Diving Deep into Coral Conservation
April 25, 2019
By Andrew Bywater, Life Support Systems Technician
I began trudging waist-deep into black seawater, the chill rising up my torso as the ocean slowly began filling my wetsuit. Weighed down by nets, collection cups, syringes and other scientific equipment, I was convinced why only a few people have had the opportunity to witness what was to come on this moonlit night. Diving into the unpredictable ocean near midnight, as most sane people are asleep in their warm beds, seems like an extreme venture. Only those crazy enough to study an immobile, expressionless living rock can witness one of nature's most spectacular underwater events.
The synchronized spawning of Curacao's coral reefs takes place annually (sometimes multiple times per year for some species) and is critical for the survival of the many species that call this small Caribbean island home. Multiple variables play in to this event, including temperature, day length, light intensity and the lunar cycle. All these factors must line up perfectly to put these animals in the mood (yes, corals are animals, but more on that later).
Floating together at the surface, the group performed one last check of our equipment before our dive leader proclaimed "lights on," so our path down would be illuminated. We emptied our buoyancy control devices and start to sink. As we descend to a depth of 8 meters, we place our coral spawn collection nets in a central, easily accessible area of the reef. The nets are identified by a reflective label that shines likes buried treasure when spotted by our dive lights. This way, each researcher will be able to see the nets as we gather them when the main event begins.
Prior to this dive, a few days were spent in a classroom learning to identify the target corals for the study. A brief daylight dive allowed us to scout the area and pick out particular coral colonies that we expect to spawn. I have been looking at corals my entire life in aquariums, and picking a coral that is about to spawn out of hundreds is just as difficult as it sounds. A "spawning calendar" was given to each diver, published by coral scientists, to estimate the spawning window for each target species.
As I began traversing to the dark unknown, I stuck to my assigned grid. My field of view was limited to about 10 feet in front of me and just a few feet on the sides, thanks to my underpowered handheld flashlight. The ever-present thought of what could be lurking outside of my small visual range was a concern, but the fact that I was surrounded on all sides by creatures that I have dedicated my life to protecting was calming in a weird, nerdy sense.
After 30 minutes into the dive, I had already photographed a sleepy sea turtle, interacted with a Caribbean reef octopus, and spotted more reef fish than I could count. All of these things by themselves would make for a wonderful night dive, but the real reason we were all there was just about to begin, and no classroom PowerPoint could have prepared me for what I was about to see.
A small "puff" of sperm from a great star coral (M. cavernosa) was the first clue. This particular species is a gonochoric broadcast spawner, meaning it has separate male and female colonies. It almost appeared as if this one polyp was testing the waters in a sense, because within seconds the entire colony swelled and released a white cloud into the water column. As sexual reproduction goes, it takes two to tango. Before I could even reach for my collection syringe, a nearby female great star coral made her presence known by releasing hundreds of stringy bundles of brown eggs. How she knew to release her eggs at the same time is still uncertain (although science points to chemical cues), but it couldn't hurt that these corals have had millions of years to perfect the act.
Dating back to the Triassic period, corals have evolved to reproduce both asexually and sexually. Most corals we see today in zoos and aquariums are produced via asexual reproduction: a small fragment is snipped off of a mother colony and left to grow into a colony itself. Genetics tells us that asexual reproduction yields an identical copy. This is a great method to sustainably produce more corals, but in a changing environment it may not be the ideal scenario for their wild counterparts.
Coral sexual reproduction is a rather new venture that is proving successful in coral restoration. With sexual reproduction, new coral individuals are created that could hold the secrets to adaptability. Large coral colonies release millions of potential recruits during each spawning event. Current research is focusing on the post-larval survivability of these coral hopefuls. With less than a 1 percent chance of making it to adulthood, we need to figure out what these animals need to survive. Ex-situ research (performed in a laboratory) offers a controlled environment in which we can further study the water quality and husbandry needs of these fragile corals.
Climate change, pollution and overfishing are all factors influencing the current degradation of the world's coral reefs, and it is a global problem. The value of these ecosystems is estimated to be in the billions of dollars, and the welfare of entire countries relies on coral reefs for sustainability and economic survival.
In the meantime, it is up to our universities, nonprofits, and zoo and aquarium colleagues to direct their efforts towards coral research. Time is running out, but all hope is not lost. A few brilliant coral researchers have recently discovered how to induce broadcast coral spawning in the lab and have published their findings online, for free. The materials and methods are there; we just need to pull together as a community to help these fascinating animals survive for a few more million years.
This opportunity was something I never thought I'd get to experience. My respect and appreciation for the ocean started at a young age, and to finally see first-hand how these amazing creatures have perfected the art of reproduction was humbling to say the least. I will continue to fight for the conservation of coral reefs, and I urge everyone to learn more about these fragile ecosystems and ways to help.
Frog Blog: My Ecuadorian Travels Part IV
April 10, 2019
By Chawna Schuette, Herpetarium Keeper
One of the last stops we made after leaving Machala was to a large pond off the highway. We pulled over to where two kids were selling fruit at a stand and an old man was sitting on the front porch surrounded by geese. We were very interested in the large pond on their property, and my Ecuadorian colleagues asked permission to take samples of the plant life from the landowner. We started collecting samples of a plant resembling duckweed and putting it in the bottles.
The children came to see what we were doing and we asked them in Spanish if they knew of any good spots to find tadpoles or frogs and the little kids disappeared. When the little boy returned, he showed us a pot with a few tadpoles in it. We were all very excited! We said, “Donde?” The boy and girl motioned for us to follow them behind the house, across some boards they had laid out to allow them to cross the puddles easily. There, below the Cacao trees, they started racing each other to catch the most tadpoles. There were several different species of tadpoles, and we all pitched in to collect the tadpoles swimming in the puddles from among the decomposing leaves just below the beautiful Cacao orchard. Once we had the animals we needed for the research facility, we secured them, and I gave the kids each a gold dollar coin. Not knowing this, my colleague, Patricio, also gave them each a $1 coin. This made the two kids very happy and they were smiling from ear to ear.
The kids had so much fun helping us, and their connection to nature and awareness of what lives in their own yard was impressive. Many children do not have the opportunity and experience to be familiar with animals and nature, much less show gratitude for it and have it pay off, so I was as excited as they were to see them have that moment. All of us thought how exciting it would have been to have been children and have scientists come to our houses and ask us for help looking for animals when we were kids. I hope it encourages them to continue to love animals and nature and keep learning. We took a few photos and waved goodbye to the smiling kids and family. It was a great trip.
Frog Blog: My Ecuadorian Travels Part III
April 01, 2019
By Chawna Schuette, Herpetarium Keeper
We traveled to a very special type of habitat, the Ecuadorian dry forest near the Pacific Coast. This habitat has many unique endemic plant and animal species, including specially adapted trees and cacti. We were in search of the Pacific horned frog (Ceratophrys stolzmanni).
As we drove down a dirt road to a location these frogs were last known to be, the vehicle approached many clusters of butterflies on the road. As we got close, they would fly up all around us like gold and white confetti. We were all in awe of the beautiful sight. We saw three wild tegu (a type of lizard) along the road as well.
When we arrived, we took a two-mile hike in search of tadpoles of C. stolzmanni. We took in the sights of the beautiful weaver birds, the plant life and unique invertebrate species. We saw tarantulas and foam nests of other frog species, but no sign of the horned frog until we reached the end of the trail, where we found a mud pond left by some construction workers. There we saw tons of tadpoles, and they were the species we were looking for! We were very excited and collected the tadpoles.
We waited until later in the evening to search for the adults. I was lucky enough to find the first one of the night. I was so excited to see him. I brought him up to my colleagues and showed them through the window and gave him a little frog kiss, "Perfecto!"
As the night went on, lots of horned frogs emerged, and we caught many more. This was extremely special and timed perfectly. These frogs are hard to locate, even in areas where their populations are still doing well. They only come to the surface seasonally, and normally only for a short period of time to breed and lay eggs. This was a very successful visit to this location indeed, and it was such a treat to see this species in the wild!
