Monday, December 4, 2017

A Panamanian Vacation

By Tyus Loman

            After a day of driving and crossing the Costa Rica/Panama border, our bus finally reached its destination, a small port town on the Atlantic coast. Our group exited the bus, and we loaded into a small motorized boat. We started our thirty-minute boat excursion through a picturesque setting; the sea was clear blue, the coast was visible in the distance, the sun radiated and reflected off the water, and mangroves were scattered throughout. We passed by numerous tranquil beaches, and eventually our boat slowed. The boat entered what appeared to be a man-made tunnel in the mangroves, and we reached a secluded dock on Isla Colón, one of the islands in the archipelago of Bocas del Toro. I looked out and saw a large pastureland flanked by dense forest in the background. As far as I was concerned, we had reached a tropical paradise.
            We emptied the boat and started across the pastureland, avoiding numerous cows and a lone horse until we reached a fenced off area. Within the fence was the biological station; it included a two-story living quarters, library, laboratory, dining hall and lounge area, and even a volleyball court. Peter, the man in charge of the station, gave us a quick introduction of the haven he called home. In the dining hall, a dart board hung on the wall, a hammock spanned across two pillars, and the room was furnished with multiple tables and a couch. I could not imagine more calm and ideal living conditions.

            The next morning, we set out for our swimming and buoyancy tests, followed by multiple hours of snorkeling, an activity we would become quite familiar with the next few days. Bocas del Toro has a considerable amount of living coral reef, especially relative to the rest of the highly bleached Caribbean reef system. The marine biodiversity we encountered was incredible; we saw numerous moon jellies, a group of squids, multiple sting rays, and various families of corals and fishes. As well, we studied the habits of damselfish, a territorial herbivorous fish, using planted sea grass. The fish would chase away any fish that neared their food source, even to the point that one nibbled my finger when I attempted to collect the sea grass for examination.

            The incredible biodiversity of Bocas del Toro was not limited to the marine life. On Isla Colón, a three-toed sloth appeared at the station. To intimidate us, the assumed predators, the sloth stood up and spread its arms wide. Despite its best intentions, the pose simply made the creature look adorable. Also, we came across a Boa constrictor in the leaf litter. As well, the forest was dense with a plethora of frogs, especially yellow Oophaga pumilio with black spots. We even stumbled across a Diasporus diastema, more commonly known as a dink frog, a species that is quite difficult to find.
           Our quaint research station on the secluded Isla Colón is a great example of an island left highly-undisturbed by human interaction. In contrast to the other islands of Bocas del Toro that had been highly impacted by tourism, Isla Colón has retained much of its natural beauty. Despite the great economic advantages of tourism, Isla Colón is an example of why many of nature’s beauties must be protected.

Sunday, December 3, 2017

Fossorial Calling Behavior of an Endangered Frog

By Rowan Etzel

           Back at Las Cruces Biological Station, several of us found some frogs exhibiting new calling behavior for their species, which happens to be endangered. Because these observations appeared to be novel, I decided to take on the task of writing up our observations in greater detail, perhaps eventually for submission to a scientific journal. Here are those notes:
Ptychohyla legleri, Legler’s Stream Frog, is a moderately sized nocturnal red-eyed treefrog, usually found near small streams in premontane wet forest of southern Costa Rica and western Panama. Males are thought to call during February–July in vegetation above flowing water, and have been found calling from rocks in streams at Las Cruces Biological Station, Costa Rica. Amplexus and oviposition behaviors are unknown for the species in the wild, but observations in captivity observed males to be territorial and defend small egg-laying cavities under an artificial waterfall where eggs were laid below the waterline. Clearly, the naturally history is poorly described for this frog.
            On 10 October 2017, we found six male P. legleri making advertisement calls for females at a first-order stream at Las Cruces. At about 4 PM, we heard two individuals calling from a short seepage down a vertical bank of the stream. Upon closer examination, the individuals were located one each within two separate burrows in the bank. The burrows were elevated 30–50 cm above the stream, ca. 15 m apart, and were ca. 3–4 cm in diameter. Water coursed down the stream bank around the burrow entrances and was also present within the burrows.  The individuals were perched 3–4 cm within the burrows and were half-exposed from the water. Upon shining a flashlight into the burrows, the individuals both stopped calling temporarily and retreated beneath the surface of the water. After a few minutes without exposure to a flashlight, they resumed calling with the typical advertisement call. The individuals chorused together, with one individual leading and the second calling in response to the first. Shortly thereafter, we located a third individual ca. 15 m upstream that was calling from within leaf litter adjacent to the stream. A fourth individual was also calling here near the third, but it eluded visual detection.

           When we returned after dark, we captured three more individuals. First, we located who we presume was the undetected fourth individual from the afternoon; it was a male and he was calling from among gravel beneath a rock. The final two individuals were found ca. 15 m upstream from the third and fourth, and were found calling together from underneath two rocks adjacent to the stream and were situated within small puddles with leaf-litter and twig organic detritus.

            We think our observations represent undescribed calling behavior for P. legleri which may provide insight into the breeding biology of the species. First, we observed individuals calling from subterranean burrows. It’s unclear whether those individuals constructed the burrows themselves, or used pre-existing burrows created by other mechanisms. In addition to the more typical nocturnal calling behavior, we also observed individuals that called diurnally in the late afternoon from within hidden calling sites such as terrestrial burrows and retreat sites beneath rocks. To us, terrestrial advertisement is uncommon among the hylid frogs of Central America, so this is atypical. Calling from covered locations such as terrestrial burrows may provide two functions. First, concealed calling sites may afford individuals additional protection and concealment from potential predators. In addition, these sites also resemble oviposition sites used by individuals in captivity. So, we think that these observations of terrestrial/fossorial calling may provide insight into where the frogs may lay eggs. 

Saturday, December 2, 2017

Curiosities from Greater Depths

By Michael Cornish

            Gliding over reflective turquoise waters towards an island destination was as thrilling as we had hoped; the smell of salt and whichever organic compounds that give the sea its signature scent was new to this course and we were all apt to embrace it.  A new country, new ecosystems to discover, what could be more exciting?
            We had just spent nearly two days in a bus traveling from the cloudy mountains of Monteverde, Costa Rica, to the coastal Bocas del Toro region of Panama where we were to spend a week studying marine life.  Mountains touched the clouds behind us as we motored away in colorful fiberglass boats pushed along by sputtering two-stroke Yamaha engines. Split between two boats, we made our way from the mainland towards a research station on the island Isla Colón.
            Steaming along while thinking about the excitement ahead, I heard a familiar noise.  Sounding like a draining bath tub, I remembered that it was the sound of a fouled propeller, a sound I have heard many times while navigating dinghies through seaweed. We abruptly stopped so our captain could remove the piece of rubbish caught in the prop. Problem solved, we continued on our way.

            Eventually, we approached an island and I expected, anytime, to see a beach we would land on. All of a sudden, while passing some mangrove trees, we, at a considerable pace, shot into a hole in the trees and cruised through a tunnel in the mangrove swamp.  A few hundred feet into the swamp, the captain slowed the boat as we approached a clearing with a small dock and bodega signed “[the] Institute for Tropical Ecology and Conservation”.  We got out of the boat and made our way, about a quarter of a mile, up a hilly pasture to the station.  Small, neat buildings made of yellow pine with red metal rooves were to be our base for the week.
            Early the next morning, we went back out in the boat to a small reef bordered by a lush mangrove swamp. When we arrived, our only instructions were to say within site of the boat and look for interesting things. Snorkeling though the clear water revealed some amazing creatures; the patch reef was dominated by the delicate fingers of fire coral, domed brain corals, and the thumb-shaped fingers from corals of the family Porites that were home to countless species of invertebrates, fish, and algae. Between colonies of these calcified reef-building species were a plethora of other sessile (unmoving) invertebrates. Green, blue, and red sponges of all shapes and sizes formed colorful rock-like structures that were often inhabited by brittlestars, gorgonian corals (soft corals that look like small, leafless trees), feather duster worms (which filter feed using feather-like appendages), crawling fire worms, yellow mantis shrimps living in small holes, amongst many others.  These coral flats were also patrolled by many different fishes.  Small yellow and black gobies (shark-nose gobies) were numerous-often perched on a small coral branch or on top of a brain coral, sand-colored blennies cruised the sandy bottoms between coral patches, and wrasses of all different colors cruised above the reef. Herbivorous fishes, such as the French angelfish (when juveniles), parrotfish and surgeonfish (Caribbean blue tang), swam about the reef searching for algae to graze upon.

            Towards shore, the mangrove swamp was home to even more fish. The roots of the mangrove trees sat in crystal clear waters that teemed with the juvenile fish which use these habitats as nurseries.  Because of this, the disappearing of mangroves threatens commercially-fished species that live in mangroves as juveniles. As I swam across the reef towards it, a layer of cold, fresh water grew as I got closer to the mangrove.  The water went from a turquoise to an emerald color which was surprisingly clear. The tubers from the mangrove trees shot into the water as if they were trees placed upside down in the water. On them were numerous oysters and other mollusks.
            The days that followed consisted of field work on the reef, conducting a project examining herbivory on seagrass we placed in the territories of aggressive damselfish. By placing pieces of seagrass at 0.5m distances from the middle of a territory, we looked at how much herbivory occurred and where, in hopes that it could indicate how far away from the territory center a damselfish was willing to defend.

            Reluctantly, we left at the end of the week, but not without a farewell from a pod of dolphins that swam past out boat on the trip back to the mainland. 

Friday, December 1, 2017

Enter the Dragon

 By Dennis Bolshakov

           Last week, the OTS Tropical Biology group went to the Bocas del Toro and Bocas del Drago regions in Panama. Arriving at midday on bus to the Caribbean coast, we unloaded our bags and placed them haphazardly onto a small boat, and got into another boat ourselves. That day, I glimpsed just a fraction of the beauty that is the sea: we rode quickly, bouncing gently on the waves while inhaling the fresh sea air. I did not touch the water, in fear of splashing everything and everyone on the boat, since even reaching into the water with my fingers creates a spray of water that expands behind me (I did however, test this thoroughly the following days).
The lifeguard, Ivan, looks out to sea on our first day of snorkeling.
            After a brief swimming and buoyancy test, we were good to go. Boating over to different areas surrounding Colon Island, we snorkeled through the reefs and mangroves that surround the island, like a cell wall and membrane. That first day was my favorite field day: partnering up with a friend and exploring the beautiful aquatic nature. The life was especially strange and wondrous to me, since we haven’t learned anything about the coral environment yet (except to avoid the fire coral!). Having only seen a few documentaries about the sea, I was bombarded with the new sights and sounds and smells of the shallow sea for the first time.
            During the following two days, we conducted an experiment with the damselfish as the focal species. Since damselfish are herbivorous yet highly territorial, we wanted to see if brackets of sea grass were less likely to be consumed close to the den of the fish where it would chase other fish away less, or further away. And so, we returned to the sites twice a day and hovered for ten minutes at each site, observing who and for how long the damselfish chase, and then collected part of the grass from the site to measure for herbivory later in the lab. Watching the fish chase others was mildly entertaining, but the experience was definitely augmented by the picturesque setting. We are so lucky to have seen such a healthy and beautiful reef, especially now, what with coral bleaching affecting reefs all over the world. Admittedly, there were occasional beer and cola cans at the bottom here, which was sad to see.
The damselfish, our focal species among a bunch of coral, urchins, and brittle-stars.

           Every day, we returned to the Institute for Tropical Ecology and Restoration (ITEC) station on Colon Island by boating into a tunnel of mangrove trees and to the small harbor there. In this mangrove, we saw bats sleeping, great egrets preening, and even a small three-toed sloth gently moving towards the foliage. Upon arrival to the harbor, we washed all our equipment and then walked about a kilometer through pastureland, sometimes shooing away the cows and horses from the path. Back at the station, there was a library, a dining room, our rooms and the volleyball net. Breakfast at 7:30, lunch at noon, and dinner at six. The electric generator was turned on only when it was used for cooking or during the evenings, so there was limited access to the outside world, which suited me just fine. I spent much of my free time reading old issues of National Geographic and playing cards and darts with the rest of the group. The place definitely has a charm to it.
           Our last full day was similar to the first: we went to a reef and got to explore it for upwards of three hours. We saw rockfish, parrotfish, jackfish. Again, schools of iridescent fry were hiding in the mangrove roots, this time pestered by some bigger fish. There was a squad of squid, calmly undulating, changing color when darting away from us, and even inking one of the students. During the afternoon, we visited the town of Bocas Del Toro, to learn about how tourism affects local nature, culture, and economics. The town was surprisingly big, with its own airport and a main road with many grocery stores, tourist stands, and expensive bars. On land, we saw a sloth crossing the lawn, and took some photos of it while the poor thing was sitting, arms out, in a defensive pose the whole time. We also saw a boa constrictor snake more than a meter in length, which was exhilarating, and many small critters (and biting bugs!) during a night hike. The next morning, we all reluctantly packed our things onto a boat and left, and, much to our surprise, a small group of dolphin swam up to our boat, as if to say goodbye. It was a wonderful and educational trip.

Thursday, November 30, 2017

Wildlife in Bocas del Toro, Panama

By Genevieve Valladao

           My favorite thing about the Tropical Biology OTS program that I’m currently in Costa Rica is the diversity of habitats that we get to see and learn about. I’ve visited a cloud forest, a páramo, a tropical dry forest, a premontane forest, and have even spent a few weeks in the concrete jungle of San José. However, up until last week, I had yet to see the Caribbean coast of Central America. Lucky for me, however, my course includes a marine unit that visits Bocas del Toro, an island archipelago off the Caribbean coast of Panama.
            A favorite way to kill time on my program is to watch the Planet Earth episode of the habitat we are visiting before we visit it. So naturally, the night before we headed to Panama we watched Planet Earth - Islands. The episode begins with a pygmy sloth searching for a mate amongst a mangrove forest. I was already excited for my trip to see the ocean creatures but when we looked up the location of the sloth scene and found it was Bocas del Toro, I realized that I would be seeing a lot more than just marine wildlife over the next week.
            The trip to Isla Colón, the island that we would stay on, started with a long bus ride from Costa Rica across the Panama border and culminated with a 45 minute boat ride out to the island. The last stretch of the boat ride went through a natural canal formed in a mangrove forest just like the one we had seen in Planet Earth. As soon as we got to the field station, the presence of one creature was immediately evident - frogs. The calls of the diurnal poison frog seemed to be welcoming us to Panama. Oophaga pumilio, also known as strawberry poison frogs, are abundant across the Caribbean coast of Central America. They contain alkaloids that are toxic to many predators and are brightly colored to warn of their toxicity. Many different color variations of the species exist and the frogs look different on each island of Bocas del Toro. On Isla Colón, the poison frogs are yellow and green with black spots.

            Poison frogs weren’t the only creature that vocally alerted us that they were there. My first morning on Isla Colón I was woken up before my alarm clock by another call that I have become familiar with over the past two months – that of the black-mantled howler monkeys. I would continue to be woken up by the howlers for the rest of my time at the research station, but the howler monkeys weren’t the only arboreal animals we got to see. One day the station director interrupted us at lunch to let us know that a three-toed sloth had found its way to the grounds of the station. The sloth was crawling slowly across the grass when we approached it to take pictures and it responded by taking up the defensive position that sloths use to try and scare of predators - sitting back and raising its arms in the air. It sat starting at us with its arms up for fifteen minutes.

            Although the terrestrial wildlife that during my week in Panama was amazing, it’s excellence was rivaled by that of the marine life we encountered. The faculty-led research project that we worked on in Bocas del Toro studied fish, so we spent most of our time in the water. From the moment we entered the ocean, we saw amazing creatures. I swam past cushion sea stars and jellyfish my first morning in Panama as I took my swim test. Each day we would go out to work on our projects, I would see something I had never seen before. During our first afternoon of data collection, I saw a burrfish perfectly camouflaged to the seafloor. Minutes later I saw what I thought was another burrfish, until I swam at it to take a video and it opened its small pectoral fins into beautiful bright blue wings – it was a Flying Gurnard. I saw many stingrays throughout my week in Panama, including one with a body over a meter long – a Caribbean Whiptail. But my favorite ocean encounter came on my last day in Bocas del Toro, when I found a group of Caribbean Reef Squid. There were about ten of them, and they lined up in perfect formation as I swam toward them. When I got too close for their liking, they began to swim away completely in sync. Throughout the rest of my day in the water, I would unexpectedly come upon the group of squid and would follow them around to watch how they would move together symmetrically through the water.
            I have seen amazing wildlife at every location that I have visited during my OTS program. As I begin my time at the last field station of my trip, I know it will be hard for it to beat the wildlife of Bocas del Toro. However, I have heard they have lots of monkeys and felines!

Wednesday, November 29, 2017

My Favorite Fish in the Sea

By Anna Lee

           This past week, the OTS Tropical Biology class took a break from life in Costa Rica and visited Isla Colon, one of the largest islands in the Bocas del Toro archipelago on the Caribbean side of Panama. While there, we completed a research projected investigating how territory defense in one species of damselfish affects herbivory of sea grass at varying distances from fish territories. To see firsthand how defensive these colorful, four-inch long fish can be, we spent a good portion of our week floating in the tropical waters and just simply observing their behavior.
Over three days, my partner and I recorded observations for seven fish. Most of the time, they were pretty predictable. Another fish would swim through the space and our focus fish would jump out of the coral they called home to remind the invader that they did not belong there. Then, there was Lazy Boy. Lazy Boy was a special fish that refused to follow the status quo. Not only did he fail to guard his territory from fish that wanted to steal food from his space, he would frequently wonder into his neighbor’s reef, leading to a quick attack.

            After watching Lazy Boy’s more…relaxed style of defense, he quickly became my favorite fish in the reef. Of course, there were fish that were more colorful, like the parrot fish nibbling their way across the sea floor or more dangerous like the barracuda reflecting the sunlight as they hunted, but I wasn’t able to appreciate their lives the way I could after spending time observing one lazy damselfish. Suddenly, I was aware of how exposed the lives of fish in our reefs are. They can’t escape the watchful eye of a student by hiding in the trees the way a terrestrial animal can. They live their lives in the open. They don’t understand the threats humans pose to our marine environment and most importantly, they don’t have anywhere to go if their reef disappears.
            In the moments we were not observing fish, we were taking in the coral reef as a whole. For the most part, the reef we were in was incredibly healthy. There were no signs of coral bleaching, an issue that is decimating reefs around the world (including other areas of Panama). Nor did we encounter commercial fisherman or tourists snorkeling the area. Even so, it is impossible to avoid noticing how humans have hurt this unique environment. The crystal-clear water can’t hide the beer cans littering the sand. The soft crunching of the parrotfish using their beaks to eat coral doesn’t drown out the sound of the motor boats passing by. Looking around at these charismatic fish that have evolved to survive in this environment, I was scared.

            At this point in my biology studies, I of course know how human influence has caused our oceans to change. Temperatures are rising with the global climate and increased levels of CO2 in the air have caused some areas of our sea to become more acidic, leading to a decline in the life that can survive there. Unfortunately, I just didn’t care. Being raised in the Midwest has not made me particularly comfortable around the ocean, and I had never seen many tropical fish outside of the tanks at my local pet store. Trying to understand the life of Lazy Boy has made me reconsider my thoughts. If I do not want to fight to protect the ocean as a whole, I can fight to protect the life of one small lazy fish, my favorite fish in the sea. 

Tuesday, November 28, 2017

Getting Inked in Bocas del Toro

By Finote Gisjman

           When I look back on my experience in Costa Rica, being a part of the Tropical Biology on a Changing Planet study abroad program, I hope that I have a handful of memories to reminisce upon. One of the places that definitely did do just that was Bocas del Toro, Panama.
            Our journey to Bocas del Toro was nothing short of exhausting. We started our trip to Bocas del Toro from La Selva Biological Station in northeastern Costa Rica. The group left at 6:00 am and traveled through the Caribbean coast down to the border between Costa Rica and Panama. Once there, we got out of the bus, exited Costa Rica, and crossed a bridge over to the Panamanian side of the border. From there we drove another two hours, until we reached a port with boats that were waiting to take us to Isla Colón, a large island in the Bocas del Toro archipelago. The boat ride took about an hour, but eventually we reached a small opening in the mangroves that led to a dock owned by the Institute of Tropical Ecology and Conservation, the place where we were staying for the next few days.
We started off our week in Panama with a short swimming test that was followed by a few hours of snorkeling. The next few days were spent working on a research project in the reef with Threespot Damselfish (Stegastes planifrons). These fish are herbivores that feed on seaweed and display intense territorial defense behavior. Adult Threespot Damselfish often maintain large territories and chase or peck intruders. Our experiment aimed to investigate the effect of this type of territorial defense behavior on herbivory of seagrass cuttings placed at different distances away from the fish’s territory (0 m, 0.5 m, 1m). We also observed each fish for periods of 10 minutes and noted the number of chases/attacks on intruders and the type of intruder (whether it was an herbivore or carnivore). Getting to work on a marine research project was a pretty interesting and challenging experience that I really enjoyed. Collecting data underwater, for instance, was not an easy task. Having to deal with the snorkels while also having to collect data on the fish’s behavior underwater was very difficult.
My favorite and most memorable moment of the trip, however, was on our last snorkeling day. As usual, we left the Institute at 8:00 am and got into the boat that would take us to our next snorkeling spot. We reached an open water area surrounded on one side by mangroves where we set the anchor down. My partner and I jumped into the water and made our way through the reef. Within the first few minutes of snorkeling, we came across a shoal of eight squids that were uniformly lined up and “hovering” in the water. The squids had pale pink torpedo-shaped bodies with bright blue dots on their sides, features characteristic to the Caribbean Reef Squid. We followed this shoal of squids for about 45 minutes through the seagrass and corals and observed their behavior. The squids, all of different sizes, seemed to continually change colors as they swam in their diagonal formation, maybe as a way to communicate with each other.
My partner and I were determined to document all of the things that we saw that day on her GoPro, so obviously getting the squids on camera was one of our main priorities. In attempts to do so, I dove down into the water slowly, trying not to make any sudden movements that would scare the squids off. This didn’t exactly work. I guess I got too close for their comfort at some point because the next thing I knew, I had been inked. Once one of them had released its ink, each squid in the diagonal line consecutively also released their ink. Soon enough, they were nowhere to be found. The only sign of their existence were the eight small pools of ink floating in the water and the footage on the GoPro.
            While in Bocas del Toro, we also came across a Three-toed Sloth that was crossing the Institute’s yard. As these animals only come down to the ground infrequently to urinate and defecate, finding a sloth right outside of our rooms was a pretty cool and unique experience. The group was extremely excited to see a sloth up-close so obviously we had to take a million pictures. When the sloth saw us approach, it sat up and spread its arms facing us. Although seemingly cute, this open-armed stance is a defensive stand against predators that shows off the sloth’s long claws, and serves as a warning.
Bocas del Toro was probably my favorite trip of the program so far. It was a very cool experience to not only travel to a different country in Central America but also get to experience what research in a marine ecosystem would be like. I hope to be able to go back some day and work at the Institute of Tropical Ecology and Conservation.