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.

​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.

Aspects of Reproductive Biology of the European Hake (Merluccius merluccius) in the Northern and Central Adriatic Sea (GSA 17-Central Mediterranean Sea)

The study focused on the macroscopic, histological, and biometric analysis of European hake females in GSA 17 (Central-North Adriatic Sea). From 2013 to 2015, 976 females were collected and analyzed monthly. Though females in spawning conditions were found during the whole year, the trend of GSI showed a peak of the reproductive season from April to July in 2014 and 2015. HSI and Kn reached the highest values in September, after the spawning peaks. In 2013, the trend of these indices did not highlight an evident peak, probably due to an adverse event that occurred in the previous winter in the Adriatic shelf. The length at first maturity (L50) was estimated by macroscopic and histological approaches, resulting in 30.81 cm for the macroscopical length and 33.73 cm for the histological length; both values are higher than the current catching legal size. For the first time in this area, batch and relative fecundity were estimated. Relative fecundity was similar to the Mediterranean and the Atlantic stocks, whereas batch fecundity values were lower compared to other fishing grounds. Overall, the analysis of reproductive parameters plays a fundamental role in the sustainable management of this resource in an area as overfished as the Central-North Adriatic Sea.

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.

Sex Ratio, Fecundity and Morphometry of the Eggs of Freshwater Prawn Macrobrachium Americanum (Bate, 1868) in the Petatlán River, Sinaloa, Mexico

Macrobrachium americanum has a high commercial value with good fishing and cultivation possibilities in Mexico. Currently there is little information on reproductive aspects so the present work analyzed the sex ratio, fecundity and morphometry of the eggs of M. americanum in the Petatlán River, Sinaloa, Mexico. A total of 31 ovigerous females were captured. The sex ratio was 0.39 F: 1 M. The partial fecundity (Pf) varied from 34, 554 to 342, 372 eggs (128, 246 ± 12, 306 eggs, average Pf). The relationships between body and length-fecundity (R2= 0.5546), cephalothorax and length-fecundity (R2= 0.4995) were adjusted to a linear model, and the total weight-fecundity to a potential model (R2= 0.5013). The average relative fecundity was 37, 132 ± 5, 162 eggs/g. A total of 7 stages of embryonic development were observed. In the first stages, the egg presents a spherical form and in the latter an ovoid shape. Maximum egg diameter values are presented in stages VII, VI and VIII. Stage II provided the largest number of eggs (1, 013, 073 eggs). It is essential to optimize the exploitation of the population of M. americanum present in the Petatlán River through the creation of scientific bases for the sustainability of the fishery.

A first assessment of atresia in the Chilean jack mackerel Trachurus murphyi (Teleostei, Carangidae) from the South-eastern Pacific Ocean

The Chilean jack mackerel Trachurus murphyi support an important fishery in the South-eastern Pacific Ocean and has declined considerably over time. T. murphyi have asynchronous ovarian development with an oceanic spawning (September to January). Despite the economic importance of this resource critical issue such as characteristics and dynamics of atresia, which affect the reproductive output, are unknown. Females of T. murphyi caught in different spawning seasons were analysed to describe patterns of prevalence and intensity of atresia. General linear models (GLM) were performed by using prevalence and intensity atresia as response variables and gonadosomatic index, condition factor, sea surface temperature, postovulatory follicles and month/year as explanatory variables. The batch fecundity and relative fecundity were compared between females showing atresia, postovulatory follicles and non-atretic females. The stages of atresia identified were alpha, beta and gamma. The GLM showed that variations in the prevalence and intensity of atresia were explained for all variables, except condition factor for prevalence, and gonadosomatic index for intensity of atresia. According to our results, the dynamic of alpha and beta atresia could be considered a potential proxy for any disruption of spawning season. The batch fecundity and relative fecundity were lowest compared with other Trachurus spp. This is the first assessment comparing fecundity between atretic and not atretic females for this species.

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.

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.

Reproduction of Hypoptopoma inexspectatum (Holmberg, 1893) (Siluriformes, Loricariidae) in the Southern Pantanal Floodplain, Upper Paraguay River Basin, Brazil

This work aimed to describe the reproductive biology of Hypoptopoma inexspectatum in southern Pantanal. A total of 538 individuals were sampled and analyzed from February 2009 through January 2011 in southern Pantanal. We did not observe differences in sex-ratio, and both sexes presented positive allometric length/weight relationship (LWR). Reproduction occurs mainly from January to February. Females reached first maturation (L50) with 37.80 mm and males with 45.80 mm. Absolute fecundity is estimated in mean=177.43 (sd±127.06) oocytes and relative fecundity in 3.12 (sd±2.23) oocytes/mg. Fecundity is positively correlated with standard length (Spearman r= 0.43; p=0.013), and total spawning is a used spawning strategy for H. inexspectatum.