Selectivity studies on beach seine deployed in nearshore waters near Accra, Ghana

摘要

Beach seine is known to be biologically and ecologically destructive. Over the years there have been increased concerns from fishery managers and stakeholders in West Africa and beyond to reduce this destruction of fish resources by the gear. Total bans for periods in the year or the use of a bigger mesh size (25 mm) at the cod end have been investigated. A covered cod end experiment was conducted in the nearshore waters at Tsokome near Accra (Ghana) during June and September 2012 to contribute to find a solution to the management problem posed by the gear. The temporal variability of effort, catch, species composition of the 10 mm and 25 mm cod ends; the gear selectivity; and the revenue of each bag were studied and compared. A total of 60 species belonging to 35 families was recorded. The four dominant taxonomic families were: Penaeidae, Carangidae, Haemulidae and Trichiuridae in order of importance. The selection factors were high and almost the same for the dominant species Brachydeuterus auritus, Chloroscombrus chrysurus and Peneaus notialis. This suggests the need to raise the Lc through adoption of increased mesh size regulation. The use of the 25 mm bag was 25% more financially rewarding than that of 10 mm bag. The 10 mm bag was found to catch species of smaller size. Educational programmes for all relevant stakeholders about the gains of using a bigger mesh size at the cod end and immediate strict enforcement of the relevant provisions of the Fisheries Law 2002, Act 625 of Ghana are among the recommendations to help save fish resources from further degradation.