Asian Journal of Fisheries and Aquatic Research
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Isolation and Characterisation of Indigenous Phosphate Solubilising Microbes and their Probiotic Potentials in Malawi Aquatic Ecosystems
No full textPhosphate solubilizing microbes (PSM) were isolated from the rhizosphere of different aquatic plants, water and benthic soils of aquatic ecosystem with the aim of having cheap and environmental friendly biofertiliser and probiotics. Extensive research has been performed with respect to PSM isolation from the rhizospheres of various plants in different locations, but little is known about the in-depth of PSM and their probiotic potential in Malawi aquatic ecosystem. Isolates were screened on the basis of solubilizing inorganic Phosphorous (P) using Pikovskaya’s media, soil and rock supplemented. Molecular characterization of the conserved genes (16S rRNA and 18S rRNA) and biochemical test were employed in taxonomic analysis. Candidacy of strains was primarily based solubilisation index of more than 3 complimented by production of diverse plant growth promoting, bioremediation and probiotic traits. The selected strains with commercial implications were identified as Alcaligenes ammonioxydans, Enterococcus faecium, Citrobacter braakii, Enterobacter cancerogenus, Geotrichum sp. and Aspergillus sibiricus. Isolates showed higher solubilisation values In-vitro through synergistic effect of co-inoculation. The present compilation of these diverse diazotrophs along with P solubilisation, probiotic and plant growth promoting traits potentially suggests that these indigenous microbes can be exploited as biofertilisers. The present study explores potentiality of indigenous microbe’s ability to solubilize insoluble phosphates like tricalcium, aluminium, and iron phosphate for development of biofertiliser
Investigating Total Petroleum Hydrocarbon (TPH) Level in the Gills, Tissues and Carapace of Blue Crab (Callinectes sapidus): A Study in the New Calabar River, Choba, Rivers State, Nigeria
No full textThis study investigated the total petroleum hydrocarbon (TPH) concentrations in the gills, tissues, and carapace of Callinectes sapidus collected from three stations (Choba, Rumualogu and Ozuoba) along the Choba axis of the New Calabar River. Results reveal distinct spatial and temporal patterns in TPH distribution. Spatially, gill TPH levels ranged from 4.3 to 4.6 mg/kg, showing no significant differences among stations (p > 0.05). Tissues exhibited slightly higher concentrations (5.6 to 5.8 mg/kg) with significant variation between specific stations (p < 0.05), while carapace concentrations were the highest (9.1 to 9.4 mg/kg) but also stable across locations (p > 0.05). These findings indicate that tissue concentrations may be more indicative of exposure levels. Comparisons with existing literature highlight variations in TPH levels among different marine organisms, with our results aligning with studies indicating lower concentrations in exoskeletal structures. Temporal analysis across June to August showed stable TPH levels (gills: 4.5 mg/kg; tissues: 5.7 mg/kg; carapace: 9.3 mg/kg) without significant monthly variation (p > 0.05). This consistency suggests that environmental conditions and TPH sources remained relatively unchanged during the study period. Overall, while gills and tissues remained within WHO recommended limits for safe consumption; caution is warranted regarding the carapace. Elevated levels may indicate potential bioaccumulation and associated ecological and health risks
Sustainability Assessment of Calamba Fisherfolks Producers Cooperative (CFPC) in Calamba City, Laguna, Philippines
No full textAims: To assess the sustainability of a cooperative, the Cooperative Fisherfolks Producers Cooperative (CFPC) in Calamba City, Laguna, Philippines.
Study Design: The study design was primarily qualitative utilizing United Nation- Food and Agriculture Organization’s (UN-FAO) sustainability assessment of food and agriculture systems (SAFA). The scientific community, policy makers, fisherfolks, industry players and other stakeholders will greatly benefit from this study by capturing the holistic way of analyzing a particular agri-fishery system. Thereby, highlighting the importance of scrutinizing each of the sustainability pillars- environment, economic, social and governance.
Place and Duration of Study: Specifically, data was collected from thirty (30) Calamba fishermen in July 2022 that served as the primary data source and is complemented by relevant secondary data analysis. The goal of the inquiry is to thoroughly assess the sustainability of CFPC from an environmental, economic, social and governance standpoint. It is in accordance with the standards specified in the SAFA framework.
Methodology: UN-FAO’s SAFA guidelines/tool addressing the sustainability pillars of: socio, economic, environmental and governance were employed to the CFPC’s management/ officers through interviews (using questionnaire) and focus group discussion (FGD). Along with these, were the consultations made with the cooperative officers, experts and the industry. Secondary data were also analyzed to support the responses made by the respondents.
Results: CFPC is vulnerable to typhoons and to fishkill due to the degrading quality of water in the Laguna Lake. The issues also included the unstable volume of production that resulted to net losses, especially during the lean season. Consequently, the study found a low to moderate sustainability score in terms of environmental integrity (41%) and economic resiliency (52%). On the other hand, the study found a moderate rating on good governance (73%) and social responsibility (76%) due to active government support, aid provided by the cooperative to its members, and gender equality.
Conclusion: The study found an overall sustainability level of 63% for CFPC, indicating a moderate performance for the sustainability pillars: economic, environment, social and governance. Hence, it is recommended to: establish impact and performance assessment within the CFPC, utilization of effective microorganism (EM)/ probiotics in Laguna de bay, product diversification and construction of inland hatchery for quality fry/fingerlings
Physicochemical and Heavy Metals Characteristics of Some Industrial Wastewaters in Minna, Niger State, Nigeria
No full textWastewater are polluted water from effluents of industries, anthropogenic and agricultural activities; which may contain toxic materials that are harmful to the environment. Most wastewater from industries flows into the water bodies, farmlands where food crops are cultivated for consumption. This study assessed the heavy metals and physicochemical components of some industrial wastewaters in Minna, Niger State, Nigeria. Wastewater samples were collected from gold mining and pharmaceutical company sites. The samples were analyzed using standard methods and procedures. The results showed the presence of heavy metals such as lead (Pb), zinc (Zn), Iron (Fe), Copper (Cu) and Cadmium (Cd) at different levels with Pb recording the highest concentration (2.58±0.00 and 1.08±0.00) in the industrial effluents. There were significant (p<0.05) difference in the monitored physicochemical parameters (temperature, turbidity, electrical conductivity, pH, biochemical oxygen demand, dissolved oxygen demand, nitrate and phosphate) in both effluents in different concentrations. The study revealed the need for post-treatment risk assessments on the spent materials from industries before disposal into the environment and immediate regulatory intervention is recommended
The Role of Salinity Gradient in Regulating Biomass Yield and Lipid Biosynthesis of Chlorella vulgaris for Biofunctional Feed
No full textSalinity is a pivotal abiotic factor influencing microalgal physiology, with direct implications for biomass productivity and biochemical composition. This study investigated the effects of four salinity gradients (25, 28, 31, and 34 ppt) on the growth performance, biomass yield, chlorophyll content, and lipid accumulation of Chlorella vulgaris under controlled laboratory conditions. Cultures were maintained for seven days in a completely randomized design with three replicates per treatment. Results revealed significant (p < 0.05) differences among treatments, with the highest cell density (110.5 × 10⁶ cells/mL), biomass yield (10.25 g), chlorophyll-a concentration (3.38 mg/L), and lipid content (43.07%) observed at 34 ppt, closely followed by 31 ppt. Increased salinity within this optimal range appeared to induce moderate osmotic stress, enhancing photosynthetic pigment synthesis and redirecting metabolic flux toward lipid biosynthesis without severely compromising growth. Water quality parameters remained within optimal limits across treatments, ensuring that salinity was the primary driver of observed physiological differences. The parallel enhancement of biomass quantity and lipid quality under higher salinity conditions underscores the potential of salinity modulation as a cost-effective strategy for improving the nutritional and commercial value of C. vulgaris biomass. These findings provide a robust foundation for the development of optimized cultivation protocols in aquaculture and biofunctional feed production, particularly in saline or brackish water systems, contributing to sustainable microalgal biotechnology and the circular bioeconomy. Future applications of this research could further enhance large-scale production techniques, offering a sustainable alternative feed source for aquaculture while reducing dependency on costly ingredients, such as fish oil
Embryonic Development and Early Larval Survival Rate of the False Mussel Mytilopsis adamsi at Different Salinity Levels
No full textThe false mussel (Mytilopsis adamsi) is an economically important bivalve species with significant potential for aquaculture development in tropical regions. Understanding the optimal environmental conditions for embryonic development is crucial for successful hatchery operations and species management. This study investigated the effects of salinity on embryonic development duration and early larval survival rate of M. adamsi to determine optimal conditions for reproduction and early larval development. Fertilized eggs were exposed to four salinity treatments (10, 20, 30, and 40 ppt) and monitored for 21 hours. Embryonic development was tracked from unfertilized egg stage (UE) through early larval stage L-3, recording developmental progression and timing. Early larval survival rates were assessed at 21 hours post-fertilization. Water quality parameters including temperature, pH, dissolved oxygen, and ammonia were monitored throughout the experiment. Significant differences in survival rates were observed among salinity treatments (p < 0.05). All salinity treatments demonstrated complete developmental progression with 100% advancement to L-3 stage by 21 hours post-fertilization. Early larval survival rate followed a quadratic relationship with salinity (R² = 0.8251), with peak performance at 30 ppt (77.36 ± 2.82%) and 20 ppt (76.19 ± 4.17%). Low salinity (10 ppt) resulted in delayed development but maintained moderate survival rate (71.05 ± 6.39%), while high salinity (40 ppt) achieved rapid initial development but exhibited the lowest survival rate (54.63 ± 1.62%). The optimal salinity range for M. adamsi embryonic development and early larval survival is 20-30 ppt. This range provides the best balance between developmental efficiency and reproductive success, making it ideal for aquaculture applications. Despite achieving complete morphological development across all treatments, developmental completion does not guarantee physiological fitness, as evidenced by significant survival rate variations between salinity treatments. The findings have important implications for hatchery management and understanding the species\u27 ecological distribution in estuarine environments
Community Structure of Macrozoobenthos as a Bioindicator of Water Quality in Situ Sipatahunan, West Java, Indonesia
No full textThis study aimed to determine the water quality of Situ Sipatahunan based on the macrozoobenthic community structure as a bioindicator. The research was conducted from May 19 to June 20, 2025, using a survey method with purposive sampling for data collection. The observational data were analyzed descriptively and comparatively. The results revealed 4 classes and 11 species of macrozoobenthos, with the highest abundance found in Pomacea canaliculata (49 ind/m²; 63%). Water quality status in Situ Sipatahunan, based on macrozoobenthos, was classified as lightly to moderately polluted. This was indicated by the evenness index values ranging from 0.53 to 0.80, suggesting that the population at each station was in an unstable to relatively stable condition, with overall moderate evenness of the macrozoobenthic community. The Family Biotic Index (FBI) ranged between 4.11 and 4.69, also indicating light to moderate pollution levels. Accordingly, Situ Sipatahunan can be categorized as being polluted by certain organic materials.patients. These predictors, however, need further work to validate reliability
Nutritional Precision in Aquaculture: Tailoring Threonine Intake to the Growth and Health Needs of Fish
No full textThreonine, an essential amino acid, plays a vital role in promoting growth, maintaining health, and enhancing the overall performance of fish in aquaculture. Different fish species require varying amounts of threonine due to their unique physiological and metabolic characteristics. An adequate supply of threonine is necessary for protein, mucin, and antibody synthesis that are key components that support growth and immune response. This amino acid also contributes to intestinal integrity, improves nutrient absorption, and helps reduce oxidative stress. Determining the precise threonine needs of each fish species is important for achieving better growth rates, efficient feed utilization, and stronger disease resistance. A deficiency in threonine can result in stunted growth, poor fillet quality, and higher vulnerability to infections. Therefore, incorporating the correct threonine levels in formulated diets is essential for enhancing fish productivity and sustaining aquaculture operations. Species-specific dietary formulations that meet threonine requirements can significantly improve fish production efficiency and contribute to long-term food security
Organo-somatic Index and Condition Factor of Clarias gariepinus (Burchell, 1822) Sub-adult Exposed to Sub-lethal Concentrations of Gold Crew Oil Spill Dispersant
No full textOrganosomatic index and condition factor of fish is one way to assess the general health of fish and monitor the influence of environmental factors on fish. The organosomatic index and condition factor of Clarias gariepinus exposed to sub-lethal concentration (0.0ml/L (control), 0.075ml/l, 0.15ml/L, 0.3ml/L and 0.6ml/L) of gold crew oil spill dispersant was conducted over a two-week period. Ten fish (three replicates) were kept in a static renewal state for two weeks in a row and the liver, spleen, heart, gonad and viscera were excised on a weekly basis and weighed using a digital weighing scale, before the excision of the organs the fishes were first weighed and the length taken in cm. Physical and chemical parameters of the test medium was also conducted in-situ using a multi-parameter checker (Extech DO 700).Results for physicochemical variables revealed values for; temperature; week 1; 28.30°C (0.15ml/L ) - 27.20°C(0.0ml/L), week 2; 26.00°C (0.0ml/L,0.075ml/ and 0.3ml/L) -25.67°C (0.15ml/L and 0.6ml/L) , pH; week 1 ; 4.82(0.15ml/L) -4.06 (0.0ml/L), week 2: 7.38 (0.0ml/L) -5.94 (0.6ml/L), DO; week 1: 6.12mg/l(0.0ml/L) -5.00mg/l (0.15ml/L, 0.3ml/L and 0.6ml/L), week 2: 6.01mg/l (0.0ml/L) – 4.93mg/l (0.3ml/L), TDS: week 1 89.00mg/l(0.6ml/L)-154.00mg/l(0.3ml/L), EC: week 1: 188.33 µs/cm (0.6ml/L) - 166.33 µs/cm (0.0ml/L), week 2: 357.67 µs/cm (0.0ml/L) - 238.67 µs/cm (0.075ml/L). Results for organosomatic index revealed values for; HSI; week 1; 0.41 (0.0ml/L) - 2.52 (0.15ml/L), week 2; 0.93(0.075ml/l) – 1.52 (0.6ml/L); GSI; week 1; 1.58 (0.6ml/L) – 3.83 (0.15ml/L), week 2; 1.11 (0.0ml/L) – 4.66 (0.6ml/L), VSI; week 1; 2.91(0.6ml/L) – 3.70(0.15ml/L), week 2; 1.50 (0.0ml/L) – 4.33(0.6ml/L), SSI; week 1; 0.11(0.0ml/L) – 0.24 (0.15ml/L), week 2; 0.06(0.15ml/L) – 0.15(0.3ml/L), CSI; 0.07(0.3ml/L) – 0.16(0.075ml/L and 0.15ml/L), week 2; 0.11(0.0ml/L) – 0.19(0.6ml/L). Condition factor values revealed results for; week 1; 0.57(0.15ml/L) – 1.00(0.0ml/L), week 2; 0.71 (0.3ml/L) – 1.05 (0.075ml/L) depicting poor physiological condition for fishes in the treatment group. There is therefore urgent need for public awareness campaigns to educate communities about the risks associated with the dispersant use and the importance of minimizing their environmental footprint
Growth of Kappaphycus alvarezii Seaweed from Tissue Culture Cultivated with Different Initial Seed Weights
No full textAbstract-Seaweed, commonly called seaweed, is one of the abundant biological resources in Indonesian waters, covering around 8.6% of the total marine biota. The area of seaweed habitat in Indonesia reaches 1.2 million hectares, making it the largest in the world. One type of seaweed that is commonly cultivated is Kappaphycus alvarezii. This study aims to analyze the effect of different initial seed weights on the growth of K. alvarezii seaweed from tissue culture. This study lasted for 45 days, carried out from May to June 2024, located in the waters of Gerupuk Hamlet, Gerupuk Village, Pujut District, Central Lombok Regency, West Nusa Tenggara. Data were analyzed using Analysis of Variance (ANOVA) with a 95% confidence level. If there is a significant effect (significantly different) from each treatment, further testing will be carried out using the Duncan test with the same confidence level. Meanwhile, water quality data and tissue sections were analyzed descriptively. The results of this study indicate that the use of different initial seed weights can increase the absolute weight of K. alvarezii tissue culture results ranging from 27.94g - 49.52g, the specific growth rate ranges from 0.39% - 3.14%. Carrageenan yield ranges from 0.37% - 0.54%. Seaweed production ranges from 307.2 - 998.2 g / m². The tissue structure of K. alvarezii seaweed with different seed weights obtained the results of P1 (25g) showing the results closest to the tissue structure before maintenance. The measurement of water quality during the study including salinity, pH, temperature, and phosphate was still ideal while light intensity and nitrate were not ideal for K. alvarezii seaweed cultivation. This study concludes that K. alvarezii seaweed cultivation with different initial seed weights can affect the specific growth rate but does not affect the absolute weight