FROM DIVE'S ARCHIVE - FIRST PUBLISHED SUMMER 2018
The Best Exotic Marine Life Hotel: Walindi in PNG
A small resort on the island of New Britain in Papua New Guinea has been at the forefront of marine conservation and research for more than a generation. Louise Murray talked to the scientists who frequent Walindi Resort and enjoyed some first-hand insights into everything from the wanderings of larval fish, to the pecking order among clownfish
There is a fair chance that if you visit Walindi Plantation resort on Kimbe Bay in Papua New Guinea, you will be mixing with some interesting characters. Charismatic Australian owners Max and Cecilie Benjamin have long welcomed leading reef scientists and the best underwater photographers in the world to the area. At any time during your stay you may bump into researchers chilling over a beer at the bar – world experts in the behaviour of certain reef fish; or hear an informal presentation before dinner from the team from Australia’s James Cook University, who have been surveying the reefs of the bay every year since 1996.
Thanks to these annual surveys we now know that the bay is home to more than 860 species of fish, which is more than the number of species found in the Hawaiian Islands and the entire Caribbean combined. At least 413 species of hard coral occur here, making the coral community in Kimbe Bay one of the most diverse of any single location in the world. Human population pressure has been relatively low and these are some of the most pristine reefs in the Coral Triangle region.
I talked with Peter Buston, a professor and evolutionary ecologist at the Boston University Marine Program, who first visited PNG in the late Nineties for the field research part of his PhD. He returned in 2017 to Kimbe Bay to continue his work with clownfish. He quickly filled me in on the importance of the area and then rounded out my knowledge on clownfish.
‘On a global scale the reefs here are in fantastic condition considering the pressures of climate change,’ Peter pointed out.
It turns out that one of my favourite photographic subjects on the reef, the clownfish and its host anemone, is also one of the most obliging of reef fish for long-term study. Peter explained that they are long lived – large females can reach 30 years of age; they rarely leave the safe embrace of their host anemone’s tentacles, so are easy to find; they are visually identifiable as individuals; and they live in relatively stable social groups of up to four non-breeders dominated by a large breeding female and a smaller breeding male.
They are robust creatures and can tolerate a degree of scientific interference in their lives. That includes capture by net, removal to a boat for weighing and measuring, and fin clipping for genetic studies (the clipped fins grow back, you’ll be pleased to know).
‘They are tough little fish,’ says Peter. ‘Our work must be akin to an alien abduction experience for them, and for some individuals, one that happens relatively often. Yet we are sure that they continue to grow, reproduce and thrive afterwards.’
For marine biologists, the humble clownfish Amphiprion percula, is the equivalent of the white mouse for lab biologists, or the fruit fly for geneticists – the ‘go-to’ experimental model of choice.
‘In Kimbe Bay we study 120 groups of clownfish on 10 different reefs close to shore,’ Peter explained.
Clownfish groups are not families in the sense that the fish are related to each other. The largest fish in the group is the only female, the next largest is the male, and the others are non-breeders who are hermaphrodite – capable of becoming male or female. The group maintains a strict size relationship that separates the individuals, with each fish 80 per cent of the size of the fish above it in the hierarchy. The smaller fish stay small by restricting their food intake. If they do not, the penalty is eviction from the group and certain death.
Clownfish can wait between five and ten years for one of the larger fish to die, before becoming one of the breeders – most never make it. There is really no alternative to the long wait, as moving to an adjacent anemone is dangerous and would possibly mean attempting to evict the existing occupants. You might imagine that these non-breeders assist in parenting, but they don’t, they just hang out waiting to progress up the pecking order for the slim chance of becoming one of the breeders.
As an evolutionary biologist, Peter seeks to answer the question that has puzzled biologists as far back as Darwin, when he formulated his theory of evolution in Origin of the Species in the 19th Century: why do some individuals give up their ability to reproduce?
Tina Barbasch is Peter’s PhD student and is looking at parental care by clownfish. She explains that if parents share the care, it is in the interests of one parent to offload onto the other parent as much of the work of aerating and cleaning the eggs as possible on to the other parent, giving themselves more time to feed. The female lays her eggs in a patch at the base of the host anemone. Obligingly, the eggs change colour every day during their seven-day development into free swimming larvae, so their developmental stage can be easily monitored right up to a successful hatching.
‘We know through experiments where we feed one group supplementary fish food, and not another, that well-fed groups do better in the sense that they provide more care to their eggs, and produce more eggs over time,’ says Tina, who works with clownfish groups both in the wild at Kimbe, and in aquaria at home in the lab.
There are significant differences in behaviour between lab fish and their wild relatives. It’s a pretty safe and cushy life in the aquarium, free of the predatory dangers of life on a crowded coral reef. Curiously, in the wild, males and females share the work of keeping the eggs oxygenated, while in the lab only the male fish takes on that job.
Judging just how well Mum and Dad are doing is simple. Tina sets up a simple point-and-shoot video camera on a tripod attached to a surface marker buoy. She then leaves the area during a thirty-minute recording period when she can monitor behaviour without a diver present, before returning and moving on to the next group.
‘It is physically very demanding, says Tina. ‘Over the course of five dives a day, starting at 7am, we might swim at least a kilometre, and have to haul our gear in and out of the boat repeatedly. Once back at our base, I have to catalogue and back up all the video. By the end of four months I have more than 400 hours of video footage to categorise.’
At the beginning and end of each research period, all the fish have to be netted, popped into Ziploc bags and measured with calipers. It takes about a week to catch and measure every fish in the 120 groups studied.
Dr Maya Srinivasan is another frequent scientific visitor at Walindi and also serves on the board of the NGO Mahonia Na Dari Research and Conservation Centre (see box on page 69), founded by Max and Cecilie Benjamin in 1997 to promote marine environmental education in Kimbe Bay. Dr Srinivasan is a coral reef ecologist at James Cook University’s College of Science and Engineering, and was the first of many PhD students from JCU to work on the reefs of Kimbe Bay. She spent eight months of each year there between 1998 and 2001, conducting her PhD research on the arrival of reef fish larvae on reefs.
She continues to do research in Kimbe Bay, and clearly loves working in New Britain. She explained: ‘It’s important to know where fish larvae go. Until very recently, marine reserves were usually set up in places where there were a lot of fish, and we hoped that the larvae produced there would seed the neighbouring reefs with young fish, We did not know what happened when larvae left the reefs where they were born. We had no idea if larvae produced in marine reserves were seeding fished areas.’
She has been involved in a research project, led by Geoff Jones at JCU, that follows the fate of larvae of two different reef species, a clownfish and a butterflyfish. This research has been published recently in the scientific journal Nature Ecology and Evolution.
The two species differ in the way they lay their eggs and their larval durations. The orange clownfish lays eggs on a hard surface at the base of its host anemone, and cares for the eggs for six to seven days until they hatch. The larvae spend about one week as plankton, which is a very short larval duration for a coral reef fish.
The vagabond butterflyfish has pelagic eggs that hatch within 24 hours, and the larvae spend about 28 to 45 days as plankton. Despite these differences, the team has found a similar result for both species, in that about 30 to 40 per cent of the larvae collected at a particular location had returned to the same place as their parents.
Other larvae were found to have travelled up to 100 kilometres in a week. These fish larvae may only be the size of a grain of rice but instead of being passive drifters in the currents, they can actively swim, even against currents. They can orientate themselves using
an internal magnetic compass, similar to the one used by migrating and navigating birds.
As they reach the end of their larval phase, their sensory abilities increase. They can detect the chemical cues given off by terrestrial vegetation falling into the water to locate offshore island reefs, and can tell the difference between fringing reefs of islands and offshore reefs without islands.
Geoff and his team have been following the fate of clownfish larvae for five generations at three offshore islands in Kimbe Bay, covering an area of almost 10,000 sq km. They are able to track the fate of offspring by taking a small sample of the tail fin of almost all of the clownfish population at each island, and using DNA parentage analysis to match juvenile fish to their parents. They have found that even when anemonefish juveniles return to the same reefs as their parents, they hardly ever settle into the same anemones as their parents, which is probably to avoid inbreeding. There have been just three exceptions to this in more than 1,000 newly settled fish collected over the past 12 years (one of the three, the team discovered, mated with its grandmother).
Another JCU research study, following fish larvae of the coral trout and stripy snapper on the Great Barrier Reef, has shown that larvae produced in no-take marine reserves can make a significant contribution to replenishing populations in fished areas. Following the fates of coral reef fish larvae will help with the design of marine protected areas around the world.
‘Without the influence and passion of Max and Cecilie, we would not be working at Kimbe, and perhaps the special nature of the reefs would have been missed. Both have put a lot of time and energy into establishing Mahonia Na Dari, and keeping it running over the last twenty years,’ says Maya.
Max and Cecilie Benjamin are long- term residents of Papua New Guinea. Both originally from Australia, they came to PNG in 1966 and 1972 respectively to work as government agricultural officers. Max purchased Walindi Plantation in 1969. The property included over a mile of beach fronting onto Kimbe Bay. They
learned to dive in 1976 and made a pilgrimage to the Red Sea; at the time considered the world’s leading scuba diving destination.
‘It was obvious to us that what we had at home was far superior in many ways, but it was not until the late Eighties that the scientists started to visit and confirmed that Kimbe was both remarkably special and warranted protection,’ says Max.
In 1993 the Nature Conservancy organisation conducted the first scientific assessment of Kimbe Bay coral reefs over a ten-day period. The Benjamins accommodated the scientists at Walindi Plantation and provided the logistical support to get the teams out into the bay.
That survey documented, for the first time, that Kimbe Bay contained some of the most diverse coral reefs in the world. Papua New Guinea is home to almost five per cent of the planet’s marine biodiversity. And virtually all of the Indo-Pacific hard-coral species are to be found in its waters.
Over the past 22 years, building on the work of that first survey, scientists from James Cook University have been conducting annual surveys of the area’s fish, coral and coral reef invertebrates. In 1997, the couple started Mahonia Na Dari, an NGO whose name means ‘Guardian of the Sea’ in the local Bakovi language. Its goal is to bring marine environmental education to the local communities and facilitate scientific studies that will further the knowledge of the marine life in the bay and, in the longer term, ensure the protection of the reefs.
With the agreement of the local villages, a marine managed area was established, consisting of four inshore reefs which were closed to fishing and the collection of marine life.
Now the bay is to be the marine flagship for the protection zones currently being set up by the PNG parliament - the first in the country.