405_April_24

MARINE BIOLOGY WITH MIKE SCOTLAND - FISH IDENTIFICATION

Red Tooth Triggerfish, Odonus niger , live on slopes in deeper waters.

Juveniles of the Pallid Triggerfish, Sufflamen bursa can be seen in Sydney waters in summer.

dorsal fin and anal fins are used for fine locomotion in Triggerfish, similar to how a leatherjacket manoeuvres with fine motor movement. It gives them a unique swimming style. The fish scales on the caudal peduncle in front of the tail are strongly spiked and are defensive in nature. Many Leatherjackets have prominent spines on this region but they are usually much more developed and look more like weapons in some species. Leatherjackets often have soft scales with sharp erectile spines all over their body. The mouth is right at the tip of their head in both Triggerfish and Leatherjackets. This is called a terminal mouth. Triggerfish have eight powerful teeth top and bottom capable of smashing shells, crabs, corals and pretty much anything it wants. The eyeball is a really high on their head on both fish

families. There is a thin gill slit immediately above the pectoral fins. Look carefully! You can see this in the photos. They do have a gill plate or operculum but it is covered by a layer of tough skin. This peculiar feature is common to the both families. Triggerfishes. have a deep groove in front of the eye on both sides going toward the snout. Generally, they have a massive tail fin but there is a lot of variety in the size and shape. The Red Tooth Triggerfish is an open water swimmer and has trailing edges top and bottom on its lunate tail fin. There are differences between Leatherjackets and Triggerfish. Leatherjackets have a more prominent ventral fin. The ventral fin in Triggerfish is usually more rudimentary in most species or it is less visible. Male and female Triggerfish are pretty much identical.

Titan Triggerfish smashing the reef to bits,

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DIVE LOG Australasia #405 - April ‘24

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