The length-weight relationship of indigenous and non-indigenous fish species from the small-scale fisheries of Rhodes, Greece

Abstract

Allometric data of marine fish species from Rhodes, southeastern Aegean Sea are scarce. Their collection is crucial as they provide important information on the ongoing changes of small-scale fisheries in Rhodian coastal marine waters, a highly affected region of the Eastern Mediterranean by biological invasions. Monthly experimental trials and random samplings with static nets were conducted from April 2021 to March 2022 in the coastal marine waters of eastern Rhodes, Levantine Sea. Experimental boat seining was deployed in November 2022 in the coastal waters of northwest Rhodes, Aegean Sea. Total length and total weight of several individuals of 21 fish species were measured and the length-weight relationships of 12 indigenous and nine non-indigenous fish species were examined. The allometric coefficient (b) did not differ significantly from 3.00 for most of the species (70%), demonstrating isometric growth. Positive and negative allometry were found for three indigenous and three non-indigenous species. The largest and heaviest species were the bluespotted cornetfish (Fistularia commersonii), with a maximum TL of 117.60 cm and the silver-cheeked toadfish (Lagocephlaus sceleratus), with a maximum weight of 4640.90 g. Statistically significant positive allometric relationships were found for three non-indigenous fish, namely the bluespotted cornetfish, the devil firefish (Pterois miles) and the dusky spinefoot (Siganus luridus), suggesting that these species are thriving in the under-study area.