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This study aimed to evaluate the effects of Bifidobacterium animalis and Bifidobacterium lactis on growth, length-weight relationship and some biological indices of rainbow trout, Oncorhynchus mykiss fry. An iso-nitrogenous (50% crude protein) diet was supplemented with three different concentrations of a mixture of equal quantities of the two strains of Bifidobacterium, namely T1 (1×107CFU/g), T2 (2×107CFU/g), T3 (3×107CFU/g) and a control (without bacteria). A total of 480 trout fries with an initial mean body weight of 0.53±0.19 g were randomly divided into four groups, each with 4 replicates. The fries were distributed into 16 fiberglass tanks (20 L total capacity) each filled with 15 L of water (water exchange rate of 2 L min-1 and permanent aeration) at a density of 2 fries per liter. During the 8-week feeding trial, the mean water temperature was 17.66±1.33°C and that of pH was 7.63±0.08. All fish groups demonstrated positive allometric growth. Trout fries fed with diet T1 recorded significantly higher (P<0.05) gonadosomatic index, specific growth rate and mean weight gain. The highest final mean length (14.12±4.57 cm) was recorded in fry fed with diet T2. The lowest concentration of Bifidobacterium, T1 induced the best growth and it enhanced the biological indices of O. mykiss. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A population of sea urchins, Paracentrotus lividus, from the central west coast of Portugal was studied to characterise their reproductive biology and possible relationships with environmental factors. An annual gametogenic cycle was found, with a broad spawning season, from May to November, according to a relatively synchronous gamete maturation process. Depending on the environmental factors (temperature, photoperiod), two separate periods could be distinguished, with more individuals maturing and spawning at the same time. When this happened, the first event evolved when temperature rose to a critical point, and the second occurred afterwards, when temperature decreased significantly. Notwithstanding, it was found that individuals matured later than previously described for other populations (e.g., north of Portugal), mostly in late spring, with a higher gonadosomatic index in May. A new classification scale was proposed for identifying the stages of P. lividus gametogenic cycle, based on new findings. It contributed to its simplification and easier comprehension. This study provides useful information for a differentiated sustainable management of P. lividus, according to local conditions. Establishing a closed harvesting season might be considered, based on the differences observed between Portuguese populations and other European ones. [ABSTRACT FROM AUTHOR]

Parameters belonging to the physical status and gonadal size of certain fish provide crucial information for assessing both the productivity and fecundity of declining fish populations. These parameters are vulnerable to the negative impacts of disease agents such as internal or systemic parasites. Although parasitic diseases might influence these parameters, the literature investigating these pathophysiological alterations is scanty. Therefore, the current study represents one of the scarcest studies that document the possible link between parasitism, gonadal health, and the growth of European hake (Merluccius merluccius). Screening of imported European halves indicated a relatively high prevalence of Anisakis pegreffi Larvae 3 infestation, with an 80% prevalence rate, a mean intensity of 24.4, and a mean abundance of 19.5. However, the prevalence of Anisakid larvae infection in native fish was 36% with a mean intensity of 7.36 and mean abundance of 2.65.The current research revealed remarkable ovarian pathology that involved several forms of degenerative changes in ovarian tissues. Such gonadal pathologies were attributed to the damaging effect of the retrieved Anisakis pegreffi Larvae 3. Gonadosomatic index of both heavily infected imported / native hakes was relatively impacted by the progressive gonadal pathology resulting from Anisakis pegreffi L3 infection. Morphometric measurements of the gonads and body have revealed that, gonadosomatic index of both heavily infected imported / native hakes was relatively impacted by the progressive gonadal pathology resulting from Anisakis pegreffi L3 infection.

Fish populations in their natural habitats depend on the spawning and recruitment of fingerlings, two processes that are critical to the survival of fish populations. Reproduction is one of the most significant part of fish biology. To offer a biological foundation for managing the spotted sea bass (Dicentrarchus punctatus) fishery in Bardawil Lagoon, North Sinai, Egypt, this study aimed to explore the reproductive biology of this species. Monthly specimens of the spotted sea bass (n= 2050) were obtained from the commercial catch from selected landing sites of the Bardawil Lagoon during January 2020 to December 2021. The fish sex ratio recorded 1 male: 1.587 females and 1 male: 1.584 females during 2020 and 2021 fishing seasons, respectively. A stability of sex ratio was noticed, whereas the female ratio was 61.3% and male ratio was 38.7% during both 2020 and 2021 fishing seasons. Gonadosomatic index (GSI) increased progressively from September to February; the highest values were recorded in December at 6.76 and 8.17 for females and 4.46 and 5.59 for males during the two fishing seasons 2020 and 2021, respectively. Thus, the spawning season for the spotted sea bass is between November and February. The length at the first maturity was estimated at an average length of 21.6cm for both sexes. Fecundity was estimated for 78 ripe ovaries ranging between 29475 (15cm in total length and 38.3g in weight) and 621440 eggs (34.7cm in total length and 368.4g in weight). Based on ovarian histological examination, December is the period of maturation. To prevent overfishing and enable female spotted sea bass (D. punctatus) to reproduce, grow, and recruit into the fishery, we suggested permitting the use of mesh sizes larger than those used at Bardawil Lagoon. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 selfsustenance. 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. [ABSTRACT FROM AUTHOR]

This research aims to determine the optimal dose of boiled mackerel tuna mixture on HI-PRO VITE 781 feed on gonadal maturity index and feed conversion ratio of transgenic mutiara catfish G4 in indoor hatchery maintenance at optimal temperature. This research was conducted at the Hatchery of the Faculty of Fisheries and Marine Sciences, Universitas Padjadjaran. The method used was an experimental method with a completely randomized design (CRD) method with four treatments, namely the difference in the dose of boiled mackerel tuna administration in comercial feed and three replications. The treatment in this study was the administration of boiled mackerel tuna doses of 3.5%, 2.5%, 1.5% in mixed feeds to G4 transgenic mutiara catfish and tested on non-transgenic mutiara catfish with a percentage of 3.5% female weight biomass and then added an 30 g HI-PRO-VITE 781 with two times feeding frequency. The research parameters included gonad maturity index and feed conversion ratio. The results showed that feeding a mixture of boiled mackerel tuna and HI-PRO-VITE 781 had a significant effect on the gonadal maturity index and feed conversion ratio. Feeding boiled mackerel tuna at 1.5% was the best treatment with a gonadal maturity index of 47.16% for females and 4.98% for males and a feed conversion value of 1.19 for 56 days of rearing. [ABSTRACT FROM AUTHOR]

The results of the study of the distribution and biology of the duskyfin glassy perchlet Parambassis wolffii (Bleeker, 1850) in the Mekong Delta in 2019–2020 are presented. It is established that the species reaches the highest abundance and biomass in the freshwater part of the delta. The water temperature at which individuals of the species were encountered was 27.8–34.1°C, salinity, up to 1.51‰, depths, from 2 to 35 m. The maximum total length of females and males was 20.0 and 14.7 cm, respectively, and the maximum age was 6 years. The parameters of the von Bertalanffy equation are as follows: the maximum length is 17.2 cm, the growth rate constant is 0.18, t0 = −2.35. The value of the coefficient b in the equation on the weight-length relationship is 3.002 ± 0.056 for females (isometry) and 2.774 ± 0.064 for males (negative allometry). Intersexual differences by the in Fulton' condition factor were established: in females 3.71 ± 0.04, in males 3.53 ± 0.03. The first mature individuals were found at a length of 7–8 cm at the age of 1+. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Research on the reproduction of snappers helps to manage and conserve them. The spotted rose snapper Lutjanus guttatus is a gonochoric species caught year-round in Navidad Bay, Jalisco, Mexico. This work aims to analyze the reproductive aspects of the spotted snapper L. guttatus caught in Navidad Bay on the southern coast of Jalisco, Mexico. Analyzed fish came from commercial catches. Organisms were sampled monthly from January 1998 to December 2008, and total length, total weight, sex, gonad weight, and gonadal phase were obtained for each specimen. Histological analysis was performed to define the gonadal phase and measure the oocytes' diameter. The total length range in the catches was 14.0 to 61.0 cm; 2889 females and 2792 males were collected for a sex ratio 1.0:0.97. The oocyte development is asynchronous, with a diameter range from 33.9 to 407.9 µm. The testicle is of the lobular type, with a well-defined spermatic duct. A main reproductive season from June to September was identified, although fish with mature gonads were observed in all months. The best condition was observed before the reproductive period. Average lengths at sexual maturity were 30.09 and 30.05 cm for females and males, respectively; the average length of capture in females (32.2 cm) and males (31.7 cm) corresponds to 66.6 and 64.6% of organisms that had reproduced at least once before being captured. Given the importance and continuous capture of L. guttatus in the study area, we recommend further studies to improve the understanding of reproductive and fishing activities. [ABSTRACT FROM AUTHOR]

The study aims to afford a deeper knowledge on reproductive biology of Mystus bleekeri from Surma River, Bangladesh in a multidisciplinary way. Though, the species is in demand as food and ornamental fish in Bangladesh but still now comprehensive details on reproductive biology of this species is scanty. Total 600 fish samples were derived from commercial catches from July 2018 to June 2019. Periodic differences in sex ratio, size distribution, condition factor (Kn), fecundity, gonadosomatic index and gonadal maturation cycle were assessed. The results showed 384 (64%) female and 216 (36%) male with an overall sex ratio of 1.77: 1 (female: male). Mean total length (TL) and body weight (BW) of all fish studied were 14.85 ± 3.38 cm TL and 27.54 ± 15.76 g, respectively. The Kn varied with length groups, the highest (1.45 ± 0.23) and lowest (0.89 ± 0.18) values obtained in 16.0–16.9 and 10.0–10.9 cm TL groups, respectively. The highest Kn was documented in October while the lowest was in January. Monthly GSI values showed two peaks in July and November for both the sexes. The fecundity was found to vary from 1120 to 14790 eggs with average value of 4968 ± 3047 with 14.4–18.3 cm in TL and 19.97–34.7g in BW. The relationship of fecundity with TL and BW was F = 1.385TL13.405, r2 = 0.885 and F = 5.201BW4.827, r2 = 0.944. Partial behavior of spawning together with allochronic oocytes development has also been found through histology. The results of this study could be used for predicting the response of populations of fish in Surma River and/or other where to human interferences and environmental change.

The present study elucidates the pattern of the reproductive activity of the invasive Pterygoplichthys disjunctivus male (n = 113) and female (n = 124) fish in Polgolla Reservoir, Sri Lanka. The reproductive activity was studied based on the gonadosomatic index (GSI), macroscopic and microscopic features of the testes and ovaries, and the serum testosterone and progesterone level during a 12-month study period. The monthly GSI of male fish (P = 0.0001) was the highest (0.333 ± 0.08%) in October and the lowest (0.044 ± 0.01%) in January whereas in the female fish, the GSI was not changed significantly (P = 0.1780) during the 12-month period of sampling. The mean monthly serum testosterone concentration (P = 0.0244) was the highest (0.396 ± 0.332 ng/ml) in March and the lowest (0.085 ± 0.156 ng/ml) in August, while the mean serum progesterone concentration of female fish showed no significant difference (P = 0.4798). Histological examination revealed that the testes with seminiferous tubules filled with sperm and the ovaries with mature oocytes were present throughout the year. Therefore, based on the results of histology and reproductive characteristics, we concluded that both male and female P. disjunctivus in Polgolla Reservoir are breeding throughout the year.

Abstract Background Selection pressure due to parasitic infestation puts adverse effects on birds’ fitness concerning survival and reproductive success. The present study was conducted on Eurasian tree sparrow at Shillong (25°34′ N, 91°53′ E), India, for a year to examine ectoparasitic infestation by Myrsidea balati and Sturnidoecus ruficeps. The parameters on the annual prevalence of infestation, annual cycles of gonadosomatic index (GSI), molt, hematocrit percentage and the time spent in behavior display were recorded. Results The infestation of both lice species ran parallel to GSI in both sexes of sparrow. Further, the intensity of infestation was higher in males. The increase in number of ectoparasites was found positively correlated with the increase in GSI in the birds. However, it was negatively correlated with feathers molt. Thus, the infestation of both parasites was maximum during the reproductive phase and minimum during the period when the birds were undergoing the process of molt. Seasonal variation in hematocrit percentage shows decline during high infection in females and during molt in both the sexes. The time spent in showing behavioral traits to limit infection was the longest during high infestation. Conclusions We conclude that the tree sparrow adopts various adaptive strategies like feathers molt and longer display of behavioral traits during their breeding and/or non-breeding seasons to control parasitic load and avoid energy conflict with high energy demanding processes like reproduction and molt.

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.

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Diamond mining in southern Namibia creates seawalls that hold the ocean at bay, yet seawater overwashes or seeps through to fill landward excavated areas, forming numerous coastal ponds that reach 380 000 m2. These ponds span ages of 1–40 years, with the oldest ponds lying in the north, and the younger ponds in the central and southern areas. We investigated occupation of these mining ponds by marine fishes. The ponds offer sheltered, warm, nutrient-enriched environments, but become hypersaline after 10–12 years. The ponds contained predominantly west coast steenbras Lithognathus aureti and southern mullet Chelon richardsonii, with smaller numbers of seven other fish species, and all nine species being marine. The ichthyofauna was thus depauperate, but similar to that of periodically closed estuaries in the region. The size composition and gonadal development of both predominant species suggest they may breed in at least the younger ponds. However, in older, hypersaline, northern ponds, L. aureti transitions into an entirely female population via protandry, precluding breeding there. Body condition was low for both species in the northern ponds, and gut fullness greatest in the southern ponds. Growth of both species was faster in the ponds than in the sea, but after initially fast growth, L. aureti reached a plateau, suggesting stunting thereafter. Chelon richardsonii attained larger sizes in the ponds than in the ocean. For 10–12 years before hypersalinity sets in, the ponds constitute suitable habitat for fish. They are not estuaries as they have minimal freshwater input, but they do create conditions corresponding to closed estuaries that are otherwise scarce along this arid coastline. However, for a nursery function to be realised, the marine fish must return to the sea or else the ponds become an 'ecological trap'. [ABSTRACT FROM AUTHOR]

Parameters belonging to the physical status and gonadal size of certain fish provide crucial information for assessing both the productivity and fecundity of declining fish populations. These parameters are vulnerable to the negative impacts of disease agents such as internal or systemic parasites. Although parasitic diseases might influence these parameters, the literature investigating these pathophysiological alterations is scanty. Therefore, the current study represents one of the scarcest studies that document the possible link between parasitism, gonadal health, and the growth of European hake (Merluccius merluccius). Screening of imported European halves indicated a relatively high prevalence of Anisakis pegreffi Larvae 3 infestation, with an 80% prevalence rate, a mean intensity of 24.4, and a mean abundance of 19.5. However, the prevalence of Anisakid larvae infection in native fish was 36% with a mean intensity of 7.36 and mean abundance of 2.65.The current research revealed remarkable ovarian pathology that involved several forms of degenerative changes in ovarian tissues. Such gonadal pathologies were attributed to the damaging effect of the retrieved Anisakis pegreffi Larvae 3. Gonadosomatic index of both heavily infected imported / native hakes was relatively impacted by the progressive gonadal pathology resulting from Anisakis pegreffi L3 infection. Morphometric measurements of the gonads and body have revealed that, gonadosomatic index of both heavily infected imported / native hakes was relatively impacted by the progressive gonadal pathology resulting from Anisakis pegreffi L3 infection. [ABSTRACT FROM AUTHOR]

The results of the study of the sex and size-age structure, growth, maturation, sexual inversion, dynamics of the gonadosomatic index and mortality of 1948 individuals of the picarel Spicara flexuosa caught in the Crimea water area in 2020–2021 are presented. The total sex ratio in catches is biased towards females (3.5 : 1.0); sex inversion was recorded in 50% of females with a total body length of 13.5 ± 0.05 cm at the age of 3+. The maximum length of females is 15.1 cm, males, 22.0 cm; the weight is 29.0 and 132.2 g, respectively. The maximum age of females and males is 4 and 7 years, respectively. The values of the parameters of the von Bertalanffy equation are calculated: for females, the asymptotic length is 15.69 cm, the asymptotic weight is 32.0 g, the growth coefficient is 0.49 year–1; for males, 18.32 cm, 59.7 g and 0.44 year–1, respectively. A value of the exponent in the length-weight relationship is 2.68 for females (negative allometry) and 3.0 for males (isometry). The sexual maturity of 50% of females occurs at a length of 10.34 ± 0.21 cm at the age of 1+. The peak of spawning occurs in June. The rates of total, natural and fishing mortality are 1.2, 1.9 and 0.3 year–1, respectively in both sexes; the exploitation rate is 0.25, which indicates a low fishing pressure. It is established that S. flexuosa from northern populations is characterized by larger maximum sizes, a higher growth rate and a longer life expectancy. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

ABSTRACT The Brazilian bocachico is a rheophilic fish from the northeast region of Brazil that holds great economic and scientific interest. The absence of evident sexual dimorphism and the invasive character of sexing methods and evaluation of gonadal maturation are obstacles to its artificial reproduction. In this scenario, ultrasonography emerges as a non-invasive method for sexing. The objectives of this study were to establish an ultrasound sexing method for Brazilian bocachico and select equations to estimate the gonadosomatic index (GSI), gonad weight (GW), and gonad volume (GV) of live bocachico. A total of 32 bocachico fish (18 females and 14 males) were analyzed ultrasonographically and morphologically. The association of morphometric and ultrasonographic parameters was investigated using Pearson Correlations. The following prediction equations were selected using multiple regression analysis: GSI = 16.22 × transvarea; GW = 30.3 × transvarea; and GV = 0.001260036 × pixels. A model capable of predicting the sex of the animals based on the ultrasonographic parameters was obtained using partial least-squares discriminant analysis with principal component analysis. The significance level adopted was P < 0.05. In conclusion, ultrasonography is a useful tool to perform sexing and evaluate the gonads during the breeding season, contributing to artificial reproduction in captivity.

The Peruvian moonfish (Selene peruviana) is an important fisheries resource that is landed in the main fishing harbors of Ecuador. At the local level, little information is available regarding the biology of this species, which hinders the development of management plans. The present study evaluates the reproductive characteristics of S. peruviana such as the size at sexual maturity and reproductive cycle. Specimens were obtained from artisanal and industrial catches from January 2017 to December 2018. The morphometric characteristics, sex, and maturity stage of 886 specimens were determined, and the gonadosomatic index (GSI), hepatosomatic index (HSI), and relative condition factor (Kn) were estimated. The length-weight relationship and length at sexual maturity (L50) were evaluated with an allometry equation and multi-model analyses, respectively. The mean capture size (total length, TL) was 23.62 cm for males and 22.97 cm for females. A sex ratio (M:F) of 0.70:1.00 (χ2 = 26.28, P < 0.05) was obtained. The allometric factor of the length-weight relationship for both sexes (b) was 2.63 (t = 12.16, P < 0.05), and the coefficient of determination (r2) was 0.89, which suggests that negative allometric growth was present. The L50 (TL) was estimated to be 22.61, 23.86, and 23.27 cm for males, females, and sexes combined, respectively. The monthly GSI, HSI, and Kn values were significantly different (K-W, P < 0.05) among study months. The maximum GSI values were observed in February and March, which constituted the period of highest reproductive activity. The HSI and Kn values exhibited similar trends. The size at sexual maturity was similar to the average catch size, which could indicate that S. peruviana is currently at the limit of its optimal catch size.

The study aims to afford a deeper knowledge on reproductive biology of Mystus bleekeri from Surma River, Bangladesh in a multidisciplinary way. Though, the species is in demand as food and ornamental fish in Bangladesh but still now comprehensive details on reproductive biology of this species is scanty. Total 600 fish samples were derived from commercial catches from July 2018 to June 2019. Periodic differences in sex ratio, size distribution, condition factor (Kn), fecundity, gonadosomatic index and gonadal maturation cycle were assessed. The results showed 384 (64%) female and 216 (36%) male with an overall sex ratio of 1.77: 1 (female: male). Mean total length (TL) and body weight (BW) of all fish studied were 14.85 ± 3.38 cm TL and 27.54 ± 15.76 g, respectively. The Kn varied with length groups, the highest (1.45 ± 0.23) and lowest (0.89 ± 0.18) values obtained in 16.0-16.9 and 10.0-10.9 cm TL groups, respectively. The highest Kn was documented in October while the lowest was in January. Monthly GSI values showed two peaks in July and November for both the sexes. The fecundity was found to vary from 1120 to 14790 eggs with average value of 4968 ± 3047 with 14.4-18.3 cm in TL and 19.97-34.7g in BW. The relationship of fecundity with TL and BW was F = 1.385TL13.405, r² = 0.885 and F = 5.201BW4.827, r² = 0.944. Partial behavior of spawning together with allochronic oocytes development has also been found through histology. The results of this study could be used for predicting the response of populations of fish in Surma River and/or other where to human interferences and environmental change. [ABSTRACT FROM AUTHOR]

Information on reproductive biology is essential for both fisheries management and aquaculture. In this study, samples of Alectis indicus (90 females and 97 males; size ranges: 1.2-7.8 kg, 47.0-99.9 cm for females and 1.6-7.3 kg, 52.3-100.0 cm for males) were acquired from a local fish supplier in Trang Province on the coast of the Andaman Sea, Thailand, between November 2020 and October 2021. The results revealed that the sex ratio of sampled A. indicus was not different from 1:1; size at first maturation was 69.7 cm for males and 67.7 for females; gonadosomatic index (GSI) ranged from 0.03 to 1.20% in males and from 0.27 to 2.91% in females; percentage of post-vitellogenic oocytes (%PVO) ranged from 0 to 34.45%; and GSI showed positive moderate correlation with %PVO (r = 0.497, p = 0.0001). Based on GSI and %PVO, female A. indicus presumably spawned year-round with two peaks, in July and November-December, whereas the peak of male GSI value occurred in July. Female GSI and %PVO that marked the spawning peaks were 1.24-1.63% and 16.19-18.98%, respectively, while male GSI at the spawning peak was 0.79%. The information obtained not only benefits understanding of reproductive biology of A. indicus in the Andaman Sea but is also useful for efforts at captive breeding of this species. [ABSTRACT FROM AUTHOR]

The difficulty to dissect and weigh very tiny gonads and several fish specimens for the purpose of computing gonadosomatic indices (GSIs) due to non-availability of reliable electric power supply under field conditions, necessitated the study. This paper presents the performance of the gonad length indices vis-a-vis the traditional GSIs. The gonad elongation ratio (GER) (i.e. gonad length as a function of fish standard length expressed as a percentage) is here proposed for use in analyzing teleost fish breeding seasonality. The West African amphibious mudskipper, Periophthalmus barbarus (Linneaus, 1766) (Teleostei: Gobiidae) from the Imo River estuary, Nigeria, was used as the trial species. Monthly mean testicular and ovarian elongation ratios were examined vis--a--vis the classical testicular and ovarian gonadosomatic indices. The monthly mean gonad elongation ratios followed similar monthly mean sequences of the corresponding gonadosomatic indices. Mean GSI was 0.192 in males (range 0.097 -- 0.347) and 1.197 in females (range 0.512 -- 3.398); whereas mean GER was 16.5 for males (varied from 12.9 to 19.2) and 19.5 in females (ranged between 16.8 and 25.3). However, the gonad elongation ratios fluctuated more finely than the gonadosomatic indices. It is 2 - 3 times much easier and faster to determine gonad elongation ratio in the field than the gonadosomatic index. The determination of gonadosomatic indices require the use of sensitive electronic balance and reliable electric power supply while these are not necessities for the determination of gonad elongation ratios. Being a quantitative measure, the gonad elongation ratio can be subjected to statistical reliability estimates such as standard deviation, standard error and confidence intervals. The gonad elongation ratio which is quantitative and has biological interpretation that is analogous to the traditional gonadosomatic index, is recommended for use. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Simple Summary: Amphibians are especially sensitive to temperature due to their lack of thermal regulation. Aquatic temperatures influence growth and development during the larval period and may impact sexual development. This study examined the rearing of axolotl salamanders from juvenile to adulthood at four temperatures to examine how this factor influenced reproduction output. Rearing temperature affected egg and testis production and indicates that males and females should be reared at different temperatures to optimize reproductive output. Additionally, axolotl salamanders may be especially sensitive to high temperatures suggesting that the reintroduction and translocation of axolotls into former and new habitats should identify water temperature as an important component in conservation efforts. 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. [ABSTRACT FROM AUTHOR]

The present study elucidates the pattern of the reproductive activity of the invasive Pterygoplichthys disjunctivus male (n = 113) and female (n = 124) fish in Polgolla Reservoir, Sri Lanka. The reproductive activity was studied based on the gonadosomatic index (GSI), macroscopic and microscopic features of the testes and ovaries, and the serum testosterone and progesterone level during a 12-month study period. The monthly GSI of male fish (P = 0.0001) was the highest (0.333 ± 0.08%) in October and the lowest (0.044 ± 0.01%) in January whereas in the female fish, the GSI was not changed significantly (P = 0.1780) during the 12-month period of sampling. The mean monthly serum testosterone concentration (P = 0.0244) was the highest (0.396 ± 0.332 ng/ml) in March and the lowest (0.085 ± 0.156 ng/ml) in August, while the mean serum progesterone concentration of female fish showed no significant difference (P = 0.4798). Histological examination revealed that the testes with seminiferous tubules filled with sperm and the ovaries with mature oocytes were present throughout the year. Therefore, based on the results of histology and reproductive characteristics, we concluded that both male and female P. disjunctivus in Polgolla Reservoir are breeding throughout the year. [ABSTRACT FROM AUTHOR]

The production of triploid bivalves has elicited great interest because their reproductive investment is known to be lower than that of diploids. Reduced reproductive investment is expected to improve the survival and growth of triploid bivalves compared to diploids as the energy spared from reproduction could be used for other metabolic needs. However, the reduction of triploid fertility varies among species, therefore, its impacts on survival and growth are variable. In this study, we compared the reproductive investment of diploid and triploid mussels between two age and size groups (1-year-old ˂ 30 mm, and 2-years-old ˃ 50 mm). We measured gonadosomatic index (GSI), gonad volume fraction (GVF), gonad maturation, and sex ratio. Results demonstrated that while triploid mussels do invest part of their energy in reproduction, they had lower GSI and GVF than diploids. In all tested groups, triploid gonads were less mature than those of diploids, and their sex ratio was significantly altered, with the absence of female triploids. Furthermore, triploid gonads showed signs of gamete resorption, suggesting that the gametes of triploid mussels could serve as energy reserves. This study reveals that triploid mussels invest less energy in reproduction which suggests that the spared energy could be used to improve other metabolic need and survival. We conclude that triploid mussels could be of great interest for aquaculture because they may have better resistance to post-spawning weakness and better recovery due to gametes resorption. • Triploid mussels invest less in reproduction than diploids do. • Triploid mussels have reduced gonadosomatic index and gonad volume. • Gametes of triploid mussels do not show full maturation. • Triploid mussels have an altered sex ratio, with the absence of females. [ABSTRACT FROM AUTHOR]

To optimize the dietary crude protein (CP) levels on the reproductive performance of genetically selected magur (Clarius magur), a 90-day feeding trial was conducted. One hundred and fifty brooders, ranging from 95.33 to 96.16 g, in a 1:1 male-to-female ratio, to fifteen 1000 L tanks, with each treatment replicated thrice were distributed following a completely randomized design. Five semi-purified diets with differing protein levels (25 %, P25; 30 %, P30; 35 %, P35; 40 %, P40; and 45 %, P45) were prepared for the trial. The results displayed that fish fed diets comprising 35 % and 40 % dietary crude protein (CP) exhibited higher specific growth rate (SGR), respectively. Similarly, these groups had higher weight gain percent (WG%) with reduced feed conversion ratio (FCR), respectively in comparison to other groups. The gonadosomatic index (GSI) of females significantly increased (P < 0.05) up to 40 % protein levels and then decreased, while males exhibited reduced values only in the P45 group. Both male and female hepatosomatic index (HSI) increased significantly (P < 0.05) with increasing dietary CP levels. Dietary CP level increment resulted in decreased visceral fat index in females but had no effect on males. Absolute and relative fecundity significantly (P < 0.05) increased up to 40 % dietary protein level. Estradiol levels in females increased with rising protein levels up to 40 %, but decreased at the 45 % level. Conversely, 17-α,20-β di-hydroxy progesterone (DHP) increased significantly in females from 35 % to 45 % protein level, while males exhibited the highest levels at 30 % and 35 % protein levels. In males, mRNA expression of follicle-stimulating hormone receptor (FSHR) was lowest, whereas luteinising hormone receptor (LHR) and 11β hydroxysteroid dehydrogenase (11β HSD) expression increased in the P30 and P35 groups (P < 0.05). Females showed significantly increased mRNA expression of LHR and CYP19a1 (Cytochrome p450 aromatase) in P35 and P40 groups (P < 0.05). Regarding reproductive performance metrics such as fertilization rate (%), hatching rate (%), and larval survival (%), the P35 and P40 groups exhibited significantly higher values (P < 0.05). Second-order polynomial regression and broken line analysis revealed the optimum dietary CP for magur broodstock based on GSI was 36.79 %, while based on reproductive performance, it ranged between 36.1 % and 36.14 %. • Growth and oocyte maturation in magur broodstock were influenced by dietary protein levels • At 35–40 % dietary protein levels reproduction related genes are upregulated in female magur • ptimum dietary protein level for magur broodstock was found to be 36.1–36.14 % [ABSTRACT FROM AUTHOR]

Aquatic ecosystems face significant exposure to endocrine-disrupting chemicals (EDCs), which can mimic, block, or alter the synthesis of endogenous hormones. Bisphenol A (BPA), a widely known EDC, has been phased out from consumer products due to concerns about its potential impacts on human health. In its place, bisphenol S (BPS), an organic compound, has been increasingly used in the production of polycarbonate plastics, epoxy resins, thermal receipt papers, and currency. Vitellogenin (Vtg), a yolk precursor protein synthesized in the liver and present in oviparous fish, particularly males, serves as a pertinent biomarker for studying the effects of estrogenic EDCs on fish. This study aimed to assess the impact of BPS on reproductive parameters and hepatic vitellogenin expression in Channa striatus. The LC50 of BPS was determined to be 128.8 mg/L. Experimental groups included control and BPS-exposed fish, with sub-lethal concentrations of BPS (1 mg/L, 4 mg/L, and 12 mg/L) administered and effects monitored at seven- and twenty-one-day intervals. Significant decreases in gonadosomatic index (GSI), ova diameter, and fecundity were observed in BPS-exposed Channa striatus. Hepatic Vtg mRNA expression was downregulated in female and upregulated in male following BPS exposure. Serum hormone analysis confirmed the estrogenic activity of BPS. These findings underscore BPS's ability as an endocrine disruptor to interfere with hormone synthesis and disrupt spermatogenesis and oogenesis processes in Channa striatus. This research contributes to understanding the endocrine-disrupting effects of BPS on aquatic organisms, highlighting potential ecological implications and the need for continued monitoring and regulatory considerations. • Bisphenol S treatment led to remarkable decrease in the reproductive indices of Channa striatus. • BPS exposure caused downregulation of hepatic VTG mRNA expression in females and upregulation in males. • The endocrine disturbances of BPS arise from hormonal imbalances and hepatic VTG mRNA expressions of the species. [ABSTRACT FROM AUTHOR]

A population of sea urchins, Paracentrotus lividus, from the central west coast of Portugal was studied to characterise their reproductive biology and possible relationships with environmental factors. An annual gametogenic cycle was found, with a broad spawning season, from May to November, according to a relatively synchronous gamete maturation process. Depending on the environmental factors (temperature, photoperiod), two separate periods could be distinguished, with more individuals maturing and spawning at the same time. When this happened, the first event evolved when temperature rose to a critical point, and the second occurred afterwards, when temperature decreased significantly. Notwithstanding, it was found that individuals matured later than previously described for other populations (e.g., north of Portugal), mostly in late spring, with a higher gonadosomatic index in May. A new classification scale was proposed for identifying the stages of P. lividus gametogenic cycle, based on new findings. It contributed to its simplification and easier comprehension. This study provides useful information for a differentiated sustainable management of P. lividus, according to local conditions. Establishing a closed harvesting season might be considered, based on the differences observed between Portuguese populations and other European ones.

The present study contributes information to the testicular development and reproductive aspects of Glossogobius giuris (Hamilton 1822), one of the target fishes in the Mekong Delta. Trawl nets were used to monthly collect fish specimens from January to December 2020 in four sites along Bassac River, from Cai Rang, Can Tho (CRCT) to Long Phu, Soc Trang (LPST), Hoa Binh, Bac Lieu (HBBL) and Dam Doi, Ca Mau (DDCM). Data analysis of 632 Glossogobius giuris individuals showed that five-stage of sperm development was found in testis histological slides. At stage IV of the testis, different phases of the sperm were observed, indicating that it is a multi-spawner, releasing sperms many times during the breeding season. Further analyses of the testis about apparent frequency and gonadosomatic index showed that this goby can release sperms monthly with a peak in the main wet season. The length at first maturity was observed at 7.24, 7.18, 7.43, and 6.57 cm of TL in CRCT, LPST, HBBL, and DDCM, respectively. The findings contribute essential information to fish population management and sustainable exploitation.

Simple Summary: Lepidorhombus boscii is a flatfish of high commercial value. However, the existing knowledge about the biology and ecology of this species is scarce. The aim of this study is to describe the reproductive cycle of L. boscii in the eastern Adriatic Sea. The sex ratio of L. boscii was 1:0.89 (female:male), and the size at first sexual maturity was 19.2 cm for females and 20.3 cm for males. Previtellogenic and vitellogenic oocytes are present in the ovaries throughout the year. L. boscii has a prolonged spawning season in the Adriatic Sea with the main spawning season between November and March. 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. [ABSTRACT FROM AUTHOR]

The striped piggy, Pomadasys stridens (Forsskål, 1775), is one of the successfully colonized Lessepsian immigrants entering the Mediterranean through the Suez Canal. This study was carried out to understand to what extent the reproduction strategy adopted by this species had played a role in its successful establishment. The study is based on samples collected during the monthly trawl surveys conducted between January 2017 to November 2020 in the Northeast Mediterranean. The annual gonadal development cycle was estimated by observing the Gonadosomatic Index changes. Seasonal patterns in energy intake and allocation were acquired from Hepatosomatic, Digestosomatic, and Relative Body Condition indices. The results indicated that the species has prolonged gonadal development periods, during which spawning occurs twice, in early summer and at the onset of the winter. A comparison of all indices involved indicated that the species feeds and develops gonads at the same time before summer spawning, feeds heavily and stores energy during the warmest period, and uses the stored energy in the winter spawning. As these features do not differ much from their congenerics inhabiting the geography they originated from, it is suggested that it was not the ecological plasticity of the species that is the basis of their success but the reproductive traits they have fitted well to the Mediterranean Ecosystem. [ABSTRACT FROM AUTHOR]

The Brazilian bocachico is a rheophilic fish from the northeast region of Brazil that holds great economic and scientific interest. The absence of evident sexual dimorphism and the invasive character of sexing methods and evaluation of gonadal maturation are obstacles to its artificial reproduction. In this scenario, ultrasonography emerges as a non-invasive method for sexing. The objectives of this study were to establish an ultrasound sexing method for Brazilian bocachico and select equations to estimate the gonadosomatic index (GSI), gonad weight (GW), and gonad volume (GV) of live bocachico. A total of 32 bocachico fish (18 females and 14 males) were analyzed ultrasonographically and morphologically. The association of morphometric and ultrasonographic parameters was investigated using Pearson Correlations. The following prediction equations were selected using multiple regression analysis: GSI = 16.22 × transvarea; GW = 30.3 × transvarea; and GV = 0.001260036 × pixels. A model capable of predicting the sex of the animals based on the ultrasonographic parameters was obtained using partial least-squares discriminant analysis with principal component analysis. The significance level adopted was P < 0.05. In conclusion, ultrasonography is a useful tool to perform sexing and evaluate the gonads during the breeding season, contributing to artificial reproduction in captivity. [ABSTRACT FROM AUTHOR]

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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. [ABSTRACT FROM AUTHOR]

Background: Selection pressure due to parasitic infestation puts adverse effects on birds' fitness concerning survival and reproductive success. The present study was conducted on Eurasian tree sparrow at Shillong (25°34′ N, 91°53′ E), India, for a year to examine ectoparasitic infestation by Myrsidea balati and Sturnidoecus ruficeps. The parameters on the annual prevalence of infestation, annual cycles of gonadosomatic index (GSI), molt, hematocrit percentage and the time spent in behavior display were recorded. Results: The infestation of both lice species ran parallel to GSI in both sexes of sparrow. Further, the intensity of infestation was higher in males. The increase in number of ectoparasites was found positively correlated with the increase in GSI in the birds. However, it was negatively correlated with feathers molt. Thus, the infestation of both parasites was maximum during the reproductive phase and minimum during the period when the birds were undergoing the process of molt. Seasonal variation in hematocrit percentage shows decline during high infection in females and during molt in both the sexes. The time spent in showing behavioral traits to limit infection was the longest during high infestation. Conclusions: We conclude that the tree sparrow adopts various adaptive strategies like feathers molt and longer display of behavioral traits during their breeding and/or non-breeding seasons to control parasitic load and avoid energy conflict with high energy demanding processes like reproduction and molt. [ABSTRACT FROM AUTHOR]

Shrimp scad Alepes djedaba is widespread in tropical waters and commercially important fish species of Pakistan. Feeding habits and fecundity rate were studied for A. djedaba from Balochistan, Pakistan. Total of 111 specimens were examined to perceive the feeding habits and 102 specimens for fecundity rate. Total of 16 ovaries were taken from stage four for estimation of fecundity rate. Frequency occurrence and numerical abundance were used to evaluate the feeding behavior. In frequency occurrence method different food items was observed. Fishes were found at 46% in guts, digested food at 34%, shrimp at 14% and shrimp larvae were found at 6%. While, fishes were observed at 48.74%, digested food at 33.17%, shrimps at 13.32% and shrimp larvae at 4.77% according to numerical abundance. These results show that A. djedaba is carnivorous in nature. The lowest fecundity rate was 8693 and highest rate was 73246, the average of fecundity rate of A. djedaba was found to be at 37220. Based on present findings it is evident that the fish has an extended spawning period throughout the year with a peak in July and August. The positive correlation (R²= 0.976) was observed between fish (weight) and fecundity rate during present study. [ABSTRACT FROM AUTHOR]

Wing reduction is a common feature of upland insect communities. This phenomenon is thought to be primarily driven by selection against flight, which is typically unfavorable in upland environments due to high winds and cold temperatures. In some insect taxa, wing-reduction has been directly linked to increased fecundity. However, few studies have directly tested for shifts in fecundity linked to flight musculature. Here we test for dispersal-fecundity trade-offs in the widespread subalpine stonefly Zelandoperla fenestrata. Our analysis of 450 stoneflies across 81 localities reveals significant dispersal-fecundity tradeoffs. Specifically, we identify a positive association between the size of their flight muscles and the length of their wings, and a negative association between wing length and ovarian mass. Furthermore, we found a significant negative relationship between flight musculature and ovary mass. These results represent a rare example of a dispersal-fecundity tradeoff in the wild, and illustrate that such tradeoffs can potentially involve corresponding reductions in both flight musculature and wing development. Our findings suggest that widespread taxa subject to variable environmental conditions may benefit from flexible allocation of energetic resources., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Evolutionary Biology.)

Some biological and reproductive aspects of the Mystus bleekeri from Dekhar Haor were investi-gated. From the commercial catches, a total of 600 sample collections were performed on a month-ly basis from July 2017 to June 2018. Total length (TL, cm), body weight (W, g) and individual’s sex were identified between 216 male (36%) and 384 female (64%) fish (ratio 1.00: 1.78). Mean TL and Wofsampleswere14.85±3.38cmand27.54±15.76g,respectively.TheTLofmaleandfemaleranged from 6.9-21.3 and 7.80-24.60 cm, respectively; and W ranged from 5.3-63.3 and 6.70-76.40 g,respectively.Inlength–weightrelationshipofthisfishdepictedanegativeallometricgrowth(b=2.408) with a condition factor (Kn) of 1.04±0.11. Fish of 16.00-16.90 and 10.00-10.90 cm length groups demonstrated the highest (1.45±0.23) and lowest (0.89±0.18) Kn values, respectively which wassignificantlyvariedamongdifferentlengthgroups.MonthlystudyofgonadosomaticindexshowedtwopeaksinthemonthofMay-JuneandNovemberforbothsexes.Theresultsofthisstudy provide baseline data on some biological aspects of M. bleekeri, which would be useful in predicting the responses of M. bleekeri populations in Dekhar Haor.

Abstract In many insect taxa, there is a well‐established trade‐off between flight capability and reproduction. The wing types of Acridoidea exhibit extremely variability from full length to complete loss in many groups, thus, provide a good model for studying the trade‐off between flight and reproduction. In this study, we completed the sampling of 63 Acridoidea species, measured the body length, wing length, body weight, flight muscle weight, testis and ovary weight, and the relative wing length (RWL), relative flight muscle weight (RFW), and gonadosomatic index (GSI) of different species were statistically analyzed. The results showed that there were significant differences in RWL, RFW, and GSI among Acridoidea species with different wing types. RFW of long‐winged species was significantly higher than that of short‐winged and wingless species (p

Skipjack is an important commercial species with a tropical distribution, although captures in the Mediterranean Sea have been recorded for decades. The western Mediterranean Sea, specifically the Balearic Sea, is a spawning area for several tuna species. We hypothesized that the western Mediterranean warming in the last few decades could lead to the expansion of skipjack tuna spawning areas from tropical areas to the Mediterranean Sea. We analysed 454 individuals (41.8-81 cm straight fork length) caught by sport fishing vessels in offshore trolling championships in Spanish Mediterranean waters during summer months from 2014 to 2019. Analysis of the gonadosomatic index and microscopic examination of the ovaries (n=192) showed that the skipjack is reproductively active in the western Mediterranean, particularly in the Balearic Sea. These results indicate that the skipjack has expanded its distribution and spawning area from tropical waters to the Mediterranean, probably owing to the gradual warming detected in the area in the last few decades. This new spawning activity in the area should be monitored in the near future to study the possible impact on other tuna species that share the distribution range and spawning area with skipjack tuna in the western Mediterranean.

In Ecuador, Peprilus medius is an important fishery resource whose destination is for local consumption and export. There are few local studies on its reproductive biology, and its capture is not regulated. Therefore, this study evaluates the most relevant aspects of its reproductive activity. Samples were obtained monthly from January to December 2017 from the capture of the purse seine fleet and the artisanal gillnet fleet landing near Manta. The morphometric analysis included the length-weight relationship, estimated using the allometry equation. The size at sexual maturity is based on the L50 criterion; the reproductive cycle was determined according to the monthly analyses of the gonadosomatic index (GSI), hepatosomatic index (HSI), and relative condition factor (Kn). A total of 334 specimens were analyzed, with average sizes of 22.0, 21.87, and 21.91 cm of total length (TL), for males, females, and combined sexes, respectively. Sex ratio was 1.17M: 1F (P > 0.05), while the length-weight relationship showed negative allometric growth for both males and females (b = 2.58; CI95% 2.48-2.72). Size at sexual maturity L50 was estimated at 21.84 and 21.23 cm TL for males and females, respectively. The GSI and HSI values and Kn showed significant differences among months (P < 0.05), with a marked seasonality during the single reproductive period. Mean size at first capture of 21 cm TL is recommended. [ABSTRACT FROM AUTHOR]

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