405_April_24

MARINE BIOLOGY WITH MIKE SCOTLAND - FISH IDENTIFICATION

The male Toothbrush leatherjacket.

Valerio Visconti, Research Scientist

about early Summer to Autumn, January to May. As soon as the water temperature hits the winter minimum of fourteen degrees and then begins to rise, their gonads begin to grow larger. Gonads are presumably growing in June and July. They reach maximum size in August and September and this coincides with the middle of the mating period. These gonads increase about five fold in weight. This is a powerful adaptation to help the survival of the fish during the leaner times of winter when food shortage is more likely. Leatherjackets are serial spawners. They mate possibly every few days over the five months. One

I was in touch with Valerio, several years ago, who was doing a Doctorate on the Velvet leatherjacket in Auckland University. He found some interesting insights into the reproductive lifestyle of Meuschenia scaber , the Velvet leatherjacket. He used the technique of collecting more than five hundred Leatherjackets by spearfishing and then taking them back to the lab for close examination. Following are some of the results he found. They breed between August and December. Both Males and females’ gonads shrink to a tiny size from

The Orange Fin leatherjacket at North Solitary Island

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DIVE LOG Australasia #405 - April ‘24

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