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Breeding Space as a Determinant of Growth Morphometrics, Gonadal Development, and Hepatic Condition in Clarias gariepinus (Burchell, 1822)

100%
Ekpo I. P., Ekpo P. B., Ekpenyong B. N., Ozah H. P.
World News of Natural Sciences
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2025
|
vol. 62
261-276
EN
This study investigated the impact of breeding space, specifically pond size, on growth, reproductive performance, and metabolic health in Clarias gariepinus (African sharptooth catfish), a species of significant aquaculture value. Ten fish samples sourced from ponds of varying sizes were assessed for morphometric parameters, including standard length (50.8 - 59.3 cm) and body weight (1400 - 2000 g), along with reproductive status measured by the Gonadosomatic Index (GSI: 0.2 - 5.0) and metabolic health assessed by the Hepatosomatic Index (HSI: 0.6-3.7). Fish reared in larger ponds showed significantly greater mean body length (58.9 cm) and body weight (1950 g) compared to those in smaller ponds (53.2 cm and 1450 g, respectively; p < 0.05). Similarly, liver weight and HSI values were higher in the large-pond group (HSI mean 3.4) relative to small-pond fish (HSI mean 1.2), indicating enhanced energy reserves. Correspondingly, GSI values were significantly elevated in larger ponds (mean 4.3) compared to smaller ponds (mean 1.1; p < 0.05), suggesting improved reproductive readiness. An inverse correlation (r = –0.68, p < 0.01) was observed between GSI and HSI, consistent with energy mobilization toward gonadal development during peak reproduction. Nevertheless, fish in optimal environments maintained relatively high levels of both indices, signifying the importance of adequate nutrition alongside space. These findings underscore pond size as a critical determinant of growth, reproduction, and metabolic condition in C. gariepinus. The study recommends that aquaculture practitioners prioritize larger, well-managed pond systems to optimize fish health and productivity. Regular monitoring of GSI and HSI is also advised to inform management decisions. Further research is warranted to delineate the interactions between breeding space and environmental variables to refine sustainable practices, meeting global aquaculture demands while ensuring fish welfare.
2
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Silver Catfish [Chrysichthys nigrodigitatus (Lacepède, 1803)] as Nature’s Sentinels: Decoding Morphometric and Meristic Indices to Safeguard Calabar River’s Future

100%
Ekpo I. P., Ekpo P. B., Ozah H. P.
World News of Natural Sciences
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2025
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vol. 63
|
issue 2
56-67
EN
Aquatic ecosystem health is fundamentally linked to water quality, which is influenced by both natural processes and anthropogenic activities. The Calabar River, a critical freshwater resource in Nigeria, is increasingly threatened by pollution, habitat destruction, and climate change, adversely affecting its biodiversity and ecosystem services. Fish species, such as the Silver Catfish [Chrysichthys nigrodigitatus (Lacepède, 1803)], are widely acknowledged as effective bioindicators due to their sensitivity to environmental changes. This study investigates the potential of Silver Catfish as sentinels of environmental health in the Calabar River by assessing their morphometric and meristic characteristics alongside relevant physiochemical parameters of the river water. Over a three-month period, Silver Catfish specimens were collected monthly from Nsidung Beach, Calabar South. Morphometric traits, including body length and weight, and meristic counts such as fin rays, were analyzed in the laboratory. Concurrently, key physiochemical parameters temperature, dissolved oxygen, pH, turbidity, conductivity, total dissolved solids, and total suspended solids were measured to characterize water quality. Results revealed significant seasonal variability in morphometric indices, indicating potential environmental influence on fish growth and condition, whereas meristic features remained constant, suggesting genetic stability. Water quality parameters fluctuated, reflecting the impact of anthropogenic pressures and natural changes. The integration of these biological and environmental data highlights the suitability of Silver Catfish as effective sentinels for monitoring ecosystem health in the Calabar River. This study provides critical baseline data to inform sustainable management and conservation strategies aimed at safeguarding the river’s ecological integrity and supporting local communities reliant on its resources.
3
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Investigating the Effectiveness of Aquatic Plant Species as Bioindicators for Detecting Petroleum Hydrocarbon Pollution in the Marsh Ecosystems of Ogoniland, Niger Delta, Nigeria

76%
Ekpo P. B., Ekpo I. P., Inaku A. G., Ogbaji H. O., Unoh F. B., Job I. E., Effiong N. M.
World News of Natural Sciences
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2025
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vol. 62
106-118
EN
The Niger Delta region, particularly Ogoniland, has faced extensive environmental pollution due to petroleum activities, raising concerns about the contamination of aquatic ecosystems. This study aimed to investigate the levels of Total Petroleum Hydrocarbons (TPHs), Polycyclic Aromatic Hydrocarbons (PAHs), and n-Alkanes in four aquatic plant species Eichhornia crassipes, Phragmites karka, Typha domingensis, and Nymphaea lotus from Ogoniland and evaluate their potential as bioindicators for petroleum contamination. Samples of these aquatic plants were collected from the polluted area and analyzed using Soxhlet extraction for TPHs, spectrofluorometry for total petroleum hydrocarbon quantification, and gas chromatography for PAHs and n-Alkanes. The results revealed that Eichhornia crassipes accumulated the highest concentration of TPHs at 18.7 ± 1.2 µg/g dry weight, followed by Typha domingensis (18.1 ± 1.2 µg/g), Phragmites karka (17.5 ± 1.1 µg/g), and Nymphaea lotus (15.8 ± 1.0 µg/g). Similarly, Eichhornia crassipes also showed the highest PAH levels at 112.5 ± 8.4 ng/g, whereas Nymphaea lotus had the lowest PAH concentration at 101.2 ± 7.5 ng/g. The study found a predominance of high molecular weight PAHs and identified a biogenic origin for most n-Alkanes, with Phragmites karka reflecting some anthropogenic influences. These findings suggest that Eichhornia crassipes is the most effective bioindicator for petroleum contamination among the studied species, highlighting the value of aquatic plants in environmental monitoring. Future research should focus on the long-term effects of petroleum pollutants on these plants and assess how seasonal variations might influence contaminant levels.
4
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Evaluation of essential Oils extracted from Ocimum gratissimum L. (scent leaf) as organic preservative in comparison with synthetic preservative (dichlorvos) in grains storage

76%
Ekpo P. B., Abu G. I., Ekpo I. P., Chinyere O.-A., Ogbaji H. O., Job I. E., Achimole C. C.
World News of Natural Sciences
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2025
|
vol. 62
183-197
EN
The use of synthetic preservatives in grain storage has raised concerns about environmental pollution, toxicity to humans and animals, and development of pesticide-resistant pests. This study evaluated the efficacy of essential oils extracted from Ocimum gratissimum (scent leaf) as organic preservatives for grain storage, comparing their effectiveness to the synthetic preservative dichlorvos. The essential oils were extracted using a suitable method and analyzed for their chemical composition. The major constituents of the essential oils were identified as eugenol, linalool, etc. The oils were then tested for their insecticidal properties against common grain pest (Callosobruchus maculatus). Grains were treated with different concentrations of essential oils (of 0.5, 1.0, 1.5 ml) and dichlorvos (concentration of 0.5, 1.0 mL), and stored for a specified period of one month and data was collected within 4 days of application of treatments. The results showed that the essential oils exhibited significant insecticidal properties, reducing pest growth in grains. The efficacy of the essential oils was comparable to dichlorvos, with 85.0 percent mortality of pests. The study suggests that Ocimum gratissimum essential oils could be a viable alternative to synthetic preservatives like dichlorvos for grain storage, offering a safer and more environmentally friendly option for farmers and consumers. The use of these oils could also contribute to sustainable agriculture and food security. Further research is needed to explore the commercial applications of these essential oils and to optimize their use in grain storage.
5
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Fingerprinting Environmental Contaminants in Lemna Dumpsites: A Biomarker-Based Approach for Assessing Ecological Risk in Tropical Regions

76%
Ekpo P. B., Ekpo I. P., Ogbaji H. O., Unoh F. B., Chinyere O.-A., Onajite E. O.
World News of Natural Sciences
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2025
|
vol. 62
167-182
EN
This study evaluated environmental contamination and biological stress at the Lemna dumpsite in Calabar Municipality, Nigeria, through integrated biochemical and physicochemical analyses. Soil and water samples were assessed for oxidative stress biomarkers, DNA damage, lipid peroxidation, and contaminant levels. Enzymatic activities of catalase (4.82 ± 0.21 U/mg protein), peroxidase (2.91 ± 0.17 U/mg protein), and glutathione S-transferase (5.34 ± 0.22 U/mg protein) were significantly elevated in soil samples compared to water (3.15 ± 0.18, 1.87 ± 0.14, and 3.92 ± 0.19 U/mg protein, respectively), indicating increased oxidative stress in soil microbial communities exposed to heavy metals and organic pollutants. The comet assay revealed pronounced DNA fragmentation in soil microbes, with tail length of 38.6 ± 2.4 µm and 52.4 ± 3.1% DNA in tail, compared to water samples (27.2 ± 2.1 µm and 40.8 ± 2.7%). Lipid peroxidation, measured by malondialdehyde concentration, was also higher in soil samples (8.12 ± 0.31 nmol MDA/g) than in water (5.76 ± 0.29 nmol MDA/g), confirming oxidative membrane damage. Physicochemical analyses showed acidic soil pH (5.4 ± 0.2), elevated total organic carbon (4.3 ± 0.5%), and heavy metal concentrations of lead (62.5 ± 3.2 mg/kg), cadmium (3.1 ± 0.2 mg/kg), and chromium (77.2 ± 4.1 mg/kg), all exceeding WHO permissible limits. Water quality assessment indicated slightly acidic pH (6.2 ± 0.3), high turbidity (22.5 ± 1.7 NTU), and significant microbial pollution with total coliforms at 920 MPN/100 mL and positive E. coli presence, reflecting fecal contamination likely from leachate. These findings demonstrate severe environmental degradation at the dumpsite, with clear biological effects on soil microorganisms and public health risks from contaminated water. The study underscores the urgent need for remediation strategies, improved waste management, and continuous environmental monitoring to mitigate ecological and human health impacts.
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