DEPARTMENT OF AQUACULTURE AND FISHERIES MANAGEMENT

This study investigated the effects of deep and air frying on the shelf life of Atlantic mackerel (Scomber scombrus) stored at ambient temperature in Ziplock packages. The fish samples were divided into salted and unsalted portions, fried using both methods, and stored for six days. Microbial analyses were conducted at intervals to determine bacterial and fungal loads. Results showed a steady increase in microbial counts over time, with bacterial counts rising from 7.4 cfu/gm on day 0 to 29.6 cfu/gm on day 6, and fungal counts from 30.7 cfu/gm to 74.9 cfu/gm. Air-fried samples consistently showed lower microbial growth compared to deep-fried ones, while salted samples exhibited slower spoilage rates than unsalted ones. These findings suggest that air frying combined with salt treatment effectively enhances the microbial stability and shelf life of fried Atlantic mackerel stored at ambient temperature.

The abundance of duckweeds in earthen fish ponds is a phenomenon that warrants detailed study due to its ecological, economic, and management implications. This study investigated the abundance, spatial distribution, and management of Lemna minor (duckweed) in earthen fish ponds along the Ikpoba River in Benin City, Edo State, focusing on Oredo and Ikpoba-Okha Local Government Areas. Structured questionnaires and field assessment were used to collect
data from 100 fish farmers, while descriptive and spatial analyses were performed to evaluate duckweed coverage, biomass, and management practices. Results showed that Lemna minor was relatively abundant, with mean coverage of 63.8% (40.8 g/m²) in Oredo and 66.2% (42.9 g/m²) in Ikpoba-Okha, particularly concentrated at pond inlets where nutrient inflow was greatest. Most farmers were educated (54.2%) males aged 30–39 years (56%), mainly culturing Clarias
gariepinus (60.2%) under intensive systems. About 63.2% of respondents reported duckweed presence, primarily during the rainy season (86.6%), with 28.3% perceiving it as beneficial for water shading and nutrient removal, while 17.2% considered it harmful due to oxygen depletion and feeding obstruction. Manual removal (54.3%) and biological control (21.7%) were the most common management practices, though only moderately effective. It concludes that L. minor
proliferation indicates nutrient-rich pond conditions and recommends integrated management through nutrient regulation, regular monitoring, and biological control to enhance sustainable aquaculture productivity

Microplastic (MP) contamination of freshwater ecosystems is a significant environmental and public health concern globally. The paucity of data on MP contamination in Chrysichthys nigrodigitatus from the Ikpoba River, Benin City, Nigeria, warranted this investigation. This study determined the levels, types, and estimated daily intake (EDI) of microplastics in C. nigrodigitatus from three stations along the river over three months (July-September), using visual identification and Fourier Transform Infrared (FTIR) Spectroscopy for polymer confirmation. The mean levels of MPs in fish ranged from 0.0113 in August at Station 3 to 0.0163 in September at Station 2, with no significant difference (p>0.05) between months at each station. The plastic load (particles/fish) ranged from 0.00103 in September at Station 1 to 0.00136 in September at Station 2, showing significant temporal variation (p<0.05) at Station 1. The frequency of occurrence (FO) of MPs ranged from 0.33 in July at Station 1 to 1.00 in September at Stations 1 and 3. Physical classification revealed that fragments were the most dominant MP type (39.29%). FTIR analysis confirmed the presence of polyethylene, identified by characteristic absorbance wave numbers at 2925 cm⁻¹, 2850 cm⁻¹, 1430 cm⁻¹, and 710 cm⁻¹.The estimated daily intake (EDI) of MPs for humans through the consumption of C. nigrodigitatus was calculated to be low. The findings confirm the prevalence of microplastics in Ikpoba River and their ingestion by a commercially important fish species. It is recommended that continuous monitoring, effective waste management policies, and public enlightenment campaigns be implemented to mitigate plastic pollution and protect the river's ecosystem and associated public health

A study was conducted in Benin city, located in South South Nigeria, to investigate the insect pest species affecting three distinct fish species: Clarias spp, Tilapia spp, and Synodontis spp, Orechromis niloticus and Hemichromis spp. The common insect pests identified infesting all three fish species included Dermestes spp and Tribolium spp. The data collected included the total count of insect pests infesting each fish species and the distribution of the insects in their two life stages, larvae and adults. Analysis of this data was performed using simple percentage calculations. The results indicated that Tilapia spp exhibited the highest susceptibility to insect pests. The ranking of susceptibility was as follows: Tilapia > Synodontis > Clarias. Notably, Tribolium spp emerged as the predominant insect pest, with an infestation rate of approximately 61.7% on Tilapia spp and 100% on Clarias spp. Necrobia spp followed with an infestation rate of 31% on Tilapia spp and 80% on Synodontis spp. Furthermore, the study observed the distribution of adult and larval stages of these insect pests. The findings revealed that the majority of the insects infesting the five species of smoked fish in Benin city, Edo state, Nigeria, were in the larvae stage.

The study is aimed at determining the effects of some selected drying method on the nutritional quality of Apple Watersnail (Lanistis libycus) purchased at Ikpoba hill market One hundred and Fifty (150) Apple snail (Lanistis libycus) specimen was obtained from a fish seller and taken to the Faculty of Agriculture processing unit where processing was carried out using some selected methods. They were slaughtered, removed from the shell to collect the meat and discard the shell. They were weighed before been spiced and then dried using the different processing method (sun drying, smoked drying and oven drying).They were then taken to the lab for analysis. Statistical analysis using Genstat computersoftware was used to compute the result for proximate composition. The result from this study will assist in determining the most appropriate method of processing with regards to nutrient availability and amount of moisture content hence the method that has the best rate of preservation.

One of the most recent and emerging contaminants today, is plastic. These plastics through improper waste disposal and runoff, find their way to water bodies. This plastic when they fragment or occur in very small sizes (<5mm) are termed microplastic. They can be classified on physical characteristics or chemical characteristics. They pose risk to both fish and consumers of the fish. The fish samples were analysed within 24hrs of collection. The fish were digested using 10% KOH, and purified using H2O2. The filtrates were examined under microscope to identify the microplastic particles, which were physically confirmed using the hot needle method and confirmed chemically using Fourier transfer infrared spectroscopy. Microplastics occur at all stations through the three months under study. The microplastics found based on morphological characteristics are pellet, foams, fibre, filaments, and fragments, while on polymer characteristics, there were two namely; polypropylene and polyethene. The type of microplastic prevalent in each station had a relationship to the prevalent economic activities at the watershed. For example, at station 3 (Ikpoba bridge), the
prevalent economic activities at the water fronts are car and rug washes, the prevalent plastic is polypropylene

This study determined the effects of culture facilities; (Earthen pond, Concrete tank, and Tarpaulin tank) on the nutritional value and organoleptic properties of Clarias gariepinus in Benin Metropolis. Thirty catfish samples (Ten samples from each culture facility) of average weight of 500g obtained from a reputable farm in Benin city were euthanized, eviscerated, degutted, and thoroughly washed under running water. The samples from the earthen pond, concrete tank, and tarpaulin were tagged sample A, B, and C respectively. The proximate analysis of the fresh and smoked-dried samples was done according to standard methods. Organoleptic assessment was done by trained panelists. The result reveals that C. gariepinus raised in the concrete tank had the best general acceptability in terms of appearance, texture, aroma and taste, although, there was no significant difference (P

Periwinkles are small edible snails commonly available for sale in the southern part of Nigeria. The increasing awareness that periwinkle is highly proteinous, one of the cheapest sources of protein and help for body and mental development as increased the demand in different country. The study investigated the effect of oven – drying and smoke – drying methods on the proximate composition of periwinkle (Tympanotonus fuscatus) preserved in natural agents. 50g of periwinkle were measured for each drying method and preserved with salt, lime, lemon and alum within 24 hours. Each sample were dried at about 55 oc – 70 oc. The samples were labelled T1 -T13 including the fresh sample. T5 retained the least moisture (p<0.05) and had the highest fat content, fibre content and ash content (p<0.05). There was a substantial difference between (p<0.05) the crude protein and carbohydrate contents of the preserved samples using the different drying processes. T5 had more excellent qualities compared to the others and should be the recommended drying procedure for retaining excellent qualities

Fish is a vital source of dietary protein for many Nigerians, but domestic production has not kept pace with population growth, leading to increased reliance on imports. Traditional preservation methods like smoking play a key role in ensuring year-round availability, but also raise concerns around contaminants and health risks. This study investigates consumer preferences and perceptions regarding fresh versus smoked fish in Benin City, Nigeria. The background highlights that fish is highly perishable, requiring techniques like drying, smoking, freezing, and brining to extend shelf life. Smoking remains the dominant preservation method in Nigeria, offering benefits in accessibility and shelf-life, but also potential quality and safety issues. Limited research has explored consumer choices between fresh and smoked fish products, especially in inland urban areas. This study assesses the extent to which cultural, economic, and health/safety factors influence consumer preferences for fresh versus smoked fish. It also identifies key demographic segments and their buying behaviors. Surveys will be conducted with fish consumers at major markets and the university community in Benin City. The findings can provide important insights to help the fishing industry, retailers, and policymakers better meet evolving consumer demand for fresh and processed fish products in Nigeria.

Fish seed production is a fundamental aspect of aquaculture, ensuring the continuous supply of high-quality fish seeds for commercial and subsistence fish farming. This study examined the fish seed production practices in Ovia North-East and Ovia South-West local government areas of Edo State, Nigeria. The objectives were to assess the socio-economic characteristics of fish seed producers, evaluate their management practices, analyze production output, and identify constraints affecting fish production in the study area. The non-probability chain referral sampling procedure was employed, with data collected from 100 fish hatchery operators using structured questionnaires. The collected data were analyzed using S.P.S.S Version 15.0, and presented using descriptive statistics, including tables, charts, and percentages. The findings revealed that fish seed production is largely undertaken by middle-aged (51.9%), experienced (40.5%), and predominantly male operators (94.9%). Also, Clarias gariepinus and Heterobranchus bidorsalis (97.5%) were predominant species bred in hatcheries. Water quality management was a key concern, as many operators relied on basic flow-through systems (73.2%) and oxygenation methods (25.6%) to maintain optimal conditions. Broodstock reuse was common, with most operators (89.7%) allowing a recovery period of 3 – 4 months before reuse. The study identified poor water quality leading to fry mortality (55.7%), financial constraints (27.9%), feed availability and cost (13.9%), and theft (2.5%) as the major challenges faced by hatchery operators. Based on the findings, the study recommends enhanced training programs, targeted funding schemes, better water quality management strategies, and security measures to enhance efficiency and overall productivity of fish seeds in the study area. Also, further studies should be carried out on other aspects of the fish seed production value chain to enable a comprehensive understanding of the fish seed production in the study area.