Combined Sexes Research Articles

Fishery characteristics, population dynamics and the impacts of the invasive red swamp crayfish (Procambarus clarkii) in the Nile River, Egypt

Alien intrusive species are one of the extreme pressures on biodiversity for their rapid reproduction and adaptation to new environments. Crayfish Procambarus clarkii entered Egyptian freshwater ecosystems at the beginning of 1980's. After many years of negative effects of its introduction onto the Egyptian waters, it became one of the commercially important species. Population parameters of P. clarkii are estimated based on 1355 specimens collected from the Nile off El-Minya during 2019–2020. The isometric growth of the species under the study is confirmed according to the obtained b-value of length–weight relationship (LWR). Annual sex ratio (female : male) was in favour of females with an annual sex ratio 1.44 : 1. The values of growth coefficient (K) and the asymptotic total length (L∞) were assessed for males, females and combined sexes. Using mortality estimates, the exploitation ratio was 0.64 year–1. Investigation of relative yield per recruit (Y'/R) and analysis of relative biomass per recruit (B'/R) for P. clarkii in the Nile off El-Minya provides the highest (Y'/R) at Emax = 0.81 and the E0.5 (utilisation level that preserves the spawner stock biomass at 50% of the virgin spawning biomass) was 0.38. From fisheries management point of view, the current exploitation level should be decreased to that maintain the spawning stock biomass (from 0.64 to 0.38).

Reproductive and Growth Parameter Estimation Utilizing Length-Stratified Age Samples of Sandbird Octopus (Amphioctopus aegina) near Phetchaburi Province, Thailand

This study aimed to analyze the growth parameters and age-length relationships of the sandbird octopus (Amphioctopus aegina) along the coast of Chao Samran Beach, Phetchaburi Province, Thailand. This included determining reproductive stages, the gonadosomatic index, and size at first maturity. A total of 1,436 specimens comprising 782 males and 654 females were collected using octopus traps during January to December 2021. The mantle length and weight of each specimen were measured. Reproductive stages were assessed to determine the gonadosomatic index and size at first maturity, and growth parameters were estimated using the von Bertalanffy growth equation. Results showed that males exhibited a mantle length range of 3.1—7.5 cm (mean: 5.2±0.7) and a weight range of 5.99—94.00 g (mean: 35.34±11.24). Mantle length at first maturity for males was 4.2 cm, with full maturity at 7.0 cm. Females had a mantle length range of 2.8—9.4 cm (mean: 5.7±0.9) and a weight range of 7.70—105.00 g (mean: 45.43±17.00). Mantle length at first maturity for females was 5.9 cm, with full maturity at 7.5 cm. GSI values were highest in both sexes in February, April, May, June and November, suggesting reproduction occurred through much of the year, and females showed a large peak in May. GSI values were lowest in both sexes in September. The smallest recorded mantle length was 2.8 cm in May, and the largest was 9.4 cm in January. The specific values of t0 for males, females, and both combined sexes were -0.017719, -0.014519, and -0.00672, respectively. These findings provide valuable insights into the growth and reproductive biology of A. aegina, which can inform sustainable management and conservation efforts for this species.

Consumption of Total and Specific Alcoholic Beverages and Long-Term Risk of Gout Among Men and Women

Previous studies on alcohol consumption and incident gout have mostly included men or combined both sexes, and the sex-specific associations between alcohol consumption and gout are poorly understood. To evaluate the consumption of total and specific alcoholic beverages in association with incident gout in men and women. This prospective cohort study included 401 128 participants in the UK Biobank aged 37 to 73 years who were free of gout at baseline (2006-2010). Participants were followed up through December 31, 2021, and data were analyzed between August 2023 and June 2024. Questionnaire-based consumption of total alcohol and specific alcoholic beverages. The outcome was incident gout, identified using hospital records. Multivariable Cox proportional hazards regression models were used to estimate sex-specific hazard ratios (HRs) and 95% CIs of incident gout associated with alcohol consumption, with a particular consideration of reverse causation bias. The main analysis included 179 828 men (mean [SD] age, 56.0 [8.2] years) and 221 300 women (mean [SD] age, 56.0 [8.0] years). Current drinkers showed a higher risk of gout than never drinkers among men (HR, 1.69; 95% CI, 1.30-2.18) but not among women (HR, 0.83; 95% CI, 0.67-1.03). Among current drinkers, higher total alcohol consumption was associated with a higher risk of gout among both sexes and more strongly among men than women (men: HR, 2.05 [95% CI, 1.84-2.30]; women: HR, 1.34 [95% CI, 1.12-1.61]). The most evident sex difference in the consumption of specific alcoholic beverages was observed for beer or cider (men: mean [SD], 4.2 [4.8] pints per week; women: mean [SD], 0.4 [1.1] pints per week). Consumption of champagne or white wine, beer or cider, and spirits each was associated with a higher risk of gout among both sexes, with beer or cider showing the strongest association per 1 pint per day (men: HR, 1.60 [95% CI, 1.53-1.67]; women: HR, 1.62 [95% CI, 1.02-2.57]). Some inverse associations between light to moderate consumption of specific alcoholic beverages and gout were eliminated after adjusting for other alcoholic beverages and excluding individuals who had reduced alcohol consumption for health reasons, self-reported poor health, or had cardiovascular disease, cancer, or kidney failure at baseline, or developed gout within the first 2 years of follow-up. In this cohort study, higher consumption of several specific alcoholic beverages was associated with a higher risk of gout among both sexes. The sex-specific associations for total alcohol consumption may be associated with differences between men and women in the types of alcohol consumed.

Studies on sex ratio, condition factor and patterns of phenotypic estimation in stock identification of snow trout, Schizothorax esocinus Heckel, 1838 inhabiting the colder Indian Himalayan region

Schizothorax esocinus, a nutrient-rich food fish offered in Asian countries, is rapidly declining due to severe fishing pressure and pollution in its wild environment, requiring active conservation strategies. Our study examined 196 specimens to elucidate critical biological parameters including sex ratio, length-weight relationships (LWRs), Fulton's condition factor (K) and morphometric-meristic parameters. The general sex ratio was not substantially departed from the predicted value of 1 : 1, with the exception for the month of May, where χ2 = 4.15 which is greater than the calculated value of 3.84. The correlation between the length and weight was reported as Log W = 0.134209 + 2.5218 log L for males, Log W = 0.19173 + 2.6751 log L for females and Log W = 0.162116 + 2.594 for combined sexes. Schizothorax esocinus demonstrated a negative allometric growth as indicated by the allometric parameter b for the LWR. The two sexes showed no significant differences in morphometric measures. So, this study included combined-sex regression analysis. These comprehensive findings highlight the critical need for conservation efforts in India and neighbouring countries to preserve this valuable fish stock for future generations.

Infestation of the spider crab Menaethius monoceros (Epialtidae: Brachyura) from the Egyptian Red Sea coasts by Parasacculina pilosella (Polyascidae: Rhizocephala: Cirripedia

The results of this study showed that out of 287 individuals (135 males and 152 females) of the spider crab Menaethius monoceros collected from the Red Sea and the Gulfs of Suez and Aqaba, 15 individuals (6 males and 9 females) were infected with Parasacculina pilosella (Van Kampen & Boschma, 1925) (Polyascidae: Rhizocephala: Cirripedia: Crustacea). A total of 20 externae were recorded, including 11 singles, three doubles, and only one triple on the infected crab abdomens. The overall infection rate was 5.23% for the combined sexes at all sites, declined to 4.44% in males, but increased to 5.92% in females, reaching a higher rate of 16.07% in the populations of Marsa Alam and Shalateen sectors during summer. The examined externae have variable colors, sizes, and shapes based on their sexual maturity, which has been classified into four stages: immature or virgin, early mature, maturing, and late (spent externae). The largest number of externae was eight extruded on the 3rd abdominal segment, while it decreased to six, two, and one on the 4th, 2nd and 5th segments, respectively. The size of externae varied from 1.3 × 1.0 × 1.0 to 6.3 × 4.5 × 2.5 mm (Breadth × Height × Thickness). These results showed changes in the external secondary sexual characters of the infected males, represented by the remarkable broadness of the abdomen fringed with marginal setae and invagination of the sternum, but were limited in infected females.

Growth parameters and stock assessment of Carangoides bajad Forsskal, 1775 (Carangiformes: Carangidae) in Jeddah fisheries

ABSTRACT The stock status of Carangoides bajad in Jeddah fisheries was assessed by estimating the growth parameters, mortality rates and size at first capture (Lc), then applying the results to estimate the yield and biomass per recruit. The length-weight relationship could be described by the power equation: W = 0.011 L3.019 (R2 = 0.99) for combined sexes. Von Bertalanffy Growth Parameters L∞, K and t0 were estimated to be 71.53 cm, 0.224 year −1, and −0.52 year, respectively. The total, natural, fishing mortality coefficients and exploitation were calculated to be 0.72 year −1, 0.337 year −1, 0.383 year −1, and 0.53 year −1, respectively. Beverton and Holt (1957) model was used to estimate the yield and biomass per recruit at Fcur and Lc and found to be Y/R = 291 g and B/R = 759 g. Compared with the two biological reference points Fmax = 0.56 year −1 and F0.1 = 0.346 year −1, the Fcur value was very close to the F0.1 value required to get the optimum Y/R. We recommend avoiding any increase in Fcur, and increasing Lc to be 38 centimetres to increase the B/R from 759 g to 793 g, which would increase the probability of sustaining sufficient recruitment to the fishery of C. bajad in Jeddah fisheries.

Length-weight relationship and condition factor of threadfin goby Sicyopterus longifilis de Beauford, 1912 (Teleostei: Sicydiinae) at Ummiding and Matama Rivers, West Sulawesi, Indonesia

Abstract. Tikawati, Omar SBA, Nur M. 2024. Length-weight relationship and condition factor of threadfin goby Sicyopterus longifilis de Beauford, 1912 (Teleostei: Sicydiinae) at Ummiding and Matama Rivers, West Sulawesi, Indonesia. Biodiversitas 25: 2074-2085. Threadfin goby Sicyopterus longifilis (de Beaufort, 1912) is an amphidromous species known as 'penja' in the postlarval phase. Therefore, this research aimed to analyze the length-weight relationship and condition factors of goby fish in Ummiding and Matama Rivers, West Sulawesi. Fish sampling was conducted 12 times, twice monthly, during new and full lunar phases from July to December 2023. Each fish was measured for the total length, weighed, and dissected to determine the sex. The results showed that the length-weight relationship of goby fish in Ummiding River for male and female fishes were W = 0.000011L3.0250 and W= 0.000023L2.8422, respectively. In Matama River, the length-weight relationship for male and female fish was W = 0.000008 L3.1193 and W = 0.000005 L3.2228, with a combined sexes value of W = 0.000006 L3.1839. According to the statistical tests, the Ummiding River male fish had isometric growth due to a balanced length and body weight increase. In contrast, female fish had hypoallometric growth type (b<3), where the increase in length was faster than body weight. Male, female, and the combined sexes of the species in Matama River had hyperallometric growth type (b>3) since the increase in length was slower than body weight. The condition factor values exceeded 1.0, showing that Ummiding and Matama Rivers supported threadfin goby life. The acquired threadfin goby length-weight relationship and condition factors are now used as a guide for managing and conserving the species in this region.

The Growth of Crayfish, which Serves as an Indicator of Clean and Healthy Water Ecosystems in the Mediterranean Region

The narrow-fingered freshwater crayfish, also known as Pontastacus leptodactylus in scientific terms and referred to as such in Turkish, is a prevalent species in the inland waters of the Mediterranean region. This crayfish serves as an indicator of clean and healthy water ecosystems due to its high sensitivity to pollution and environmental changes. Its presence signals the maintenance of water quality and a balanced ecosystem. In a study on 283 freshwater crayfish in Hirfanlı Dam Lake during July and August 2023, it was observed that 53.36% were male and 46.64% were female. Length ranged from 80.44 mm to 121.11 mm, and weight varied between 11.61 g and 43.93 g. Average length and weight for males were 95.9874 ± 6.4603 mm and 24.1861 ± 5.3696 g, for females were 95.0981 ± 5.5519 mm and 21.5193 ± 3.4488 g, and for combined sexes were 95.5724 ± 6.0594 mm and 22.9422 ± 4.7579 g. The length-weight relationship (LWR) was established for females (W=0.00166359 ×TL2.0767), males (W=0.00019587×TL2.5651), and all individuals (W=0.00037111 ×TL2.4162). Exponential values "b" for LWR were 2.0767 (r2=0.993), 2.5651 (r2=0.986), and 2.4162 (r2=0.987), respectively. The study compared traditional LWR approaches with artificial intelligence methods for growth analysis, suggesting the latter as a viable alternative in assessing freshwater crayfish growth in aquatic systems.

A Study of Length-Weight, Relationship and Condition Factor of Bagrus Bayad in Kiri Reservoir Shelleng Local Government Area Adamawa State, Nigeria

The Bagrid fishes are commonly known as naked catfishes, they are commercially important species found in Nigeria fresh waters especially in Rivers and Lakes such as Niger, Kaduna, Benue, Lake Chad, and other inland waters. The study is aimed at investigating the length- weight, relationship and condition factor of Bagrus bayad. A total of 282 individuals of B. bayad were randomly sampled for a period of 6 months. B. bayad sample collected were dissected. All the data collected were subjected to one-way analysis of variance (ANOVA). Descriptive statistic, regression analysis, graph (bar chart) mean and standard deviation were used in calculating the data for analysis. Result from the data analysis showed the slope (b) value for male = 1.996 which is less than 3.0, hence the male fish shows a negative allometric growth pattern. While that of the female showed that the b value was 3.2971 which is positive allometric growth pattern and the combined sexes analysis shows that b = 2.330, which indicated a negative allometric growth pattern. The condition factors showed that the Male has K = 2.893, Female has K = 3.122 and the Combined Sexes Condition factor is K = 3.002. B. bayad exhibited both negative and positive allometric growth pattern with a strong positive correlation between the total length and weight of the species and also the species are in good physiological condition in the Reservoir.

Population dynamics of the data-poor tiger shark (Galeocerdo cuvier) in the Northwest Pacific Ocean: Measurement of growth parameters and mortality rates

Although tiger sharks (Galeocerdo cuvier) are found globally in major oceans, comprehensive biological and fishery data pertaining to the Northwest Pacific Ocean are scarce. Accordingly, this study was conducted to understand the challenges in measuring tiger sharks’key life history parameters, including von Bertalanffy growth and mortality rates, which are essential for the construction of robust stock assessment models. To evaluate these parameters, we used the TropFishR software package to analyse observer-recorded length-frequency data acquired from the Nanfangao fish market between January 2015 and December 2022. An electronic length-frequency analysis indicated that the asymptotic length and growth coefficient derived for the combined sexes of the tiger shark population were 366.087 FL cm and 0.245 year−1, respectively. Mortality rates were calculated using a length-converted catch curve and empirical models; the results revealed that the annual rates of total (Z), natural (M), and fishing (F) mortalities were 0.346, 0.168, and 0.178 year−1, respectively. Notably, the observed exploitation rate (E) was slightly high at 0.514 year−1. Our findings may facilitate the development of effective strategies for preserving the tiger shark population in the study region by leveraging this initial information for further stock assessment analyses, thereby enabling a more comprehensive evaluation in the future.

Age and growth of the blue shark Prionace glauca (Linnaeus, 1758) in the Ecuadorian Pacific: Bayesian multi-models.

The blue shark Prionace glauca plays a critical role as a predator in marine ecosystems but is threatened by by-catch. To obtain more precise biological data, a Bayesian approach was used, and 536 vertebrae samples collected during 1 year at the landing stage called "Playita Mía" Manta, Ecuador, were analysed. The objective was to estimate the age and growth parameters of the species. The size of the specimens varied between 116 and 310 cm in total length (TL). Using a Bayesian approach based on the Markov Chain Monte Carlo (MCMC) method, growth parameters were evaluated. The von Bertalanffy model was the one that best fitted the data and provided more adequate estimates (females: = 325.50 cm, = 53.23 cm, and k = 0.12 years; males: = 331.47 cm, = 51.59 cm, k = 0.12 years -1; combined sexes: = 329.65 cm, = 53.64 cm, k = 0.11 year-1). The results indicated that females and males have a similar growth, and that the species has a slow growth. Further studies using multi-model Bayesian approaches and covering a broader range of sizes in the Pacific Ocean are suggested. These studies will provide crucial information for the management and conservation of this species.

Pericardial Diseases Mortality Trends in Brazil From 2000 to 2022.

Background Pericardial diseases manifest in various clinical forms, including acute pericarditis, constrictive pericarditis, pericardial effusion, and cardiac tamponade, with acute pericarditis being the most prevalent. These conditions significantly contribute to mortality rates. Therefore, this article aimed to analyze mortality trends in the Brazilian population based on age and sex, shedding light on the impact of pericardial diseases on public health outcomes. Methods This is a retrospective time-series analysis of pericardial disease mortality rates in Brazil (2000-2022). Data was obtained from the Department of Informatics of the Unified Health System (DATASUS), and the 10th edition of the International Classification of Diseases (ICD-10) codes: I30, I31, and I32 were included for analysis. We gathered population and demographic data categorized by age range and sex from the Brazilian Institute of Geography and Statistics (IBGE). Subsequently, we computed the age-standardized mortality rate per 100,000 individuals and assessed the annual percentage changes (APCs) and average annual percentage changes (AAPCs) using joinpoint regression, along with their corresponding 95% confidence intervals (CIs). Results In terms of mortality trends based on sex, overall mortality rates remained stable for males and combined sexes over the study period. However, there was a notable increase in mortality rates among females (AAPC=1.18), particularly between 2020 and 2022, with a significant APC of 27.55. Analyzing pericardial diseases across different age groups (20 to 80 years and above), it wasobserved that mortality rates significantly increased in the 70-79 and 80 years and above age groups throughout the study period (AAPC=1.0339 and AAPC=3.4587, respectively). These two age groups experienced the highest significant rise in mortality between 2020 and 2022. Other age groups did not exhibit a significant change in AAPC. Conclusions This comprehensive analysis spanning two decades (2000-2022), examined the mortality trends of pericardial diseases in Brazil and revealed relative stability overall. Males exhibited an overall higher mortality number due to pericardial diseases; however, females showed the most significant increase in mortality trend throughout the whole period. In the first segment (2000-2015), mortality rose across all cohorts, which was attributed to substandard healthcare facilities and infectious diseases like tuberculosis. The second segment (2016-2020) saw a decline in mortality, likely due to improved healthcare, particularly the increased availability of echocardiograms. However, the third segment (2020-2022) witnessed a sharp rise in mortality, coinciding with the COVID-19 pandemic, with post-COVID-19 symptoms, particularly pericarditis. Pericarditis-related death rates declined compared to pericardial effusion, and mortality rates correlated directly with age, with older cohorts experiencing higher mortality due to increased comorbidities, and decline in health and immunocompetency.

Age and growth of the crocodile shark, Pseudocarcharias kamoharai, in the Eastern Tropical Pacific Ocean

ABSTRACT The age, growth, and longevity parameters of crocodile shark, Pseudocarcharias kamoharai, from Santa Rosa, Ecuador were estimated. A number of 328 organisms were analyzed, 158 females (69 to 117 cm total length, TL) and 170 males (72.5 to 110 cm TL). The relationship between the vertebra's radius and TL was moderate (r2 = 0.63), indicating a relation between structure growth and the organism's size. Females were four to 14 years old and males were four to 12 years. The multimodal approach determined that the suitable equations were: The Von Bertalanffy growth function model with a fixed L0 (45.5 cm TL), VBGM2P (L∞ = 118.4 cm cm TL, k = 0.15) for combined sexes with a weight of evidence (Wi) to its favour of 43.9%; logistic growth model (L∞ = 109.5 cm TL, k = 0.41, L0 = 33.1 cm TL) for females with Wi = 28.4% and VBGM2P (L∞ = 110.4 cm TL, k = 0.16) for males with a Wi = 39.4%. No model obtained a sufficient evidence to be declared the best adjusted. The calculated longevities were 18 years for combined sexes, 16 for females, and 14 for males.

Preliminary life history of the Critically Endangered bottlenose wedgefish Rhynchobatus australiae from Southeast Asia

The bottlenose wedgefish Rhynchobatus australiae has experienced substantial population declines throughout its range. However, there is a lack of life history information (age, growth, and maturity) available for this species to inform conservation and management efforts. A total of 48 R. australiae samples were purchased from 2 fishing ports in Singapore between July 2018-July 2019. Species identification was confirmed by mtDNA barcoding using the NADH2 region. Length of specimens ranged from 506-1645 mm total length (TL), and ages ranged from 0-11 yr. Multi-model analysis was used to estimate growth parameters using a Bayesian approach with informative priors. The von Bertalanffy model was the best fitting growth model for the combined sexes (L∞ = 2814 mm TL; L0 = 517 mm TL; k = 0.07 yr-1), for females only (L∞ = 3053 mm TL; L0 = 504 mm TL; k = 0.06 yr-1), and for males only (L∞ = 2741 mm TL; L0 = 497 mm TL; k = 0.07 yr-1). Preliminary results indicate that females and males may mature at different ages and lengths, with females (A50 = 3.25 yr; L50 = 1014 mm TL) matured younger and at smaller sizes, than males (A50 = 5.03 yr; L50 = 1197 mm TL). R. australiae has an estimated theoretical longevity of 40 and 47 yr for males and females, respectively. This study provides the first preliminary species-specific life history information for R. australiae, suggesting that this species in Southeast Asian waters is slow-growing. This information will further the biological knowledge available for this species and can be used to help design effective management and conservation measures.

Biological and growth parameters of Plotosus lineatus in the Mediterranean Sea.

This study examined the age distribution and growth characteristics of the striped eel catfish (Plotosus lineatus), which is an invasive alien species in the eastern Mediterranean. A total of 1,011 samples were collected from Iskenderun Bay (Turkey), with lengths ranging from 5.1 to 16.8 cm, predominantly comprising females (1:1.92). Age 3 represented the majority in the population (52.03%). The value of the scaling exponent "b" of the length-weight relationship was less than "3" for both sexes (females: 2.28; males: 2.26; combined: 2.27). The results for the von Bertalanffy growth parameters were observed for the combined sexes as, L∞ = 24.9934 cm, k = 0.1718 year-1, and t₀ = -1.7707 years. The striped eel catfish populations in Iskenderun Bay exhibited negative allometric growth patterns and were predominantly composed of adult individuals. This study presents the dataset on the length-weight correlations, age-growth characteristics, and von Bertalanffy growth parameters of Plotosus lineatus in the Mediterranean Sea, thereby significantly contributing to comprehending the stock dynamics. It is anticipated that this study will make a significant contribution to the management of P. lineatus stocks, given its invasive nature.

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.

Measurement of the Growth of the Main Commercial Rays (Raja clavata, Raja brachyura, Torpedo marmorata, Dipturus oxyrinchus) in European Waters Using Intercalibration Methods.

The intercalibration of age readings represents a crucial step in the ageing procedure; the use of different sampling methods, structures, preparation techniques, and ageing criteria can significantly affect age and growth data. This study evaluated the precision and accuracy of ageing for the most important North Atlantic (NA) and Mediterranean (M) ray species, Raja clavata, Raja brachyura, Torpedo marmorata, and Dipturus oxyrinchus, through exchange exercises carried out by readers from different laboratories. In addition, growth parameters were estimated from the obtained data. A total of 663 individual batoids were analysed. R. clavata and R. brachyura samples were obtained from both the NA and the M, while vertebral centra of T. marmorata and D. oxyrinchus were only available for the M. High reading variability was observed for all four evaluated species in terms of CV, APE, and PA. D. oxyrinchus and T. marmorata showed relatively slow growth and the von Bertalanffy model with fixed t0 and Gompertz's model were, respectively, the most precise models for each of these species. In R. brachyura, females had a faster growth rate compared to combined sexes. The vbt0p proved the most precise model for describing growth in this species, and no statistical differences were found between the NO and the M. For R. clavata, the best-fitting model was the vbt0p for females and males in the NO and for females from the M, while the best-fitting model for males from the M and sexes combined for both areas was log.p. Distinct growth patterns were observed between the two study areas.

Assessment of Length-weight Relationship, Sex Ratio, Condition Factor and Socioeconomic Values of Nile tilapia in Lake Hawassa

The length – weight relationship, condition factor and sex ratio in Lake Hawassa were evaluated over a period of seven weeks from May to June 2019. The growth coefficient ‘b’ obtained for male, female and combined sexes were 3.17, 3.17 and 3.19 respectively. The ‘b’ value differed significantly (p<0.05) from the value of ‘3’ for all the male, female and combined sexes, indicating a positive allometric growth. The condition factors ‘K’ for male, female and combined sex were 0.97, 1 and 0.94 respectively. There was a significant difference in condition factor between the male, female and combined sexes (ANOVA, p< 0.001). The sex ratio of male and female O. niloticus significantly different (χ2 = 5.78, p< 0.05) from the expected 1:1 ratio. The study conducted to reveal the potential of Nile tilapia to produce fishmeal showed that at least 15.12% of Nile tilapia fish which otherwise would have been discarded as a waste product have the potential to become a fishmeal, such that Lake Hawassa has the potential to produce 27.66 tons of fish meal from annual catch of 182.94 tons of Nile tilapia. The impact of socioeconomic values of Nile tilapia both on fishermen and consumers have been shown as the livelihood of 88% of the fishermen respondents is based on fishery activity with no other source of income with nearly two thirds of the respondents have a monthly income between 1000 to 2000 birr and annual median income of 18,000 birr. This study also revealed that 90% of the fishermen respondents have been given awareness or training that improves their fishing practices. More than three quarter of the fishermen agreed that the long distance of fish markets from residential areas have reduced the accessibility of the fish resource to the consumers. And also there is strong statistical evidence that supports unhygienic fish processing practices contributed more to the problems and constraints of the socioeconomic values of Nile tilapia. On the other hand consumers’ spending capacity depends on their monthly income and also consumers’ consumption habit depends on factors like the cost of fish, proximity of the fish market and buying power. Further research needs to be undertaken to address some of the problems facing the fishery activity such as lack of proper fish processing, storage and marketing facilities.

First report on population dynamics and stock status of Badis badis in a wetland ecosystem (NW Bangladesh): Insights from new recorded maximum length

Badis badis (Hamilton, 1822) is a popular ornamental fish species in the world. This study provides valuable insights into some biological indices of B. badis using a sample of 293 individuals. These individuals were captured from June 2021 to May 2022 using several traditional fish harvesting gears and traps in the Babu Mondoler beel, a wetland ecosystem in NW Bangladesh. Biometric data were collected for each individual, contributing to a comprehensive understanding of this species. The recorded results revealed a wide range of total length (TL), varying from 2.30 to 11.33 cm. Notably, we observed a maximum length of 11.33 cm TL and a maximum body weight (BW) of 18.18 g, ranging from 0.20 to 18.18 g, setting a new record and showcasing the diversity in size within the population. The estimated allometric coefficient (b) showed that combined sexes had negative allometric growth (b = 2.67). Growth parameters were assessed as L∞ = 11.93 cm, K = 0.95 year−1 and Ø′ = 2.13. The tmax was 3.16 years. The Lm was measured at 7.02 cm TL and tm = 0.89 year. In this study, KF (1.4240 ± 0.3194) was best for the wellbeing of B. badis in the study area. The a3.0 was estimated at 0.0079 and the relative weight WR (100.90 ± 16.994). Physiological status showed that maximum fatty fish were observed at 10.00–12.00 cm TL; lowest at 4.0–6.00 cm TL. Moreover, the Z, Mw, F and E were estimated to be 3.29 year−1, 1.45 year−1, 1.84 year−1and 0.56, respectively. Additionally, the Lopt for this species was found to be 7.91 cm TL. The findings from this study hold great potential for enhancing the assessment and management of the specimen in the study area and its ecological community. These valuable insights into the population parameters, growth patterns, and exploitation rates of B. badis can inform future management strategies, ensuring the sustainable utilization of this fishery resource in Bangladesh and others neighboring countries.

Morphological features and length-weight relationships of <i>Sarotherodon galilaeus</i> from Oyan Lake, Southwestern Nigeria

Oyan Lake is one of the major sources of fish protein supply to many parts of Southwestern Nigeria. Investigation was conducted on the biometrics, length-weight relationship and condition factor of Sarotherodon galilaeus in Oyan Lake. Fish samples were obtained from fishermen using gillnets, hook and line, cast nets and traps. One hundred and thirty samples of S. galilaeus were collected for the study, comprising eighty-three (83) males and forty-seven (47) females with sex ratio of 1:0.57 (male:female). The mean total lengths for combined sexes, males and females were 15.5±0.15, 15.7±0.19 and 15.3±0.26cm while the mean total weights were 81.0±2.78, 83.8±0.56 and 75.9±4.70g, respectively. No significant difference (p>0.05) was observed between mean total lengths of males and females. However, mean weight of males was significantly higher (p<0.05) than females. Mean eye diameter (EYD) and length of caudal peduncle (LCP) were significantly higher (p<0.05) in females. The range of number of pectoral rays (PRA) (12-14), number of pelvic rays (PVR) (4-5), number of anal spines (ANS) (2-3) and number of pelvic spines (PEVS) (1, no range) were the same in both sexes. There was strong correlation between weight/total length (r=0.93) and total length/length of dorsal fin base (r=0.72), while there was no correlation between body depth/head length. The mean condition factor (k) were 2.07±0.02 (combined sexes), 2.08±0.03 (males) and 2.03±0.03 (females). Growth was isometric for both sexes: males, 3.24 and females, 3.06. The results suggested that Oyan Lake is suitable for S. galilaeus.