Biological studies of the invasive species Nemipterus japonicus (Bloch, 1791) as a Red Sea immigrant into the Mediterranean

Abstract The rate of fish invasion into the Mediterranean Sea has increased in recent decades; collectively they have significant ecological and economic impacts in the eastern Mediterranean. One of this species is Japanese thread fin bream Nemipterus japonicus that gradually get abundance in the Egyptian Mediterranean coast bottom trawl catch. During 2011, monthly samples of N. japonicus caught off Abu Qir area, Alexandria-Egypt, were used to estimate some biological parameters of this immigrant species. Females were more in abundance than male in the catch deviated to smaller size than male. Spawning season extended from April to November with highest activities in July. Maximum observed age was 3 years for both sexes with no significant difference between their lengths at age. Length-at-age was fitted to the Von Bertalanffy growth models. Present results of the Mediterranean Sea population showed lower biological (e.g. growth and longevity) condition comparing to original indo-pacific population.