Comparative Study of Different Gill Net Mesh Sizes in the Exploitation of Bonga fish (Ethmalosa fimbriata) and Sardines (Sardinella eba) in Brass Coastal Waters, Bayelsa State, Nigeria

Abstract

A comparative study of different gill net sizes in the exploitation of bonga (Ethmalosa fimbriata) and sardines (Sardinella eba) were conducted for 3 months between January and March 1998 in Brass River. The area is located between Latitude 4o 2" and 4 o 6 " and longitude 6 o 2 " and 6o 5" stretching from Akassa at the River mouth to Doukungbene near the upper edge of Clarendou. Three Mesh size of gill nets (35mm, 60mm and 70mm) were used for Bonga and Sardine fishing. The result obtained indicated that larger size classes of fish were obtained with the increase in mesh sizes of nets. In addition, marked variation in mean values (t test > t 0.05) and distribution ( w > P0.05) of the size classes were observed (for Ethmalosa fimbriata and Sardinella eba ) irrespective of the mesh sizes. Also the Principal component analysis (PCA) showed high selection for larger fish sizes (in the component weighting) in the catch, which were favoured by the bigger mesh sizes (70mm).