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)

2023-10-06T10:33:13+07:00

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)

2023-10-05T13:32:42+07:00

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)

2023-10-25T14:00:50+07:00

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

2023-12-04T14:37:22+07:00

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

2023-11-07T18:09:08+07:00

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.

Effect of Different Diets on Productivity and Biochemical Values of Rainbow Trout Eggs (Oncorhynchus mykiss Walbaum, 1972)

2023-10-17T11:44:18+07:00

The nutritional status of broodstock is an important determinant of egg quality and fry viability in fish species. This study investigated the effects of different broodstock diets on egg productivity and quality in rainbow trout (Oncorhynchus mykiss). Rainbow trout broodstocks (average initial weight 731.25±0.39 g) were fed one of three diets for 75 days: two commercial rainbow trout diets with different protein and fat contents (C and F1 groups), and a semi-wet diet composed of a mixture of trout fry feed and fresh horse mackerel (F2 group). At the end of the study, the C group showed the highest specific growth rate and feeding day growth coefficient values. There were no significant differences in absolute and relative egg production between the dietary groups (p>0.05). However, diet did impact egg nutritional composition and color. The C group eggs had higher levels of omeg-3 and omeg-9 fatty acids, while omeg-6 fatty acids were highest in the F1 group eggs. Total amino acid content, including aromatic, branched-chain and essential amino acids, was highest in the F2 group eggs. The C group eggs also displayed greater chroma, yellowness, and redness compared to the F1 and F2 eggs (p<0.05). In summary, while egg output was similar between rainbow trout broodstock dietary groups, the amino acid profiles and lipid profiles of the eggs differed by diet. Specifically, the Ʃomega-3 PUFA, DHA and Ʃomega-3/ Ʃomega-6 ratios in feeds impacted measures of egg quality like color and nutritional value. These findings highlight the importance of broodstock nutrition in determining the composition and quality of rainbow trout eggs.

Taxonomic Status, Length-Weight Relationship and Condition Factor of Channa stewartii (Playfair, 1867) in Morigaon District, Assam, India

2023-07-26T22:09:55+07:00

The Assamese snake-head fish, Channa stewartii (Playfair, 1867) is endemic to the Brahmaputra River Basin (upper, middle, and lower) in India and Bangladesh, as well as the Ganges River basin extending from southern Nepal south-eastward. This study aimed to examine the taxonomic status and the length-weight relationship and condition factor of C. stewartii populations from a newly found community in Assam, Morigaon district, India. Taxonomic assessment involves morphological examination and comparison with existing literature to confirm the species identity. The morphological observation clearly indicated that C. stewartii specimens were distinguished by their blue fins with black patches, red fin edges, and reddish-pink pectoral fins. The female fishes have slightly duller, yellowish colours than the males, although they still have brighter colours than the males. Phylogenetic analyses also showed that our recent collection was clustered with C. stewartii from Assam, India. Measurements of C. stewartii length-weight relationship exhibited that both male (b = 3.389) and female (b = 3.396) showed a positive allometric growth. Additionally, the condition factor (K) for both sexes exceeded 1, indicating the well-being and health of the fish in their habitat. The findings contribute to the understanding of the ecological characteristics and population dynamics of C. stewartii in Morigaon district, providing valuable information’s for fisheries management and conservation efforts in the region.

Effect of Iron Nanoparticles on the Intestinal Bacterial Flora and Histology of the Intestine and Kidney in Stellate Sturgeon (Acipenser stellatus Pallas, 1771)

2023-12-11T17:01:31+07:00

Regarding the important role of iron in the physiological process in fish bodies and the presence of iron nanoparticles (Fe-NPS) in the aquatic environment, this study was designed to evaluate the effects of Fe-NPS on the intestinal bacterial flora and histology of the intestine and kidney in a stellate sturgeon (Acipenser stellatus Pallas, 1771). Juvenile stellate sturgeon, averaging 182.09±9.05 g, were fed with diets containing varying doses of Fe-NPs: 0 (T0), 25 (T1), 50 (T2), and 100 (T3) mg per kg of food for 60 days. Based on the glucose and cortisol levels in different treatments, it seems that the best dose of Fe-NPs for stellate sturgeon was 50 mg·kg^-1 food (T2) under experimental conditions. The most important histological changes observed in the intestine were the shortening of the intestinal villi, a high number of mucus-secreting cells, and mucosal secretions within the intestinal tract. These changes in the kidney were shrinkage of renal glomeruli, increasing Bowman’s capsule space, mild degeneration of renal tubules, and infiltration of white blood cells into the kidney tissue. The most effective dose of Fe-NPs was 50 mg·kg^-1 Fe-NPs with a less negative effect on fish intestine and kidney histology. Fe-NPs led to a significant increase in the mean total count of aerobic bacteria and lactic acid bacteria. Generally, the fish food supplemented with 50 mg·kg^-1 Fe-NPs led to the least stress and histological damage in the kidney and intestine and the highest number of intestinal bacterial flora in the stellate sturgeon.

Acute Toxicity of DDT on Embryo and Larval Growth of the Pacific Oyster, Crassostrea gigas (Thunberg, 1793): A Case Study in the Saigon–Dongnai River, Vietnam

2023-12-11T17:00:41+07:00

Dichloro-Diphenyl-Trichloroethane (DDTs) are potent organic toxins widely used in agriculture and malaria prevention. The extensive use of DDTs has raised concerns about their adverse impacts. This study aimed to evaluate the toxicity of DDTs on Pacific oyster (Crassostrea gigas) larvae and embryos in the lower Sai Gon-Dong Nai River. We exposed oyster larvae and embryos to sediment samples containing DDT concentrations of 0.01, 0.05, 0.1, 0.5, and 1 mgּּ·kg^-1, as well as artificial seawater samples with DDT levels of 0, 0.1, 1, 10, and 100 µg·L^-1. The analysis results revealed a significant adverse impact of DDTs on the survival ratio of larvae and the cell division of embryos in both water and sediment samples compared to control samples. The Effective Concentrations in embryo cell division capacity (EC₅₀) after 2 and 24 h of exposure were 66.88 and 4.62 µg·L^-1 in artificial seawater and 1.1 and 0.3 mg·kg^-1 in sediment, respectively. Lethal Concentrations (LC₅₀) were 4.62 µg·L^-1 and 0.3 mg·kg^-1, respectively. Transmission Electron Microscopy (TEM) and Scanning Electron Microscope (SEM) images further confirmed the significant morphological disruptions caused by DDTs after 24 h of exposure. These findings indicate that DDT toxicity poses a threat to oyster farming in coastal areas, where chronic pesticide exposure is likely.

Utilizing Hydroacoustic Method to Assess Small Pelagic Fish Distribution in Cenderawasih Bay, Indonesia

2023-12-29T06:50:41+07:00

Cenderawasih Bay is one of the territorial waters of Indonesia with high fishery potential. In 2022, the Indonesian Goverment revealed that the bay's small pelagic fishery potential reached 135,140 t, yet the utilization rate remains at only 0.3, indicating underutilization. This shows the necessity of estimating fish distribution in the bay to maximize the use of small pelagic fisheries resources. The hydroacoustic method, known for its extensive survey coverage and minimal environmental impact, can be employed to estimate the distribution of small pelagic fish. Therfore, this research aims to investigate the distribution of acoustic parameters of small pelagic fish using a split beam echosounder, specifically the SIMRAD EY-60, to obtain fish SV value and distribution data. SV (Scattering Volume) values were coverted to TS (Target Strength) values and projected onto a spatial distribution map. The distribution of fish exhibited a varied range of values, with the highest SV value ranging from -59.7 to -57.4 dB and the highest TS values ranging from -59.4 to -46.7 dB. Fish distribution was more concentrated in areas with warmer temperatures and dispersed evenly across different salinity ranges, with a higher concentration of fish detected in areas with elevated chlorophyll levels.

First Record of Two Species of Engraulids, Thrissina gautamiensis Babu Rao, 1971 and Stolephorus tamilensis Gangan, Pavan-Kumar, Jahageerdar and Jaiswar, 2020 (Engraulidae: Clupeiformes) from the West Coast of India

2023-10-25T13:51:22+07:00

The coastal regions of India, encompassing the Bay of Bengal to the east and the Arabian Sea to the west within the northern Indian Ocean, host diverse marine ecosystems. This study focuses on fish specimens collected during a survey conducted in Goa, situated along the western coast of India. Morphological examination of the collected samples revealed the presence of two anchovy species, Thrissina gautamiensis Babu Rao, 1971 and Stolephorus tamilensis Gangan, Pavan-Kumar, Jahageerdar and Jaiswar, 2020, marking their inaugural documentation on the western coast of India. Distinguishing characteristics such as the termination of the maxilla before the base of the pectoral fin, a body depth comprising 23–28% of the standard length, presence of enlarged teeth in both upper and lower jaws, as well as the counts of gill rakers and anal fin rays, were utilized to differentiate T. gautamiensis from its congeners. Conversely, diagnostic traits including a concave pre-opercular margin, the absence of a pre-dorsal spine and a double-pigmented line posterior to the dorsal fin, as well as the lack of scattered melanophores between the dorsal fin and caudal peduncles, along with gill raker counts, were employed to confirm the identification of S. tamilensis. Comparative analysis of the morphological features of the examined specimens with those of the holotypes of both species further corroborated their taxonomic assignments. This discovery underscores the need for comprehensive investigations into the diversity, distribution, and ecological dynamics of small pelagic species inhabiting Indian waters.

Heavy Metal Accumulation in Lake Sediments in the Impact Zone of Trout Cage Farm

2024-02-01T11:40:09+07:00

Chemical residues from aquaculture, especially heavy metals, are harmful to environment. The present study assessed the seasonal dynamics and potential toxic effects of heavy metal accumulation (Cr, Cu, Zn, and Pb) in lake sediments within the impact zone of the trout cage farm (Lake Ladoga, Russia). The tasks included the layer-by-layer analysis of total content of the heavy metals and their labile forms in sediment cores collected in the winter and autumn seasons. Four sites located directly next to the cages and three reference sites (150, 600 and 1000 m from the farm) were studied. Sediments cores collected using gravity corer were analyzed for total content analysis, where sediment samples were decomposed with strong acids (HClO₄, HF, HCl, and HNO₃), and the labile forms were extracted by ammonium acetate. The results showed that sediments under fish cages were significantly polluted by Zn and Cu especially towards the end of the active feeding period (autumn), thus potentially increasing sediment toxicity. Therefore, Zn and Cu can be utilized as geochemical markers for assessing the thickness of the accumulated contaminated sediment layer in the impact zone of cage farms. Pollution of the sediments by heavy metals is local and limited to the studied bay. Hence, there is no risk of secondary pollution of the water column according to the RAC index. However, the absolute content (mg·kg^-1) of labile Zn is much higher under the cage than at reference sites.

Assessing Environmental Factors for Seagrass Transplantation Site Suitability in Thailand

2024-02-09T15:51:37+07:00

This study aims to identify the environmental factors influencing seagrass distribution, with the aim of evaluating the suitability of an area for seagrass growth. Upon determining factor values, we assessed the accuracy of the methods used to ensure the reliability of those values for proposed seagrass restoration sites. R programming and structured interviews were used to identify relevant factors, while a Geographic Information System (GIS) was utilized to pinpoint six suitable seagrass transplantation sites in the Gulf of Thailand and another six in the Andaman Sea. The selection of factors to evaluate the suitability of sites for seagrass transplantation included the presence of natural barriers that mitigate storm surges and diminish wave energy, their proximity to seagrass beds, shore elevation above the lowest low water mark, extent of seagrass coverage, sediment grain size, and organic matter content. The Simple Additive Weighting (SAW) method proved effective in identifying potentially suitable seagrass habitats. The overall accuracy of the suitability maps for seagrass transplantation ranged from 60.0% to 93.3%. Notably, high-suitable and very high-suitable sites for seagrass transplantation were identified in Phangan Island’s Nai Wok Bay (81%), Thalen Bay - zone 3 (75%), Na Tham Bay at Samui Island (62%), and Tan Island - east side (55%), respectively. Our findings underscore that identifying areas and the specific types of habitats suitable for seagrass restoration can significantly inform decision-making and facilitate the implementation of actions aimed at restoring seagrass ecosystems.

Replacement of Fish Meal with a Combination of Fermented Fish and Soybean Meal in the Diet of Juvenile Asian Seabass, Lates calcarifer (Bloch, 1790)

2023-09-13T05:02:26+07:00

Fish meal is commonly used as a protein source in fish feeds due to its high protein content. However, the supply of fish meal is becoming uncertain due to decreased stocks caused by climate change and overexploitation. Consequently, researchers are exploring less expensive alternatives to replace fish meal in fish feeds. This experiment aimed to determine the effects of replacing fish meal with a combination of soybean meal (SBM) and fermented fish (FF) in the diet on the growth performance and feed utilization of juvenile Asian seabass (Lates calcarifer Bloch, 1790). Six isonitrogenous (40%) and isolipidic (5%) experimental diets were formulated. Fish meal was replaced with 0% and 10% of SBM in diet 1 (D1) and diet 2 (D2), respectively. In the other four diets, FM was replaced by gradual levels of SBM and FF as follows (%SBM/%FF): 20/10, 20/20, 30/10, and 30/20 (designated as diet 3-diet 6; D3-D6). A commercial feed was used as a comparative diet (D7). Fish, with an initial weight of 3.32–3.33 g, were fed twice daily until satiation for 90 days. The final body weight (FBW), specific growth rate (SGR), and feed intake (FI) of fish fed D1 were significantly difference (p<0.05) but did not significantly differ from those of fish fed D2 and D3. Similarly, the FBW, SGR, and FI of fish fed D3 were not significantly different from those of fish fed D7. In conclusion, fish meal can be replaced by a combination of 20% SBM and 10% FF in the diet for juvenile Asian seabass without any adverse effects on growth performance, body indices and feed utilization.

Temporal Changes in Zooplankton Community Composition and Abundance in Chemical and Organic Rice Fields in Buri Ram Province, Thailand

2023-12-27T23:37:51+07:00

Rice fields present a unique ecosystem characterized by seasonal fluctuations in soil, water conditions, rice growth, and associated organisms including algae and invertebrates. This study analyzed zooplankton diversity and abundance patterns between organic and conventional chemical rice fields over a growing season in a paddy field site in Buri Ram Province, Thailand. The aim of this study is to compare differences in zooplankton community structure based on cultivation method and temporal changes along a growing season. Environmental parameters and zooplankton samples were collected from adjacent 3 organic and 3 chemical rice fields between September and November 2019. A total of 67 zooplankton taxa encompassing 3 major groups were identified (55 rotifers, 8 cladocerans, and 4 copepod larval stages). Overall, zooplankton abundance showed no significant differences between organic and chemical rice fields. However, organic fields exhibited higher Shannon-Weiner diversity and supported more zooplankton taxa compared to chemical fields. Margalef species richness and Pielou evenness were similar between rice field types. In terms of temporal variability, zooplankton did not show statistically difference in overall mean abundance, but Shannon-Weiner diversity and evenness showed a slight drop in October when compared to September. Although total abundance was comparable, differences in zooplankton community composition and diversity metrics highlight distinctions between organic and conventional cultivation that may arise from contrasting agricultural practices.