The NY Times features posts from Stuart Sandin

Posted by on Nov 18, 2010 in Featured, People1 comment
An underwater view of a coral reef in the Line Islands.
An underwater view of a coral reef in the Line Islands. Photo by Jennifer Smith.

Thursday, Nov. 4

Last night, sitting on the deck of the ship, I smelled fire. Not a fire that would cause the captain of the Hanse Explorer to sound the alarm, but fire from the island off our starboard side. The people of Tabuaeran — which is also known as Fanning Island — were stoking the flames to cook fish that they had caught from the surrounding coral reefs earlier in the day. This was the first time I had smelled smoke during this expedition.

Our team is in the midst of a monthlong research cruise in the Line Islands, an archipelago in the remote central Pacific. According to many metrics, these islands are among the most isolated on the planet, and they depend on the already-remote islands of Hawaii as nearest port of refuge. (Mind you that Honolulu is more than 1,200 miles to the north of us.) We are here to study the ecology of coral reefs, taking a holistic perspective of each of the major biological players on the reef —the fish, corals, algae, and even the bacteria and viruses — and estimating how fast each of these groups grows.

Why, you may ask, did we travel so far to study growth rates on coral reefs? There are certainly simpler ways to reach coral reefs than by chartering a 158-foot yacht and spending the greater part of a year arranging the logistics. The answer lies specifically in the location’s remoteness. The Line Islands have been difficult to reach for all of human history, and as such have remained largely outside the influence of people. It is here in the Line Islands that we have a chance to study the basics of coral reef ecology, not simply the remains of coral reef ecology. The reefs here have not collapsed, and the hand of humans is somewhere between light and nil. It is surprising how rare it is to study coral reefs without lamenting solely what has been lost.

If you read reports about coral reefs, the news is typically bad. Reef fisheries are collapsing due to overexploitation. Seaweeds are growing out of control when too much pollution is dumped, often leading to the spread of invasive species. And when the seawater gets too warm (as happens during intensive El Nino events), the corals can go into a form of heat shock and die. Fishing, pollution, and climate change are the main stories on coral reefs, and we are trying to prevent these culprits from killing all reefs before our children or grandchildren get to enjoy them. But in order to manage coral reefs in the presence of people, we have to understand how coral reefs work in the absence of people. The Line Islands give us a rare opportunity to do so.

A research diver collecting data on fish populations. 
A research diver collecting data on fish populations. Photo by Jennifer Smith.

Today we started our work on Tabuaeran, finding an abundance of corals and countless dinner-plate-sized fish sprinting around the reef. A dive like this would sell for a lot of money in many popular destinations, and many of my fishing friends would love a day spent with hook and line in these waters. Happily, these coral reefs are thriving, not collapsing.

We arrived to Tabuaeran by way of Palmyra Atoll and Kingman Reef. Unlike Tabuaeran, these islands are uninhabited and support some of the biggest and healthiest coral reefs on the planet. The fish on the reefs are huge, and sharks and large snappers dominate. The corals on the reefs are also spectacular, with table corals that look like underwater satellite dishes and dome corals the size of the satellites they are trying to reach. A dive at these islands would also sell for much more money.

A variety of fish call the coral reefs of Palmyra Atoll home.
A variety of fish call the coral reefs of Palmyra Atoll home. Photo by Stuart Sandin.

A critical question remains: what does it mean ecologically for a reef to be “heavy” — by which I mean some ineffable quality of being impressive and even a bit daunting? But even more importantly, what does it mean for humans trying to live off of the services provided by their reef if the heaviness is lost? Because the reefs of Tabuaeran are changed relative to Kingman and Palmyra, has some critical service been lost to the local humanity? The answer is not simply academic. Millions of people depend on the productivity of coral reefs. The fires onshore are a demonstration of the importance of understanding productivity of the sea. The reefs below us are feeding the residents of this island.

By comparing the reefs of inhabited and uninhabited islands in this remote part of the Pacific, we are looking for the sweet spot of human activity. We cannot feed humanity by not fishing, and we cannot feed humanity by fishing too much. Somewhere in between is the solution, and the people of Tabuaeran may just have found this perfect balance. Floating here in the true middle of the Pacific Ocean, we are taking steps to provide new answers.

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Life in Nemo’s World

A small school of fish swimming over a patch of Acropora coral on Tabuaeran Island.
A small school of fish swimming over a patch of Acropora coral on Tabuaeran Island in the central Pacific. Photo by Jennifer Smith.

Wednesday, Nov. 10

Imagine being a small fish on a coral reef. My Ph.D. adviser once described the life of a reef fish as being similar to a small mammal in the waning ages of the dinosaurs: Millions of years ago, our warmblooded forebears were probably scampering around, perpetually paranoid that a big reptilian mouth would appear to end their furry existence prematurely. This image is now burned in my head, and I cannot stop imagining a Cretaceous scene as I watch fish on coral reefs.

A few days ago we were working on Palmyra and Kingman, uninhabited central Pacific islands that have remained largely outside the impact of fishing hooks and nets. I could imagine firsthand the anxiety of being small in a world of big predators. On each dive we were visited by dozens of reef sharks the length of my body, and we were stared down by red snappers showing teeth that could easily have removed a finger or two. These predators were curious and looking for a meal. Fortunately, none of them viewed any member of our team as particularly appetizing.

A two-spot red snapper, Lutjanus bohar, searches for prey.
A two-spot red snapper, Lutjanus bohar, searches for prey. Photo by Stuart Sandin.

While these predators are an exciting addition for divers looking to learn from so-called pristine coral reefs, the setting is much more austere for small-bodied fish trying to stay alive. Much like the early mammals, the little fish must keep a constant watch for the big and toothy predators nearby. This piscine paranoia indicates a tough living for the prey fish, but also makes for a tough living for a scientist trying to catch the same prey.

Four of us on this expedition are collecting fish to gain a better understanding of the factors that influence their growth and survivorship. Does the omnipresent fear of being eaten change the basic life history of fish? We are catching the smaller prey fish from the reef, including a few species of damselfish, surgeonfish and anthias.

Catching these fish on the uninhabited islands, however, has been a challenge. When we approach a particular fish, it darts away. Some species dash through the water column, well out of range for us to reach. Others duck into the reef itself, passing through the countless holes and crevices that define a complex coral reef. In short, we had to be very quick to catch the fish that we needed on the predator-heavy reefs of Palmyra and Kingman.

It is not surprising to learn that fish want to avoid being caught by a hand net or the spear of a giant bubbling sea monster (that is, me in scuba gear). What is surprising, however, is that yesterday we had far fewer troubles catching these same species. Fish that we had seen giving divers a wide berth were now curious, swimming casually around us. With a simple swipe of a net or shot from a spear, we could catch our prey. Why was this so much easier?

The answer, I believe, lies in the biology and geography of the Line Islands, which lie south of the Hawaiian Islands. Yesterday was our first day diving on Tabuaeran island, one of the three inhabited islands of the archipelago. Five years ago, many of us on this ship first visited the Line Islands to learn about what is “pristine” for a coral reef, and how this changes with human activities like fishing.

A school of Ember parrotfish, Scarus rubroviolaceus, in the Line Islands.
A school of Ember parrotfish, Scarus rubroviolaceus, in the Line Islands. Photo by Stuart Sandin.

We found some results that might not be surprising, like the fact that with increased fishing activity there were fewer fish on the reef. More surprising, however, was the fact that in the absence of fishing the reefs were dominated by large-bodied fishes, typically the predators. The coral reefs of Kingman and Palmyra are ruled by sharks, snappers, groupers and trevally, all fish with sharp teeth that look at their smaller-bodied compatriots as potential meals. These predatory fish are disproportionately removed by fishermen here on Tabuaeran and other inhabited islands.

With many of the predators gone, the fish live a more tranquil life. Without the ubiquitous fear of being consumed, the prey fish appear somewhat lackadaisical. They seem accustomed to the safety, and now see the bubbling sea monster instead as a floating curiosity. This curiosity, however, is not shared by all of the fish on the reef. Remember that the predators are now the prey, the prey of fishermen.

So while we were able to approach countless small fish during today’s dive, we could not get anywhere close to the big fish. The reefs here have some large-bodied predators, but these fish gave us a very wide berth. The predatory fish that have survived here have learned not to get suckered into chasing floating chunks of meat (a k a bait on hooks) and not to approach swimming bipeds, especially ones with pole spears. How the tables have turned!

Way back in time, mammals became successful when a meteor hit our planet and the dinosaurs perished. We are seeing a similar transition on coral reefs, as the predators are removed and the prey fish gain capacity. The effects of fishing are certainly not as extreme as the celestial impact that ended the age of the dinosaurs, but in some parts of the tropics we are getting close.

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A Precious Haul of Toxic Snapper

A view of spear fishermen from below. Fishing provides food for the community on the island of Teraina.
A view of spear fishermen from below. Fishing provides food for the community on the island of Teraina. Photo by Jill Harris

Thursday, Nov. 11

The people of Kiribati live from the sea. The coral reefs of this Pacific island nation are not just museums for divers and snorkelers, but sources of food. Essentially, every family in Kiribati depends on the near-shore fishes to top their plates and fill their stomachs. Reef fisheries worldwide, in fact, provide upwards of one-half of the protein for the tens of millions of people who live in the coastal tropics.

It is not surprising, therefore, that the people of Kiribati really know how to fish. On each of the inhabited islands that we have visited, we have worked with fishermen to help us to collect the fish needed for our study. While we dedicate our efforts to collecting smaller species that are of less interest for the fish-eating public, the fishermen provide invaluable help in collecting the larger species that are more commonly eaten.

A group of local fishermen preparing to board our ship where they will sell us the day’s catch. The hard hats they wear offer some protection from the rough seas; the samples they bring us are invaluable.
A group of local fishermen preparing to board our ship where they will sell us the day’s catch. The hard hats they wear offer some protection from the rough seas; the samples they bring us are invaluable. Photo by Mark Vermeij.

On Tabuaeran, the fishermen taught us where to find the red snapper. Look on the windward side of the island, we were told, far from where the people live and fish. A few mornings ago we positioned the ship on the wave-exposed eastern shoreline and launched a couple of our inflatable boats. Far from the villages on the island (small villages, mind you, as the total population of Tabuaeran is about 3,000), our hooks finally caught snappers. Look in the “poison zone,” we were told, the parts of the coastline where the fish are toxic and bad to eat. (Ciguatera poisoning is common in many tropical, predatory fishes, arising from the bioaccumulation of a toxin produced by a dinoflagellate.) We met a man named Christmas who was fishing from a tiny outrigger canoe in the poison zone near the lagoon entrance; he sold us half a dozen snappers of all sizes.

The fishermen also showed us a variety of fishing techniques, ranging from standard to downright impressive. The people spearfish, stock ponds with hardy fish and use gill nets, but simple hook-and-line fishing remains the most common technique in the Kiribati Line Islands. The means of baiting the hook, however, is far from common in my book.

A pair of fishermen joined us a few nights ago on our search for snapper. They had brought some small fish as bait and a bag of beach rocks. Once we arrived at the decided fishing site, they each grabbed a bait fish, bit its head off, chewed for a while, and then put the masticated mess onto a rock. They then placed the hook of their line atop the garnished rock, wrapped the fishing line around the package, and threw the whole bundle overboard. When they felt the rock hit the bottom, they tugged at their line, thereby unraveling the line and freeing the fish paste, leaving the hook a set distance above the reef in a cloud of precisely prepared bait. We visitors caught some fish that evening, but these two men certainly led in the fish tally.

On Teraina, the next inhabited island that we visited, we again worked with islanders for help in finding snappers. We had only three days on the island, so time was of the essence. We offered a bounty for each red snapper that was caught. Although we met a few fishermen during our first day on Teraina and directly discussed our request and proposed reward, two full days passed and we saw no product. Needless to say, on the third day I grew nervous. We were asking for poison fish, and in fact were offering to pay for this locally valueless commodity. How could this offer go wrong?

In the late afternoon we got a radio call from the island: Some fishermen would visit our ship in the early evening with the poison fish they had caught. I should have expected this negotiation to follow a protracted schedule typical of many who live on islands, with an off-the-grid pace of life — island time, so to speak. Two hours after sunset, an aluminum boat approached the stern of our vessel with four men on board, all wearing hard hats. Why the hard hats, we wondered?

The explanation looked like this: Teraina has no harbor, no bays, no dock, and no protected landing for small boats. The island simply has a beach with a small cut through the reef, limiting the waves to breaking only on the edges of the beach. A full 10 feet or so of the beach remains wave-free during calm conditions. Needless to say, conditions on this central Pacific atoll are not always calm, and this form of boat launching and landing is implicitly hazardous. The hard hats are a form of protection, real or psychological, to get these men safely through the transition from land to sea.

Stuart Sandin, left, and Christian McDonald returning from a long day of sample collection. Even their best efforts cannot yield as many target species as local fishermen can provide in a few hours.
Stuart Sandin, left, and Christian McDonald returning from a long day of sample collection. Even their best efforts cannot yield as many target species as local fishermen can provide in a few hours. Photo by Mark Vermeij

When the men arrived, they pointed into the bottom of their boat. I saw one of the snappers from a distance and grinned. We had been fishing for a couple hours in the afternoon and had caught only a handful of target fish. These men had caught many more. Home turf advantage is really something.

We are heading to Jarvis Island now, an uninhabited island under the protection of the United States. We are back to fending and fishing fully for ourselves. We are up for the challenge, and hopefully we picked up a few tricks along the way. But it remains to be seen how many on our team will try to decapitate bait with their teeth!

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With Cooler Waters, Planktivores and Sharks

Data collection is made more interesting by some “toothy” spectators.
Data collection is made more interesting by some toothy spectators. Photo by Stuart Sandin.

Monday, Nov. 15

Yesterday we arrived at Jarvis Island, the southernmost member of the Pacific Remote Islands Marine National Monument. The reefs and surrounding waters of Jarvis and six other remote islands of the American-controlled Central Pacific, including Kingman and Palmyra, were given this heightened level of protection by President George W. Bush in the final weeks of his administration. To get to Jarvis, we nosed our way across the equator, reaching the island here, which is less than one half of a degree south of the equator. Given this geography, I was surprised when we splashed into the water and proceeded quickly to the verge of hypothermia.

O.K., I may be exaggerating a touch here. We are in the tropical Pacific Ocean, and according to most standards the water is warm, about the temperature of a swimming pool. The surprise, however, is that the temperature of our salty swimming pool has been getting cooler as we have traveled closer to the equator, from over 80 degrees Fahrenheit on Kingman (about 370 miles north of the equator) to less than 75 degrees Fahrenheit here on Jarvis. This temperature change is comparable to traveling north along the East Coast in autumn, hopping in outdoor swimming pools from Florida to Maine.

The conundrum with this pattern is the direction of the change. Typically as one travels closer to the equator temperatures get warmer, but in these reef waters the pattern is reversed. Although the surface waters may consistently get warmer with decreasing latitude, the directions of ocean currents, especially deeper ocean currents, shift. The culprit in the Central Pacific is the equatorial undercurrent, a flow of cool water moving along the seafloor from west to east. When this undercurrent reaches an obstacle, like an island or atoll, some of the water is pushed upward, mixing with the water near the surface and chilling the coral reefs.

So what is the impact of this cooler water on Jarvis for our work? First, it makes us don more layers of neoprene to keep us warm during dives. Beyond the effects on our wardrobe, though, the cooler water changes much of what we see underwater.

For the fish, the water from the deep delivers nutrients and food in the form of small plants and animals, the plankton. Along the steep reefs of the western shore, schools of small, brightly colored fish fill the seascape. These are the planktivores, the species that make a living feeding on the small particles floating through the water column. This added productivity of small fish appears to fertilize the bigger fish. Colleagues who had visited Jarvis before alluded to the many predatory groupers and sharks in these waters. They did not exaggerate. We have already shortened a couple of dives because of the attention that we attract. The winner was the site with more than 50 sharks milling about, seemingly waiting for the visitors from above.

At Jarvis Island, top predators like these sharks patrol the waters.
At Jarvis Island, top predators like these sharks patrol the waters. Photo by Kattie Barott.

Sometimes the big fish patrolling the reef waters can become visually overwhelming, and any good marine biologist knows the best approach is to mimic an ostrich and put one’s head in the sand (or in this case, into the reef). Hiding this way from the big predators does not help one to fully escape toothy friends. Every couple of feet a subtle movement attracts the eye: the apparent panting of a moray eel. Moray eels need to circulate water to get enough oxygen past their gills, so they rhythmically open and close their mouths in a gesture often confused with aggression. Looking even closer, one sees thousands of feathers emerging from tiny tubes. These are the feeding structures of boring worms, animals named more for their capacity to drill into limestone rather than for their deficient conversational skills. In every hole, crevice and groove, there seem to be mouths hungry for food.

A moray eel with an open mouth could appear aggressive but this creature means no harm. That is simply how they breathe.
A moray eel with an open mouth may appear aggressive, but this creature means no harm. That is simply how it breathes. Photo by Jennifer Smith.

In most reef environments, we try to describe differences in the reef organisms and ecology based on differences in the activities of humans. In places where we fish more, there are smaller fish. In places where we dump more sewage, the corals are less abundant. But here in the Central Pacific, we are not limited to studying only these human effects. Instead, we can also investigate how coral reefs should be structured, and how this structure changes naturally. We are fortunate to have the islands of the new Pacific marine monuments protected both for the sake of conservation and for learning about how the world works around us.

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  1. It was so wonderful to read that there are still abundant coral environments! Working at Scripps Insitute of Oceanography with corals has helped me to indulge a deep appreciation for them. Glad to know that there are still places where I can see them outside of a wetlab!

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