DIVELOG JUNE 406

the one and only time I have seen a baby Blue devil and It is a very rare and treasured moment. Clearly, the only way that they can survive is by being extremely secretive. Blue Devils are in the Genus Paraplesiops. They are correctly called the Eastern Blue Devil, Paraplesiops bleekeri. Blue Devils are in the family PLESIOPIDAE, a family of fish known as ‘prettyfins’. It might surprise you to learn that other members of this family include the Scissortails scientifically known as the Assessors, Hula Fish and Comets. Scissortails are a tiny fish that live in coral caves on the Barrier Reef. They are there in the millions but go under the radar. My favorite Scissortail is the Golden or Yellow Scissortail, a version found in Tufi, Tawali and Walindi, PNG and the Far North Queensland reefs. This tiny golden gem is extremly shy. Another related fish are the Comets, Calloplesiops altivelis, If you love to watch fish, I guarantee that your first encounter with a Comet will hypnotise you. You will be hooked for life by these beautiful fish. They live in deep dark caves and feed at night. Comets are extremely shy and fairly rare. I have seen them in Fiji and Lembeh. An even stranger relative of the Eastern Blue Devil is the Sydney Hula Fish. These tiny ribbon like fish are very common and overlooked by most divers. Years ago, I ran a Marine Biology course on Ocean Trek at Jervis Bay. I had designed an exercise to study Eastern Hula Fish.

Careful observation of marine life can unveil deep dark and fascinating wonders in the sea. The very heart of wonder. I watch the school of Eastern Hula fish. I notice that they have a tiny territory a few metres wide. They rise up into the water column to pluck on plankton.There are several larger adults mostly in the cente of the loosely structured school. Tiny juniors live on the extremities of the school The reason is that a predator can take juveniles at the edge of the safe zone. Breeding adults live close to the middle where it is slightly safer. It is a deliberate strategy of survival. Next I did a basic population count. We estimated twenty to thirty fish in a school. The next schools were perhaps ten metres away, Some were deeper. A few conservative estimates of the numbers followed by a rough calculation of the meterage of Jervis Bay’s rocky reefs and we come up with a population in the Billions. I often like to say that the greatest experiences we can have on planet Earth is to have a close encounter with nature. Many people say ‘my bucket list is I want to see Orcas and Polar Bears, watch Lions in the wild and Rhinoceroses. For me, diving right here in Sydney, can provide the same world class thrills A close encounter with a massive Smooth Stingray is close to seeing wild lions or Rhinos in Africa. On the other hand, to unveil secrets such as these of the humblest fish in the sea is a phenomonen of massive numbers. It is also a thing of beauty and wonder! Who would believe it?

66

DIVE LOG Australasia #406 - June ‘24

www.divelog.net.au