With their torpedo-shaped bodies, juvenile dusky whaler sharks can be seen in Cabbage Tree Bay Aquatic Reserve. In the early stages of their lives they are about one metre in length. As they grow, they can migrate thousands of kilometres as they move between colder and warmer water, driven by food sources and mating.

Video text transcript

(Sian is sitting on the rocks overlooking Cabbage Tree Bay.  She describes the dusky whalers recently found in Cabbage Tree Bay.  The video contains overlay shots of dusky whalers with Sian observing them underwater in the bay.)

Sian Liddy: Dusky whalers are generalist apex predators characterised by that typical torpedo shaped body.

In Cabbage Tree Bay Aquatic Reserve, we see juveniles, which are down here in the early stages of their lives when they’re around about one meter in length. As they grow, they’ll start to undertake migrations of some thousands of kilometres as they move between colder and warmer water, driven by food sources, mating and things like that.

They’re eating things like bony fish, squid and as adults they can even eat smaller species of shark as well.

They have about a three year breeding cycle so that’s one potential reason that we see fluctuating numbers in the bay is because they’re not reproducing every year, so they have a really long gestation period and it takes them a while to recover before that female will be ready to reproduce again. Considering that this species of shark, the dusky whaler can take up to around 20 years to reach sexual maturity. So it really important that we have no-take aquatic reserves like Cabbage Tree Bay to help protect these juveniles when they’re at this vulnerable stage in their life from fishing pressure to which they are quite susceptible to ensure those juveniles can survive to help them grow and be able to reproduce to replenish those stocks and keep the population healthy for the future.

If you’re lucky enough to see any of the beautiful juvenile dusky whalers here in Cabbage Tree Bay when you’re snorkelling or diving, it’s important that you try not to stress them out as they can be quite skittish and will jet off quickly and just keep your distance as you’re enjoying the beautiful interaction that you have with this gorgeous shark species.