Feeding habits and trophic morphology of inshore lizardfish (Synodus foetens) on the central continental shelf off Veracruz, Gulf of Mexico

The inshore lizardfish, Synodus foetens, is one of the most common coastal demersal predators on the continental shelf of the Gulf of Mexico (GOM), but the biology and feeding ecology of this species is virtually unknown. Between November 2001 and January 2003 (10 collections), 603 individuals of S. foetens ranging from 112 to 420 mm standard length (SL) and 13 to 630 g (wet weight) were collected from the continental shelf of Alvarado, Veracruz, Mexico. About 60% of the individuals had empty stomachs with the stomach fullness of the remaining individuals being distributed as follows: 5% full (24.8%), 50-75% full (13.5%), and completely full (1.7%). The mean (+/- SD) wet weight of stomach contents was 12.1 +/- 10.8 g during the rainy season, and 19.0 +/- 13.0 g during the nortes season. Seventeen prey items were identified, with the majority thereof being fish. The most important prey items were Upeneus parrus, Loligo pealei, Engyophrys senta, Trachurus lathami, and Anchoa hepsetus. Seasonal changes in the diet were observed, with U. parrus and L. pealei being the most important prey during the nortes season, whereas E. senta and L. pealei were the main items during the rainy season. Prey size selection was evident among size classes of S. foetens, although no trophic overlap was observed among size classes (C-lk <= 0.004). High trophic level values were determined for all size classes by season (rainy season = 4.67, nortes season = 4.84), and indicated this species belongs to the piscivorous trophic guild that preys upon both demersal and pelagic species.