Regional assessment of important biological indices in the population of red cornetfish (Fistularia petimba Lacepède, 1803) along the eastern Mediterranean coasts of Türkiye

Abstract

The Lessepsian migrants of the family Fistulariidae, which are widely distributed in the Eastern Mediterranean coasts of Türkiye, are represented by two species, Fistularia commersonii and Fistularia petimba. This study focused on estimating various biological indices of red cornetfish Fistularia petimba Lacepède 1803, eastern Mediterranean coast of Türkiye. The biological indices determined were: FI- Fullness index, HSI-Hepatosomatic index, GSI-Gonadosomatic index, EQ-Encephalization quotient, VSI-Visceral index, IWL-Zihler index, Fulton-K: Fulton-Condition. For this study, 65 red cornetfish specimens (♀:40, ♂:23, immature: 2) caught as by-catch in the nets of commercial trawlers, operating in the study area in the winter of 2021 were studied. The estimated length-weight relationship (LWR) was W=0.0001L3.34 (R2= 0.89) and the species exhibits a positive allometric growth. The mean index (M±SD) and range values calculated from the obtained data are as follows: FI 1.05±0.13 (0.83-1.26); HSI 0.43±0.05 (0.23-0.62); GSI 1.27±0.20 (1.08-1.46); EQ 0.0024±0.0003 (0.0022-0.0025); VSI 3.14±0.39 (2.08-4.20); IWL 12.37±1.54 (4.41-20.3) and Fulton-K 0.47±0.06 (0.43-0.51). According to these results, it can be hypothesized that this Lessepsian species is well established and thrives in the eastern Mediterranean coasts of Türkiye. Although it is evaluated as the least concern category (LC) in the IUCN Red List 2013, we believe that the species has an invasive potential. Therefore, this study, in which biological index parameters were presented for Fistularia petimba, may be important in terms of fisheries management, planning measures to reduce distribution and combating invasiveness.