Celalettin AYDIN
Abstract
This study aimed to determine escapes from codend, underneath of footrope and above headline model in bottom trawl net widely used. Fishing trials were carried out between August 2006 and February 2007 with “EGESUF”. Different experiment bags, Rtext 620 and 24 mm mesh sizes, were constructed to obtain escaping species. Bosom bag was attached under the bottom model and rigged throughout the selvedge. Upper bag laced to the outside of headline above the upper model and cover was fitted over the codend. A nominal 40 mm polyethylene codend was used. The trawl catches were sorted into species. Length measurement was made in total length for abundant fish species which were annular sea bream (Diplodus annularis), red mullet (Mullus barbatus) and scald fish (Arnoglosus laterna). Non-parametric and parametric statistical tests were applied to analyze data. A total of 24 933 specimens belonging to 34 species were caught from 9 valid hauls. Upper bag, bosom bag, covers and codend catch value were determined as 0.1 %, 2.8 %, 41.6 % and 55.6 %, respectively. While the highest Jaccard similarity coefficient was calculated 0.50 between codend and cover, the lowest was 0.05 between upper and bosom bag. Although there were significant differences between bosom bag, cover and codend for annular sea bream and scald fish specimen (Kruskal Wallis analysis of variance, p0.05), the differencesbetween cover and codends specimens were not significant for the red mullet (Wilcoxon matched pairs test, p>0.05 z=0.478). Kolmogorov Smirnov test indicated that annular sea bream and red mullet were length-dependent (p