Fishes of the UAE 10



Fishes of the UAE 10

by R.W. Brown

In this article we take a look at two fish of the same family: Acanthuridae. They are common in the Eastern Region (Dibba to Fujeirah) but less so in Abu Dhabi waters.

Family Acanthuridae are known as Surgeon Fishes, so-named because of the rather curious sharp scalpel-like bones or spines which they can deploy from slits on either side of the caudal peduncle. These spines swing out into action whenever the fish is threatened and are a very effective deterrent against predators.




Caudal Spines

Fig. a) shows the position of the slit from which the spine is deployed.

Fig. b) shows the plan view of a typical Surgeon fish with its caudal spines deployed. The shape of the spines can vary and the ones shown here are for the Acanthurus species.

Most Surgeon fish will shy away when approached by humans. However, the scalpel-like spines are extremely sharp and should a person invade the fish's territory, particularly during the mating season, an attack is quite likely.

Acanthurus Dussumieri



Known commonly as the Queen Surgeon Fish, A. dussumieri is a spectacular fish. It has been sighted only a few times in local Gulf waters but is quite common in the Eastern region.

Description

The body shape is as shown in the drawing. Body colouring is mainly mauve with an orange flash below the dorsal fin. The head is orange with black wavy lines and a prominent longitudinal orange mark appears through the eye region. Dorsal and anal fins are mainly yellow with blue fringes. The caudal fin is a deep blue bordering a yellowish caudal peduncle.

Habits and Habitat

A. dussumieri is normally found in shallow waters (less than 10 metres) around rocky and coral coasts. It is a rather shy fish especially when approached by divers. These fish normally congregate in small groups to feed off the coral. They often split into pairs -- darting around coral heads and through rocky crevices.

Zebrasoma Xanthurum



Commonly known as the Yellow-tailed Sailfin-tang, this fish is considered by many people to be one of the loveliest coral fishes. It is more common in Abu Dhabi waters than the previous species, being often sighted singly or in pairs near an offshore coral reef, oilfield structure or ship wreck.

Description

The body of Z. xanthurum is highly compressed and is purplish blue with dorsal and anal fins of the same colour. There are numerous small dark spots on the head, throat and breast. The pectoral and. caudal fins are bright yellow. Z. xanthurum is relatively small, growing to a maximum length of about 20 cms.

Habits and Habitat

This species is found mainly around shallow water coral reef areas. It is very fast and agile, often seen darting in and out of coral holes and crevices. Z. xanthurum has been observed mainly in pairs and tends to remain close to the reef, rarely straying into open water areas. Feeding habits seem to be coral reef oriented, the pointed snout and small mouth being ideally suited to picking off the coral polyps and other minute coral inhabitants.

 


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