Some morphometric features of congeneric pipefish species (Syngnathus abaster Risso 1826, Syngnathus acus Linnaeus, 1758) distributed in Lake Bafa (Turkey)

The study was carried out between November 2014 and March 2016 to determine certain morphometric characteristics of two pipefish species occurring in Lake Bafa, Syngnathus abaster and Syngnathus acus. A total of 211 pipefish were captured during the sampling, including 77 individuals of S. abaster (♀: 25; ♂: 44; immature: 8) and 134 individuals of S. acus (♀: 31; ♂: 76; immature: 27). The male-female ratios were 1:1.76 and 1:2.45, respectively. A difference was found in sex ratios between the two species (p < 0.05). The mean length of the captured fish was 86.63 ± 16.77 mm for S. abaster and 82.63 ± 16.02 mm for S. acus and the relationship between the total length and weight, referred to as the length-weight relationship, was as follows: W = 0.00000001L^3.71 (R² = 0.89), and W = 0.000000007L^3.86 (R² = 0.83), respectively. Seven morphometric characteristics were analyzed. The analyses revealed that S. acus and S. abaster were significantly different from each other in terms of their body depth (p = 0.006; p < 0.05), mouth width (p = 0.004; p < 0.05) and height (p = 0.008; p < 0.05). High correlation values were obtained for TL/BD and TL/HD in S. abaster and S. acus, respectively (r > 1).

In conclusion, among the congeneric species occurring in Lake Bafa, S. abaster and S. acus are characterized by a shorter head length and total length compared to their sea counterparts.