The African Diving Experience

Fishwatch
 Triggerfish nr 7 - 11

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On this page: Wedgetail, Boomerang, Bridle, Halfmoon, Whitetail

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7) Wedgetail triggerfish, Rhinecanthus rectangulus

We found this juvenile wedgetail triggerfish, Rhinecanthus rectangulus (Bloch & Schneider, 1801)  in a tidepool at Scottburgh, KZN.   Although it is a mere 32 mm long from tip of snout to base of tail fin, it looks very similar to the adult.  This territorial species prefers shallow, rocky reefs surrounded by lots of sand.  An active fish that is wary of divers and difficult to photograph.  We saw it on the reef at the mouth of Kosi Bay, where the adult was photographed.  It is also common on the shallow barren rocks south of Jesser Point at Sodwana Bay.  The species is known from the Red Sea to East London (adults are rare in the Eastern Cape) and across the Indo-Pacific region to the Hawaiian and Pitcairn Islands.  Attains 20 cm.

Juvenile Wedgetail

Juvenile Wedgetail Triggerfish

Adult Wedgetail

Adult Wedgetail Triggerfish

8) Boomerang triggerfish, Sufflamen bursa

The boomerang triggerfish, Sufflamen bursa (Bloch & Schneider, 1801) is common on the reefs of KwaZulu Natal.  Note the distinctive boomerang-shaped marks behind the eye.  While I was lying in a cave at Aliwal Shoal waiting for a tiger shark to appear, I watched a Sufflamen bursa swimming about over the reef in front of the cave.  Every few seconds, it would change the boomerang marks back and forth from black to yellow.  I suspect that the colour of these marks, or the changing of the colours may have some territorial significance, or may be used to attract a mate.  The fish shown is 145 mm long from snout to base of tail fin; and the maximum size for the species is about 25 cm.  The species is known from depths of 3-90 m.  It occurs from South Africa to the islands of the central Pacific Ocean.

Boomerang

Boomerang Triggerfish

9) Bridle triggerfish, Sufflamen fraenatum

The bridle triggerfish, Sufflamen fraenatum (Latrielle, 1804) takes its names (fraenatum is Latin for “bridled”) from the white markings about the mouth of the adult male.  The 28 mm postlarva shown here is too young to show the distinctive adult colour pattern.  This bicoloured livery is typical of the pelagic postlarval stage of some triggerfish species.  After hatching from the demersal egg, the larval triggerfish float about in surface waters for several days as they grow and develop into recognizable triggerfish postlarvae.  The postlarvae may then drift at the surface for several weeks (or months), until they find a suitable reef on which to settle.   Soon after settlement, the postlarva takes on the colour pattern of the juvenile/adult triggerfish.  The 22 cm adult male shown here is from Sodwana Bay; the female lacks the white “bridle” stripes across the lower cheek.  Found in depths of 15-150 m.  Occurs from South Africa (south to Aliwal Shoal) to the islands of the central Pacific Ocean.  Attains 38 cm. 

Adult Bridle

22 mm Adult Bridle Triggerfish

Postlarva Bridle

28 mm Postlarva Bridle Triggerfish

Halfmoon

10) Halfmoon  triggerfish, Sufflamen chrysopterum

These two halfmoon  triggerfish were collected together at Aliwal Shoal and show the transition from the bi-coloured 38 mm pelagic postlarva to the uniformly coloured 42 mm benthic juvenile of Sufflamen chrysopterum (Bloch & Schneider, 1801).  The adult has a white or yellow stripe from the back of the eye to the lower end of the pectoral-fin base.  It is known from depths of 1-30 m and occurs from South Africa to Oman and islands of the central Pacific Ocean.  Attains 22 cm.

11) Whitetail triggerfish, Sufflamen albicaudatum

Whitetail

Two Halfmoon Triggerfish

The whitetail triggerfish, Sufflamen albicaudatum (Rüppell, 1829) is a recent discovery in our area.  The species was previously thought to be restricted to the Red Sea.  It is closely related and very similar to the halfmoon trigger, but the latter species lacks the white mark across the base of the tail fin.  This  49 mm specimen, collected last year at Aliwal Shoal, is a new record for southern Africa.  Adults (males only?) have a blue throat, which accounts for the name “bluethroat triggerfish”, which is also used for this species.  Attains 18 cm.

Whitetail triggerfish

Triggerfish Index

On this page: Wedgetail, Boomerang, Bridle, Halfmoon, Whitetail

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Text and photos Dr Phil Heemstra

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Updated on: 23/03/2001

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