Big firsts – exploration diving on the south coast and the reefs of Lava Point

Today was another great day. The highlight was diving on the south coast. This section of coast is so exposed that it is has rarely been dived, let alone surveyed. Fortunately for us, the weather and sea conditions continue to exceed expectations presenting us with a rare opportunity to explore these southern reefs.

After an update on the score of the AB’s semi-final, a generous helping of Sunday morning eggs and beans it was all hands on deck and off to the dive site in ‘Thomas’ the diving tender. When we arrived on the open coast we were surprised to see swells that had appeared small from the shelter of Denham Bay smashing on to the southern boulder coast. We decided to give the dive a shot anyway as we would be dropping into water about 18m deep and heading into the shallows. This meant we would have the opportunity to avoid the shallower wave affected sections of reef if the wave action turned out to be too big. Once we were in 4 metres of water, and a blizzard of sand, we finished up the dive safely.

Corals (centre) and red algae (foreground) on shallow boulders on the east coast of Raoul Island.

When we dropped on to the reef, we were once again reminded that the subtidal reef communities of the Kermadec Islands are different to those of mainland New Zealand. We were greeted by an array of temperate and tropical fish. Spotted black grouper, rare and protected in NZ, were plentiful. Rather than one species of kina, like on the mainland, we had three urchin species in our surveys: a species common to the seagrass beds of the tropical Indian and Pacific Oceans and two subtropical species.

Dave and Libby survey reef communities on the shallow reef walls at Raoul Island. Divers lay tape measures across sections of the reef and calculate the density of urchins by counting their numbers along each of these transects. In the bottom left section of this photo you can see more than a dozen urchins sitting on top of the large reef boulders.

After moving back to the more sheltered east coast of the island we decided to survey some of the reefs on the coast of Raoul Island. After a quick committee session looking at charts we made our way to Lava Point. As the name might suggest everything at lava point was at grand scale. In the deep there were massive grouper, in the mid-water a metre long turtle keeping watch over us, and in the shallows there were giant limpets as long as 15 centimetres. This was a spot we’d like to return to if weather and time allows.

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