Department of Marine and Fisheries Sciences

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    Studies on Abundance of Jellyfish in Beach Seine Landings along the Coast of Greater Accra Region of Ghana
    (University of Ghana, 2019-07) Adongo, P.A.
    The study was conducted in three landing villages along the coast of Greater Accra Region of Ghana, namely; Ada, La and Bortianor from November 2018 to April 2019. The purpose of the study was to assess the abundance of jellyfish in beach seine landings. Biological data was obtained primarily from local fishermen who deployed beach seine net. The jellyfish families that were encountered were four in number and a total of 2,676 individuals from 72 beach seine hauls. These were; Catostylidae (35%), Chirodropidae (31%), Rhizostomatidae (30%) and Pelagiidae (4%). Ada had 37% of jellyfish, La 49% and Bortianor 14% of the total jellyfish landings. Rhizostomatidae was the most abundant at Ada, whereas Chirodropidae and Catostylidae were the most abundant at La and Bortianor respectively. The fish families that were encountered together with the jellyfish were thirteen and consisted of 352,228 individuals. They were; Carangidae > Portunidae > Penaeidae > Dasyatidae > Sciaenidae > Haemulidae > Cynoglossidae > Sphyraenidae > Sparidae > Stromateidae > Lutjanidae > Trichiuridae > Sepiidae; in order of decreasing abundance. Physico-chemical parameters at each site where fishing was carried out were collected. Five water quality parameters (DO, Conductivity, TDS, Phosphate and Chlorophyll-a) out of the eleven water parameters measured were identified to contribute significantly to the biological variations observed. A Canonical Correspondence Analysis (CCA) was used to identify which of the principal water quality parameters influenced abundance of both jellyfish and fish at each site. Decreasing DO, Conductivity and Chlorophyll-a levels influenced a decrease of jellyfish at Ada while increasing DO, Conductivity and Chlorophyll-a influenced an increase of jellyfish at La. Conversely, decreasing levels of TDS and Phosphate led to a decrease in Bortianor.
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    Aspects of the Structure and Sustainability of the Fisheries in the Cross River Estuary of Nigeria-the Role of Community-Based Management
    (University of Ghana, 2015-07) Antigha, A.A.; Armah, A. K.; Nyarko, E.; University of Ghana,College of Basic and Applied Sciences School of Biological Sciences Department of Marine and Fisheries Sciences
    This study focused on aspects of the structure and sustainability of the fisheries in the Cross River estuary with a view to addressing the unsustainable fishing activities in the Cross River estuary. The physicochemical characteristics of water were analyzed in order to determine the quality of water and health status of fishes in the study area. These included surface temperature, pH, DO, turbidity, salinity, alkalinity, phosphate and nitrates. The catch rates and catch composition of the multispecies gillnet fishery in the estuary, exploitation rates, sizes of fishes and socioeconomic factors were also investigated in order to determine their vulnerability to human and environmental factors. The water quality of the area showed a significant variation in turbidity at the locations of study, 52.2 NTU at Esuk Anansa, 30.3 NTU at Esuk Okon, and 21.8 NTU at Esuk Anantigha, with a range of 21.8 - 52.2. However, the general water quality was within the tolerable limit of fish during the study period. The mean weight of monthly catches sampled averaged 21.2 kg (range 15.3 kg to 27.0 kg).The mean CPUE was 7.1 kg/boat/trip. The catch composition revealed that Pseudotolithus elongatus accounted for 56.69%, by weight, Ethmalosa fimbriata was 30.28% by weight, while Chrysicthys nigrodigitatus was 7.53% by weight. The results of the study showed that these species are being threatened as a result of unsustainable fishing methods leading to harvesting of small fishes mostly between 10 and 15cm of length. The socioeconomic status of artisanal fishermen, traders and mangrove loggers in the estuary was determined with the view of updating knowledge on the socioeconomic indices, fishing gears, prime catches of the fishes in the area, in order to suggest management measures for the fishery and ecosystem of the area. The study recommends the introduction of community-based coastal resource management approach for the sustainability of the fisheries and the ecosystem of the area.