Researchers in the McCauley Lab use a diverse collection of methods and apply a variety of perspectives to better understand the dynamics of ecosystem assembly, function, and change. We collect data using binoculars, mass spectrometers, satellites, sonar cameras, and computer simulations - to name but a few tools in the lab toolbox. Non-uniformity in approach and method is celebrated as a foundational strength of the science in our research group. Despite this diversity, many of us in the lab value in common the scientific inspriation that can be draw from direct field experiences. Here we celebrate this shared appreciation for empirical experience with this collection of "dispatches" from lab researchers embedded in their field research.

 

It was still dark out when we departed the field station. Groggily, we loaded up the truck with our dive gear and SCUBA tanks while sipping coffee to try to wake up. The clock was already ticking. We had 30 minutes to get to the dock in Caracasbaai before the ferry was scheduled to leave.

This was a risky yet critical endeavor. Our aim: collecting sediments from the reefs of Klein Curaçao, a tiny, uninhabited island located approximately 15 miles off the southeast point of Curaçao. Less visited or fished than Curaçao, the reefs there would provide a more ‘pristine’ end member with which to compare our other Caribbean samples. The orientation of the island, which was nearly perpendicular to the trade winds, meant that the leeward side would be quite sheltered despite lacking any lagoonal environments. But would the sediments be fine enough to contain shark dermal denticles? This was the gamble.


We arrived at the dock just in time and confirmed that no recreational divers were joining the group. We would therefore have the flexibility to select our dive sites and use the tour group’s dingy to lift our heavy sediment samples to the surface. We decided to board the ferry.

Curacao
After a rough 1.5-hour ferry ride, the island’s barren landscape came into view. A thin strip of white sand beach intersected the cerulean sea and stormy sky. A lighthouse, accompanied only by a rusting shipwreck, rose in the distance, breaking the otherwise flat horizon. ‘Paradise,’ thought the tourists. ‘Healthy reef,’ thought our team.


Descending along the reef slope, I was astonished by the vibrant reef and number and size of the fish. Large parrotfish swam by in a swirl of colors and movement, and I had a standoff with a toothy barracuda within minutes of entering the water. This reef was obviously full of life. While the staghorn coral (Acropora cervicornis) had likely died off in the 1980s like in many other places in the Caribbean, many other coral species abounded.
The fine sand on the beach was a good sign. Feeling the sediment along the reef substrate, we found that the gamble had paid off. There were patches of fine, silty carbonate sediments! I let out a sigh of relief through my regulator and signaled ‘okay’ to my dive buddy. We collected eight bulk samples in spots where sediments had accumulated on ledges or patches between corals. Here, the sand grains were often held in place by an interlocking matrix of dead staghorn coral, limiting mixing.


The day, however, was far from over. Upon arriving back at the dock on Curaçao, we loaded the samples and gear into the truck and began what should have been a 20-minute drive home. Except that it was Shrove Tuesday of Carnival and half of Willemstad was blocked off for the big parade. After desperately searching for a clear route, we stopped to get directions from a police officer, who gave us the disheartening news that we would have to drive around half of the island to get home. An hour and a half later, we finally reached the station, exhausted yet victorious. What a roller coaster of a day and a fitting end to the expedition.

Read more about how we use dermal denticles to reconstruct shark communities in our report in Marine Ecology Progress Series, and check out the videos from our field work at https://baselinecaribbean.com/. E. Dillon


Here in the Solomon Islands, searching for the elusive bumphead parrotfish, we spent this week diving in waters that boast some of the highest fish biodiversity in the world, second only to Sipadan, Malaysia.

The aptly-named Grand Central had fish rushing off in all directions including schools of red-bellied fusiliers (Caesio cuning), titan and redtooth triggerfish (Balistoides viridescens and Odonus niger), as well as lone grey reef sharks (Carcharhinus amblyrhynchos) and great barracudas (Sphyraena barracuda).

Shallower in the water column, giant clams (Tridacna sp.), false clown anemonefish (Amphiprion ocellaris), and Christmas tree worms (Spirobranchus giganteus) retreated into their homes.

Despite the staggering number of creatures, the odds were still not in our favor and we spotted only a single bumphead parrotfish (Bolbometopon muricatum), the animal we've come all this way to observe.

At first, the looming outline looked more like a shark in shallow water. We froze and then frantically bumped our fists to our foreheads – our underwater signal for our bumpheaded friends; its genus Bolbometopon is Greek for "onion-brow." Seemingly unphased, the bumphead turned and left before we could catch it on film.

At our first sighting, we had had jumped off our boat without our masks, fins, or snorkels, eager to see the bumpheads down below, but the fish had vanished almost as soon as we saw it. Apparently, after generations of spear-fishers on snorkel, bumpheads are often skittish around any kind of swimmer.

Diving with scuba gear the next time allowed us to settle into their habitat fairly unnoticed, so much so that a meter-long giant came up close and stuck around. From experiences like this on our initial surveys, we're getting the impression that bumpheads here occupy deeper waters than those in areas where they have been fished less.

We'll soon be heading southeast to more remote (and less fished!) reef systems surrounding the town of Munda, known for its World War II relics and world-class diving. M.Wujec & A. Reid.

Originally published in NGS Voices.

Day two of the Giant Sea Bass Count. I am in the process of doffing my dive gear when I see a diver scramble up the ladder and, still in full gear, rush over to me from across the boat. "I saw three! I saw three black seabass!" I quickly jot down all the details from his dive and mark the location on the GPS. An hour later we get ready for the next and final dive of the weekend in the Southern Channel Islands.

Giant sea bass (Stereolepis gigas), also known as black sea bass, are large fish that range from Baja California, Mexico to Humboldt Bay in northern California. These slow growing giants can weigh over 550lbs and were historically targeted by commercial fisheries in California and Mexico. Black sea bass landings peaked in the 1930s and markedly declined thereafter until a law enacted in 1981 prohibited the commercial and recreational take of giant sea bass, allowing only the landing of one incidental catch per fishing trip. Currently, IUCN Red List considers black sea bass to be critically endangered, but information on their numbers and biology is scarce - for a fish as conspicuous as the giant sea bass, surprisingly little is known.

The first week of August marked the first citizen science Giant Sea Bass Count, a collaborative project between researchers at UCSB and CSU Northridge. For the count, SCUBA divers all along the California coast were encouraged to get in the water and report any giant sea bass sightings, or lack thereof. Using this information, we can start to build estimates of how many of these critically endangered fish live along our coast. A. Guerra.


With one hand restraining a seven foot Galapagos shark and one hand left open to manually communicate the next steps in our sampling regime to my Kiribati colleagues, I quietly reflect upon the exciting challenges of doing science in a different cultural context. The full extent of the rewards I would reap by embedding myself in this unique environment here on Teraina could never have been anticipated before actually arriving on the atoll's coralline shores.  Today, I and my research a team are wrapping up the last of our efforts tagging and sampling coastal sharks armed with little more than hand-lines, rudimentary fish hooks, a Gilbertese dictionary, and lava-lavas.

Teraina, one of 32 atolls that make up the nation of Kiribati, is perhaps one of the most remote places on the planet. It has been my home and the base of our research for the past three months.  Teraina’s  1,700 inhabitants live in hand-built coconut structures, electricity is limited to a handful of solar systems, there is no running water, and the ocean is the primary source of food for nearly all residents. My aim here is to work with the communities on the island to learn more about the ways that residents rely on, and consequently shape their coral reef ecosystem that surround them. Our principle interest is in studying the ecology of Kiribati artisanal shark fisheries as revenue from sharks (mainly from the sale of their fins) is one of the main sources of cash income to this remote community and it seems that the long-term sustainability of this fishery may be in peril. On a daily basis, I accompanied local fishermen in their pursuit of tuna, reef fish, and sharks while recording data about the overall effort and efficiency of different fishing strategies. I will travel off Teraina in a week on a supply ship – the same vessel that dropped me off, and the only ship I will have seen during my stay. There is much to be learned back in lab but I find myself already counting the days before my return to this special part of the Pacific. T. White.


Our team squats silently in the reeds by a crystal clear spring watching a pod of four hippopotamus digest last evenings meal. A school of azure cprinid fish the size of large trout laconically idle by the rears of each hippo waiting for the digestion to advance to its terminus. It is a scene of tranquil coprophagiac beauty.

We are collecting blood from these fish and other constituents of this spring pool community to assay the ecological importance of nutrients imported into these springs by the hippos. Back in the lab we vaporize these bits of river life and measure their isotopic ratios to gauge how much of their carbon was derived from the back end of the hippo and how much was autochthonously produced by aquatic plants growing in the spring. Mzima is world famous because of the clarity of its waters that emerge abruptly from a fissure in Tsavo’s dark volcanic rock just a few hundred meters ahead of us. The murky composition of many of East Africa’s sediment laden lowland water waters blocks light penetration and inhibits algal growth. For this reason we are particular keen to learn how reliant Mzima’s fish are on the allocthonous hippo-derived energy and how much energy they draw from sources generated within the pools themselves. Fun to think that so much can be learned by unlocking the chemical story stored in all of these colored vials that are slowly amassing here in the grass by our feet. D. McCauley

 

“Beep…beep...beep..beep.beep.” The signal intensity on our acoustic receiver alerts me that I’m coming in close range of the manta we’ve been tracking for the past 30 hours. The shrill beeping helps me shake off my weariness and I peel my eyes in the direction of the boat’s bow, looking for any sign of our study subject in the heavy darkness. And as I nudge my field assistant into attention we’re both mesmerized by something wonderfully surreal: about 5 meters in front us we begin to see two wingtips gently pierce the surface of lagoon. It is our manta, but it looks more alien than we’ve seen it during the day- it’s entirely aglow in a phosphorescent green! As it glides through the water it must be disturbing clouds of bioluminescent plankton. After several elegant barrel rolls the manta silently fades back into the inky black depths of the lagoon, leaving only a trail of flickering electric blue sparks in its wake.

It is in moments like these that you get to fully appreciate and marvel at these strange, yet decidedly graceful, rays. I have long been amazed at how little is known about even the most basic elements of the biology of this majestic animal. What kinds of habitats are most important to these rays? What are the energetic needs of mantas and where are these demands met? How has our influence on the ocean reshaped their ecology and behavior? It is in hope of contributing answers to these questions that I find myself awake in the middle of the night trailing mantas in one of the most remote places on the planet

Good observations of mantas are all too often fleeting and mantas on the whole are intractable study subjects. This necessitates engineering creative solutions for learning more about their ecology. To overcome these barriers we use a variety of scientific tools including these ultrasonic acoustic tags that allow us to follow mantas, sonar cameras that let us sound to image their movements, and stable isotopes that clue us in to where and why they feed.  These and other sources of data contribute valuable insight into the biology of this elusive ray and we hope will support its management and conservation. P. DeSalles