The puffer fish Lagocephalus sceleratus (Gmelin, 1789), family Tetraodontidae, is a Lessepsian species which has invaded the Eastern basin of the Mediterranean Sea. The present work is the first study that gives an account of length-weight relationship, condition factors and feeding habits of L. sceleratus in the eastern coast of Libya.L. sceleratus were randomly sampled monthly during January to December 2015 from the artisanal catch of Ain El-Ghazala lagoon (a total of 146 specimens) and Derna coast (22 specimens) on eastern Libya. Ain El- Ghazala fish had total length ranging from 19.5 to 73.4 cm corresponding to total weight of 149.3 to 4000.5 g. Total length of Derna L. sceleratus ranged from 49.5 to 73.4 cm corresponding to total weights of 1657.2 to 4011.8 gm. The length (L) weight (W) relationship W = 0.01881 *L2.8774, n = 146, R2 = 0. 7135 reflects a near isometric growth for Ain El- Ghazala fish (b = 2.8774). Fulton and Clark condition factors (KF and KC) of Ain El- Ghazala L. sceleratus were high in spring (1.34 and1.23 consecutively) and summer (1.43 and 1.21) and low in winter (1.21 and 1.13) and autumn (1.25 and 1.16).Mollusks (72.5%), supplemented by crustaceans (17.4%) and fishes (10.2%), composed the diet of Ain El-Ghazala L. sceleratus. Mollusks dominated the diet in all seasons, followed by crustaceans, then fishes. Feeding intensity was high during spring (83.5%) and autumn (72.6%) and low in winter (41.6%) and summer (28.3%). Uptake of mollusks decreased as L. sceleratus size increased, while that of crustaceans and fishes increased. Derna L. sceleratus of all sizes (49.5-73.4 cm) fed only on fishes (100%).
Keywords: Condition Factor, Length-Weight Relationship, eastern Libya, food and feeding, lagocephalus sceleratus, mediterranean sea. lessepsian.
