BRANTA — Angela M. Lamptey
Modelling of the Waterbird-Fisheries Interactions of the Sakumo II Lagoon, near Tema, Ghana
Institution: University of Ghana
Supervisors: Prof F K E Nunoo, Prof E H Owusu
Details: MPhil, 2008
Dept. of Marine & Fisheries Sciences, School of Biological Sciences, University of Ghana
Subject Keywords:Seabirds, fisheries, interactions, Sakumo II Lagoon, Ghana
Species Keywords: Long-tailed Cormorant, heron, egret, tern
Interactions between piscivorous birds and fish are of great significance to both bird and fishery management. The analysis of competition between birds and fisheries typically proceeds through a series of characteristic steps. First, the state of fish and bird stocks are characterized, followed by the analysis of rate variables, including food intake by birds, diet composition of birds and fishing yields. Finally the impact of bird predation on fishing yield is assessed. The study aimed to describe and quantify the level of interactions between waterbirds and fish production, of the Sakumo II lagoon, during the peak and lean seasons of waterbirds and fish production in Ghana. Data on bird species occurrence, abundance and feeding rates were defined on the field during the study period. A simplified conceptual model in the form of a Forrester diagram was developed to explain resource partitioning and competition between bird and man in the lagoon. The model included the interactions between man, fish, and birds; as well as the environmental and biological factors influencing these interactions. A total of 44,644 individuals of waterbirds were counted during the study period, 66% of these were piscivorous birds. An estimated total number of 180,542,592 individuals and 68,775.30 to 7,391,491.02 kg of prey items were consumed by piscivorous birds during the study period, with stalking mode of feeding by egrets (Ardeidae) consuming the largest proportion of prey items, thus the most dominant feeding mode. This constituted 3.20 % of the total fish production of the lagoon. Statistical analysis of results led to the conclusion that feeding rates and success of piscivorous birds is dependent on the production of fish in the lagoon. The most important gear employed is the cast net, followed by the drag net. Productivity of the Sakumo II lagoon was found to be 1207.95 Kg per day and yield was estimated to be 65.01 Kg/ha per month during the study period. Total daily catch was 2,867.83 kg and total catch for the study period was 87.11 tonnes. Sarotherodon melanotheron was found to be growing allometrically. Recommendations included the need for pragmatic management of lagoon with best scientific data from both bird and fish population dynamics and ecology.
Ahulu, Angela .M., F.K.E. Nunoo and Erasmus H. Owusu 2006. Food preferences of the Common tern, Sterna hirundo (Linnaeus 1758) at the Densu floodplains, Accra. West African Journal of Applied Ecology 9: 141 – 148.
F.K.E. Nunoo, Josephine, O. Boateng, Angela M. Ahulu, Kwame A. Agyekum and Ussif Rashid Sumaila 2009. When trash fish is treasure: The case of Ghana in West Africa. Fisheries Research 96: 167 – 172.
Lamptey, A. M., Ofori-Danson, P. K., Abbenney-Mickson, S. Glud, R. N., Madsen, H. B. and Abekoe, M. K. 2013. The influence of land-use on water quality in a tropical coastal area: case study of the keta lagoon complex, Ghana, West Africa. Open Journal of Modern Hydrology 3: 188 - 195.
Lamptey, A.M. and Ofori-Danson, P.K. 2014. The status of fish diversity and fisheries of the Keta Lagoon, Ghana, West Africa. Ghana Journal of Science 54: 3-18.
Lamptey, A.M. and Ofori-Danson, P.K. 2014. Review of the distribution of waterbirds in two tropical coastal Ramsar Lagoons in Ghana, West Africa. West African Journal of Applied Ecology 22(1): 77-91.
Nyarko, E., Lamptey, A.M. and Owiredu-Amaning, D. A. 2015. Application of Water Quality Index for assessment of the nearshore coastal waters of Accra. Journal of Pollution Research 34(4): 657-666.
Wehye, A.S., Ofori-Danson, P.K. and Lamptey A.M. 2017. Population Structure and some aspects of Biology of Pseudotolithus Senegalensis and Pseudotolithus Typus within the Coastal Waters of Liberia. International Journal of Fisheries and Aquatic Research 2(2): 8-16
Wehye, A.S., Ofori-Danson, P.K. and Lamptey A.M. 2017. Population Dynamics of Pseudotolithus Senegalensis and Pseudotolithus Typus and Their Implications for Management and Conservation within the Coastal Waters of Liberia. Fisheries and Aquaculture Journal 8: 201. doi: 10.4172/2150-3508.1000201