Discovering Remote Reefs and Blue Holes with Johnny Gaskell

The world's oceans remain the Earth's last frontier for discovery, with 95% of the underwater world still currently unexplored. We caught up with Johnny Gaskell, the marine biologist with a mission to find and document the Great Barrier Reef Marine Park's undiscovered coral reefs.

Johnny grew up in Longlea, Victoria, a long way from the ocean, which consists of a few farms and a couple of creeks and waterholes. Fascinated by the aquatic life in the creeks, he chose to study Marine Biology in Warrnambool, Victoria and focused the first 10 years of his career working with temperate marine life. Johnny’s work in marine education in Melbourne lead to his first published book, Beneath Our Bay, a guide that details the marine animals of Port Phillip.

He moved to Ningaloo Reef, Western Australia and worked as a Dive Master before crossing the country to the Whitsunday Islands where he currently works as Living Reef Manager on Daydream Island, while assisting as a researcher with Sharks and Rays Australia.

Discovering remote reefs & blue holes

What I love about the ocean is that every time you get in, you are exploring and witnessing another world of wildlife interaction. No snorkel is ever the same and you learn something new every time. When exploring underwater in the ocean there is no set path, no suggested itinerary, no signage or target to reach in the distance. Just swim and see where you end up. The fact that most of the seabed is unexplored, including many parts of the Great Barrier Reef, means anyone can be the one to witness a marine community for the first time.

My mission over the past few years has been to determine where coral currently exists in the Great Barrier Reef Marine Park and witness it for myself. As part of this mission I have stumbled across a range of amazing sites with incredible coral cover and diversity. Included in these sites were 6 blue holes, 3 of which had no documentation that I could find, so may have never been surveyed or explored before. Around the Whitsundays in particular, discovering sites that still have coral cover post-cyclone Debbie has been the main mission.

A lot of planning goes into the Blue Hole missions, to film for the purposes of gathering data. They are found out at the Hardline Reefs, which are roughly 200km offshore and over 250km away from where we leave in the Whitsundays. The key is to time the tides and weather conditions perfectly, so that we reach the Blue Holes and return safely. A few of the Holes are inside lagoons that have reef edges which are exposed to trade winds. The Hardline Reefs also experience incredible currents and huge tide variations, so the water movement is unlike anywhere else I’ve seen in the reef. In the channels between some reefs the current exceeds 10 knots.

For that reason, we need neap tides and a three day forecast of under 10 knots to ensure access is safe. On top of this, the whole area is unsurveyed waters, meaning there are no navigational charts of any kind that let you know where the reef is and where deep water is. We have to rely solely on what we can see from the front of the boat, and a pre-downloaded cache of Google Maps.

I feel like I have seen every representation of coral health, coral stress and coral recovery at every site I have been to this summer. It really is a mixed bag, but the reality is that this year seems to be the worst bleaching on record for the Whitsundays. To gauge the full impact, we still need to wait and see how well it recovers over the next few months. We have seen some coral death, but for the most part, the corals seem to be recovering this year.

I see this year as a stern warning for us all. It is now clear that all sections of the Great Barrier Reef are at risk of bleaching due to climate change, and if the temperature increase is sustained across a couple of months in the future, we may lose a significant percentage of colonies and species locally. It is important that we do whatever we can to reduce our carbon footprint as individuals and as a nation.

Words and photography by Johnny Gaskell