Page 120 - Invasive_Species_2013

Mediterranean invasive species factsheet

FISHES

Reproduction Common name: Dusky spinefoot

Forwad-projecting
spine Caudal fin truncated
identification

Scientific Name:
Siganus luridus
Picture

Key identifying features
Brief history
The body is deep, ellipsoid, and compressed; the
scales are small and embedded in the skin. The Oval shape
body
maximum length reported is 30 cm (total length; Anal fin with
7 spines
commonly 5–20 cm).The dorsal fin (13–14 spines
and 10 soft rays) begins above the pectoral fin base.
The pelvic fin begins behind the pectoral fin base,
and its inner spine is connected by a membrane to adults are solitary but groups of 3 or 4 adults have
the abdomen. The anal fin (7 spines, 9 soft rays) also been observed; the juveniles form larger
begins beneath the 8th to 10th dorsal spines and has schools. However, huge schools of adults (up to
a rounded margin. The caudal fin is truncated. The 5,000 individuals) are sometimes observed along the
anterior spines of the median fins are slender and Mediterranean coast. It feeds on a wide range of
sharp, and the posterior spines are stout; all the benthic algae, mainly coarse brown algae, but
spines are venomous. The anterior nostril has a long, seagrasses are also reported in its diet. Siganus
broad flap covering the posterior nostril when luridus feeds at more or less the same rate in all
depressed. The mouth is small with distinct lips. The seasons. It may suddenly stop and erect its fins
maxilla does not reach the vertical plane through the (dorsal, anal and pelvic), presenting an encircling
eye. The incisor teeth are in a single row. The colour array of venomous spines to potential predators.
is dark brown to olive green with a touch of yellow on
the fins, but varies regionally. At night, the colour is
very mottled.

Field identification signs and habitat

It occurs in small schools in shallow water close to
the bottom. It prefers hard bottoms of compacted
sand with rock, usually covered with vegetation. The

Siganus luridus. Photo: O. Sagué Siganus luridus. Photo: P. Bodilis - ECOMERS

Monitoring Marine Invasive Species in Mediterranean MPAs: A strategy and practical guide for managers 117