Gonadosomatic Index Values Research Articles

Life history of Mexican species of the genus <i>Tlaloc</i> (Cyprinodontiformes, Profundulidae)

Fish of the genus Tlaloc are distributed from southern Mexico to Central America and are a distinctive example of the endemic fauna of the Mesoamerican highlands, which has been scarcely studied in Mexico. The present study provides basic life-history data for the species Tlaloc hildebrandi, T. candalarius, and T. labialis, which are native to the headwaters of the Grijalva-Usumacinta basin in southeastern Mexico. We collected 918 specimens to determine their Length-Weight Relationship (LWR), Relative Condition Factor (Kr), sex ratio, Gonadosomatic Index (GSI), fecundity, and size at first sexual maturity. Both sexes of all species had positive allometric growth, except for T. candalarius females (isometric). Mean Kr and sex ratio values differed significantly among species. Females’ GSI values differed significantly among species but were highest during the dry season in all three species. Absolute fecundity was positively correlated with standard length and weight. Sexual maturity was reached at different lengths among species. Based on these results, we suggest that all three species present an opportunistic life strategy, which is very common in fish of the order Cyprinodontiformes. These results represent a first contribution on the life-history of this group of fish and provide basic information that is fundamental to ensuring their conservation.

Negligible additive effect of environmental concentrations of fragmented polyethylene terephthalate microplastics on the growth and reproductive performance of Java medaka exposed to 17β-estradiol and bisphenol A

To investigate whether environmental concentrations of fragmented polyethylene terephthalate (PET) microplastics (MPs) have additional or combined effects on endocrine-disrupting activity, Java medaka (Oryzias javanicus) were exposed to 17β-estradiol (E2; 5, 10, 50, and 100 ng L−1), bisphenol A (BPA; 5, 10, 50, and 100 µg L−1), and E2 and BPA combined with PET MPs (1 and 100 particles L−1) for 200 days. The growth parameters, such as body length and weight, were significantly decreased by the highest concentrations of E2 and BPA. A significant reduction in egg production was observed in female fish exposed to BPA, with an additive toxic effect of PET MPs. A female-biased sex ratio was observed in fish exposed to both chemicals. Exposure to E2 significantly increased the hepatosomatic index (HSI) in both sexes, while no significant effect was observed in the gonadosomatic index (GSI). Exposure to BPA significantly increased the HSI in female fish and decreased the GSI in both sexes of fish. An additive effect of PET MPs was observed on the GSI value of female exposed to BPA. Significant elevations in vitellogenin (VTG) levels were observed in both sexes due to exposure to E2 and BPA. Additive effects of PET MPs were observed on VTG levels in males exposed to E2 and BPA. Taken together, even long-term treatment with PET MPs induced only a negligible additive effect on the endocrine-disrupting activity in Java medaka at environmentally relevant concentrations.

Loss of bmp15 function in the seasonal spawner Atlantic salmon results in ovulatory failure.

Bone morphogenetic protein 15 (BMP15) is an oocyte-specific growth factor important for successful female reproduction in mammals. While mutations in BMP15/Bmp15 cause ovulatory deficiency and/or infertility in certain mammalian species, loss of bmp15 in zebrafish, a continuous spawner and the only bmp15 knockout model in fish to date, results in complete arrest of follicle development and later female-to-male sex reversal, preventing to examine effects on ovulation/fertilization. Here, we used Atlantic salmon, a seasonal spawner, and generated bmp15 mutants to investigate ovarian development and fertility. Histological and morphometric analyses revealed that in biallelic frameshift (bmp15 fs/fs) mutant ovaries, folliculogenesis started earlier, resulting in an advanced development compared to wild-type (WT) controls, accompanied by a weaker expression of the (early) oocyte-specific factor figla. This precocious ovarian development was followed in bmp15 fs/fs females by enhanced follicle atresia during vitellogenic stages. Although genes involved in steroid synthesis and signaling (star, cyp11b, cyp17a1 and esr1) were dramatically higher in late vitellogenic bmp15 fs/fs mutant ovaries, estradiol-17β plasma levels were lower than in WT counterparts, potentially reflecting compensatory changes at the level of ovarian gene expression. At spawning, bmp15 fs/fs females displayed lower gonado-somatic index values and reduced oocyte diameter, and the majority (71.4%), showed mature non-ovulating ovaries with a high degree of atresia. The remaining (28.6%) females spawned eggs but they either could not be fertilized or, upon fertilization, showed severe malformations and embryonic mortality. Our results show that Bmp15 is required for proper follicle recruitment and growth and later ovulatory success in Atlantic salmon, providing an alternative candidate target to induce sterility in farmed salmon. Moreover, since loss of bmp15 in salmon, in contrast to zebrafish, does not result in female-to-male sex change, this is the first mutant model in fish allowing further investigations on Bmp15-mediated functions in the ovulatory period.

Effect of long-term temperature-controlled rearing on growth traits and sexual maturity of common carp (Cyprinus carpio)

Many economically important fish have a long sexual maturation cycle, with the first sexual maturation time exceeding four years, which poses a long-term challenge for the cultivation of excellent varieties of these fish. Gonadal development and reproductive timing of fish are closely related to changes in environmental temperature. This study used the common carp as an economic fish model and set up three aquaculture modes for a one-month old common carp population: constant temperature test group (CTTG), normal temperature control group (NTCG), and variable temperature control group (VTCG). A long-term (approximately 11 months), temperature-controlled aquaculture experiment was conducted. The results of growth traits and gonadal development tests showed that at 10 months, the body length and weight of the CTTG were significantly higher than those of the other two groups. At seven months, the gonadosomatic index (GSI) value of CTTG was also significantly higher than that of the other two groups; At 10 months, the serum estradiol (E2) concentration of CTTG was significantly higher than that of the other two groups, while the testosterone (T) levels of VTCG and CTTG were significantly higher than those of NTCG, and only the 11-ketotestosterone (11-KT) concentration of VTCG was significantly higher than that of the other two groups. Simultaneously, qPCR analysis of sex hormone regulatory genes revealed that the expression of Cyp19a1a in CTTG ovaries was significantly higher than that in NTCG and VTCG ovaries, whereas the expression of Cyp11b and Hsd11b2 in VTCG ovaries was significantly higher than that in NTCG and CTTG ovaries. At 12 months, artificial reproduction revealed that only fish from the CTTG (66.67%) successfully laid eggs and fertilized normally. The results indicate that long-term constant temperature cultivation at 28 °C starting from the juvenile stage is not only beneficial for the body growth of common carp, but also promotes their gonadal development. This may be due to the conversion of T into E2 by Cyp19a1a in the common carp, ultimately facilitating the functional development of gonadal tissue under hypothalamus-pituitary-gonadal (HPG) axis regulation, normal egg laying, and fertilization. This study reduced the normal first sexual maturation time of common carp by at least 50% and provides a reference for the rapid cultivation of excellent varieties of other economically important fishes.

Assessing the temporal isolation barrier between two closely related species of the genus Fissurella off the southwestern coast of South America

ABSTRACT Knowledge of the reproductive isolation mechanisms that prevent gene flow between species is essential for understanding the process of speciation. In this study, we investigate the spawning periods in Fissurella cumingi and F. latimarginata, two closely related sympatric species of keyhole limpets with external fertilization, as a potential prezygotic barrier between them. The reproductive cycle was assessed in two distinct locations in northern Chile using the gonadosomatic index (GSI) and gonadal histology. Species, locality, and sex were designated as predictive variables, while average GSI values, as well as those of partial and total spawning, were considered dependent variables. Both species exhibit a continuous gametogenic cycle throughout the year, characterized by multiple spawning events. A generalized linear model (GLM) factorial ANOVA design revealed that neither species, locality nor sex were significant factors with respect to the GSI and partial spawning scores. However, sex was found to be the only significant factor related to total spawning. No significant interactions were observed among predictive factors. These findings suggest that reproductive periods may not serve as effective barriers to gamete encounters between species. Our study prompts questions about how closely-related externally-fertilizing species maintain reproductive isolation.

Effects of Synthetic Hormones on Fertilization, Fecundity, Hatching and Gonado-Somatic Index of Giant Snakehead (Channa Marulius) in Captivity

The effects of a crude protein (40% CP) diet on the spawning performance of giant Snakehead (Channa marulius) broodstock were assessed in this study through a three-week feeding trial. Mature C. marulius brood stock (N = 36) was taken from the brooders pond and stocked into nine small experimental breeding ponds, each measuring 4mx2mx1.5m (LxWxD). Following acclimatization, all male and female C. marulius broodstock with an average weight of 1.5–2.5 kg BW and a length of 70 cm were removed from the small breeding ponds. The current study's objective was to induce breeding in C. marulius by injecting synthetic hormones intramuscularly and monitoring fertilization, fecundity, hatching, and gonado-somatic index. Using a completely randomized design (CRD), nine fishponds were split into three treatments (T1, T2, and T3) during the study period, each with three replicates. In addition to evaluating the effects of artificially applied hormones, Conceptal® (T1), Suprefact® (T2), and Ovaprim® (T3), this study aimed to comprehend the reproductive biology of C. marulius. The hormones were injected into the test fish at the following proportion (0.3ml, 0.4ml and 0.5ml to male and 0.8ml, 0.9ml and 1.0ml to female’s ml/kg body weight) and then released into the earthen ponds for large scale production of seed. Two-way analysis of variance (ANOVA) was used. The results showed no successful spawning on Conceptal®. The gonado-somatic index (GSI) estimates for the study period showed that Suprefact had the highest average GSI values for both males and females (3.32±1.62% and 1.67±0.18%, respectively), followed by Ovaprim (1.13±0.56 and 1.22±0.68, respectively). Absolute fecundity was also estimated. The result showed that fish stimulated with suprefact (T2) obtained the highest average fecundity (3079.3±100.7%), fertilization rate (96.33±1.20%), hatching rate (94.67±2.40%), and survival rate (95.75±1.51%), then in ovaprim fecundity rate (1669.3±836.5%), fertilization rate (58.00±29.02), hatching rate (61.27±30.65), survival rate (64.67±32.34%), respectively. In conclusion, the use of Suprefact® and Ovaprim® can optimise the results of C. marulius breeding induction in small experimental breeding ponds, ensuring higher-quality eggs and a greater number of normal larvae.

Egg Quality and Fecundity of Clarias gariepinus Broodstock Cultured at Different Water Depths in Indoor Concrete Tanks

Aims: To investigate the fecundity and egg quality of C. gariepinus broodstock raised at 0.50 m, 0.75 m and 1.0 m pond water depth. Study Design: Treatments were assigned using complete randomized design. Place and Duration of Study: Fish Farm Complex of the Akwa Ibom State University (AKSU), Nigeria. Methodology: Nine female broodstock of C. gariepinus averaging 2.51 – 2.53 kg and 64.30 – 67.24 cm were raised for six months at 0.50 m, 0.75 m and 1.0 m pond water depth; referred to as treatments A, B and C, respectively Experimental fish were fed 42% crude protein commercial feed. The fecundity, relative fecundity, gonadosomatic index (GSI), egg weight and size were assessed. Results: The results revealed that the egg quality significantly (P=.00) increased with the water depth of the broodstock culture tank. Egg weight and GSI values from treatment C (363.40±0.57 g and 14.40±0.01 %, respectively) were significantly (P = .007) higher than those of treatment A (267.30±0.06 g and 10.66± 0.06 %, respectively) but showed no significant difference with those of Treatment B (331.07±1.20; 13.09±0.04 %). The corresponding egg diameter (1.01±00; 1.08±0.03 and 1.21± 0.01g), fecundity and relative fecundity of broodstock also increased with pond water depth (P = .003): 182,120.0±503.67, 72.66±0.40 > 185,618.3± 745.98, 73.37±0.18 > 188, 967.1± 295.19, 74.89±0.18, respectively. Conclusion: The water depth of the broodstock maintenance pond enhances fecundity and egg quality; it is better at 1.0 m depth for successful fry production. Broodstock may be maintained at lower pond water depths for growth purposes; prior to breeding.

Histological Evaluation of Purple Sea Urchin (Paracentrotus lividus) Gonads: Influence of Temperature, Photoperiod Regimes, and Diets

Understanding and controlling reproductive cycles and gonad maturation in cultivated species are crucial in aquaculture. The sea urchin Paracentrotus lividus, known for its edible gonads, requires careful maturation control for both reproduction and commercialization. This study explores the impact of temperature, photoperiod, and diet on gonad development to enhance year-round aquaculture practices. Using two independent cultivation systems, we manipulated environmental conditions to mimic different seasons. Sea urchins were exposed to natural or manipulated temperature and photoperiod conditions and fed either natural (Ulva spp.) or formulated diets. The gonadosomatic index (GI) and histological analysis were used to assess gonad development. The results revealed a clear correlation between environmental conditions, diet, and gonad maturation. Manipulated conditions accelerated maturation, with sea urchins showing advanced stages compared to natural conditions. Furthermore, sea urchins fed formulated diets exhibited higher GI values, indicating enhanced maturation. Histological analysis confirmed accelerated maturation, particularly in females. This study underscores the feasibility of controlling gonad maturation through environmental manipulation and diet, enabling year-round marketable gonad production. Providing formulated diets rich in polyunsaturated fatty acids, notably docosahexaenoic acid (DHA), enhances the commercial value of sea urchins. These findings optimize aquaculture practices for P. lividus, highlighting its adaptability to the maximal production of gonads throughout the year.

Exploring the reproductive features of Clupisoma garua from Ganges River, Bangladesh: insights into eco-climatic factors for sustainable management and advancements in aquaculture practices.

The Garua bacha, Clupisoma garua, holds considerable commercial and nutritional significance as a fish species. This study investigates the relationships between GSI (gonadosomatic index) and eco-climatic conditions, and provides comprehensive insights into several facets of reproduction, such as size at first sexual maturity (Lm), spawning season, peak spawning period, and proposes sustainable management strategies for C. garua in the Ganges River, northwestern, Bangladesh. Since January to December 2017, 570 female individuals have been gathered from the Ganges River using cast nets, gill nets, and square lift nets on a monthly basis. The total length (TL) of the specimens varied from 3.90 to 26.30cm. Lm was estimated as 14.30cm based on the results of the TL vs. GSI, MGSI (modified gonadosomatic index), DI (Dobriyal index), 14.00cm through TL-FL regressions, and 15.18cm depending on Lmax for this species. Furthermore, the spawning period was observed from May to August, peaking in June and July, based on greater GSI, MGSI, and DI values. Throughout the peak spawning season, there was not a significant differ from a value of 100 in the relative weight (WR) of the female species. During the spawning season, a substantial association between temperature and GSI (p = 0.0038); rainfall and GSI (p = 0.0043); DO and GSI (p = 0.0043); pH and GSI (p = 0.0002); and alkalinity and GSI (p = 0.0001) was detected. Analyzing a 55-year data series (1964-2018), it became clear that an increase in average air temperature of 0.0289 °C and a decrease in rainfall of 2.988mm per year might possibly delay the spawning season of this species. As a consequence, the results of this study provide crucial information for developing management strategies to safeguard C. garua populations in the Ganges River and its adjacent ecosystems.

Insights into reproductive dynamics and feeding biology of Sphyraena putnamae Jordan and Seale, 1905 exploited in the Indian EEZ

The sawtooth barracuda Sphyraena putnamae, widely distributed in the Indo-Pacific region, isone of the commercially important barracuda species exploited by trawls in the Indian EEZ.The present study examined 2,135 S. putnamae collected during 2014-2020 from differentfish landing centres along the Indian coast, to elucidate their reproductive and feedingbehaviour. The fork length of sampled females and males varied from 12.5 to 130.9 cm and16.5 to 90.0 cm respectively. Negative allometric growth was observed with a significantdifference (p<0.05) between the sexes. The observed sex ratio (Female:Male) was 1.23:1,indicating the dominance of females. Size at sexual maturity for females and males wereestimated at 55.3 and 45.4 cm fork length respectively. The higher proportion of spawningcapable individuals and higher gonadosomatic index (GSI) values in females observedduring March to May and November-December revealed the bimodal and protractedspawning nature of this species. Absolute fecundity increased with fork length and weightand varied from 70,080 to 10,18,068 oocytes with an average of 3,16,568 oocytes. Thestomach vacuity index of females and males was 49.09 and 47.92% respectively. Fifty-nineprey items were identified in the diet, with a predominance of fishes confirming S. putnamaehas a piscivorous feeding behaviour. Keywords:Management, Protracted spawners, Piscivore,Sawtooth barracuda, Sex ratio

Biochemical composition and condition of wild blackfin snook Centropomus medius through the reproductive cycle

The blackfin snook, Centropomus medius, is a valuable fish in American and Mexican markets, mainly from catches. Nonetheless, information and studies about the biology of this species still need to be made available; thus, its aquaculture should be developed. This study aimed to describe the seasonal changes of proximate composition during a reproductive cycle of C. medius, analyzing differences between tissues and their changes related to the reproductive process. The snook specimens were collected in Magdalena Bay, Baja California Sur, Mexico, and measured every month from September 2001 to November 2002. Liver, gonads, muscle tissue, and intraperitoneal fat (IPF) were sampled and weighed. The gonadosomatic index (GSI), hepatosomatic index (HSI), IPF ratio, and condition factor index (K) were calculated. The biochemical composition was analyzed in the gonad, liver, and muscle. The reproductive period (RP) of wild C. medius in Baja California Sur, Mexico, was from June to December. The spawning period was recorded at summer temperature (25-30°C) and photoperiod (>13 h daylight) starting in September. High GSI values (gonad development), low HSI values (lipid reserve mobilization), low IPF, and low K ratio were related to elevated temperatures. Moreover, variations were observed in protein, total lipid, triglycerides, and glycogen content in muscle, liver, and gonad according to the reproductive phase. A positive correlation was demonstrated between protein contents in muscle, gonad, and K, with lower concentrations during RP, while liver protein composition showed an opposite pattern. Lipids were mainly present in the liver, and the concentration decreased during RP while muscle increased. The results obtained in this study show differences in the proximate analyses in the liver, muscle, and gonads throughout the year concerning different phases of the reproductive cycle, indicating a great dependence of this process on the mobilization of reserves during C. medius reproduction. Therefore, understanding the feeding requirements to pursue the management of this species in captivity for aquaculture development is greatly important.

Effects of Varying Dietary Levels of Hibiscus rosa sinensis Leaves Powder on Growth and Gonads Development in Nile Tilapia Oreochromis Niloticus (Linnaeus, 1758)

Aims: The purpose of this study was to explore the possible use of Hibiscus rosa sinensis leaf powder as a reproductive inhibitor in Oreochromis niloticus
 Place and Duration of Study: From 10th February to 21st June 2021 at the Kanhé-Moyo Integrated Fisheries and Aquaculture Research and Application Farm located in the locality of Baho'o belonging to the Baham District,in the West Region of Cameroon
 Study Design: 720 Oreochromis niloticus fingerlings with an average weight of 13±2.5g were randomly distributed in 12 happas arranged in an earthen pond measuring approximately 10 x 20 m and fed 3 experimental diets, formulated from a control diet to contain Hibiscus rosa sinensis leaf powder at doses of 3.5, 4.5 and 5.5 g/kg of feed respectively.
 Methodology: After 45 days post-treatment, survival and zootechnical growth parameters were assessed. Histological examination of the gonads was used to determine the impact of treatment on gonadal development at 45 and 65 days post-treatment respectively.
 Results: The results show that the different treatments had a similar effect on survival (P˃0.05), with an average value of 97.91 ± 3.81%. Analysis of the growth parameters of fishes from the different batches treated with different doses of H. rosa sinensis leaf powder revealed that the dose of 4.5 g/kg of H. rosa sinensis had a significantly greater effect than the other treatments applied in terms of Mean Final Weight (with a mean value of 24.77±0.27g), Mean Weight Gain (with a mean value of 3.63±1.18 g), mean specific growth rate (with a mean value of 1.13 ± 0.40%/day) and Mean Daily Gain (with a mean value of 0.25±0.08 g/d). However, analysis of the gonado somatic index at 45 and 60 days post-treatment of batches treated with different doses of H. rosa sinensis leaves revealed a significantly higher effect of the 3.5 g/kg dose on the gonado somatic index in both males and females. Observation of the testicular structures of the males from the treated batches revealed alterations reflecting an inhibition of gonadal development, which justifies the low gonado somatic index values observed in these different treated batches compared with the control batches. These alterations were also observed in the ovarian tissues of the treated females both at 45 and 60 days post-treatment. However, observations of the gonadal structures of satellite males and females at 60 days post-treatment revealed partial restoration of gonadal tissue in both males and females.
 Conclusion: The results of this study indicate that Hibiscus rosa sinensis leaves could be used as an alternative ecological method for inhibiting reproduction in Oreochromis niloticus. The results will help local producer networks to improve tilapia production.

Fluctuating and Stable High Temperatures Differentially Affect Reproductive Endocrinology of Female Pupfish.

For many fishes, reproductive function is thermally constrained such that exposure to temperatures above some upper threshold has detrimental effects on gametic development and maturation, spawning frequency, and mating behavior. Such impairment of reproductive performance at elevated temperatures involves changes to hypothalamic-pituitary-gonadal (HPG) axis signaling and diminished gonadal steroidogenesis. However, how HPG pathways respond to consistently high versus temporally elevated temperatures is not clear. Here, sexually mature Amargosa River Pupfish (Cyprinodon nevadensis amargosae) were maintained under thermal regimes of either stable ∼25°C (low temperature), diurnal cycling temperatures between ∼27 and 35°C (fluctuating temperature), or stable ∼35°C (high temperature) conditions for 50 days to examine effects of these conditions on HPG endocrine signaling components in the pituitary gland and gonad, ovarian and testicular gametogenesis status, and liver gene expression relating to oogenesis. Female pupfish maintained under stable high and fluctuating temperature treatments showed reduced gonadosomatic index values as well as a lower proportion of oocytes in the lipid droplet and vitellogenic stages. Females in both fluctuating and stable 35°C conditions exhibited reduced ovarian mRNAs for steroid acute regulatory protein (star), cholesterol side chain-cleavage enzyme, P450scc (cyp11a1), and 3β-hydroxysteroid dehydrogenase (3bhsd), while ovarian transcripts encoding 11β-hydroxysteroid dehydrogenase (11bhsd) and sex hormone-binding globulin (shbg) were elevated in females at constant 35°C only. Ovarian aromatase (cyp19a1a) mRNA levels were unaffected, but circulating 17β-estradiol (E2) was lower in females at 35°C compared to the fluctuating temperature condition. In the liver, mRNA levels for choriogenins and vitellogenin were downregulated in both the fluctuating and 35°C conditions, while hepatic estrogen receptor 2a (esr2a) and shbg mRNAs were elevated in 35°C females. Taken together, these results demonstrate the potential for elevated temperatures to impair ovarian steroidogenesis and reduce egg envelope and vitellogenin protein production in female C. n. amargosae pupfish, while also shedding light on how thermal regimes that only intermittently reach the upper thermal range for reproduction have differential impacts on reproductive endocrine pathways than constantly warm conditions.

Níveis de íons no conteúdo do trato gastrointestinal de jundiá Rhamdia quelen (Siluriformes: Heptapteridae) são relacionados ao período reprodutivo

ABSTRACT: The current study tested the hypothesis that an increase in the ionic levels (Na+, Cl-, Ca2+, Mg2+, and K+) in the gastrointestinal tract (GIT), and hepatosomatic index (HSI), gonadosomatic index (GSI), and Fulton’s condition factor (FCF) are associated with the reproduction period of silver catfish (Rhamdia quelen). So, we verified ionic levels of the fluid phase of the different portions of the GIT content, HSI, GSI, and FCF of silver catfish in different seasons in a dam in southern Brazil. The highest Na+ and Cl- levels in GIT were found in spring. The stomach’s Na+ and Cl- values were lower than the other segments. The K+ and Ca2+ levels in GIT were higher in winter, except in the stomach, where the values increased in summer. The highest K+ levels were reported in the anterior intestine. The highest Ca2+ levels in winter and spring were reported in the anterior and mid-intestines. In summer, the Mg2+ levels in the intestine were lower. The values of GSI and FCF were higher in winter and spring, and those of HSI were higher in winter. In conclusion, ions in the GIT and HSI, GSI, and FCF were higher in the reproduction period (winter for spring).

Improvement of the reproduction and gonado-somatic index of Archachatina marginata with a medicinal plant (Thymus vulgaris) in the Equatorial Zone of Cameroon

A study was carried out to assess the reproduction and gonado-somatic index of Archachatina marginata with a medicinal plant (Thymus vulgaris). Three hundred adult snails were randomly partitioned into four treatments and six replicates of 15 comparable snails. The Treatment T0 (control) received only the experimental diet. The other treatments (T0.25, T0.5, and T0.75) received, in addition to the experimental diet, Thymus vulgaris powder at 0.25%, 0.5% and 0.75% respectively. The results showed that the lowest value of egg weight (1.33 0.66) was registered in animals receiving 0.5% of Thymus vulgaris in the diet compared to other treatments. In contrast, the lowest value of egg length (14.68 1.14) was recorded in the control group. The lowest (16.25 0.00) number of clutches per treatment was registered in animals that received 0.5% of thymus vulgaris in the diet compared to the control group and other treatments. The hatching and fertilization rate values increase with increasing Thymus vulgaris in the diet, while the reverse was observed for the mortality rate. The highest value of gonadosomatic index (0.020.00) is recorded in animals receiving the highest level of thymus vulgaris (T0.75) in the diet, followed by animal in the control group (T0). The total protein and triglyceride increase significantly (p<0.05) with increasing Thymus vulgaris in the treatment that is receiving Thymus vulgaris in the diet. Contrarily, the total cholesterol decreases significantly (p<0.05) with increasing level of Thymus vulgaris in the diet. In conclusion, Thymus vulgaris at 0.75% can be used in the diet of breeding snails.

Feeding Habits and Reproductive Biology of Newly Discovered Endemic Glassfish, Parambassis waikhomi Geetakumari & Basudha, 2012 of Manipur

Parambassis waikhomi Geetakumari & Basudha, 2012, locally called Ngamhai in Manipuri dialect, is carnivorous in nature, mainly feeds on zooplankton, larvae, nymph etc. The alimentary canal of P. waikhomi is short with well demarcated stomach, and villiform teeth in both the jaws. The values of relative gut length (RGL) ranges from 0.44–0.5 for the specimens whose gut length ranges from 24.12–30.6 mm and body size range from 50–70 mm in total length of body. The maximum values of Gonado-somatic index (GSI) for males and females were observed in April i.e., 1.9439 and 10.2976 respectively. The absolute fecundity determined in the size range of 43.52–63.15 mm in total length and 1.51–4.95 g in body weight ranged from 16860 eggs for ovary weight of 0.15g to 55076 eggs for ovary weight of 0.49g. The species generally breed on pre-monsoon (March). These findings will be helpful for aquaculturist and fisheries resource management strategies as this is an endemic potential ornamental species which can be introduced in ornamental fish industries and its popularization to the rest of the world.

Antropojenik aktivitelerden etkilenen nehirden toplanan Cyprinidae familyasına ait balık türlerinin gonad sağlığı durumları

Many freshwater ecosystems are contaminated with heavy metals released by municipal wastewater, cultivation and factory wastewater. The aim of the study was to evaluate the negative impact of metal pollution on the fish reproductive system. It was performed using the gonadal histopathology, hepatosomatic index (HSI), and gonadosomatic index (GSI) of three fish species, Capoeta damascina, Squalius semae and Alburnus sellal inhabiting in Karasu River (Erzurum, Turkey) contaminated by various anthropogenic activities. The highest GSI values were determined for each sex according to the seasons, and lower GSI values were observed in polluted stations in all three species. It was observed that HSI values in fish varied significantly from station to station. In addition, an increase in ovarian and testicular lesions (degeneration in oocyte and spermatocytes, atresia, congestion, infiltration, edema, vascular hypertrophy, fibrosis) was detected in the polluted areas. The results clearly showed that the metal pollution in the river adversely affected the reproductive system of the fish species living in the river.

Advances in Aquaculture Hatchery Techniques of Sea Urchin Sphaerechinus granularis (Lamarck, 1816) (Echinoidea: Toxopneustidae): Broodstock Conditioning and Spawning Induction.

In response to the growing demand for sea urchin gonads (roe or uni) in Asian and European markets and the concerns regarding the overexploitation of wild populations, this preliminary study addresses the need for cost-effective protocols in echinoculture. The primary focus of this research was to evaluate the gonadosomatic index (GI) in captive-conditioned Sphaerechinus granularis over a five-month period and compare it with that of their wild-caught conspecifics. Additionally, two different spawning induction methods were assessed: potassium chloride (KCl) injection and agitation. Results indicate that captive-conditioned sea urchins exhibit significantly higher GI values when compared to their wild-caught counterparts. Furthermore, it was observed that the agitation method is equally effective as the KCl injection in triggering a positive response, i.e., gamete ejection, while maintaining lower mortality rates among the subjected S. granularis. In conclusion, this preliminary study underscores the pivotal role of broodstock conditioning in supporting the sustainability of sea urchin aquaculture. Moreover, the spawning induction method through agitation emerges as a viable alternative to the traditional intracelomic KCl injection, offering comparable efficacy without compromising the survival of the broodstock. These findings have significant implications for the development of sustainable sea urchin farming practices.

Reproductive Traits of an Endangered Loach, Triplophysa kashmirensis (Hora, 1922) in Kashmir Himalaya, India

In this study, a total of 180 specimens of Triplophysa kashmirensis were studied. The total length of specimens varied from 54.85 mm to 130.17 mm for the weights 2.21 g and 21.03 g respectively. Maximum GSI (gonadosomatic index) value was demonstrated in the month of November with the peak value of 1.23 in males and 20.67 in females. The absolute fecundity varied from 561 to 11,386 eggs and relative fecundity from 914 to 1441 eggs per gram body weight. The average absolute fecundity recorded was 3,851.61 ± 266.61 whereas average relative fecundity was 418.45 ± 19.25 per gram body weight. The chi-square (χ 2) test indicated that there is significant difference (p≤0.05) between the Absolute fecundity in different months. The resultant average sex ratio, male: female was 1:0.8, indicating a significant dominance of males (p < 0.05). The length at first maturity (L50) for females of Triplophysa kashmirensis was estimated at 86 mm.

Acceleration of gonadal maturity of female striped catfish, Pangasianodon hypophthalmus (Pisces, Pangasiidae) by irradiation to low-power soft-laser

This study was aimed to investigate the effects of red photodiode soft-laser irradiation on gonadal maturity and egg quality of female striped catfish, Pangasianodon hypophthalmus. Four female striped catfish (weighing 700–800 g) at stage I of gonadal maturation (for all treatments) were exposed four times (once a week) to different doses (0.2, 0.4, 0.6, and 0.8 J/cm2) of red photodiode soft-laser in the reproductive acupoint. Doses of 500 IU and 0.5 mL per kg body weight of human chorionic gonadotropin (hCG) and Ovaprim™, respectively were injected intramuscularly at week 4 (positive control), and no treatment (negative control). Finally, gonadal maturation stage (GMS), gonadosomatic index (GSI), hepatosomatic index (HSI), fecundity, and egg diameter were measured at week 5. The results showed that red photodiode soft-laser irradiation of 0.4 J/cm2 dose accelerated GMS IV at early week 3 (100 %) and increases GSI (3.42 %), HSI (1.26 %), fecundity (67,665 eggs/body weight), and egg diameter (1.01 mm) compared to the other treatments. Treatments of 0.2, 0.6, and 0.8 J/cm2 doses, and positive and negative controls only reached GMS III (75 %), III (25 %), I (100 %), II (25 %), and I (100 %), respectively. GSI values were 2.20 %, 1.47 %, 0.93 %, 0.44 %, and 0.42 %, respectively and HSI values were 1.07 %, 0.85 %, 0.7 7%, 0.66 %, and 0.53 %, respectively. Females irradiated with doses of 0.2 and 0.6 J/cm2 had fecundities of 38,822 and 29,530 eggs/body weight, respectively, and egg diameters of 0.88 and 0.29 mm, respectively. These results suggest that a red photodiode soft-laser irradiation accelerates gonadal maturity and improves egg quality in female striped catfish.