Growth parameters of the invasive blue swimming crab Portunus segnis (Forskål, 1775) (Crustacea) in the North-Eastern Mediterranean, Türkiye

Abstract

The blue swimming crab, Portunus segnis, is a Lessepsian and the most abundant and economically significant crab species on the Mediterranean Sea coast of Türkiye. However, there are a few studies on the growth of P. segnis in Türkiye. Our objective is to determine the allometry, and growth parameters of P. segnis in Iskenderun Bay, the Northeastern Mediterranean. Blue swimming crabs were sampled using a bottom trawl net from July 2014 to June 2015. Totally 320 specimens were caught. The carapace width (CW) varied from 38.1 to 163.17 mm (mean: 109.88±27.56 mm) and the total weight (TW) was measured at a minimum of 3.46 and a maximum of 324.36 g. The width (CW)-weight (TW) relationships of the crabs were estimated as log(TW)=2.9028CW-9.0664 (R2=0.7452) for the females and log(TW)=2.9773CW-9.3842 (R2=0.8433) for the males. The carapace width-weight relationships of both sexes indicated that the growth pattern is allometric (p<0.05). The von Bertalanffy growth parameters were computed as CW∞=166.00 mm, K=1.2 year-1, t0=-1.62 years, C=0, WP=0.20, and Φ´=4.519 for all crabs. The von Bertalanffy growth parameters of P. segnis were determined on the coasts of Türkiye, for the first time.