indicates that Pseudecheneis sulcata is a moderately fecund fish when compared to certain low fecund species and some exceptionally fecund fish with tens of thousands of eggs. Relative fecundity ranged from 65.47 to 129.11 with a mean of 88.98 ± 4.35. The present study demonstrated that absolute fecundity was moderately correlated with total length (r = 0.45) and strongly linked with body weight (r = 0.78), and ovary weight (r = 0.80). Mean gonadosomatic index (GSI) was recorded the highest in January (15.7 ± 1.22%), and showed a decrease in the subsequent month of February (10.3 ± 0.75%), March (6.25 ± 0.28%) and April (1.66 ± 0.40%). The trends of GSI might have indicated that the sucker throat catfish was a batch spawner, with spawning season occuring between January and March.

ON FERTILITY OF BLACK-BACKED SHAD ALOSA KESSLERI KESSLERI (GRIMM, 1887)

The article highlights the results of studying the individual absolute fertility (IAF) of black-backed shad Alosa kessleri kessleri (Grimm, 1887). The data were obtained during the species’ spawning run in the Volga River. A positive correlation was established between IAF and the linear indicators, weight and age of producers. IAF ranged from 38.0 to 333.9 thousand eggs. The average absolute fecundity of herring varied from 38.8 to 259.2 thousand eggs. In the 1970s black-backed shad of 26-42 cm long had fluctuations in the average absolute fecundity from 88.4 to 258.5 thousand eggs. At the present stage, the size range of spawning shoals suggests that maturity in black-backed shad occurs at a body length of 22-45 cm, the reproductive capacity is regulated by early maturation. The results of studies on the fertility of black-backed herring of various lengths in 1 g of ovary have been obtained. There has been registered a wide range of fluctuations in the number of eggs (from 4033 to 14147 pcs). Differences in the size of ovaries indicate a qualitative definiteness of the physiological readiness of females in the pre-spawning period. The fluctuations in the average individual absolute fertility were revealed depending on body weight and age. Fertility in one-size groups and the reproductive capacity of the population as a whole change due to habitat conditions. The conditional indicator of the population fertility was calculated. The results of the obtained fertility data compared with the data of previous years indicate a 1.5-fold decrease in reproductive capacity of the population at the present time, which indicates a stressed state of the reproductive capacity of female species

On the reproductive biology of the invasive Armoured Sailfin Catfish Pterygoplicthys pardalis (Castelnau, 1855) (Siluriformes: Loricariidae) from the natural drainages in Thiruvananthapuram, India

The present paper deals with the breeding biology of the invasive fish Pterygoplicthys pardalis from the natural drainages of Thiruvananthapuram, Kerala. The specimens were collected from Amayizhanchan Thodu, a natural drainage running through the heart of the city. A total of 145 males and 142 females were collected from January to December 2018. The sex ratio was determined monthly as the percentage of males to females (M: F). Monthly mean gonadosomatic index (GSI) values were compared using R stat, and GSI was plotted monthly to identify the spawning seasons. The gonads were examined and different stages of maturity were noted using standard methods. The length at first maturity was also found out. The fish exhibit courtship behaviour and the eggs are deposited in burrows and also along the crevices in the granite walls; the burrows are guarded by the male fish till the young ones are hatched out. The sex ratio showed an average mean value of 1.04: 1 and showed no significant departure. The size at first maturity was 23.9 cm standard length. The ova diameter studies show the presence of ripe ovaries throughout the year, with peaks during March and April and between August and September and in December, indicating the fish is a batch spawner. The absolute fecundity ranges from 923 to 14,777 eggs, and the relative fecundity ranges 0.0142–0.0015. Regression analysis showed a significant relationship (P <0.001) between absolute fecundity and the total length, the total body weight, and ovary weight. The strong breeding behaviour, the presence of accessory respiratory organs, the absence of natural enemies and parental care makes Pterygoplichthys pardalis a successful invader in the natural drainage. More biological studies are needed for the successful eradication of the species from the invaded ecosystem.

​Assessment of Fecundity and Its Relation with Body Parameters of Common Carp, [Cyprinus carpio (var.) communis] in Dal Lake, Kashmir

Background: Fecundity is an important parameter in fisheries that predicts the reproductive capability of fish stock. Information on the fecundity of Common carp is helpful in estimating the amount of offspring produced in spawning season, which is essential for the stock assessment of the species. Assessment of the fecundity of a fish is essential for evaluating the commercial potentialities of its stock, life history, practical culture and actual management of the fishery. Common carp is a commercially important fish which has the potential to meet the demand of food in the country. Scanty of data is available on fecundity parameter of common carp in Kashmir waters. Therefore, this research work aims to estimate the fecundity of Common carp collected from the Dal lake of Kashmir. Methods: The present study aims to estimate the fecundity of Common carp, [Cyprinus carpio var. communis] existing in Dal Lake, Kashmir. The 30 fish samples were collected once every month from the month of January 2018 to December 2018. Fishes were brought to Fisheries Resource Management (FRM), Faculty of Fisheries, SKUAST-K Laboratory for the estimation of total length, weight of fishes and weight of ovaries. Gravimetric and actual counting method was used for the estimation of fecundity. Result: It was observed that the number of eggs varied from 16650 (for a fish with total length 180mm and total weight 120 g) to 129000 (for a fish with total length 430 mm and total weight 1300 g. The mean absolute fecundity was recorded as 68864.07± 6563.59 for a fish with a mean total length of 301.43 ± 13.93 mm and mean total weight of 435.1 ± 66.51 g. The relative fecundity ranged from 99.2-240.8 and the mean relative fecundity was 185.96. Significant positive correlation was found between fish weight and absolute fecundity. (r= 0.907, p less than 0.01), fish length and absolute fecundity (r= 0.976, p less than 0.01), Ovary weight and absolute fecundity (r= 0.998, p less than 0.01). Relative fecundity showed a significant negative correlation with weight, length and absolute fecundity (r= -0.747, p less than 0.01; r= -0.419, p less than 0.05 and r= -0.460, p less than 0.05 respectively.

Observations on impact of stunting on breeding performance of farmed rohu Labeo rohita (Hamilton, 1822)

Breeding performance of stunted rohu Labeo rohita (Hamilton, 1822) was compared with normally reared rohu. Randomly selected stunted and normal fishes were tagged and reared together in a single earthen pond for broodstock development. Both groups exhibited growth enhancement during the broodstock development period, though normal fishes were found larger in size than the stunted fishes, after the rearing period. Gonadosomatic Index (GSI) of female fishes indicated a similar trend of ovary growth in both the groups. Breeding performances of the broodstocks were evaluated by induced breeding trials. Parameters such as absolute fecundity, relative fecundity, number of spawns produced and hatching percentage were significantly higher (p<0.05) (almost double) in normal fishes than the stunted fishes. The present results indicate that the stunting process (6 months) is having detrimental effect on the breeding performance of rohu and thus stunted fishes are not ideal for broodstock development.

Some Aspects of Reproduction in Long Whiskered Catfish, Sperata aor (Hamilton 1822), from North-East Bangladesh

Different reproductive aspects such as sexual maturity, spawning, gonadosomatic index, fecundity, and histological changes in gonads of captive reared Sperata aor were investigated for a period of one year. Male and female fish were identified by based on morphological characteristics. The spawning season was found to be extended from May-August. Gonadosomatic index reaches maximum in August and lowest in September. Absolute fecundity varied from 59255 to 70586 with an average value of 64920. Absolute fecundity had been reported to be increased with total length, body weight. Histological study of ovary of S. aor indicated the presence of four developmental stages viz, early perinucleolar s oocytes, late perinucleolar oocytes, yolk vesicle stage and yolk granular stage. Findings reveal that, S. aor has group asynchronous manner of ovarian growth and used to spawn numerous times in a year under favorable environmental conditions. The testes histology represents the presence of spermatocyte, spermatid, and spermatozoa. This species builds nests during breeding season and fries are found within the nests.

Comparative Studies on Gonad Development, Fecundity and Oocyte Maturation of Spotted Snakehead, Channa punctatus (Bloch, 1793) in Different Water Bodies

The present study was carried out to compare gonad development, oocyte maturation and fecundity of the spotted snakehead (Channa punctatus) fish during January to November 2015 in different water bodies (such as pond, Joghati baor and Bhairab river) in Jashore, Bangladesh. Mean GSI (gonadosomatic index) values of the female C. punctatus during January, March, May, July, September and November were significantly highest in pond, followed by those in Joghati baor and the lowest in Bhairab river. Absolute fecundity during the month of July in pond, baor and river was 30,006±2,027, 23,629±2,356 and 16,659±2,486, respectively, and the relative fecundity was 5064±183, 4865±106 and 4641±138 eggs, respectively. Mean ova diameter in pond, baor and river in March was 0.25±0.04 mm, 0.16±0.02 mm and 0.21±0.03 mm; in May was 0.36±0.03 mm, 0.29±0.03 mm and 0.23±0.04 mm; in July was 1.06±0.06 mm, 0.95±0.05 mm and 0.87±0.03 mm; and in September was 0.84±0.04 mm, 0.82±0.03 mm and 0.72±0.05 mm, respectively. Mean GSI values of the male C. punctatus during January, March, May, July, September and November were significantly higher in pond than those in baor and river, respectively. The mean highest GSI for female was found to be 6.06±0.11 in pond during the month of July, while the lowest GSI of 0.30±0.08 was in Bhairab river during November. The highest GSI value for male was obtained to be 0.70±0.16 in pond during the month of July, while the lowest GSI of 0.12±0.03 was found in Bhairab river during January. However, significant differences (P<0.05) were found in GSI values, absolute fecundity, relative fecundity and ova diameter of C. punctatus during different months in pond, Joghati baor and Bhairab river. The findings from the present research would immensely be useful for captive breeding and seed production techniques of C. punctatus for aquaculture production, sustainable management and species conservation.

Sex hormones changes in blood and their effect on fecundity of African catfish (Clarias gariepinus Burchell, 1822) after being injected with different doses of human chorionic gonadotropin (HCG) hormone

This study was conducted to investigate the effect of different doses injection of human chorionic gonadotropin (HCG) hormone on fecundity and serum sex hormones (FSH, LH, estrogen (E2), progesterone (P4), testosterone (T)) of African catfish (Clarias gariepinus). African catfish spawners were intermuscularly injected with different doses of HCG (500, 1500, 3000, 6000 IU/kg female), and group is not injected as a control; males were injected at half the female dose. The results showed that, fish group injected by 6000 IU HCG/ kg female had the highest gonadsomatic index, absolute fecundity and relative fecundity, while, the lowest value of absolute fecundity and relative fecundity were recorded with 500 IU HCG/ kg female. The group injected with the highest amount of HCG (6000 IU/ kg female) recorded the lowest value from egg diameter, while the highest egg diameter was observed in 500 IU HCG/ kg female. In females, the group injected with 6000 IU HCG/ kg female reflected the lowest level of FSH and the highest level of LH and the highest level of P4 compared to other treatments. Level of T recorded the highest level with 1500 IU HCG/ kg female. The control group reflected the highest level of FSH and E2, while the control group reflected the lowest level of T and P4 level. In males, serum FSH, LH, P4 and E2 in male groups injected with HCG were relatively higher than those recorded in the control group. The highest level of T was recorded in treatment injected with the highest dose of HCG and decreased in other treatments until recorded the lowest level of T in the control group. It was observed, HCG hormone has successfully and accelerate induced spawning in African catfish (Clarias gariepinus) and increased in reproductive performance with the increase in HCG dosage and as compared to group not injected.

Fecundity, histomorphology of the ovary and size at first maturity of Neolissochilus hexagonolepis (McClelland) in Tamor River, Nepal

Neolissochilus hexagonolepis (McClelland, 1839) is one among the notable species in snow-fed torrential rivers of Nepal. The present study attempts to investigate some reproductive traits of N. hexagonolepis, including the length at first maturity, fecundity and its relationships with biometric variables like lengths (TL, SL, and FL) and weights (TW and OW) of the fish in the mid-reaches of Tamor River, Nepal. A total of 109 fish samples were collected from the river. For each individual, total length (TL), standard length (SL) and fork length (FL) were measured in a fully stretched condition to the nearest 1mm using a measuring tape and graduated ruler, while total weight (TW) and ovary weight (OW) was measured using a digital balance with the precision of 0.01 g. The mean absolute fecundity (F) was 8356.44 ± 4612.59 and ranged from 2398.6 to 20160. SL was more significantly correlated with absolute fecundity (R2=0.59; p<0.001) than other body metrics. The results showed that female individuals of N. hexagonolepis attained the first sexual maturity at TL 32.9 cm. N. hexagonolepis exhibited a protracted breeding period with its ovaries passing through six different stages of maturation. The finding of the present study may serve as a protocol for fishery biologists and managers to promulgate adequate regulations for continual fishery management in the River Tamor, Nepal.

Age, Growth, Reproduction and Fecundity of Roach Rutilus rutilus from Volvi Lake, Northern Greece

The roach, Rutilus rutilus, is a Cyprinid which is widely distributed throughout freshwater systems in Europe. It is one of the most abundant and important commercial fish species in Greece. Age, growth, reproduction and fecundity of roach were studied in Lake Volvi from 1997-1998 females had higher growth in length (L∞=277.18 mm, k=0.097) than adult males (L∞=185.60 mm, k=0.148). All males older than one year and larger than 70 mm, and all females older than two years and larger than 80 mm were sexually mature. The breeding period spanned from the end of March till mid April. Fecundity ranged from 2,036 to 31,653 eggs (mean 8,102 eggs) and relative fecundity from 76.06 to 333.94 eggs/g (mean 186.78 eggs/g). Diameter of eggs were 1.3 ± 0.07 mm and weighted 0.0011 ± 0.0002 g . The weight of eggs were independent of length and age of individuals (P>0.05), however, there was a significant relationship between weight and egg diameter (P<0.05). Absolute fecundity depended on length, weight and age of the females. The relationship between absolute fecundity and length were less obvious in the case of relative fecundity and egg size. Estimated growth was at the lower end when compared with other studies conducted elsewhere.