Pempheris vanicolensis Species Gallery (0040)

Pempheris vanicolensis Species Gallery (0030)

Pempheris vanicolensis Species Gallery (0020)

Scientific Name:

Pempheris vanicolensis

Common Name:

Vanikoro sweeper

Taxonomic Group:

Fishes

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Information

Key Identifying Features

This small to medium-sized fish can grow to 20 cm. Its body is deep and strongly compressed, the belly is triangular, the mouth is oblique, and the eyes are large. The dorsal fin is very short, usually higher than long, and much shorter than the anal fin. An obvious distinguishing feature is the dark leading edge of the short dorsal fin, expanding to produce dark tips on the soft rays (total 6 spines, 9 soft rays); the posterior region of the tail fin is also dark. The pectoral fin is translucent with a distinct black outline forming a Vshape along the lower edge. The anal fin (3 spines, 31–43 soft rays) is very long. The lateral line is complete, gently curved, and extends onto the tail fin.

This fish is brown bronze in colour, with a greenish sheen over the back. The pectoral fins are yellow without a black basal spot; the tip of the dorsal fin is black, and the base of the anal fin is often black.

Identification and Habitat

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.

Reproduction

The spawning season lasts from April to September in the Mediterranean, and the eggs and larvae are planktonic.

Similar Species Description

The body shape and the habitat of this species differ significantly from all other Mediterranean species and a misidentification is unlikely.

History and Route of Introduction

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.

Ecological Impacts

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.

Economic Impacts

No impact is likely. Due to its relatively small size and its nocturnal habits, it has little importance in local fisheries.

Management Options

These include a) early eradication of new populations by MPA technicians through hand fishing, and b) maintenance of healthy and abundant assemblages of top predators to encourage natural control through predation.