STOMACH CONTENT ANALYSES OF TILAPIA ZILLII AND HEMICHROMIS FASCIATUS IN THE GOLINGA RESERVOIR IN THE TOLON DISTRICT OF THE NORTHERN REGION OF GHANA

Abstract

The food habits of Tilapia zillii and Hemichromis fasciatus in the Golinga Reservoir were studied from November 2013 to April 2014 by employing the points and frequency of occurrence methods. Condition factor and some physicochemical parameters such as temperature, conductivity, pH and dissolved oxygen of the water were monitored. Out of 85 stomachs of Tilapia zillii containing food, the fish fed mainly on 48.95 % of plant materials, 26.02 % of algae and 12.03 % of debris, 9.58% sand grains and 4.04 % of insects. Of the 107 specimens of Hemichromis fasciatus examined,the species preferred fish and fish parts (50.33 %), insects (22.17 %) and zooplanktonic organisms (17.42 %) such as rotifers and cladocerans to algae (4.01 %) and debris (1.03 %). All water parameters were found to be within permissible limits for aquatic life and livestock use and other domestic purposes except for conductivity which was low (85.46 ± 0.018 μS/cm). Mean temperature was 27.74 ± 0.13 oC, dissolved oxygen was 7.76 ± 1.0 mg/L and pH 7.02 ± 0.03. The mean condition factors of T. zillii and H. fasciatus were 3.25 and 3.93 respectively suggesting that the fish were in a very good condition. Considering the observed food habits of the two species, H. fasciatus can be classified as invertevore – piscivore and T. zillii a herbivore – detritivore. The broad spectrum of food items eaten by these cichlids and their preference for different food items could be strategies adopted to avoid interspecific competition as such a potential for polyculture. Again due to the varied distribution of these food items in the water, the fish are able to judiciously utilize its food resources in the water. The study revealed low numbers of Tilapia zillii which affected further investigation into its size distribution. It is recommended that populations of H. fasciatus should be reduced to prevent it from rastically reducing the numbers of Tilapia zillii and other non carnivorous fish species.