Gonad Weight Research Articles

Beyond Hunger: A Connection Between Diet and Gonadal Development of a Ladybird Beetle.

Food availability shapes morphology, physiology, growth, reproduction, and overall fitness of insects. Countless research in coccinellids reported the effect of diet in terms of quality and quantity on reproductive output. But fewer studies have reported the direct effects of food on the gonadal development in both sexes. In nature, ladybird beetle Cheilomenes sexmaculata exhibit food preference, favouring Aphis craccivora (nutritious prey) over Aphis nerii (poor prey). We hypothesized that beetles consuming nutritious prey in abundant quantity will have larger and heavier gonads. The current study assessed the effect of food preferred and its fluctuations on the gonadal development of C. sexmaculata. First instars were collected randomly from experimental stock and reared on two different diet regimes for a lifetime. After eclosion, beetles from each dietary regime were dissected daily to assess gonadal development until maturity. Here, we documented total developmental duration, body weight, weight of gonads, GSI, total area of gonads, length, and number of testicular lobules/ovarioles across different treatments. Both quality and quantity of diet significantly affected development period, body weight, and gonadal parameters in both sexes except for GSI in males and number of ovarioles in females that reared on varied diet quality, which were found to be similar. Aphis craccivora in abundant supply positively affected the growth and development of the gonads in C. sexmaculata. Beetles reared on the abundant supply of nutritious prey with larger and heavier gonads than those reared on limited supply or poor prey. This study improves our understanding of the development of gonads in ladybird beetles, which may be helpful in improving the mass rearing of ladybird beetles.

Reproductive performance of Channa striata in wetland ecosystems: a fuzzy logic approach to water quality and eco-climatic factors for long-term sustainable management and aquaculture advancement.

The striped snakehead, Channa striata, is commercially and nutritionally important due to its medicinal properties, such as wound healing and antimicrobial abilities. This study investigated the reproductive biology of C. striata in relation to hydro-climatic changes using a fuzzy logic approach for long-term management in the wetland ecosystem (Gajner beel), Bangladesh. A total of 1200 C. striata individuals were collected monthly during January to December 2019 using various fishing methods. Measurements of total length (TL), body weight (BW), and gonad weight (GW) were taken with a precision of 0.01cm and 0.01g, respectively. The GSI (gonadosomatic index in %), MGSI (modified gonadosomatic index in %), and DI (Dobriyal index) were used to determine size at sexual maturity (Lm) and the spawning season. Results revealed a wide range of TL, ranging from 12.7 to 46cm. The Lm was estimated between 21.7 and 25.33cm based on various model as TL vs. GSI, MGSI, and DI; TL-fork length (FL) regressions; and maximum length (Lmax) for this species. The spawning period was observed from April to July, peaking in May, indicated by higher GSI, MGSI, and DI values. Eco-climatic factors showed a significant relationship with GSI, except for total dissolved solids (TDS). Rising temperatures and declining rainfall could delay spawning of C. striata. A fuzzy logic approach was employed to predict future GSI changes over extended periods (e.g., 50 or 60years), enabling anticipation of shifts in the timing and duration of the spawning season. Finally, the findings of our research might be effective to carry out specific conservation efforts of C. striata in response to climate variability in sub-tropical water.

Evaluating Silvering Stages in European Eels: A Study on Biological and Morphometric Variations in the Asi River, Türkiye

The European eel (Anguilla anguilla) undergoes significant morphological and physiological changes during its transition from the yellow to the silver stage, which are critical for its long-distance spawning migration. This study aimed to investigate these changes in European eels from the Asi River, located in Hatay, Türkiye, during their silvering process. A total of 96 eels were sampled in February 2019, and various morphometric measurements, including total length, body weight, eye dimensions and height, and pectoral fin lengths, were taken. Liver and gonad weights were also measured to assess the hepatosomatic index (HSI). The length–weight relationship for silver eels was described by the equation, W = 0.0072 × L2.732, with silver-stage eels showing a higher growth rate compared to yellow-stage eels, which had a relationship of W = 0.0184 × L2.397. The average total length of silver eels (431.2 ± 16.7 mm) was significantly greater than that of yellow eels (382.4 ± 11.9 mm). Additionally, pectoral fin length was significantly longer in silver eels (20.8 ± 1.1 mm) compared to yellow eels (14.8 ± 0.9 mm). The hepatosomatic index (HSI) for silver eels was also found to be higher than for yellow eels, indicating increased liver size as an adaptation for energy storage during migration. Eye height, a key indicator of silvering, showed a substantial increase during the transition, with silver-stage eels having an average eye height of 5.3 ± 0.2 mm compared to 4.2 ± 0.1 mm in yellow-stage eels.

Maternal undernutrition in the first eighty days of gestation negatively programs ovarian development in dairy calves.

We hypothesized that in dairy cattle maternal energy restriction applied during two gestational windows (up to day 80 or 120 of gestation) impairs ovarian and cardiovascular development in juvenile female offspring. We also investigated the role of maternal leptin and testosterone in developmental programming in calves. Holstein-Friesian heifers were randomly assigned to one of three experimental groups; starting 10days before artificial insemination, they were individually fed at: (i) 0.6 of their maintenance energy requirements (M) up to day 80 (Nutrient Restricted, NR80) or (ii) day 120 of gestation (NR120); (iii) 1.8M until day 120 of pregnancy (Control, CTR). Plasma leptin concentrations increased transiently in nutritionally restricted heifers pregnant with a single female calf, but maternal testosterone concentrations were not influenced by diet. Calves had similar body growth, but daughters of NR80 and NR120 had impaired ovarian development, as assessed by reduced gonadal weight, fewer surface antral & primary follicles and recovered COCs, as well as lower circulating AMH concentrations. Cardiovascular morphology and function in the offspring were not influenced by maternal diet, as determined by peripheral arterial blood pressure, echocardiography, post-mortem heart weight and aortic circumference. Regardless of its duration (until day 80 or 120 of gestation), nutritional restriction resulted in a similar alteration of ovarian development in juvenile progeny, but cardiovascular development was unaltered. Evidence suggests that the window of development that encompasses the peri-ovulatory period to the first 2.6months of gestation is critical in ovarian programming and that maternal leptin may be involved.

Reproductive biology of fringescale sardinella (Sardinella fimbriata Valenciennes, 1847) from Malampaya Sound, Palawan, Philippines

Reproduction is a fundamental biological process that is essential for the continuous survival of fish species. Understanding their early life history and reproductive biology can explain how the population behave over time. A total of 1,238 fish samples were examined to determine the reproductive patterns and period of fringescale sardinella (Sardinella fimbriata) from Malampaya Sound, Palawan, Philippines. Monthly sampling from April 2023 to March 2024 revealed a 1:1 sex ratio. Gonadal examination of the fish revealed the presence of spawning individuals throughout the study period. The minimum size of matured fish observed was 11.0 cm and 11.1 cm for male and female S. fimbriata, respectively. The peak of spawning was April as indicated by the highest calculated GSI of 7.62% and fecundity of 18,465. A smaller peak was again observed in the month of September. The length at maturity was estimated to be 11.4 and 8.8 cm for males and females, respectively. Fecundity ranged between 2,700 to 36,067 eggs per spawn for size class between 11.1-14.8 cm and weight 13.07-31.93 g. Regression analysis between fecundity and morphometric characteristics such as body length, weight, eviscerated weight, and gonad weight revealed a positive correlation. Very low coefficients of determination were computed, ranging between 0.0028-0.1233. A significant association between fecundity and the morphometric variable gonadal weight was observed, as shown by the p-value of 0.0000. These outcomes are valuable data in the formulation of conservation and management strategies for the area. Implementation of appropriate conservation measures, monitoring of environmental parameters, strict enforcement of fishery regulation, coupled with increased environmental awareness and community participation will guarantee the long-term sustainability of the fringescale sardinella population and the preservation and sustainable use of marine biodiversity in Malampaya Sound.

Study of Hepatosomatic Index, Gonadosomatic Index and Fecundity of Tengra Fish (Mystus gulio)

The tengra fish (Mystus gulio) is an important commercial species found in the coastal regions of West Bengal, India and Bangladesh. M. gulio is an important species within its ecosystem and has significance in local fisheries. Its adaptability to both freshwater and brackish environments makes it a resilient species. This study investigated the hepatosomatic index (HSI), gonadosomatic index (GSI), and fecundity of M. gulio to better understand its reproductive biology. Specimens were collected monthly from the Meghna River estuary between February and June 2023. The GSI was found to be highest in August (9.95±0.15%), indicating the peak spawning season. The HSI showed an inverse relationship with GSI, being lowest in March. Fecundity ranged from 88,495 to 264,104 eggs, with a mean of 171,581±17,855. Fecundity was positively correlated with total length, body weight, and gonad weight. Statistical analysis revealed significant differences in GSI and HSI between sexes and age groups (virgin vs 1+ year). Regression models showed that fecundity was highly dependent on gonad weight (r2=0.809) compared to length (r2=0.047) and weight (r2=0.216). M. gulio is an important brackish water fish with good taste and nutritional value. While it is optimally exploited from the East Coast of India, its culture potential is being explored through polyculture experiments and research on seed production and farming techniques. These findings provide valuable insights into the reproductive dynamics of M. gulio and can inform management strategies for sustainable fisheries. However, further research is needed to fully understand the reproductive biology of this catfish across its range to inform sustainable management strategies.

Effects of buccal cavity parasite Ceratothoa carinata (Isopoda, Cymothoidae) on the condition and reproduction of its host fish Japanese scad Decapterus maruadsi.

All species of the isopod family Cymothoidae are obligate fish parasites, extracting nourishment through hematophagy and tissue consumption. To elucidate the detrimental effects of this parasitic relationship upon the host fish, we examined body length, weight of body, gonad, liver and stomach contents, and condition factor of Japanese scad Decapterus maruadsi infected with the buccal cavity parasite Ceratothoa carinata in different seasons. During the host fish's breeding season in July, the wet weight and condition factor of male and female host fish ages 1 and 2 were conspicuously diminished. No impacts were detected in September, after the breeding season. We found no impact of the parasite on the stomach content weight or signs of prey fish in the stomachs. Thus, parasite infection with C. carinata potentially diminishes the reproductive success of the host fish by negatively impacting the host's physiological condition, particularly during the breeding season.

The Reproductive Biology of Auchenoglanis biscutatus and Protopterus annectens from Lower River Benue Wadata, Makurdi-Nigeria

Data on the reproductive biology of Auchenoglanis biscutatus and Protopterus annectens were collected between april 2019 to march 2020. Reproductive parameters including sex ratio was determined as number of males by number of females, gonadosomatic index as total gonad weight by body weight and expressed in percentage while fecundity was obtained via volumetric and gravimetric methods. There was a slight dominance of males over females of both species (1.1:1) with more immature individuals caught within the study period. Higher GSI, gonad length and gonad weight (0.87±0.06, 15.94±0.89 and 3.01±0.19) were recorded in Auchenoglanis biscutatus during dry season while GSI and gonad weight (4.06±0.62, 5.63±0.45) of Protopterus annectens and number of mature fishes (0.35) were higher during rainy season. The relative fecundity for Auchenoglanis biscutatus investigated had no significant difference in both seasons (7.99±0.94, 8.22±0.78) while the relative fecundity for Protopterus annectentens differed significantly among the wet and dry seasons (3.43±0.94, 0.48±0.22). The relative fecundity of Protopterus annectens (11.59±2.04) was higher than that of Auchenoglanis biscutatus (8.04±0.75).it was concluded that the study of the sex ratio indicates that males were higher than females.

The potential ameliorative role of Dimercaptosuccinic acid against the toxicity of Titanium Dioxide Nanoparticles on Caelatura nilotica clams.

The prevalent use of nanoparticles has adverse negative effects on biosystems. Subsequently, this study aimed to use Caelatura nilotica to assess the ecotoxicity of TiO2 NPs and how Dimercaptosuccinic acid (DMSA) improves these effects. Two concentrations of TiO2 NPs (25 and 150 µg/L) were used for 28 days. TiO2 NPs bioaccumulation, gonadal weight, gonado-somatic index, and histopathological alterations of gonads were determined. The tissues' accumulation of TiO2 NPs was concentration-time-dependent: it was 78.5 ± 28.93 μg/g dry weight in the exposed clams to 150 µg/L TiO2 NPs after 4 weeks of exposure. The gonadal weight and gonado-somatic index significantly decreased of the exposed group to 150 µg/L TiO2 NPs over the experimental period that they ended with values (1.01 ± 0.57 gm, 19.15 ± 7.75%, respectively). There are some histological alterations in the gonads of C. nilotica such as necrosis, deteriorated connective tissue, increased fibrous tissue, a reduced presence of mature sperms and mature ova, and irregular shapes of testicular/ovarian follicles. When using Dimercaptosuccinic acid (DMSA), this led to a reduction in accumulation of TiO2 NPs by the end of the experiment. So, C. nilotica is a promising model to reflect the adverse nano-toxics. DMSA emerges as a potentially valuable chelating agent that abolishes the negative effects of these nanoparticles.

First Record of Snakehead Gudgeon (Ophiocara porocephala) in Sorong, West Papua, Indonesia

Aims: As reported this paper, the new record of O. porocephala has helped to improved the knowledge of the species as it extends the distribution range. Study Design: Short Communication. Place and Duration of Study: This research was conducted from September to November 2021. Sampling was carried out in the Tampa Garam mangrove forest swamp located in Tampa Garam Village, Maldum Mes Distric, Sorong City. Methodology: The morphology of fishes has been the primary source of information for taxonomic and evolutionary studies. There were numerous characters available for morphological study. Results: O. porocephala had a horizontally and terminally wide mouth with a large enough distance from the posterior area of ​​the eye. O. porocephala had ideal eye spacing with small eyelids and large corneas, two dorsal fins and an anal fin each with a distance of 1 and 22mm between the dorsal fins, the anterior dorsal consists of spines fins, while the posterior was weak fins. Fish habitat was found in mangrove areas or in estuarine areas with a salinity of 11 ppt, small fish lived in shallow areas while larger fish lived in deeper areas. The brightness of the air when the fish were isolated was 100%. Oxygen levels at 4 mg/l. O. Porocephala obtained during the study, consisting of gender is 1 female and unidenified. Meanwhile, the fish size in the class 10,9-225,39 cm and gonad weight is 2,62 of female fish with categorie gonad maturity is 3. Conclusion: Based on the results of research, fish that live in mangrove areas are carnivorous, with large fish species having a total length of 18,4 cm and small fish less than 10 cm, further research needs to be carryout base on the feed habit and maturity of this fish.

A Study of Age, Sex Ratio, Gonado-Somatic Index, Fecundity, and Breeding Season, of Nile Tilapia (Oreochromis niloticus Linnaeus, 1758) from Khashm El-Girba Reservoir and Atbara River, Eastern Sudan

This study aims to investigate some reproductive aspects of Nile tilapia, Oreochromis niloticus in the Khashm El-Girba reservoir and Atbara River, eastern Sudan. The study was conducted during December 2015 to November 2016. Samples were collected bi-monthly basis from three localities, namely; Um Aswad (Atbara River), El-Remila, and El-Monaba (Khashm El-Girba reservoir), using beach seine nets of 1.2 cm 4.0 cm and 7.0 cm stretched mesh. A total of 1595 O. niloticus specimens were collected from all sampling sites. The age of O. niloticus was estimated using five anterior vertebrae of fish body; The results indicate that the age ranged between 0+ to 4+ years. Most of the collected fish specimens were of age 1+, with females most dominant at this age. Sex ratio was 1:1(M: F). Gonado-somatic index (GSI) of females of O. niloticus ranged between 1.965 – 2.620, and from 0.434 – 0.439 for males. Two periods of increase of GSI were observed reflecting two breeding seasons of this species. Used gravimetric method to estimate the average fecundity of O. niloticus ranged between 481 eggs in Um Aswad sampling site, and 638 in El-Remila site. The fecundity of O. niloticus has a high correlation with gonadal weight (r=0.82708) but a low correlation with standard length (r=0.47612) and total weight (r=0.50874). The results of this investigation on O. niloticus indicate that the age of the fish ranged from 0+ to 4+ years, with a sex ratio of 1:1. The Gonado-somatic Index (GSI) indicated two spawning seasons, and fecundity was found to be strongly correlated with gonad weight, and moderately correlated with total length and standard length. This results can be used formulate management policies and procedures for protecting and conserving the fisheries resources and to regulate and improve the catches of the most important commercial fish species in that region.

Transcriptome profile of sex-related gene expression and effects of cyp19a1 siRNA-silencing on sex differentiation and determination in yellow perch

In this study, we first sequenced the whole genome of the yellow perch (YP, Perca favencens) and screened transcripts of brain, liver, and gonadal tissues from fish of different sexes. By comparing known female sex-related genes in fish such as cyp19a1 and dmrt1 with YP genome, we obtained full-length sequences through genomic homology analysis. Then an experiment was conducted to evaluate the effects of cyp19a1-siRNA interference on gonadal development and sex differentiation and determination in YP. Transcriptome analysis revealed that the gonadal tissue of female YP exhibited predominantly and differentially up-regulated expression of genes than males, and cyp19a1 was predominantly expressed in the gonads while cyp19a2 showed predominant expression in the brain. KEGG pathway enrichment analysis illustrated the metabolic pathways of the top 25 enriched genes and confirmed CYP19 (P450) pathway in YP. For the cyp19a1-siRNA interference experiment, four intermittent in vivo injections of siRNA were administered to interfere with cyp19a1 gene expression in an all-female group of YP. The results collected at 180 dph revealed that the siRNA interference resulted in an incomplete masculinization and hermaphroditism of all-female monosex YP, displaying the presence of male spermatocytes along with female oocytes. In contrast, tissues from the blank control and negative control groups only contained oocytes. The appearance of the gonads in the experimental group appeared more irregular, lacking the smooth surface and typical histoarchitecture observed in the blank control and negative control groups. In addition, the cyp19a1-siRNA treatment group had significantly (P < 0.05) lower body weight than the control groups, indicating that the interference with cyp19a1 might have affected the expression of estrogen, leading to a trend similar to the growth of males; similarly, the gonad weight and GSIs of the cyp19a1 group were significantly (P < 0.05) lower than those in the control groups, suggesting that the cyp19a1-siRNA interference might have led to a trend of male type of gonadal development. Meanwhile, the treatment group had significantly (P < 0.05) higher HSI and VSI levels compared to control groups, indicating that stimulation of external siRNA might have resulted in more vigorous liver metabolism processes. Furthermore, the expression level of the dmrt1 in the treatment group was significantly (P < 0.05) upregulated compared to the control groups, suggesting the correlation roles between these two genes in the regulation of sex development. The findings provide valuable insights for future research into the underlying mechanisms involved and hold significant promise for sex control in aquaculture.

Myostatin deletion alters hormone metabolism shifts in obese skeletal muscle of C57/Bl6 mice

Objective: Myostatin deletion improves cardiometabolic disease outcomes observed in obesity without any changes in activity in mice. Hormone balance is dysregulated in obesity, resulting in low testosterone and high estradiol levels, which have been shown to correlate with higher risk for developing associated cardiometabolic disease outcomes. However, the basis of these alterations and how they impact factors that improve obese cardiometabolic outcomes are unknown. Methods: Control and obese mice ( db/db) with or without myostatin deletion to induce hypermuscularity were used. Plasme from mice were analyzed for hormone levels via radioimmunoassay (RIA). Aromatase inhibition was performed via dosing 10mg/kg/day via water. Quantitative PCR was used cytochrome P450 enzymes involved in estrogen metabolism in the liver, skeletal muscle, and visceral white adipose tissue. C2C12 overexpression of CYP1B1 and treatment with hydroxyestrogens in vitro was performed and respective enzyme mRNA expression assessed. Results: Deletion of myostatin increased muscle mass by &gt;30% and resulted in and improved glucose tolerance in the context of obesity without any changes in activity. Obesity decreased plasma testosterone 30% and increased estrogen 20% with no change in gonadal weight, which was improved in the absence of myostatin. CYP1B1, an enzyme that converts estradiol to toxic hydroxy estrogens, showed 2.5-fold expression in obese skeletal muscle, which is reduced in the absence of myostatin, with no change in other cytochrome P450s involved in estrogen metabolism. Inhibition of aromatase reduces estrogen and improves testosterone plasma concentration, indicating the excess estrogen in obesity is derived primarily from testosterone conversion. Aromatase expression was increased in obesity but unaffected by changes in muscle mass, this indicates an alteration to downstream estrogen metabolism. In C2C12 cells, overexpression of myostatin recapitulated changes in CYP1B1 expression seen in vivo, suggesting a direct link between the myokine and sex hormone metabolism. In addition, treatment of C2C12 cells with CYP1B1 derived hydroxyestrogens caused a tandem increase in SCD1 expression, indicating a causal link between CYP1B1 activity in obesity to increased triglyceride synthesis. Conclusion: In summary, obesity causes a shift in sex hormone levels towards estrogen production, which is improved by myostatin deletion. A potential mechanism responsible could be altered estrogen metabolism, leading to decreased estrogen levels without restoration of androgen levels. These data suggest CYP1B1 drives the conversion of estrogen to hydroxestrogens, known to harbor carcinogenic and pro-lipidemic influences, in skeletal muscle which may also contribute to cardiometabolic disease. Whether targeting CYP1B1 improves cardiometabolic function in obesity remains to be determined. D.W. Stepp and D.J. Fulton are supported by NIH 1R01HL147159. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Unraveling the spawning and reproductive patterns of tomato hind grouper, Cephalopholis sonnerati (Valenciennes, 1828) from south Kerala waters.

The objective of this study is to provide information on the reproductive biology of tomato hind grouper, Cephalopholis sonnerati (Valenciennes, 1828) for conservation and management purposes. Fish caught by artisanal fishermen from September 2019 to August 2021 were analysed. A total of 280 females, 31 males, and 4 transitional and 178 sex-undetermined fish were analysed. The female to male sex proportion was 9:1, and the fish reached a maximum total body length of 38.5 and 54.5 cm for females and males, respectively. The following microscopic stages were identified: immature, developing, ripe, running ripe/releasing, and spent in both males and females. Several asynchronous development patterns were observed in the studied gonads, including multiple oocyte stages and early and advanced stages of sexual transition. High gonadosomatic index (GSI) for both males and females was recorded in March, May, and November. Running ripe and releasing stages in females were identified in the months from March to June, which indicates the spawning season. The absolute and relative fecundity of the species ranged from 162,723 ± 207,267 and 239 ± 285, respectively. An exponential relationship was found between fecundity and total body length (TL), fecundity and total body weight (TW), and fecundity and gonad weight (GW).

Experimental analysis of the effect of low water temperature on oogenesis of juvenile chum salmon

The state of gonads is examined for juvenile chum salmon exposed for two weeks at low water temperature, for different stages of their embryonic-larval development. The transfer of the embryos and larvae from the water with temperature of 10.0–12.0 о C to the water with temperature of 1.3–1.8 о C slowed both somatic growth of the fish and development of their germ cells in all cases. The deficit in body weight and ovarian weight of experimental fish was not compensated later. However, the gonad weight was decreased in the somatic component and did not affect the fund of germ cells, in the medium term. The state of ovaries did not differ between the control and experimental groups of fish 50 days after the end of exposure, regardless of the initial condition of gonads in the experiment.

Status of the reproductive system of anchovy sprat (Clupeonella engrauliformis, Borodin, 1904) in the Caspian sea

The impact of negative factors on the population of anchovy sprat (Clupeonella engrauliformis, Borodin, 1904) continues, and therefore in recent years there has been a steady downward trend in the abundance and density of the species. Research catches of anchovy sprat are declining. One of the conditions contributing to the population recovery is an optimal, without critical pathologies condition of reproductive system of individuals. The purpose of this work is to study the condition of testes and ovaries of anchovy sprat. According to the histological picture of germ cells it is possible to objectively assess the state of reproductive ability of individuals. The study was carried out using the methods of classical histology. The material was gonads of females and males sampled in the summer of 2023 in the Middle Caspian Sea. According to the results of histological study it was found that gonads have different stages of maturity (II–III, III, IV and V). The presence of direct correlations between maturity indices (gonad weight, gonadosomatic index, maturity coefficient) in individuals of both sexes was found. In females, the size of oocytes of different stages of maturity is described, and the absence of correlation between cell diameter and length and mass of the individual is revealed. Distinctive features of resorption of oocytes of III and IV stages of maturity by such characteristics as shape, color and transparency of the cell are given. The proportion of females with resorbed oocytes (67%) and the average proportion of cells with developmental abnormalities (24%) were noted. The results of this study may contribute to a better understanding of the processes occurring in the reproductive glands of male and female anchovy sprat, which is very important for fish reproduction.

Reproductive features of data-deficient yellowfin snapper, Lutjanus xanthopinnis (Actinopterygii: Eupercaria: Lutjanidae), from east-coast of Peninsular Malaysia: Implications for sustainable fisheries management

Understanding the reproductive biology of fishes is crucial to making accurate and scientifically sound recommendations for fisheries management. The presently reported study is the first to report the reproductive characteristics of the data-deficient and recently described yellowfin snapper, Lutjanus xanthopinnis Iwatsuki, Tanaka et Allen, 2015, collected from the eastern South China Sea, Malaysia. A total of 572 fish specimens were sampled monthly from March 2022 to April 2023 using a gillnet and a trawl net. Subsequently, these specimens were measured and weighed. Their total length (TL) ranged from 15.3 to 26.8 cm (19.25 ± 2.04 cm; mean ± SD). Their body weight (WB) ranged from 53.5 g to 279.7 g (114.5 ± 40.3 g; mean ± SD). For the reproductive biology study, the following parameters were determined: the sex ratio, gonadosomatic index (GSI), hepatosomatic index (HSI), spawning period, fecundity, condition factor (K), length at maturity, and the gonadal maturity stages. In the sex ratio, males (M) were significantly dominant over females (F) (M:F = 1:0.75) (χ2 = 11.18). Consequently, the monthly mean GSI of pooled sex revealed a consistent trend from January to August, indicating spawning seasons with peak periods in March and April. The batch fecundity of 67 mature females (16.0–25.2 cm TL; 64.5– 279.3 g W), was determined to range from 16 405 to 94 357 oocytes. The fecundity increased with gonad weight in contrast to weight and length. The length at first maturity of females and males was 14.53 and 20.56 cm, respectively. Females matured earlier than males. Macroscopic and histological examination of gonads revealed monthly variation in the ratio of gonad stages for males and females. This study offers crucial data on the reproductive biology of L. xanthopinnis, which will help with sustainable fishery management in this area and can be used as a reference for the management of similar fish populations in other regions of the world.

Population structure and average length at the first maturation of the king weakfish, Macrodon ancylodon (Bloch &amp; Schneider, 1801) (Pisces, Sciaenidae) in the estuarine complex of São Marcos Bay, eastern amazon, Brazil

Population structure and average length at the first maturation of the king weakfish, Macrodon ancylodon (Bloch &amp; Schneider, 1801) (Pisces, Sciaenidae) in the estuarine complex of São Marcos Bay, eastern amazon, Brazil

Effects of Antarctic Krill Meal in Diet on Reproductive Performance and Embryo Quality of Eriocheir sinensis.

A 60-day feeding trial was conducted to evaluate the impact of dietary Antarctic krill meal on the reproductive performance and embryo quality of the Chinese mitten crab, Eriocheir sinensis. Three diets were formulated, incorporating varying levels of Antarctic krill meal at 0% (Diet K0), 10% (Diet K10), and 20% (Diet K20), with a control group fed razor clam Sinonovacula constricta. Each diet was randomly assigned to three replicate tanks, each stocked with 5 males and 10 females. Male and female weights were 145.38 ± 8.01 and 102.57 ± 9.73 g, respectively. The results revealed no significant differences in weight gain rate, specific growth rate, and survival rate. However, the hepatopancreatic weight and hepatopancreas index of female crabs in each group decreased, while gonadal weight and gonadosomatic index increased significantly after 60 days, with Diet K20 showing the highest values. Egg production and fecundity of female crabs reached their peak in Diet K20, with no significant differences in reproductive indices among all groups. The phospholipid content in Diet K20 was significantly higher than in the other groups (P < 0.05). Cholesterol contents in Diet K0 and the control group were significantly higher than in Diet K10 and K20 (P < 0.05). No significant differences were observed in egg diameter, egg weight, moisture, crude protein, and crude fat between the groups. The content of C20 : 2 and C20 : 4n6 was highest in Diet K0, with a significant difference compared to Diet K10 (P < 0.05). However, no significant differences were found in the total content of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids among all groups. Based on the research findings, it is recommended that the optimal level of Antarctic krill meal in diets is 20%.

Morphological relationships, growth patterns and some aspects of reproductive biology of Sind Danio Devario devario (Hamilton 1822)

This study examined the morphological relationships, growth population factors and reproductive biology of Devario devario collected from the Atrai River of Dinajpur, Bangladesh, for sustainable management and conservation aspects. The length-weight relationships (LWRs) commonly indicated the isometric growth. The Fulton’s condition factor (CFf) and relative body weight (BWr) varied across sexes. A positive correlation was found in length-length relationships (LLRs); among total length (TL), standard length, head length and fork length. The asymptotic lengths were 7.5, 7.2 and 7.5 cm, with growth rates of 0.78‒1.8, 0.6‒3.4 and 1.8‒3.6 year–1 while total mortality was 1.22‒3.06, 0.97‒7.07 and 3.70‒6.09 year–1; fishing mortality was –0.87 to –1.04, –0.97 to 1.09 and –0.05 to –0.23 year–1; natural mortality was 2.26–3.93, 1.94–5.98 and 3.93–6.14 year–1 for female, male and combined sexes respectively. The highest probability of capture (L50) was 5.74‒6.15 cm. The gonado-somatic index ranged from 32.75±1.82 to 44.12±2.73, with a peak in April to May. Fecundity was recorded from 3253±289 to 4831±342, with a significant correlation among TL, BW, gonad length (GL) and gonad weight (GW). These initial findings on D. devario will serve as the basis for future research and management.