An in-depth study of the biology, trophic ecology and catchability of the invasive pufferfish Lagocephalus sceleratus from southern Turkey, eastern Mediterranean Sea

Abstract

The silver-cheeked toadfish (Lagocephalus sceleratus) is an invasive species of highest concern. Its population must be controlled to mitigate its negative impacts on marine ecosystems, fishers, fisheries and human health. This study thoroughly investigates the biology, diet and catchability of the L. sceleratus stock from Finike, Turkey from March 2017 to February 2018 in order to better manage its invasion. A total of 751 specimens were sampled for this study with a M/F ratio of 1.25/1. The species becomes sexually mature at three and a half years of age, and Lm50 was 41.39 cm for males and 42.08 cm for females. Its spawning season in this region was from June to August, peaking in July. Its diet was mostly crustaceans in spring, fish in summer and both fish and crustaceans in winter. This species consumed a large amount of other pufferfish species, resulting in over a quarter of its fish diet. The trophic level of L. sceleratus was 4.41, demonstrating that it is indeed a top predator carnivore in the eastern Mediterranean Sea. Ingested fishing gear parts such as net pieces and hooks were found in about 10% of the fish. A slight modification of longlines using steel branch lines and a swivel hook resulted in double the catch per unit effort than standard longlines, so this technique can be used to target and control more of this invasive species, which is a national priority.

Keywords

• non-indigenous species (NIS)
• pufferfish
• catch per unit effort (CPUE)
• ageing
• stomach content analysis
• trophic level