Journals of Aquatic Sciences 25(1) 115 – 128 April (2010)
A NEW DESIGN OF A FLEXIBLE SEPARATOR PANEL (EYO GRID) TO REDUCE BY-CATCH
IN COASTAL SHRIMP BEAM TRAWL FISHERY IN NIGERIA
AMBROSE, E.E. AND ENIN1, U.I.
Fisheries Resources Division, Nigerian Institute for Oceanography and Marine Research,
Victoria Island, P.M.B. 12729 Lagos
1Institute of Oceanography, University of Calabar, Cross River State, Nigeria
Anew design of a flexible separator grid consissting of a partition and excluder panels is developed and inserted into trawl codend to reduce by-catch species in coastal beam trawl fisheries for white shrimps, Nematopa/aemon hastatus. Simultaneous paired comparisons against control codend showed that the experimental codend significantly reduced the by-catch of juvenile fishes up to 82.36% (t-test, P<0.05; 0.01)'· with a corresponding loss of 26.98% of target shrimps Nematopa/aemon hastatus. Fish specimens of 11-30cm total length were highly excluded from the experimental codend. Abundance of commercially important by-catch species weight were significantly reduced in experimental codend e.q. Pseudotolithus typus (96.68%, p<0.05; 0.01), Cynoglossus senegalensis (85.5%, p<0.05; 0.01) and Pentanemus quinquarius (81.98%, p<0.05; 0.01). At family level, reduction in the number of 9 out of 13 important by-catch families analysed were significant e.q. Sciaenidae, Trichiuridae, Clupeidae, Orepanidae and Carangidae (p<0.05; 0.01). Flattened fish families were not in number signicantiy reduced in experimental codend e.g. Carcharhinidae and Oasyatidae (p<0.05; 0.01). The design concept, by-catch and shrimps reduction characteristics of the flexible netting separator grid are discussed.
Keywords: New design, netting grid, By-catch, Shrimp, Trawl Fishery, Nigeria