Length-weight relationships of 107 osseous and 9 cartilaginous fish species on a shelf-break zone of the eastern Mediterranean Sea

Abstract

Overall and spatiotemporal total length-weight relationships (LWR) were studied for the 116 fish composing of 107 osseous and 9 cartilaginous fish species collected by otter trawl in the shelf and upper slope of Gulf of Antalya in 2014-2015. Of the 89 abundant bony species, 38 species had isometric growth, 24 species positive allometry, and 27 species negative allometry. Growth type was significantly affected with the sample size. LWRs of osseous fish species which had their body condition factor CF ≤ 1 were significantly differentiated by factors region, season and depth, but none was for the fish having CF ≥ 1. The factorial differences were found in relation with the CF. The b values for the osseous fish decreased slightly with bottom depth from lower shelf to middle shelf. The highest b values occurred for the ubiquitous fish on the entire shelf while the a values increased. At greater depths, the b values shifted the allometry from the isometry to the negative allometry. Average b value of osseous fish was 2.962 ± 0.048 (isometric), and median was 2.992. LWRs of body widthweight of batoid fish showed a b value ≤ 3. Sexual dimorphism in the LWR occurred for 10 species.