Determination of the Appropriate Hanging Ratios to Ease the Escape of Juvenile Red Mullet (Mullus barbatus L., 1758) and Annular Sea Bream (Diplodus annularis L., 1758) from a Trawl Codend

Authors: ZAFER TOSUNOĞLU, YELİZ DOĞANYILMAZ, HÜSEYİN ÖZBİLGİN

Abstract: This study investigates the relationship between total length (TL) and fork length (FL), girth (G), height (H) and width (W) of red mullet (Mullus barbatus) (n = 953) and annular sea bream (Diplodus annularis) (n = 944) collected during trawl selectivity trials carried out in İzmir Bay between July 1996 and February 1997. The FL, G, H and W of red mullet were 89, 53, 20 and 11% of the TL, respectively. For annular sea bream these values were 91, 80, 34 and 11%, respectively. The ratios for average body thickness (W/H) were 0.573 for red mullet and 0.319 for annular sea bream. The hanging ratios (E_{RM} and E_{ASB}) of codends designed to ease the escape of juveniles of these species were 0.497 for red mullet and 0.304 for annular sea bream.

Keywords: Body shape, mesh hanging ratio (E), red mullet (Mullus barbatus), annular sea bream (Diplodus annularis)

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