Stomach Content Analysis of Suez pufferfish (Lagocephalus suezensis) in Derna coast, Libya (Mediterranean Sea) and Hurghada coast, Egypt ( Red Sea)

Abstract

This study provides a comparative analysis of the stomach contents of the Lessepsian migrant pufferfish, Lagocephalus suezensis (family Tetraodontidae), across two distinct populations: the native population along the Hurghada coast (Red Sea, Egypt) and the migrant population along the Derna coast (Eastern Libyan Mediterranean Sea). A total of 283 specimens were collected monthly between January and December 2022 using trawl nets at depths ranging from 15 to 50 meters. The investigation focused on annual and monthly diet compositions, ontogenetic shifts in feeding habits related to fish length, and overall feeding intensity. The results indicate that L. suezensis is a generalist carnivore with a preference for benthic invertebrates, though diet composition varied significantly between the two locations. Along the Derna coast (n=133), crustaceans were the predominant prey group (55.7%), followed by bony fish (22.3%), marine worms (14.4%), mollusks (4.4%), and foraminifera (3.2%). Conversely, the Hurghada population (n=150) primarily consumed mollusks (41.3%), supplemented by crustaceans (26.4%), bony fish (17.9%), echinoderms (11.3%), and incidental sediments (3.1%). While mollusks, crustaceans, and bony fish were present in the diet throughout the year and across all size classes at both stations, clear ontogenetic shifts were observed. The consumption of mollusks, marine worms, foraminifera, and echinoderms decreased as fish size increased, whereas the preference for larger prey, such as crustaceans and bony fish, showed a positive correlation with fish length. Feeding intensity also exhibited seasonal fluctuations: in Derna, peak activities were recorded during spring (82.3%) and autumn (68.9%), while the Hurghada population reached its maximal feeding rate in autumn (82.4%). These findings highlight the adaptability of L. suezensis to different environments and its potential impact on local benthic communities.