Project LIHOU

December 4, 2009 — December 14, 2009

PROJECT LIHOU ("lee-hoo") explored the wilderness of this “Serengeti of the sea”. Though rarely visited by humans, its remoteness does not mean it is untouched by the effects of our everyday lives. Sea level rise, ocean warming, cyclones and ocean acidification are concentrated at the tiny coral cays: a microcosm of global climate change effects and an ideal laboratory for our work.

It's not just about the beauty of Lihou but the fact that all species and ecosystems on our blue planet are vital to the survival of our species. We are all connected.

Deep reefs were examined using a remotely operated underwater vehicle (ROV – a type of robot) – exploring habitats never before seen by humans. Scientific divers surveyed lagoons, counted fish and assessed coral bleaching. Meanwhile, wildlife ecologists documented flora and fauna associated with coral cays and collected vital data on seabirds and whales.
 Project LIHOU - Day 1  Project LIHOU - Day 2
Started the morning at about 22 degrees 27 minutes south, 151 degrees 38 minutes east, about 90 miles offshore and just south of the Great Barrier Reef. Before reaching Swaines Reef (the southern end of the Great Barrier Reef), we were entertained to flying fish, one flying squid, and twice to Bottlenose Dolphins that joined us to ride at the vessel bow. From dawn, there was a constant stream of Wedge-tailed Shearwaters . This species circumnavigates the coral sea to feed chicks left at breeding grounds along the Queensland Coast. We also two sea snakes (as yet to be identified).

For most of the day the water was quite turbid but cleared late in the afternoon, so we stopped to snorkel at Twin Cays. The small sand cay was host to thirty Black-naped Terns , a dozen Crested Terns and a few Brown Boobies. On approach we encountered a large Hawksbill Turtle .

The coral itself was severely cyclone-damaged as evidenced by the almost complete lack of live coral (less than 1% cover). There was no evidence of coral recruitment at all, which is perhaps not surprising as  this was probably the result of Cyclone Hamish, and there would have been no time for polyps to settle since. The substrate therefore was mostly coral rock with a thick layer of algae. An indicator of reef health, butterfly fishes were both scarce and only two species were seen over a 500m swim.

This kind of damage is not unusual on the Great Barrier Reef and depending on the frequency of cyclones and the ability of algae and coral to recruit, it can recover within five to ten years. So the resilience of reefs to damage is not just a factor of the number of cyclones but more importantly, water temperature and water quality, both of which are affected by land-based activities such as agriculture and of course, climate change. Read more.
 Project Lihou - Day 3
Overnight winds strengthened leading to a slightly uncomfortable swell as we headed for our second stop-off at Marion Reef. Located about 10 hours south of Lihou Reef, Marion sits alone surrounded by several hundred metres-deep water of the southern Coral Sea. Compared to the reef we visited yesterday, this reef had a better fish diversity but was still suffering from bleaching and competition with surface algae. On the way into Marion Reef, seabird numbers were relatively low but increased as we approached. Predictably (and spectacularly), Red-footed Boobies and Masked Boobies started to catch flying fish flushed from under the vessel's hull. We arrived at Marion Reef to find the sand cay we were aiming for was under water at low tide so some of the team snorkelled and others dived. Amazingly, within minutes we were watching sea snakes and White-tipped Reef Sharks. Perhaps the highlight of the day were three sightings of Manta Rays. Later at low tide, the sand cay was exposed and birds started drifting in to roost near sunset.

Read more.
 Project LIHOU - Day 4
7 December 2009 East Diamond Islet

We approached East Diamond Islet from the south and bird numbers were initially quite small, though very quickly from about 20 Nm from the island, we started to accumulate Masked and Red-footed Booby juveniles. Several times, they caught flying fish flushed by the boat. East Diamond Islet itself was, as always, amazing. Hundreds of Lesser and Greater Frigatebirds continuously soar over the island, along with thousands of other nesting seabirds including Sooty Terns, Common and Black Noddies, Red-footed, Brown and Masked Boobies, Black-naped and Crested Terns, and we found four nesting Red-tailed Tropicbirds. On arrival, a Dollarbird flew past and alighted...a very surprising record so far from land. There was one, perhaps two, Wandering Tattlers on the beach, a few Pacific Golden Plovers, four Turnstones and some Buff-banded Rails. Of particular note, we managed to relocate Fairy Terns (probable New Caledonian race). A single individual was on the beach with Black-naped Terns. Read more.
 Project LIHOU - Day 5
8 December East Diamond Islet to Cathy Cay

We did a dawn visit to East Diamond Islet as high tide was expected in the early hours and there was a chance there would still be turtles on the beach. There was a single female green filling a nest hole on the southern end, so we stood a respectful distance back and she finished off before heading back to the sea. Leaving East Diamond Islet, we headed east across Diamond Passage to Lihou Reef. Unfortunately, a brisk south-easterly wind was still creating whitecaps so we had little success locating marine mammals. Seabird numbers were also very small. At our destination, Cathy Cay, there was some great snorkelling...up to a dozen Grey Reef Sharks under the boat. On the island was a selection of Black-naped, Sooty and Crested Terns, Common Noddies, Masked and Brown Boobies. The only shorebird was a single Turnstone.
Read more.
 Lorna Cay
We departed Anne Cay at dawn and headed northeast towards Lorna Cay, a relatively large vegetated island on the northern fringe of Lihou Reef. The island is covered in low grassland with no trees, and is covered in nesting Sooty Terns, Brown Boobies and Common Noddies . The southern end is a long tombola with a narrow sand spit at the end where we find four Fairy Terns ... this oceanic subspecies was described from East Diamond Islet by us in 2006. It was never previously known from Australia.

This turns out to be a really interesting island with some great snorkelling. Though quite wave-damaged, snorkelling along the sand spit is amazing with a wealth of reef fish, moray eels and - to our delight - an aggregation of 27 female Tawny Nurse Sharks . One of the group catches sight of a fin thrashing about on the beach. One of the sharks has come right up out of the water after a crab and finds itself stranded. Racing over for a closer look, a big wave draws the 1.5 metre animal back into the water.


Read more.
 Lorna Cay, Day 2
We visited the Cay by 4:30am. We used the morning to do a full survey of the seabirds on the island. The vegetation is really interesting...there are only two dominant species of plant on the island and you can see distinct patches associated with turtle nesting holes and seabird use. The Brown Boobies reek havoc on the grassland.

The island is covered in hermit crabs. So much so, that you leave a bag on the beach only to return finding it full. It seems they gravitate to anything that might be food or a new home. At the northern end of the island, a few thousand birds nest. There were Pacific Golden Plovers in the vegetation along with Turnstones and a single Wandering Tattler on the beach. A Whimbrel is the only other shorebird. The Fairy Terns were still around, roosting with Black-naped Terns.
 
Toward the end of the morning, the Tawny Nurse Sharks start to appear in the shallows  so we grab snorkeling gear. An hour later and we've had close encounters with these docile sharks, some nearly seven feet in length.

In the afternoon, the birders head for a snorkel off the northern end of the island. Here, coral bommies over 20m high dominate the underwater scenery. Within seconds of being in the water, there is Grey Reef Shark , Hawksbill Turtle and Maori Wrasse . Amazing! The feeling of gliding over reef only a metre below the surface, then crossing canyons 20m deep is vertiginous.
Read more.
 Anne Cay
We left Lorna Cay first thing in the morning and headed south to Anne Cay, across the centre of the reef complex. Unbelievably, we only see half a dozen birds or so on the two hour crossing. At Anne Cay, the diving is extraordinary...as described by Nicola Temple from AMCS:

"Just ten metres or so below us fan corals branch out spanning two metres or so. A couple of grey reef sharks come and check us out.  We make our way along the wall, all of us in awe. There are heaps of fish here. A school of giant trevally swim among us. We startle a hawksbill turtle that is resting in a crevice. We work our way up the wall half way through our dive and the list of fish is endless. We are at about six metres when we catch sight of a Humphead Wrasse. It’s a male, about 1.5metres long and I can’t help but think of Barry. Mdive buddy points to a second one that is now approaching us from around the corner and I catch sight of a third. We are now at five metres doing our safety stop, though none of us want to leave this paradise. A fourth Humphead Wrasse comes in, then a fifth…in the end we have eight of them swimming around us. My camera is out of batteries, but the memory is ingrained in my mind forever. This has been , without a doubt, the best dive of my life."

Anne Cay itself is very different from Lorna. The brisk southeasterly trade winds pummel the eastern shore which is steep and rocky. The vegetation is more mature than at Lorna and is dominated by Brown Boobies . There is also a patch of Lesser Frigatebirds breeding near the western end. A Wandering Tattler is on the beach and very large numbers of Black-naped Terns roosting on rocks to the east. There are several sand cays very nearby where these probably breed.

There are gale force winds forecast so we head back to the boat, pull up anchor and leave Lihou Reef. We will push through the night to try and reach Marion Reef in the morning. Read more.
 Marion Cay
We travelled overnight south of Lihou Reef towards Marion Cay. An early start yields little in the way of bird life, except on the approach to Marion Cay, we see a single Bulwer's Petrel along with dozens of Wedge-tailed Shearwaters . Soon after lunch, we arrive in the northern end of Marion and stop so we can dive. There is no land here, until later. A sand cay appears and starts to attract Black-naped Terns and Crested Terns .

We relocate to a channel in the reef some way south for another dive in the afternoon then decide to head south along the eastern fringe of the reef, past the island with a lighthouse. Within a short space of time, we're surrounded by hundreds of Wedge-tailed Shearwaters , Black-naped Terns , Red-footed Boobies and Masked Boobies (these breed in large numbers on the adjacent island) and two False Killer Whales . Nathan spots a small black and white shearwater in the flock and photos are soon to confirm this is Tropical Shearwater , most likely breeding on New Caledonia and one of only three records in Australia. Does it breed on Lihou? Three Tahiti Petrels are also highlights as a sun starts to set.  Read more.
 Swaines Reef
The swell overnight was about 2m but as we approached the Swaines, it calmed off. The ocean was again very quiet, with little seen on the approach to the Swaines.

The first dive and snorkel was in more turbid water than we have seen for days and in the company of recreational fishing boats. However, the coral is in good condition and the water full of huge salps (a massive, hard gelatinous plankton). We have a great encounter with a very confiding Hawksbill Turtle .
Read more.
 Northwest Island, Capricorn Bunker Group
This was an impromptu addition to the itinerary on the way home but well worth it. Last year was a bumper turtle nesting season, and since turtles only breed every two or three years, this year was always going to be slow. In fact, it was so slow, we only saw one turtle nesting the whole week at Lihou, at East Diamond Islet one morning.

Northwest Island in the Capricorn Bunker Group, only 40 miles from the coast, was to be an exception. There were dozens of turtle tracks from the night before and we had a fantastic evening, in the company of a female Loggerhead Turtle . This is now a very rare breeding species for eastern Australia.

Some of the divers were treated to a Great Hammerhead Shark and the snorkellers saw a Banded Wobbegong - a type of Carpet Shark. On the island, we added a pair of Little Terns and about 50 Common Terns to the trip, along with nesting Bridled Terns and thousands of Black Noddies . Read more.

Comments

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Jack M. on December 14, 2009 about Project LIHOU

Fantastic sighting of the puffinus (auricularis or newelli?)...awesome.....wish we were there....Bill and Jack

Written by

Simon Mustoe


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