- Follow Us
Special to WCS by science writer, Amy West
After the mutineers left Captain William Bligh to steer his own course, Bligh probably didn’t realize he’d passed so close to an astonishing seamount rising nearly straight up from the seafloor. Of course how could he, when cannibals were most likely chasing him from Fiji? In recognition of his plight, this popular dive spot has been christened Mt. Mutiny.
Plowing through calm waters between the two large islands of Fiji – Vanua Levu and Vitu Levu – where it feels like open ocean, “land” abruptly stops you in your wake: the seamount’s peak is visible at the surface. During low tide, you could theoretically walk on it. Just a few hundred feet off its edge, the depth reaches down to 600 meters—a sheer drop.
Seamounts are usually rife with life. These undersea mountains are prime features for currents to swoop around and carry food to the diverse filter feeders such as corals and sponges. The stony and soft assemblages in turn attract an entire ecosystem of marine life that rivals most regions of the ocean. These volcanic structures can be uplifted mountains that are unhurriedly inching their way to the surface, such as the emerging island Lo’ihi in the Hawaiian Islands. Or they could be islands that have slowly eroded and sank like northern Hawaii’s Meiji seamount. We don’t know the history of Mt. Mutiny without drilling into it, but one thing is clear– it does not seem to be teeming with life. Many of the larger fish and top predators seemed to be out to lunch, or perhaps more likely, became lunch.
Seamounts are hotspots for fish, which is why fisherman love them- the suspected reason that they are missing. With support from the Waitt Foundation and Institute to help create offshore-protected areas, the first item on the agenda was to document marine life below diver depths. The Institute’s contribution of their research vessel and camera-equipped robot allowed us a quick glimpse. This steep mountain had seemingly discrete bands of life: reef-building corals for about 30 meters, then softer corals below it, and different species like larger sea fans and encrusting algae and sponges below it. After 60 meters the seamount appeared more barren and so vertical that tracks of rubble flows were noticeable- as if someone had driven an ATV up its side.
An astonishing amount of ambient light was still apparent at 150 meters, but not a lot of fish. Whether it was due to the loud, whirring vehicle or our limited field of view, dives near the surface also appeared devoid of large and abundant fish. Interestingly though, at 180 meters we found banner fish amongst saddleback snapper. One references notes a banner fish’s range to only 75 meters.
Additional dives will give us a better snapshot of the diversity. Yet, whatever this seamount’s patterns, bringing Fijis’ deeper underwater seascape to the surface is imperative. The release of oil exploration licenses around these islands calls for urgency to discover what might need protected before it could be destroyed.
On board the Waitt Institute research vessel, we are fortunate to have coral spotting guru, Dr. Don Potts from UCSC, as well his former PhD student, Dr. Stacy Jupiter, who has been WCS Fiji’s program director for the past five years. WCS’s Sea and Sky director Claudio Campagna, who specializes in the creation of Argentina’s pelagic marine protected areas, also aids in the conservation goals of this research leg.
Click on the link below to see exciting video footage from the ROV: Fiji seamount survey video
Amy West has traveled worldwide as a marine scientist, specializing in fisheries and deep-sea ecology. Now as a science communicator she brings stories about ocean realms to the public through radio, video, photography, and writing. She’s usually diving into adventurous stories that take her on or below the water.
Today was the first time that I stepped on Vatu-i-Ra Island in almost a year and a half. Right away, I knew things looked different.
“Why is there so much light streaming through the canopy?” I wondered.
And then I saw the branches and trunks of felled trees all around. Damage from Tropical Cyclone Evan? Possibly a little bit, but our hosts seemed to think that people were cutting trees to build fires for camping.
The small (2.3 ha) Vatu-i-Ra Island, located off of Ra Province, is a critically important seabird site, home to a large breeding colony of black noddies (Anous minutus), as well as dense populations of red-footed boobies (Sula sula) and lesser frigatebirds (Fregata ariel), breeding hawkesbill turtles (Eretmochelys imbricata) and the endemic pygmy snake-eyed skink (Cryptoblecephalus eximius). Due to these features, BirdLife International declared the site an Important Bird Area.
Vatu-i-Ra Island is particularly special because of an enormously successful project by BirdLife International, NatureFiji-MareqetiViti, the Pacific Invasives Initiative, the Pacific Invasives Learning Network and the New Zealand Department of Conservation to eradicate invasive rats (Rattus exulans), which were having a negative impact on bird populations. The island was declared rat free in 2008 and the bird populations have boomed. Ever since, Sione Gonewai, leader of the traditional landowners from the Yavusa Nagilogilo, has been working courageously to try to get Fiji Government to protect this critically important bird breeding ground.
But now I saw their breeding habitat in tatters. There were dead birds in the trees and on the ground. Moreover, a boat of fishers pulled ashore and started building a fire with the dead branches.
“Have you been fishing?” I asked.
They replied yes. They had come from Tailevu and worked as a crew to sell fish to a middleman based in Rakiraki, who then vends his haul at Nausori market.
“Did you know that this area is protected?” I further questioned.
They claimed no. It is somewhat understandable, given that the communities only declared the island and the northern half of Vatu-i-Ra Reef tabu in March 2012 and the protected status has been little publicized. Sione was not happy, but he agreed to let them off without penalty if they consented to be interviewed for a documentary we are making to highlight the need for increased management across the Vatu-i-Ra Seascape.
Today’s encounters highlighted to me just how urgently this protection is needed. It appeared as if perhaps a quarter of the trees have already been lost. And it would not take much for an errant match to ignite all of the dry brush that has accumulated and burn down the remaining habitat.
“Do you like the birds?” I asked the fishermen.
“Yes,” they replied. “Where there are sea birds, there are fish.”
I hope that through our efforts and assistance we can help hasten the protection of this critical bird sanctuary and ensure the adjacent reefs are managed both to support the breeding populations of birds and the fishermen from all across Fiji who depend on fish for their livelihoods.
We will soon be kicking off a campaign to protect the biodiversity and livelihoods of people and ecosystems across the Vatu-i-Ra Seascape. This project is being supported by the Waitt Foundation and the John D. and Catherine T. MacArthur Foundation. Stay tuned for more information to come.
World Oceans Day, June 8, 2013
“Did you see any sea cucumbers?” I asked Ron as he struggled to get back aboard the inflatable tender.
“What about you, Wili?” I questioned.
He simply shook his head.
Day after day as we are being towed around the inner and outer reef systems of the Yasayasamoala Group of the Lau Islands, we are coming up with zeros on our data sheets. It’s disappointing work.
In the meantime, tin drying racks in the villages of Totoya and Matuku islands have been full of the critters. So far, Wili Saladrau, from Fiji Department of Fisheries, recorded over 700 individual sea cucumber (in the dried form called “bêche-de-mer”). This includes over 60 Holothuria fuscogilva (white teatfish) that can sell for over US$50 (FJ$100) a piece to specialty buyers in Fiji.
So are the local fishers just better at finding the sea cucumbers? Probably. If I was getting paid that much money per individual harvested, I’m sure that I would “get my eye in” much quicker in order to be able to spot them on the reef. But still, the densities of sea cucumber populations are running dangerously low.
Wili, Ron Vave of the University of the South Pacific, and I were asked by the Lau Provincial Office to do an assessment of the status of sea cucumber populations during the Living Oceans Foundation Fiji expedition throughout the Lau island group. Bêche-de-mer is a major source of income to coastal communities in Lau, but there is concern that the populations are on the precipice of collapse.
Serial depletion of sea cucumbers has occurred throughout the world to feed a growing middle class market in Asia, hungry for bêche-de-mer. While bêche-de-mer have been traded for at least 1000 years, the value of the catch has increased enormously over the past two to three decades as species are exploited and crash, thus becoming rarer commodities.
Sea cucumbers are long, tubular benthic echinoderms (in the same phylum as sea urchins) belonging to the class Holothuroidae. They were once found in most temperate and tropic benthic habitats worldwide, ranging from shallow intertidal areas to the deep sea. The majority of sea cucumbers move across the seafloor ingesting detritus and other reef gunk, thus cleaning the sediments and potentially reducing the spread of harmful algae. Because they can grow to be quite large, and many are conspicuously shaped and coloured, sea cucumbers are extremely vulnerable to fishing. In addition, population recovery is hampered by their slow growth rates and long time to reach maturity. Furthermore, when populations become too sparse and sea cucumbers cannot sense other individuals of the same species, they will fail to breed, resulting in local population collapse.
There is general lack of awareness of these population dynamics in Fiji. Although use of SCUBA for fishing is prohibited under the Fiji Fisheries Act, the Fiji Department of Fisheries has been issuing exemptions to traders. These middlemen supply local community members with gear and possibly some training if they are lucky – and then the race is on to catch the last of the sea cucumbers. Young men are diving 50, 60, 70, and sometimes over 80 m to find the remaining individuals from high value species. They are dying fairly regularly. Others are suffering debilitating side effects from the bends. I met one man during surveys in western Bua Province in November 2012 who was relegated to growing watermelons after becoming incapacitated from diving related injuries.
In Lau, most of the fishers are free diving, but apparently they are quite talented and can easily reach depths between 20-30 m. Most fishers that we have interviewed so far are happy with the status of the sea cucumber fishery as they are fetching high prices and the money covers household expenses, church contributions, and higher education fees for children, as well as offers the ability to purchase some luxury items. But few of the fishers seem aware that the good fortune may soon run out. What will happen then when there are few other options for earning income out in these remote islands?
There may be potential for populations to recover if management action is taken now. It likely will not be sufficient to set up locally managed marine areas with a few no-take areas. The sea cucumbers are already so widely dispersed that they may already be unable to reproduce. More active management may be required. This could entail finding wild caught individuals and placing them in close proximity to one another within pens in the no-take areas to encourage their reproduction and dispersal of their larvae into the open areas that everyone can access to fish. This strategy should optimally be coupled with minimum size limits so that people do not remove all of the young sea cucumbers before they reach maturity.
In honor of World Oceans Day, I ponder these issues in order to raise hope by coming up with creative solutions. Over the next few years, the Wildlife Conservation Society and other members of the Fiji Locally Managed Marine Area network aim to try out several different types of management with communities to see what works, what doesn’t work, and why. Ideally we want local communities to have a better understanding of sustainable extraction rates so that they will be able to maintain livelihood benefits into the future.
Although as the petrel flies, Koro Island is not geographically far from the capital, it is not easy to get there. Didi and Wise on our team beat down giant swells and high winds to bring our boats on the 65 km crossing from Savusavu. Meanwhile, the rest of us took the Lomaiviti Princess from Suva, which dropped anchor at the Koro jetty sometime in the middle of the night. We were bleary-eyed and confused as we hopped on a carrier that disgorged us an hour up the road and onto the floors of two families’ houses to try to squeeze in some last minutes of shut-eye as the roosters cackled and the sun slowly crept over the horizon.
People from Tuatua village believe that this area (including the villages of Nasau and Nacimake) was the place of original settlement on Koro Island, as people fled from some natural disaster, possibly a tsunami, on Motoriki located south of Ovalau. We shared many of these stories after our formal presentation of a tabua (sperm whale’s tooth) to signify our serious intentions for our upcoming fieldwork.
WCS is continuing our investigation to uncover the impacts of opening tabu (locally managed fisheries closures). We recognize that it is highly unlikely that coastal communities in Fiji will keep portions of their traditionally managed fisheries closures permanently closed to fishing. But we have also observed that there are increasing pressures to turn to tabu areas for quick income when money is needed to pay provincial levies, school fees, church fees or buy communal goods for the village. We are trying to assess how much can safely be extracted from a tabu area, given its size and history, without fully compromising its ability to provide fish and invertebrates for the future.
The people of Koro have graciously welcomed us to help them better manage their island and coastal fisheries. Our plan is to conduct a short harvest in Tuatua village, followed by a longer, more intensive harvest in Nakodu village.
Tuatua is where the Tui Koro (high chief of Koro resides), but Tuatua itself was without a village chief when we arrived. The Native Land and Fisheries Commission visited during our stay with the VKB, a registry of all iTaukei (indigenous Fijians) to trace the lineages and identify the next successor to be installed. Perhaps it was due to this gap in leadership that the Tuatua tabu had been consistently opened every quarter over the past year, with even an extra opening for a recent church function. Or perhaps it was because the local managers had not received any recent advice of the consequences of too frequent harvests. Whatever the reason, the impacts were obvious. Compared with the adjacent areas open to fishing, the Tuatua tabu appeared fairly devoid of fish life.
This observation was backed up during the yavirau (fish drive). Four times, women and men from the village spread out their gill net in a semi-circle in the tabu lagoon during low tide. At the call of “Yavi!” people swam towards the net, driving the terrified fish toward their ultimate capture. Gills nets are highly non-selective – any unlucky fish caught within the vicinity of the net could potentially be caught if it does not divert its trajectory. But after 3 hours of the drive, the total haul was only 191 fish, with very few larger than 30 cm
By contrast, our first dives in the Nakodu tabu area showed much higher densities of fish that were highly unwary of us invading humans. One little grouper (Epinephelus merra) was so tame that I caught it with my bare hand! On the second day of the yavirau, the community brought in over 1500 fish from just 3 hours of effort. The weight of the haul was so large that it almost capsized the Adi Lase Bula, one of our boats. It was then a long, tiring afternoon for our team of Margy, Wise, Yashika, Akuila, Didi and Jordan, a PhD student from University of Western Australia working with us, to measure and identify all the fish.
What was the difference between the two villages’ tabu? Nakodu village has kept its tabu closed since its establishment in 2010, despite calls from family in Suva and overseas to open for Christmas feasts. Furthermore, the community had their own motivations for a harvest with an upcoming Methodist Church function for which they needed to gather enough food to feed all participants. The people of Nakodu were ecstatic with the results. They could see for themselves that their patience had paid off for an occasion where they really needed the extra food.
But questions remain. Did they take too much? How long will it take for the tabu to recover and when can they harvest again? Over the next few months, we will be busy analyzing our data to help provide some answers with the hope that we can provide better recommendations about the duration that tabu areas need to stay closed in order to provide an adequate amount of short-term gains without compromising long-term food security. Stay tuned for more answers. Moce mada.
This work is kindly supported by the David and Lucile Packard Foundation.
In 2011, I participated in a workshop during the International Marine Conservation Congress in Victoria, Canada, where experts came together to discuss which were the most critical factors that affect the ability of coral reefs to resist and recover from climate disturbance. After much deliberation, our expert consensus produced a list with 11 top resilience indicators, based on their perceived importance, evidence base in the literature, and feasibility for managers to measure. The top indicators included:
– Presence of resistant coral species
– Historical temperature variability
– Nutrient pollution;
– Coral diversity;
– Herbivore biomass;
– Physical human impacts;
– Coral disease;
– Coral recruitment; and
– Fishing pressure
We published a paper describing the selection of these indicators and how they might be used to prioritize sites for reef management in a changing climate.
However, during this process, I got to thinking. Site based measures of resilience indicators are nice, but they only allow us to say that one survey point is potentially better than any other survey point and leaves you with no information about all of the unsurveyed reef.
Wouldn’t it be even better, then, if we could combine the field data with satellite imagery to assess what are the main factors influencing the resilience indicators that we can derive from space? Then we could use those relationships to predictively map the resilience indicators over a broader spatial scale, such as across an entire fisheries management area (qoliqoli). This process would yield maps with relative values for every portion of the qoliqoli to enable us to make better decisions about how to plan marine protected areas (MPAs) and MPA networks.
We previously took this approach to predictively map characteristics of reef fish assemblages across the Kubulau qoliqoli in Vanua Levu, Fiji, and published the results in a paper in Remote Sensing. I went back to my co-authors from Simon Fraser University and the University of Queensland and asked, “Do you think we can take this same approach for mapping indicators of reef resilience?”
Our findings have just been published in a more recent issue of Remote Sensing, accessible here. We specifically focused on mapping resilience indicators for which data products were not already available. These included:
– Stress-tolerant coral taxa, as a measure of resistance to coral bleaching;
– Coral diversity, as a measure of resistance to bleaching and potentially past recovery potential;
– Herbivorous fish biomass, as a measure of recovery potential due to the ability of herbivorous fishes to remove macroalgae from the reef, thus preventing harmful coral-algae interactions and allowing space for new corals to settle;
– Herbivorous fish functional group richness, as a measure of recovery potential as fish remove algae in different ways (e.g. excavating, scraping, browsing) and it is necessary to have the full complement of types of herbivores to effectively remove most of the macroalgae;
– Juvenile corals, as a measure of recovery potential from recent coral recruitment and survival; and
– Cover of live coral and crustose coralline algae, as a measure of recovery potential both as a indicator of current coral-algal dynamics when coupled with the amount of macroalage, as well as a proxy for the amount of substrate available for coral settlement and source of new recruits.
We specifically used high resolution satellite data (<4 m pixels) to enable production of maps of resilience indicators at a scale meaningful for customary management systems in Fiji and the rest of the Western Pacific. We did not try to predictively map indicators which other people have successfully mapped (e.g. historical temperature variability, nutrients, sedimentation, physical impacts and macroalgae), but noted that our predictive maps could be combined with these data products within a spatial planning framework.
How well did we do? We were able to reasonably map relative differences in potential susceptibility to coral bleaching based on the composition of coral communities observed in the field. We were able to do this because some corals are more tolerant to environmental stress than others and they tend to be found in different environments and micro-habitats.
We also did a good job predicting distributions in the number of functional groups of herbivorous fish. This indicator likely also has strong environmental determinants as large excavators, such as bumphead parrotfish, steephead parrotfish and bicolor parrotfish, tend to be associated with forereef slopes and reef crests. We noted, though, that the total amount of “reef cleaning” performed by each group of herbivorous fish will be influenced by how many fish are present and their size. In addition, not all herbivorous fishes are created equal. A new, separate study from Fiji found that only 4 species of fish were responsible for eating 97% of the algae set out in a feeding experiment.
We did not do such a good job in predicting distributions of juvenile corals, but this was expected given that there are many factors that influence where corals may settle and how many survive. We also did not do very well in predicting coral diversity patterns. This was somewhat surprising given how much is already known about relationships between coral diversity and depth, exposure to waves and reef habitat. However, our results were likely influenced by errors in georeferencing and incomplete sampling across all of the habitat types in Kubulau qoliqoli. These issues could easily be improved upon in future studies.
What does this mean for reef managers? In the context of MPA planning, managers now have the potential to set targets for reef resilience indicators, in addition to habitat and feature representation, when designing MPA networks within decision support software (e.g. Marxan). This represents a considerable improvement over the current practice of designing or adapting MPAs based on site-based resilience score collected from relatively few sites across the planning region.