Review of the Changes in Fish Population of Three Flood Water Pools in Dinder National Park, Sudan

Fish samples were collected from three flood water pools located on the eastern and western banks of Dinder National park (DNP) during the dry season of the year 2016. The survey included Grerrisa and Ras Alfeil “mayas” and Birkat el-Timsah pool. Fish were caught by using five multifilament gillnets of mesh size 4, 6, 8, 10 and 12 cm, a length of 25 m and a depth of 1.5 m, in addition to a standard Lundgren survey type gill net. The results of the survey revealed the presence of eight species of fish belonging to six families, representing about 25.0 % of the total number of 32 fish species previously recorded in Dinder River flood water pools. Calrias gareipinus, Citharinus citharus and Heterotis niloticus dominated the catch in the three flood water pools. The highest total biomass of fish was recorded in Birkat el-Timsah pool using a gill net of 12 cm mesh size.

Considerable reduction was observed in the fish species composition during the survey. This may be due partly to loss of habitat and shelter, low levels of dissolved oxygen, relatively high water temperature, high water turbidity and insufficient amount of food during the dry period which is usually associated with low levels of water in the flood water pools.

Hence, it is recommended to conduct a comprehensive biological study on the fishery potential of the DNP during both dry and wet seasons in order to formulate a sound policy for management and exploitation of the fisheries of this vital resource. It is also essential to establish a viable aquaculture program to culture Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gareipinus) to enhance fish production in the DNP area. 

Key words: Dinder National Park, Birkat el Timsah, freshwater pools, Greirisa “Maya”, Ras el Feil “maya”, water pools, Species composition.