Fishes In Maldives: 1786)

Melichthys niger (Bloch, 1786)

English Name: Black triggerfish
Family: BALISTIDAE
Local Name: Kalhu rondu
Order: Tetraodontiformes
Size: Max. 35 cm
Specimen: MRS/P0350/89

Distinctive Characters: Dorsal fin with 3 spines and 32-35 rays. Anal fin with 28-31 rays. Pectoral fin with 15-17 rays. Prominent longitudinal ridges following scale rows on caudal peduncle. Caudal fin emarginate to lunate (except juveniles).

Colour: Dark blue-green to black. Blue-white lines at base of soft dorsal and anal fins. Submarginal blue line on caudal fin bends into lobes.

Habitat and Biology: Occurs on upper reef edge of outer slopes of seaward reefs. Feeds
predominantly on calcareous algae; also feeds on zooplankton.

Distribution: Indo-Pacific.

Remarks: Melichthys niger is very similar in appearance to, and easily confused with Mindicus
(previous page). M. niger is more widely distributed.

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Canthidermis maculatus (Bloch, 1786)

English Name: Ocean triggerfish
Family: BALISTIDAE
Local Name: Oivaali rondu
Order: Tetraodontiformes
Size: Max. 50 cm
Specimen: MRS/P0l32/87

Distinctive Characters: Dorsal fin with 3 spines and 23-27 rays. Anal fin with 20-23 rays. Pectoral fin with 14-15 rays. Mouth terminal. No enlarged scales above pectoral fin base forming distinct tympanum. Cheeks scaled and without longitudinal groove. A deep groove before eye, below nostrils.

Colour: Adults with body and head dark, lighter below with elongate white spots that can disappear with growth. All fins dark. Small juveniles with spots not confined to ventral surface.

Habitat and Biology: Occurs in offshore waters. Epipelagic throughout its life. Adults as well as juveniles are often associated with drifting objects.

Distribution: Indo-West Pacific.

Remarks: Unlike other triggerfishes Canthidermis maculatus is most often encountered offshore, where it is frequently associated with drifting flotsam. It is therefore often seen by Maldivian tuna fishermen, although there is no local market for this species so it is almost never caught. C. rotundatus is a synonym.

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