Length weight relationships, relative weight and relative condition factor of three freshwater shrimps from Greece

Abstract

Length-weight relationships (LWR), relative weight and relative condition factor were studied for three freshwater carideans (Atyaephyra acheronensis, Atyaephyra thyamisensis and Palaemon antennarius) from lotic and lentic habitats of northwestern Greece. The two atyids are Adriatic-Ionian endemics while the palaemonid is distributed in the Apennine Peninsula, Sardinia, Sicily and Adriatic-Ionian eco regions. Data were collected from 760 individuals and LWR parameters were estimated by the least-squares method. Kolmogorov-Smirnov and Levene tests were used to analyse data normality and homogeneity of variances. The b values ranged from 2.908 to 4.134. More specifically, in A. acheronensis, R2 ranged from 0.93 to 0.96, (b values = 2.983 - 3.673), in A. thyamisensis, R2 ranged from 0.61 to 0.91, (b values = 3.489 - 3,714), and in P. antennarius populations, R2 ranged from 0.47 to 0.95 (b values= 2.908 - 4.135). The relative weight showed no significant differences between sexes and species for both A. thyamisensis and A. acheronensis while for P. antennarius ranged from 53.07% to 93.56% for males and from 66.78% to 85.82 for females among the studied sites. The relative condition factor in A. thyamisensis males found 0.9 ± 0.02 and in females 1 ± 0.02 (P < 0.05) while in A. acheronensis, showed no differences between sexes. The same parameter ranged from 0.84 ± 0.02 to 1.06 ± 0.02 and from 0.79 ± 0.02 to 1.06 ± 0.02 for P. antennarius males and females, respectively. The present study contributes to the first recording on the LWR for the studied species, providing basic and valuable information for shrimp fisheries management.