Population Structure and Sexual Maturity of the Pufferfish Lagocephalus sceleratus （Osteichthyes, Tetraodontidae） in the Lebanese and Syrian Marine Waters （Eastern Mediterranean）

The pufferfish Lagocephalus sceleratus is an invasive Lessepsian species of Indo-Pacific origin that has established an increasing population over the past decade in the Levantine basin of the Mediterranean. Besides its toxicity due to the accumulation of tetrodotoxin in its body, it is causing damage to fishing gears and fishermen＇s catches. This study aims to provide data on the population structure and sexual maturity of this species in the eastern basin of the Mediterranean. A total of 214 individuals were collected in the coastal marine waters of Lebanon and Syria, between January 2012 and June 2013 by means of different types of nets and lines, on soft bottoms, at depths ranging from 10 m to 170 m. The TL （total length） of the samples varies between 10.8 cm and 71 cm. The most common size classes, represented by 125 individuals, are the ones between 30 cm and 50 cm TL, with a bulge at 40 cm, represented by 44 individuals. The average TL is 43.99 cm （standard deviation： SD = 17.65） for both males and females. The TW （total weight） of the specimens ranges between 14 g and 4,603 g with an average value of 1,458.52 g （SD = 1,329.49）. The sex ratio （M/F） is 1：1.35 with a total number of 87 males, 118 females and nine unidentified individuals. The weight-length relationship （TW = aTLb） shows a negative allometric growth with b = 2.9481 and R2 = 0.9806. The condition factor （K） is close to one for all samples. The average value of the GSI （gonadosomatic index） shows a substantial increase from winter to spring. The spawning takes place between April and June.