Reef Recovery at Lizard Island – June 2018
The cyclones and bleaching events took a heavy toll on the colourful branching corals from the Family Acroporidae, with almost complete removal of adult colonies around the island after the summer of 2016. However, our field observations in mid-2016 showed that there were certain locations where juvenile Acroporid corals had begun to grow, and our surveys of the Giant Clam populations in Watsons Bay in 2017 showed that hundreds of small corals from more than 20 species had become established at that site, even settling directly on the clam shells in many cases.
On our return to the island this year, we were able to re-photograph the corals growing on the Giant Clam shells to get an idea of their growth rate, and the results were quite astounding, with most colonies doubling or even tripling in size in only 50 weeks!
We were able to run a series of underwater video surveys on our site, and these returned density estimates of almost 2 juvenile corals per square meter. Given the fast growth rates of these corals and their abundance, these figures indicate that the Acroporid coral assemblage at this Clam Gardens site will recover quickly if undisturbed for another couple of years.
Not all places around Lizard Island are showing such quick recovery, but thankfully, all the sites we visited over the course of this expedition are now showing visible signs of coral recruitment, which were not evident just 12 months ago. We were particularly excited to find very high numbers of juvenile corals on the inner edge of North reef, approaching 10-20 corals per square meter, which is the highest density we have seen at Lizard Island so far.
The source of these new coral recruits is unknown, as most adult colonies in the Lizard Island area were killed during the bleaching and therefore could not have contributed larvae in recent years, but we do know that Acroporid larvae may stay viable for over a month during their pelagic phase, so it appears that adult corals on other reefs in the GBR have seeded the Lizard Island area, with ocean currents delivering the larvae. At some stage in the future, genetic fingerprinting techniques might be used to pinpoint the location of the parents of these new corals at Lizard Island, but for now we are very grateful that these young corals are growing so well!.
While there is no doubt that the reefs of the northern GBR around Lizard Island will need many years of undisturbed conditions to return to a state of high coral cover, there is also no doubt that the fundamental recovery potential of the reef is intact and that the recovery is already underway. Understanding the speed and dynamics of that recovery is now a research priority, and we are glad to be able to make a small contribution to that field. The GBR has evolved over the last 30 million years in a setting where it is continually recovering from various disturbances (sea-level change, cyclones, crown-of-thorns starfish), and our mission is to understand how that inherent recovery potential copes with the added stresses caused by the recent broad-scale bleaching events.
I think it is very important that people understand the GBR, even in its presently battered state, is still an amazing place to visit, that it is certainly not “dead” or “dying”, and that now more than ever, it deserves our most urgent protection efforts. I wrote a short article entitled Great Barrier Reef recovery underway at Lizard Island for the LinkedIn network which discussed this theme, and this piece has now been viewed over 7,600 times and re-shared over 100 times, which gives an indication of the interest people still have in this topic.
During the expedition we were able to introduce over 40 year-eight students from Geelong College to the wonders of the reef. One young woman, Ella McCann, admitted to me that she had been very nervous about coming on the trip, because the recent media reports about the GBR had made her think that all the coral was bleached and destroyed. Yet after seeing the reef for herself she was so exhilarated at all the marine life that she decided to follow a career in marine biology! We recorded a short interview with Ella that can be seen here.
While it is important that mainstream media is used to make the public aware of large scale disturbances such as bleaching on the Great Barrier Reef, it is concerning to me that our young people and many millions of others are viewing those media reports and concluding that the GBR is “dead” or “dying” and hardly worth visiting. Contemporary journalism that neglects to mention the different susceptibilities of corals to bleaching stress, or the ecological adaptation of the reef to disturbance and its inherent recovery potential, are not helping to present an accurate picture of the current situation and they present an obvious risk of instilling a sense of hopelessness in our younger generations, right at the time when we need that generation to be inspired to take action to help protect ecosystems such as coral reefs.
As marine scientists first and foremost, the Coral Sea Foundation team will always be working hard to ensure that accurate information on the status of the reefs we visit is available and clearly explained to both scientific and general audiences. This is true for both the reefs of the GBR, and also the broader area of the Eastern Coral Triangle through PNG and Solomon Islands which largely escaped bleaching damage through 2015-2016 and which will feature strongly in our Coral Sea Foundation Image Libraryproject.
Sea Women of Melanesia
Our trainee Lorie Pipiga successfully completed her second visit to Australia, which was capped off by a trip to the Outer Great Barrier Reef on a compliance patrol with the QPWS Marine Parks team led by Ranger Jo Petersen. This was a great opportunity for Lorie to see marine park management operations in Australia first hand and we are very grateful to the QPWS team for allowing Lorie to join the trip.
Our Expedition to Fergusson Island in early August is in the final stages of planning, with Lorie now on site organising the meeting venues for the various landowner groups with an interest in joining the Sanaroa Channel Marine Reserve Network. En-route to Alotau, I will overnight in Port Moresby and hold a meeting with a new group of aspiring trainees to discuss our strategy for moving the Foundation objectives forward in PNG. There has been incredible interest in the program from the cohort of young women that recently completed their biology degrees at UPNG, and we will look at options of running a training program for these women in the Port Moresby area, and then get them into the priority coral reef areas to start meeting with the communities and encourage joining the marine reserve program.
We would like to thank Mel Jackson, Fiona Mittag, Stacey Dowson, and Trevor & Judith Punnett for their recent generous donations. Visit our Sea Women of Melanesia donation portal if you would like to support this work.
Coral Sea Foundation Image Library
We are continuing our work on the Image Library delivery platform with software designer Tim Donovan from Real Advantage Solutions, and we are on track to have this project operational in the second half of the year. The Image Library will present 40,000 images of the reef community at 160 locations collected around the Indo-Pacific over the last 12 years, and will be a valuable resource for scientists, managers, policy makers, and anybody with an interest in coral reef ecosystems and how they are changing in this modern world.
We wish to thank Steve & Bronwyn Dearnley, John Burgess, Becky Butt, Chris Mattiacio, Andreas Mannott, Patricia Sheppard, Bernard Flewell-Smith, Lyubka Simeonova, and Alec Carlos for their recent support of this important project. Please visit our Coral Sea Foundation Image Library donation portal to help us with this endeavour.
