Journal of Fisheries and Environment

Physicochemical Quality of the Water and Heavy Metal Contamination of the Sediment, Water, and Flesh of Some Fish in the Lower Reaches of the Mono River (Benin, West Africa)

Imaculé Schadrac Baglo — 2024-04-01

This study aimed to assess the physicochemical quality of the water and the heavy metal of the sediment, water, and flesh of two species of fish most commonly consumed by residents in the lower reaches of the Mono River. To this end, four stations (Ahossanou, Codjohoué, Athiémé, Grand-Popo) were selected and surveyed during high water (October to December 2021) and low water (January to March 2022) seasons to measure physicochemical parameters and examine the ichthyofauna in artisanal catches. Water samples were taken to measure the biological oxygen demand (BOD₅), nitrite and nitrate levels. Additionally, samples of sediment, water, and fish flesh were taken to analyze heavy metal concentrations (lead and cadmium). The BOD₅ concentrations exceeded 30 mg·L^-1, indicating poor water quality. All nitrite and nitrate levels were within acceptable limits (3.28 and 44.28 mg·L^-1, respectively). The potential ecological risk posed by sediment contamination ranged from low during high water to considerable during low water seasons. Measured lead and cadmium concentrations in the water exceeded permissible limits (0.05 and 0.005 mg·L^-1, respectively). Brycinus macrolepidotus and Chrysichthys nigrodigitatus were the most abundant fish species caught in the Mono River. While cadmium levels in the fish flesh were below the WHO/FAO standard (0.05 mg·kg^-1), lead concentrations exceeded the WHO/FAO standard (0.3 mg·kg^-1). The study concluded that consumption of fish from the lower Mono River poses health risks to local communities.

The Potential of Donkey’s Ear Abalone (Haliotis asinina Linnaeus, 1758) as an Antibacterial Agent and Its Effect on Blood Cholesterol Reduction in Mice (Mus musculus Linnaeus, 1758)

Alvinola Prisca Fatina — 2024-04-01

Donkey's ear abalone (Haliotis asinina Linnaeus, 1758) is rich in essential nutrients and harbors bioactive compounds with antibacterial properties, potentially aiding in cholesterol reduction. This study focused on assessing antibacterial activity against Staphylococcus aureus (ATCC25923) and Escherichia coli (ATCC25922), determining the amino acid composition, screening for bioactive phytochemical compounds, and evaluating the effect of abalone meat extract on blood cholesterol in male house mice (Mus musculus Linnaeus, 1758) using an in vivo method. Results indicated significant antibacterial activity of H. asinina methanol extract (20% concentration) against S. aureus, while ethyl acetate extract (10% and 20% concentrations) showed inhibition zones against both S. aureus and E. coli. The n-hexane extract demonstrated antibacterial activity at a 10% concentration on both organisms, and at a 20% concentration against S. aureus. Phytochemical screening revealed the presence of saponins and alkaloids in the methanol extract. Amino acid analysis identified arginine (7,827.15 mg·kg^-1) as the highest essential amino acid and glutamic acid (14,803.9 mg·kg^-1) as the highest non-essential amino acid. Moreover, the methanol extract significantly reduced cholesterol levels in male house mice across various doses (100, 200, and 300 mg·kg^-1).

Effect of Cannonball Mangrove Xylocapus granatum Koeing Bark Extract on Wound Healing in Siamese Fighting Fish (Betta splendens)

Surawat Chingjit — 2024-04-01

Presently, there is significant exploration of natural products as alternatives to chemical drugs, with the goal of mitigating adverse environmental impacts. This study investigates the wound-healing potential of Xylocarpus granatum bark extract in Siamese fighting fish, Betta splendens, a popular ornamental fish. The extract was prepared using the decoction method. Subsequently, the obtained extract was applied at concentrations of 60, 120, and 180 ppm to treat wounds in betta fish. These treatment groups were compared to a positive control group receiving 15 ppm oxytetracycline and a negative control group receiving no treatment over a 21-day period. The results revealed the fastest healing among groups treated with either 60 or 120 ppm of X. granatum bark extract. However, the 60 ppm concentration appeared more promising due to the highest survival rate (85.0±4.3%) among treated fish. Notably, neither the negative control nor positive control groups achieved complete wound healing within 21 days, and these groups had among the lowest survival rates. Regarding the healing effects on various tissue layers, muscle tissue healing was slower in the 60 ppm group compared to the 120 and 180 ppm groups. However, for connective tissue, dermis, epidermis and scale tissues, the 60 ppm treatment group demonstrated the fastest wound healing rates. Based on these findings, X. granatum bark extract shows potential as an effective wound healing agent for B. splendens, particularly at a concentration of 60 ppm. This natural product could offer benefits for the aquaculture industry and ornamental fish enthusiasts while mitigating environmental impacts.

An Ensemble Learning Technique for Predicting Mortality Rate in Red Tilapia (Oreochromis niloticus Linn.) Fingerlings

Roongparit Jongjaraunsuk — 2024-04-01

Aquaculture has witnessed a gradual transformation owing to advancement in automatic and intelligent technology. Coupled with the power of high-performance computers, these innovations have given rise to machine learning technologies capable of extracting valuable insights from data. Consequently, these technologies are poised to usher smart aquaculture into a new era of efficiency and productivity. This particular study focused on enhancing the predictive accuracy of mortality rates in red tilapia (Oreochromis niloticus Linn.) fingerlings raised in outdoor earthen ponds with a recirculating aquaculture system. To achieve this, the study leveraged a voting-based ensemble learning technique based on the combination of three single predictive algorithms: decision tree, deep learning, and naïve bayes (EL–V _(DT_–_DL_–_NB)). The initial phase of the research involved the compilation of a comprehensive dataset encompassing parameters were temperature (^°C), dissolved oxygen (mg·L^-1), pH, total ammonia nitrogen (mg·L^-1), nitrite–nitrogen (mg·L^-1), transparency (cm), and alkalinity (mg·L^-1) date, month and mortality rate (fish·day^-1). Following the collection and cleaning of the dataset, 173 samples with 12 attributes were used in this study. The outcomes of this investigation revealed that the performance of the individual predictive models was eclipsed by the proposed EL–V _(DT_–_DL_–_NB)model, boasting an impressive accuracy rate of 90.85%, precision of 84.00%, recall of 77.50%, and AUC of 0.896. These results affirm the potential utility of the proposed model for accurately forecasting the mortality rate of red tilapia fingerling in aquaculture settings, thereby contributing significantly to the optimization of aquaculture practices.

Assessing the Population Dynamics of Cirrhinus reba (Hamilton, 1822) in River Atrai, India, for its Conservation and Sustainability as Natural Stock

Monika Ghosh — 2024-04-01

Cirrhinus reba (Hamilton, 1822), commonly known as Reba carp, is an economically important freshwater species with high demand for its taste. It has been listed as vulnerable and near threatened species in India and Bangladesh, respectively. This study presents a pioneer assessment of the length-weight relationship and population dynamics of Reba carp using a length-based approach over a three-year period in the Indian part of the Atrai River. Fish specimens ranged from 50 to 237 mm in length and from 0.90 to 184.19 g in weight. Results indicate positive allometric growth, with a unimodal continuous recruitment pattern peaking between June and August. Population parameters, including asymptotic length (L∞ = 250.95 mm), growth coefficient (K = 0.44 year^-1), growth performance index ( = 4.442), length at first capture (L_c = 83.77 mm), and size at first sexual maturity (L_m = 110 mm), were computed. This study revealed a higher fishing mortality rate compared to natural mortality, with the mean current exploitation rate (E = 0.63) surpassing E_max = 0.541, and the highest exploitation rate observed in 2022. Consequently, the annual yield exceeded the Maximum Sustainable Yield limit, underscoring the urgent need to mitigate fishing pressure, especially during the breeding season, to promote stock replenishment and ensure sustainability.