Morphochromatic spectrum through gonad development stages of the razor surgeonfish, Prionurus laticlavius (Valenciennes, 1846) (Actinopterygii: Acanthuriformes).

Gonad development stages (GDS) are a critical tool that can be easily applied in fisheries to visually discriminate mature from immature organisms and assess their reproductive condition. This study proposes a morphochromatic scale to define gonad development stages for razor surgeonfish (Prionurus laticlavius) based on morphological and structural assessments of the gonad, histologically validated using multivariate dummy matrices modeled through multiple linear regression analyses. Gonads of 271 specimens were photographed prior to preservation to describe their shape, size, color, and turgor for morphochromatic analysis. Later, gonads were processed using standard histological methods. An oocyte growth scale was designed based on oocyte diameter and follicular wall thickness for each stage. In addition, five morphochromatic gonad development stages were histologically validated: immature, developing, spawning capable, regressing, and regenerating. Morphochromatic variations were observed in the last three stages in both sexes. Results show that gonad morphology and structure of P. laticlavius are similar to those of other acanthurids, albeit with some asymmetric and morphological differences, as well as gonad morphochromatic in both sexes. These findings confirm that maturation is species-specific. Also, although not a critical character, gonad colouration was found to play a major role in distinguishing between gonad development stages along with shape, size, vascularity (females), and folds (males). Therefore, gonad colouration should not be entirely overlooked because doing so may lead to errors in determining sexual maturity stages.

Haematological, biochemical, enzymological changes and mitochondrial dysfunction of liver in freshwater climbing perch Anabas testudineus during their acute and chronic exposure to sodium fluoride.

Anthropogenic activities are increasing fluoride concentration in watercourses. The present study focuses on the sublethal toxicity of sodium fluoride during sub-chronic and chronic time periods in the freshwater fish Anabas testudineus. The 96-hour LC50 value for fluoride was found to be 616.50 mg/L. Excessive mucous production and hyper excitability, followed by loss of balance, were seen in fish under acute fluoride exposure. Significant reduction in yield and specific growth rate of fish were assessed at 15, 30 and 45-days exposure intervals. Different bio-indicators like Hepatosomatic-index, Gonadosomatic-index and fecundity were reduced significantly in fish exposed to 10% (61.6 mg/L) and 20% (123.2 mg/L) of 96 h of LC50 values of fluoride in comparison to control. Toxicant concentrations directly correlated with parameter lowering. Fluoride exposure increased plasma glucose, creatinine, AST, and ALT and reduced total RBC, haemoglobin content, Hct (%), plasma protein, and cholesterol. Moreover, fluoride exposure significantly reduces the mitochondrial membrane potential in liver. This may result in metabolic depression, haematological, biochemical, and enzymological stress. The in-silico structural analysis predicts that fluoride may impede cytochrome c oxidase of the electron transport system, hence inhibiting mitochondrial functionality. These findings collectively highlight the urgent need for stringent regulation and monitoring of fluoride levels in freshwater ecosystems, as the subchronic and chronic effects observed in A. testudineus may have broader implications for aquatic ecosystems.

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.

Intensive sea urchin harvest rescales Paracentrotus lividus population structure and threatens self-sustenance.

The harvest of the edible sea urchin Paracentrotus lividus is intensively practiced in some regions of the Western Mediterranean Sea. The removal of the largest individuals can determine an overall reduction in population size and a size class truncation that can lead to a drastic drop the self-sustenance. The aim of this study is to evaluate the variability of the population reproductive potential across 5 years in one of the main harvest hotspots of Sardinia (Western Mediterranean Sea). The breeding stock consists of commercial and under-commercial size individuals which were sampled on a monthly basis to estimate their GonadoSomatic Index (GSI) and the Individual Gamete Output (IGO). In addition, the reproductive potential of the population-Total Gamete Output (TGO)-was calculated across the 5-year period in relation with the variation of the density of the breeding stock. During the last year, the reproductive potential was also estimated in a well-conserved population of a nearby Marine Protected Area. No significant variability in GSI and IGO was found over the 5 years nor when compared with the ones of protected population in the last year. However, the intensive harvest drastically rescaled the population body-size: although density of the commercial size class remained low, density of the under-commercial size-class halved from the beginning to the end of the study. Accordingly, the proportional decrease of their gamete output contribution led to a 40% loss of the reproductive potential of the whole population in the 5-year period. Interestingly, despite the loss of reproductive potential due to the decrease of the breeding stock density, the average values of IGO slightly increased across the years leading to the highest Annual Gamete Output (AGO) during the fourth year of sampling. This positive pattern could suggest a mechanism of reproductive investments of the survivors in terms of gonad production rate or increase in spawning intensity. This work provides evidence of the direct effect of size-selective harvesting on the rapid loss of population self-sustenance. Furthermore, it lays new prospective for future research of the indirect effects of the rescaling population body-size in functional traits of the sea urchin P. lividus and that could become important for both, sustainable exploitation and ecosystem conservation management.

Reproductive characteristics of the hermaphroditic four-finger threadfin, Eleutheronema tetradactylum (Shaw, 1804), in tropical coastal waters.

This study investigated the reproductive traits of the hermaphroditic four-finger threadfin, Eleutheronema tetradactylum, along the coasts of Thailand during January to December 2021. Fish samples were collected from Pattani Bay, Thailand to assess the sex ratio, gonadosomatic index (GSI), maturity stage and fecundity. Additional fish samples were also collected from other areas to evaluate the length and weight at first sex change (Ls50 and Ws50) and length at first maturity (Lm50). The overall sex ratio for male and female was 1:0.69 with male being predominant throughout the year. Threadfin fish spawn the whole year round with peaks during moderate rainy and heavy rainy seasons. Histological examination confirmed its protandrous hermaphrodite posing multiple spawning habits. The average fecundity was 1.85 × 105 ± 1.05 × 105 eggs and positively related with standard length, body weight, gonad weight, and egg diameter (p < 0.05). The Ls50 and Ws50 were 27.58 cm and 419.39 g, and 29.71 cm and 457.28 g, for fish from Pattani Bay and Samut Prakan province, respectively. The Lm50 of male from Pattani Bay and Samut Prakan province were 25.78 cm and 25.56 cm, respectively, which were larger than those from Satun and Nakhon Sri Thammarat provinces. The Lm50 of females from Pattani Bay was smaller than that from Samut Prakan province. This study provided fundamental information on the reproductive characteristics of E. tetradactylum, which can be implemented to support management of natural fish stock and aquaculture development.

Assessing the ovarian development of Macrobrachium amazonicum (Heller, 1862) phenotypes by means of an integrative analysis.

Macrobrachium amazonicum is a species of economic interest with a wide distribution in the Americas and high morphological and reproductive variability. Three phenotypes can be observed in this species: i) large-size amphidromous, ii) large-size and iii) small-size hololimnetic prawns. In the present work, the morphological, histochemical and ultrastructural aspects of ovarian development in the three phenotypes were comparatively analyzed. In addition, the interaction between the ovary and the hepatopancreas was investigated in these phenotypes through the use of gonadosomatic (GSI) and hepatosomatic (HSI) indices. Despite the morphological differences and different reproductive strategies adopted by the females, the macroscopic, histochemical and ultrastructural patterns of ovarian development showed no differences between the phenotypes. The ovaries were macroscopically classified into five stages of development (I to V). In early stages (I and II), the ovaries are full of oogonia, previtellogenic oocytes and oocytes in primary or endogenous vitellogenesis. At these stages, the rough endoplasmic reticulum (RER) produces a granular electron-dense material and sends it to the Golgi apparatus, where it will be modified, compacted and transformed into immature yolk granules. From stage III, secondary or exogenous vitellogenesis begins (with no interruption of endogenous vitellogenesis), where follicular cells nourish the oocytes and extracellular material is absorbed by endocytic vesicles, which fuse with immature yolk granules (forming mature granules) or with existing mature yolk granules. In stages IV and V, secondary vitellogenesis continues and mature yolk granules progressively occupy the cytoplasm. In M. amazonicum, the patterns of increase in oocyte diameter are quite similar between phenotypes, being greater in the small-size phenotype. This is related to the formation of larger oocytes/eggs and the production of large lipid reserves for their larvae. Changes in GSI and HSI during ovarian development show strong similarity between phenotypes, supporting the results obtained by histology and ultrastructure. Females in stages III and IV mobilize hepatopancreas reserves for ovarian maturation, which justifies the higher HSI values recorded in these stages. On the other hand, females in stage V show higher GSI and lower HSI values, indicating a mobilization of resources for the end of ovarian development as the females are ready to spawn.

Impact of Modern Oven Treatments on Lipid Oxidation and Vitamin E Content of Fillets from Sardine (Sardina pilchardus) at Different Reproductive Cycle Phases.

The beneficial effects of sardine consumption can be related to the presence of bioactive compounds, such as vitamin E and ω3 polyunsaturated fatty acids. In any case, the levels of these compounds in sardine fillet depend on different factors mainly related to the diet and reproductive cycle phase of the fish as well as the technological treatments carried out to cook the fillets. The aim of the present study is two-fold: first, to evaluate changes in the total fatty acid profile, lipid oxidation, and vitamin E content of raw fillets from sardine (Sardina pilchardus) at different reproductive cycle phases (pre-spawning, spawning, and post-spawning); and second, to highlight how these nutritional profiles are affected by three oven treatments (conventional, steam, and sous-vide). For this purpose, raw fish was grouped into pre-spawning, spawning, and post-spawning phases according to the mesenteric fat frequency and the gonadosomatic index evaluation, and submitted to conventional (CO), steam (SO), and sous-vide (SV) baking. The ratio of EPA/DHA and vitamin E increased from post-spawning to pre-spawning, to spawning. Considering the reproductive phases, baking affected the oxidative degree differently: a CO > SO ≥ SV impact was found in the worst scenario (post-spawning), mitigated by vitamin E, to CO ≥ SO > SV in the best scenario (spawning). SV was the best treatment with high values of vitamin E in pre-spawning individuals (110.1 mg/kg). This study shows how vitamin E is correlated to the combined effect of endogenous and exogenous factors.

Fatty Acids in Waste Tissues: The Nutraceutical Value of Gonads and Livers from the Moroccan Hypophthalmichthys molitrix and Cyprinus carpio Fishes.

Fishes are an important component of human nutrition, mainly acting as source of essential fatty acids in the prevention of cardiovascular disorders. The increase in their consumption has led to a growth of fishes waste; therefore, the disposal and recycling of waste has become a key issue to address, in accordance with circular economy principles. The Moroccan Hypophthalmichthys molitrix and Cyprinus carpio fishes, living in freshwater and marine environments, were collected at mature and immature stages. The fatty acid (FA) profiles of liver and ovary tissues were investigated by GC-MS and compared with edible fillet tissues. The gonadosomatic index, the hypocholesterolemic/hypercholesterolemic ratio, and the atherogenicity and thrombogenicity indexes were measured. Polyunsaturated fatty acids were found to be abundant in the mature ovary and fillet of both species, with a polyunsaturated fatty acids/saturated fatty acids ratio ranging from 0.40 to 1.06 and a monounsaturated fatty acids/polyunsaturated fatty acids ratio between 0.64 and 1.84. Saturated fatty acids were found to be highly abundant in the liver and gonads of both species (range 30-54%), as well as monounsaturated fatty acids (range 35-58%). The results suggested that the exploitation of fish wastes, such as the liver and ovary, may represent a sustainable strategy for the achievement of high value-added molecules with nutraceutical potential.

Pharmacological intervention of biosynthesized Nigella sativa silver nanoparticles against hexavalent chromium induced toxicity in male albino mice.

Hexavalent chromium, toxic heavy metal, among the top-rated environmental contaminants, is declared a potent endocrine disruptor in humans and animals. The present study was planned to find harmful effects on the reproductive system caused by Cr (VI) and the ameliorative effect of Nigella sativa and Nigella sativa-mediated AgNP on male mice (Mus musculus). In the present study, known infertility medicine, clomiphene citrate is also used as a positive control. The main objective of the present study was to assess the ameliorative potential of oral administration of a dose of 50 mg/kg BW clomiphene citrate (control), AgNP via chemical synthesis, Nigella sativa seed extract, and Nigella sativa-mediated AgNP against the Cr (VI) at the dose of 1.5 mg/kg BW from K2Cr2O7 orally induced toxicity over eight weeks on the reproductive performance of male albino mice. Nigella sativa mediated AgNPs were characterized by UV, SEM, FTIR, and XRD. The histological analysis, smear study, antioxidant capacity test, and hormone analysis were conducted by blood samples of albino mice. Cr exposed groups showed a significant decrease in sperm head breadth (5.29 ±â€¯0.54 µ) and length (19.54 ±â€¯1.18 µ), middle piece length, tail length, LH (1.65 ±â€¯0.15 ng/mL), testosterone (2.63 ±â€¯0.29 ng/mL), SOD (61.40 ±â€¯2.48 mmol/mL), CAT (87.40 ±â€¯6.01 mmol/mL), GSH (1.54 ±â€¯0.09 µmol/mL), and no of spermatogonia (1.22 ±â€¯0.25), and spermatocytes (2.33 ±â€¯0.943). However, FSH level (160.00 ±â€¯4.98 ng/mL), seminiferous tubule CSA (1094.69 ±â€¯49.76 mm2), size of spermatogonia (41.30 ±â€¯1.24 µ), and spermatocytes (26.07 ±â€¯1.34 µ) were significantly increased. Administration of Nigella sativa and Nigella sativa-mediated AgNPs reduced the toxicity.

Effects of Water Temperature on Gonads Growth in Ambystoma mexicanum Axolotl Salamanders.

The thermal environment is a major factor influencing amphibians. For example, amphibian reproduction occurs in specific temperatures, and minor changes in this aspect could have negative impacts on this biological process. Understanding the potential effects of temperature on reproductive output is important from both an ecological and captive breeding colony point of view. I examined temperature effects on reproduction in axolotl reared from egg to adult at 4 temperatures (15 °C, 19 °C, 23 °C, and 27 °C) These adult axolotls (n = 174) were measured and weighed, dissected, and their gonads were removed and weighed to obtain an individual's reproductive allocation. Female axolotls reared at 23 °C had a greater Gonadosomatic Index (GSI) compared to axolotl reared at each of the other temperatures with axolotls reared at 27 °C having the lowest reproductive output. Moreover, all GSI pair-wise comparisons in the four temperature treatments were significantly different from each other (ANOVA, F (3, 66) = 61.681, p < 0.0001). Additionally male rearing temperature significantly influenced GSI (ANOVA, F (3, 89) = 10.441, p < 0.0001). Male axolotls reared at 19 °C had significantly greater GSI compared to males reared at the three other temperatures. There were no statistical differences among each of the other pair-wise comparisons. As seen in this experiment, axolotls may be especially sensitive to climate-driven warming due to their highly permeable skin and paedomorphic life history. Understanding how axolotls and other amphibian species adjust to the challenges of climate change is important in the management of this imperiled taxa.

Fecundity, Length at First Sexual Maturity and Gonadal Development of Lepidorhombus boscii in the Eastern Adriatic Sea.

This study presents data on the seasonal changes in population structure, maturation, fecundity and reproduction of the Lepidorhombus boscii from the central-eastern Adriatic Sea. This species is a commercially valuable fish in the Adriatic Sea; still, knowledge about its reproductive biology is very scarce. The analyses are based on the data collected between July 2020 and June 2021 by bottom trawls. In total, 963 individuals were collected out of which 508 were females (47.24%) and 455 were males (52.75%). Throughout the year, oocytes in the previtellogenic and vitellogenic stages were present in the ovaries, and the development of the ovaries followed the values of the gonadosomatic index. L. boscii has asynchronous ovarian development and a prolonged spawning season in the Adriatic Sea with the main spawning season between November and March. The oocyte diameter ranged from 34.01 to 562.72 µm (178.49 ± 129.83 µm). This study presents the first information on the reproductive cycle of L. boscii in the eastern Adriatic Sea and contributes to the understanding of the biology of this species necessary for its sustainable management.

Reproductive condition of the black-lip pearl oyster Pinctada margaritifera during the lunar phase.

This study analyzed the relationship between the lunar phase and the reproductive cycle of Pinctada margaritifera inhabiting Weno Island, Chuuk Lagoon, Micronesia. We measured indicators of maturity (gonadosomatic index [GSI] and sexual maturation-related genes) and investigated changes in the gonadal maturity stages (GMS) of P. margaritifera over lunar cycle. GSI was higher around the full moon. GMS of P. margaritifera were classified as the early gametogenesis stage, ripe and spawning stage, and spent and degenerating stage. A large percentage of oysters was observed in the ripe and spawning stage at the first quarter moon in female and the full moon in male as well as in the spent and degenerating stages at the third quarter moon in both sexes. In addition, the expression of doublesex- and mab-3-related transcription factor 2 (DMRT2) in the male P. margaritifera black-lip pearl oyster was the highest during the full and third quarter moon phases, whereas no difference in expression was observed with the lunar phase in females. In contrast, the expression of vitellogenin (VTG) was the highest in female P. margaritifera during the first and third quarters. No difference in expression was observed according to the lunar phase in males. The results suggest that the lunar phase directly affects the expression of sexually mature gonads in P. margaritifera black-lip pearl oyster.

Determination of the growth performance and reproductive season of wild Channa lucius (Cuvier, 1831) populations of genus Channa (Channidae, Perciformes) in the Mekong Delta, Vietnam.

This study aimed to investigate the growth and spawning characteristics of wild Channa lucius (Cuvier, 1831) populations in the Mekong Delta, Vietnam. The study was carried out from March 2011 to February 2012. The length-weight relationship of C. lucius was determined according to the equations W = 0.0044L3.2494 , R2  = 0.9157 (female fish) and W = 0.0047L3.2178 , R2  = 0.9434 (male fish). The length and weight of the body for female fish ranged from 16.3 to 36.0 cm and 49.0 to 550.0 g, and for male fish, from 14.6 to 38.2 cm and 46.0 to 639.0 g, respectively. Female and male fish had almost similar lengths at first maturity (21.3958 cm for females and 21.3952 cm for males). The condition factor of female fish ranged from 0.842 to 0.864 and for male fish ranged from 0.848 to 0.874. The gonadosomatic index of female fish was highest in June (1.68%) and lowest in November (0.69%); that of male fish was highest in June (0.53%) and lowest in September (0.15%). The sexual maturity rate (SMR) of female fish peaked in May, with SMRs of 33.3% (stage III) and 58.3% (stage IV). In conclusion, C. lucius has a positive allometric range (b > 3), reaching sexual maturity when its length reaches 21.39 cm for both sexes, and the spawning season begins in December but peaks in May and June.

Morphological analysis of the reproductive activity of Curimatella lepidura (Characiformes: Curimatidae).

Curimatella lepidura, commonly known as the manjuba, belongs to the Curimatidae family. To assess the reproductive activity of this species, fish were collected from three sections of the São Francisco River: section 1 = the Três Marias reservoir (TMR), section 2 = the SFR immediately downstream of the TMR, and section 3 = the SFR 54 km downstream from the TMR after the confluence of the SFR with the Abaeté River. Fish were collected bimonthly from January to December 2012. From this, the gonadosomatic index (GSI), Fulton condition factor (K), gonadal maturation stages in females and males, and diameters of vitellogenic follicles were determined. That is, this study employed histological and histometrical techniques to study the ovaries and testes of collected fish. The Fulton condition factor was statistically higher in section 1 than in the other sections, indicating that C. lepidura presents better health conditions in this section. Fish in the maturation/mature gonadal stage were collected in the November/December and January/February bimesters, coinciding with high temperatures, a long photoperiod, and abundant rainfall in this region. The mean vitellogenic follicle diameter was statistically lowest for sections 2 and 3, with a better impact on reproduction than in section 1. Overall, the results show that C. lepidura has reproductive success in lentic environments, such as in section 1, the TMR.

Declines in Reproductive Condition of Male Largemouth Bass (Micropterus salmoides) Following Seasonal Exposure to Estrogenic Endocrine-Disrupting Compounds.

Reproductive abnormalities, that could lead to possible effects at the population level, have been observed in wild fish throughout the United States, with high prevalence in largemouth bass (LMB; Micropterus salmoides) and smallmouth bass (Micropterus dolomieu). Estrone (E1) and atrazine (ATR) are common environmental contaminants often associated with agricultural land use. 17alpha-ethinylestradiol (EE2) is a contaminant associated with wastewater treatment effluent, and a representative, well-studied estrogen commonly used for fish toxicity testing. Our objective was to assess whether early gonad recrudescence in adult fish was a period of sensitivity for alterations in reproductive condition and function. Adult male LMB were exposed from post-spawning to early gonad recrudescence to either a mixture of E1 (47.9 ng/L) + ATR (5.4 µg/L), or EE2 (2.4 ng/L) in outdoor experimental ponds. Gonad samples were collected from fish just prior to the start of exposure (July), at the end of the exposure period (December), the following spring just prior to spawning (April), and post spawning (May). Gonadosomatic index (GSI) was significantly reduced in E1 + ATR-exposed and EE2-exposed males compared to control at every post-exposure time point. Reduced sperm count and sperm motility were observed in the mixture treatment (E1 + ATR) compared to the control. Sperm motility was also reduced in the EE2 treatment. These data together indicate that estrogenic endocrine-disrupting compounds can lessen the reproductive condition of adult male LMB, and that effects of exposure during early gonad recrudescence can persist at least through the subsequent spawning cycle.

Testicular development, reproducing references and length at first maturity of Acentrogobius viridipunctatus (Actinopteri: Gobiiformes) in the southwest Viet Nam.

This study provided knowledge on testicular development, spawning reference and length at first maturity (L m ) of Acentrogobius viridipunctatus-a target catching fish for food supply in the southwest Viet Nam. A total of 528 individuals were collected using trawl nets from January to December 2020 at Long Huu-Tra Vinh (LHTV), Trung Binh-Soc Trang (TBST), Dien Hai-Bac Lieu (DHBL) and Tan Thuan-Ca Mau (TTCM). Five developmental stages of testis were found, and testis diameter increased from ∼1.07 (stage I) to ∼4.82 mm (stage V). Testis stage I consisted of spermatogonia (S) which shifted to primary spermatocytes (SC1) in stage II. In testis stage III, SC1 was divided into secondary spermatocytes (SC2). At this stage, testis consisted of S, SC1, SC2 and some spermatid (ST). At stages IV and V, testis comprised mainly spermatozoa (SZ) besides S, SC1, SC2 and ST, showing that this goby was a multi-spawner. Testis frequency and gonadosomatic index analyses showed that this species released sperms yearly, with a prominent peak in the wet season. The L m decreased from 9.3 ± 0.3 cm at TBST to 9.0 ± 0.3 cm at LHTV, 8.9 ± 0.2 cm at TTCM and 6.5 ± 0.5 cm at DHBL. Findings provided fundamental data to set up suitable fishing and conserving strategies for this species.

The role of sex, season and reproduction status on blood parameters in snow trout (Schizothorax labiatus) from River Jhelum, Kashmir, India.

The current investigation was carried out with an aim to evaluate disparity in haematological and serum biochemical parameters of healthy male and female Schizothorax labiatus with respect to its four reproductive phases, i.e. preparatory (autumn), pre-spawning (winter), spawning (spring) and spent (summer). The study indicated that significant (p < 0.05) alterations were seen in gonadosomatic index (GSI) of S. labiatus with maximum value for both sexes noted in spring while minimum value in autumn. Contrary to this, the highest value of hepatosomatic index (HSI) for both sexes was noted in the autumn season and the lowest value in spring. The haemoglobin (Hb) content, red blood corpuscle (RBC) and white blood corpuscle (WBC) counts and haematocrit amount of S. labiatus also revealed significant (p < 0.05) variations with peak values noted in summer while least values were recorded during winter. It was also observed that male fishes comprised significantly (p < 0.05) maximum level of all these parameters amongst all seasons of the year, except WBC count. Erythrocyte indices specifically mean corpuscular haemoglobin (MCH), MCH concentration (MCHC) and mean corpuscular volume (MCV) exhibited insignificant (p > 0.05) alterations between the sexes. The lowest levels (p < 0.05) of serum glucose, cholesterol and urea were recorded in the pre-spawning period, i.e. winter, while as the highest values (p < 0.05) were seen in the summer because of the cessation of reproductive activities and greater availability of food. Similar trend was also noted in the amount of total protein, albumin and globulin of the fish, although insignificant (p > 0.05) variation was observed between sexes.

Reproductive Biology and Feeding Ecology of The Blue Swimming Crab (Portunus pelagicus) in Northern Coastal Waters, Sri Lanka.

Blue swimming crab (Portunus pelagicus) fishery has emerged to become an important export-oriented fishery in Sri Lanka over a decade and recently resulted in a rapid increase in the exploitation. The present study attempts to understand the reproductive biology and feeding ecology of blue swimming crab which will be vital in the management of capture fishery. Five major landing sites in the Jaffna district in Northern Sri Lanka, where blue swimming crab is frequently landed throughout the year were selected for the study. Biological parameters relating to sex, carapace width, body weight, maturity, and egg sac colour with egg sac weight were recorded at the field from November 2014 to October 2015. Randomly selected crab samples were brought to the laboratory and analysed for their maturity stages, length at first maturity, Gonadosomatic Index, fecundity, and gut contents. The study revealed that male crabs mature at a smaller size than females. The sex ratio varied greatly with time and males were always dominant in the catch. The blue swimming crabs in the Northern waters of Sri Lanka spawn throughout the year, with two spawning peaks in February and May. The total fecundity of ovigerous blue swimming crab increased with increased carapace width and body weight and it ranged from 123,482 to 3,179,928 eggs, with an average of 884,982 ± 676,420. A remarkably higher percentage of empty stomachs were observed under the present study in both mature and immature crabs and this could be due to lack of food availability in the environment and different digestibility rates of food items. The diet of blue swimming crab is highly variable reflecting the ability to adopt to different modes of feeding.

Reproductive Biology of the Sea Cucumber Holothuria mammata (Echinodermata: Holothuroidea).

Holothuria mammata is one of the most valuable species of sea cucumber, as well as one of the main target species harvested in the Mediterranean and NE-Atlantic regions. This study aims to describe the reproductive cycle of H. mammata in a coastal area of southwest Portugal. Monthly samplings were carried out for 19 months, with the concomitant collection of environmental data and biometric data. H. mammata had a sex ratio of 1:1.2 (male:female) and a size at first maturity of 142 mm for males and 167 mm for females. The gonadosomatic index (GI) peaked between April and May for both sexes. Gonad development started when days had a shorter photoperiod (9 to 13 h of sunlight) and lower seawater temperature (<15 °C), and spawning occurred later, with longer photoperiod (13 to 15 h of sunlight) and higher seawater temperature (>15 °C) and chlorophyll-a concentrations. The development of new studies to increase the biological and ecological knowledge of the populations of H. mammata is essential to create conditions for the domestication of broodstock in captivity, to allow the development of fishing regulations based on informed decisions and to create precise measures for the conservation of ecosystems.

Data on length-weight and length-length relationships, mean condition factor, and gonadosomatic index of Rutilus rutilus and Perca fluviatilis from the Ob River basin, Western Siberia.

Raw data were obtained from 250 specimens of roach Rutilus rutilus and 274 specimens of perch Perca fluviatilis at 15 sampling sites located from North to South Taiga. Fish sampling was performed using gill-nets with 22 and 28 mm mesh. Total and eviscerated weights, total and standard lengths, fish sex, gonad weight and maturity stage were recorded. Linear regression analysis of log-transformed total weight and total length values was performed. Regression slope and intercept were used to obtain length-weight relationships and mean condition factor values. Length-length relationships were calculated by the linear regression between the total and standard lengths. Gonadosomatic index was determined using the gonad weight and the total weight of fish. The data are useful for establishing biomass, fish growth patterns, relative condition of individuals within a sample or across populations.