Pempheris vanicolensis
Πληροφορίες
The Vanikoro sweeper is found mainly on shallow rocky reefs at depths of less than 20 m. Adults occur in groups under ledges in caves during daytime. At night, they leave the caves to forage on planktonic organisms in open waters, and return to their caves shortly before sunrise. The fishes form age-related groups of juvenile or adult forms which, although occurring together with other groups in the same habitat, preserve their bond during the day and even during night migrations to other habitats.
The Vanikoro sweeper feeds on planktonic crustaceans and, to a lesser extent, on polychaete worms.
The spawning season lasts from April to September in the Mediterranean, and the eggs and larvae are planktonic.
The body shape and the habitat of this species differ significantly from all other Mediterranean species and a misidentification is unlikely.
The Vanikoro sweeper is an Indo-West Pacific species that is also present in the Red Sea. It invaded the Mediterranean Sea through the Suez Canal. It was first recorded in Lebanon in 1979, and subsequently along many other coasts in the eastern and central Mediterranean Sea (Israel, Lebanon, Greece, Rhodes, Turkey, Egypt, Libya and the Gulf of Gabes in Tunisia).
This species experienced a rapid population expansion almost immediately after entering the Mediterranean, and it is now very common in the Levant.
The lack of nocturnal competitors may have facilitated the population growth and spread of this non-indigenous species in the Mediterranean. Like other Pempheridae sweepers, Pempheris vanicolensis inhabits caves during the day. There is no documented evidence of competition with the native species Apogon imberbis. However, the daily migration out of the cave to forage at night and back in the morning could increase the transfer of organic matter into the cave and thereby have an impact on the cave-associated invertebrate fauna.
No impact is likely. Due to its relatively small size and its nocturnal habits, it has little importance in local fisheries.
Golani. D and Diamant, A., 1991. Biology of the sweeper, Pempheris vanicolensis Cuvier & Valenciennes, a Lessepsian migrant in the eastern Mediterranean, with a comparison with the original Red Sea population. Journal of Fish Biology 38, 8 19-827.
