At the time the best guide book on Elasmobranches was ‘Sharks of Australia’ by G.P. Whitley, first published in 1940 and revised and reprinted in 1981. It was my bible to sharks and rays, and I marked off all the species that could be seen in the area. One shark that particularly interested me was the Colclough’s shark (Brachaelurus colcloughi) a rare species only found off southern Queensland.
The Colclough’s shark, as described in the book, was a close relative of the blind shark (Brachaelurus waddi) which is regularly encountered by divers on the rocky reefs of New South Wales, especially from Sydney north to Tweed Heads. There was little information about the Colclough’s shark, apart from the fact that it was ash grey in colour and grew to 60cm in length, but there was an illustration. This line drawing showed a shark very different from the blind shark, having squared off fins unlike the blind sharks round fins, and with the spiracle (a respiratory opening) set right back instead of behind the eye. With this information in hand and a mental picture of the shark from the book I started to search for Colclough’s sharks.
Diving at Flat Rock, North Stradbroke Island, in April 1991, my buddy, Vicki, and I were exploring The Nursery. This pretty shallow site is packed with hard and soft corals and home to a multitude of reef fish. Towards the end of the dive I spotted a grey tail hanging out of a ledge. I had a close look at the fins, and they were squared off, I couldn’t believe it I had found my Colclough’s shark in just over one year. I then tried to gently extract the shark for some photos thinking this could be a once in a lifetime opportunity. But as soon as I touched the tail it shot deep into the narrow ledge and was lost from view, and reach. Disappointed I returned to the boat.
Our second dive that day was at Shag Rock, also off North Stradbroke Island, and home to an interesting variety of marine life. Still disappointed at missing the shark I couldn’t believe it when I saw another grey tail protruding from a ledge. This time Vicki, always bold, decided that she would pull the shark out so I could take photos. Vicki managed to grab the shark with two hands and slide it out before it knew what happened. I was just about to take a photo when the shark whipped around and bit her BCD. It then twist and turned. Worried about the shark (I could see Vicki was fine as she was laughing) I indicated for her to let go, she did and the shark zoomed off into the blue.
A week later I found another one at Manta Bommies, and then another at Flat Rock, but this time I managed to get some photos. They appeared to be common off North Stradbroke Island. Over the next year I could find them on almost every dive, and sometimes up to three sharks. I was puzzled why this shark looked nothing like its close relative, the blind shark, and was also puzzled by the size discrepancy, the book said to 60cm, but some of these sharks where 1.2m long.
In April 1992 I was diving a bommie off Shag Rock when I found another grey coloured shark. It had faint brown bands, rounded fins and was roughly 60cm long. From the description in my book it had to be a brown banded catshark (Chiloscyllium punctatum), named after the young that have brown bands. This shark was actually sitting in a gutter, unlike Colclough’s sharks that were hiding under ledges. I managed to shoot several photos of it resting and then swimming slowly around the reef. This shark is supposed to be a tropical species, but the book did say as far south as Moreton Bay. I was over joyed to get photos of this lovely little shark. Two weeks later I found another one at Manta Bommies, but after a strobe flood couldn’t get any photos.
For the next two years I found dozens of Colclough’s shark and no more brown banded catsharks, these Colclough’s sharks were looking to be a pretty common species I thought.
Then in 1994 my bible was superseded by ‘Sharks and Rays of Australia’ by P.R Last and J.D. Stevens. I couldn’t wait to get a copy. It finally arrived in the mail and I spend hours pouring over the details of new species and marvelling at the illustrations. Then I got to the Colclough’s shark. Hang on a minute, that looks like a brown banded catshark. I turned to the brown banded catshark and it looked like the Colclough’s shark. Then it dawned on me, my old guide book had the illustrations around the wrong way! That explained why it looked nothing like a blind shark. So the brown banded catshark was common and the Colclough’s shark rare.
Later that year I took American marine biologist and shark expert Scott Michael diving on our local reefs. The first few days were spent looking for leopard sharks, but then we headed down the Gold Coast for a few dives. We headed out to Palm Beach Reef and had found quite a few spotted wobbegongs, Scott’s favourite shark. I was looking for more wobbies when I stuck my head under a ledge to find a large Colclough’s shark. This one was close to a metre long. I slowly extracted it and showed Scott, he was amazed, I had told him about the two I had found, but never thought he would get to see one. We both shot dozens of photos before the shark slowly swam off.
We followed it along the reef and w
ere stunned when it lead us to
another Colclough’s shark. This
one was bigger, a female just on a metre long, and she was sitting out in the
open. We both finished our film on this wonderful shark and swam back to the
boat on a high. After the dive Scott mentioned that an American biologist
reported seeing a Colclough’s shark at Forster, if true this extended its
limited range.That report had me puzzled, and stayed in the back of my mind for years. Since then I haven’t found another Colclough’s shark. But diving Halifax Park at Port Stephens in January 2002 I stumbled across a strange blind shark. It was light brownish in colour, with only faint bands and lacked white spots. It looked just like a Colclough’s shark, but the fin shape said it was a blind shark. This blind shark colour variation could have been what the American biologist saw at Forster.
With little research being done on Australian sharks it’s up to us divers to keep our eyes peeled for unusual species and behaviour.