405_April_24

MARINE BIOLOGY WITH MIKE SCOTLAND - FISH IDENTIFICATION

Toothbrush leatherjackets displaying strong pair bonding and sexual dimorphism.

After a few moments, I recover my senses and turn to the wobbegong and say. “ You will never do that again, will you ?” That is why they survive, the Sea Star told me! More than half of all species of Leatherjackets are found in temperate Australian waters. This makes the Southern half of Australia the world bio-diversity centre for this family. Australian waters have incredible bio-diversity with sixty species of Leatherjackets in the family Monacanthidae. I have always found them to be fascinating; many are very photogenic. Many of them have striking sexual di-morphism. That is, males and females look very different. A good

example is the Toothbrush leatherjacket. The female is quite plain. On the other hand, the male is much more brightly coloured especially in the breeding season. He also has a prominent set of stiff bristles, the ‘toothbrush’ along his side in front of the tail. The plain colour of the female helps her to hide amongst the seaweeds. The brighter colours of the male helps him attract a mate and display his sexual maturity. In other species, males and females are identical. The ‘all black’ Dusky leatherjacket, with the bright golden eye is one such species. Small tropical ones are often called Filefish. These include the bright green and orange Checkerboard patterned or Tessellated leatherjacket, Oxymonacanthus longirostri s, one of my favourite tropical fish. It is also called the Long Nose filefish.

The stunning Tesselated leatherjacket, (Beaked File Fish) is extremely difficult to capture in the camera

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DIVE LOG Australasia #405 - April ‘24