Comparing Invertebrate Counts

The invertebrate creatures that life on the coral reefs are in integral part of the vast and complicated ecosystem that has been referred to as the rainforest of the oceans. There is much about these ecosystems that we do not understand, and compiled with the complicated effects of human impact reefs makes it even more difficult to understand. However, after compiling years of data and the results inferred, it has been determined that there are key indicator species that can be used to determine the health of a reef. Almost as one would do with a canary in a mine shaft.

The species that have been determined by Reef Check to be indicator organisms based on economic (harvested for the aquarium trade) and ecological (balancing the algal growth) value are;
1) Banded coral shrimp (Stenopus hispidus)
2) Diadema urchins
3) Pencil urchin (Eucidras spp.)
4) Collector urchin/sea egg (Tripneustes sp.)
5) Triton (Charonia variegta)
6) Flamingo tongue (Cyphoma gibbosum)
7) Georgonian (sea fan, sea whip)
8) Lobster (Palinuridea)

While in our reef ecology class we reviewed and studied an article that studied and almost certainly concluded that the diadema (black spine) urchin was not only integral, but perhaps the most important, or key stone, invertebrate species within the coral reef ecosystem. Following a mass die out of diadema (aprox 95%) in 1984, the increase of alga was almost instantaneous. However, since the return of the diadema in recent years (since the mid 90s) they greatly reduced microalgal (from >60% to <5%) which in turn increased coral growth. The study was conducted throughout the Caribbean, but the discovery of the impact of the diadema was a place called Dairy Bull, in Jamaica. It was here that there as actually been an increase in coral cover in the past two decades (in vast contrary to the rest of the Caribbean), almost 100% more living coral and 90% less algal cover then it did in 1995. This coral growth is occurring even while overfishing is still a problem. This phase shift in coral growth  appears to always be preceded by the recovering and increased population of the diadema urchin.
Source:
http://www.int-res.com/articles/meps_oa/m403p091.pdf

On the first dive located at, Buena Vista, we discovered invertebrate species in the low single digits only. This had also been a trend in most of the dive sites we had been to prior to our Reef Check dives. In addition to the lack of invertebrates, their was large amounts of coral disease and bleaching. Their was a large amount of algal proliferation, as well as a great over abundance of georgonians. The site just looked sick.

In contrary, the second dive site, Coral gardens, looked radically healthier. The amount of diadima urchins was around 50 and pencil urchins was even more then that. Also, reef urchins, which are not counted by Reef Check would have easily surpassed 200 if they had been counted. There were more flamingo tongues, and even two collector urchins, the georgonian count was also much lower. The coral substrate itself was vastly more abundant and disease and bleaching was far less prevalent. Also, there was significantly less algal proliferation. Both sites are legally allowed to be fished and the species discovered at each site were about even.

With out conducting a purely scientific study we can not make any fact based conclusions. However, from the data we gathered and what we were able to see just from being there supports the findings of the article we studied in class and the study it was based on. The diadema urchins, and other herbivores are indeed a keystone species. They are integral to the promotion of of healthy coral and increased coral growth. In addition to this, what we observed at another site, Hol Chan, also supports the article. While not a Reef Check site (so we did not study, just notice and observe), it is protected from fishing, which means far greater number of fish species. However the overall health of the site was less the that of Coral Gardens, and in parallel to that the amount of diadema we noticed was far less.

The coral reefs are an incredibly complex biosphere, and the more we study the more we learn. Reef Check, and the observations we make while conducting it, is an invaluable asset into this learning process. Just seeing that the two locations we studied were so different and the species we found in each site is an enormous help. The fact that what we found supports conclusions by other scientific data is large step forward in the understanding of healthy reefs. Hopefully, with time , the damage that has been done to the reefs can be stopped and the health of these underwater biosphere can be returned to their natural unparalleled state of beauty.

 

 

What we are actually doing

A brief overview of what we are doing and why we are here, with out getting into too much detail or getting too complicated.

The coral reefs around the world are dying, a variety of reasons contribute to this tragic fact; over fishing, climate change, water pollutants, and degradation of terrestrial habitats are thought to be some of the causes. However, because of the sheer expanse of the coral reefs its very difficult to pinpoint many of the whys and hows. Also, these different causes have a varying effect on the complicated ecosystem of the reefs. Regardless of this, the more data we have the more solid conclusions we can come to. That is were Reef Check, and people like us come in.

Because of the expanse of the coral reefs, the job of surveying and studying them can not be left to scientists alone. Reef Check was created to establish standard parameters and methods in which citizen scientists could work with and under qualified individuals to gather the necessary data around the world. Some of the goals of Reef Check are to educate the public about the reef crisis, create a global network of volunteers, scientifically investigate the coral reef ecosystem, and to stimulate the local community into taking taking action to protect their reefs.

The first thing we do is lay out a 100m transect line along the chosen reef that meets the required criteria. This is done at two depths, one of 3m and one of 10m. Then using that line we collect four types of data:
1) A description of each reef site based on over 30 measures of environmental and socioeconomic conditions and rating of human impact.
2) A measure of the percentage of the seabed covered by different substrate types, including live and dead coral, along four 20m sections of a 100m shallow reef transect.
3) Invertebrate counts over four 20m x 5m belts along the transect.
4) Fish counts, up to 5m above the same belt.

We took the reef ecology course to learn about the reefs and their ecosystems, as well as their global impact and importance. We all had to be SCUBA certified , as well as spend time learning the diving skills required to collect the data. Then it was our job, broken up into assigned teams, to collect and record the data under these parameters.

The Great Blue Hole

So, I first became a certified diver just about 18 years ago and today has been one of, if not the, most incredible diving experience of my life. It was the summer solstice, the longest day of the year, and we spent every moment of it on the ocean, leaving at about 5 in the morning with the rising sun; we didn’t come back until the sun was setting.

image(1)

The Blue Hole is about a two and a half hour boat ride from San Pedro. It was rough going for parts of it but we all managed to keep our breakfasts down, which is quite an improvement over day one. The Blue Hole is, or was, an ancient cave that collapsed in on itself centuries ago. It goes almost 500 feet down, and it is 1000 feet across: a sight to behold from the sky, as seen in pictures. But from the boat it was unimpressive… until we went down. The dive itself is easy, off the boat, to the first shelf, to the max allowed depth and then slowly back up. But easy does not mean not amazing. We descended to the first shelf about 40 feet down, and looking out into the blackness the world seemed to fall away into an oblivion of nothing. In line we descended into the hollow darkness. At about 100 feet the wall recedes into shadow as stalactites crept into the light, and we followed. We swam through the giant rocks descending from above us as reef sharks swam in the distance. At our max depth of 130 feet the time we had down there was only about 7 minutes before we had to return to the world above. But it was worth every second. On our ascent the sharks swam closer, swimming around us, as curious as cats. A good solid safety stop and we were back to the surface, filled with awe. But the day was not over yet.

image(2)

Our second dive of the day was located at a place called Half Moon Caye. A beautiful dive site in the middle of no where, the reef was still sick, even out here. However, the amount of fish was a welcome sight. Numbering in the thousands, they were all around us. There were fish of the angel, parrot, butterfly varieties galore, along with tangs, grouper, and even some rather large barracuda, all swimming with and around us as we swam with them. After that it was time for a well-earned lunch, and on a nearby island we feasted. Curried chicken, rice and beans, plantains, and cold sodas were on the menu. All were hand cooked by the divemaster himself. After feasting we wandered down to the bird sanctuary to gaze upon the nesting grounds of the red footed boobies. Along our path, hermit crabs scuttled and iguanas watched us from the woods. Time was short, though, as we still had one more dive. Our third dive of the day was at a site called Aquarium, giant cliffs of coral and sponges lay before us. We met more curious barracuda, a lobster, and a lion fish. A sneaky turtle watched us from the wall as well. Our day of diving came to an end as we had to make it back to San Pedro, but the night awaited us.

image(3)

Back on the island, arriving with the rising of night time, we had a brief rest before hitting the town. It was lobster-fest, and we were not disappointed. All across the square people packed in to sample the wondrous food. All different restaurants had booths set up selling as many different choices of prepared lobster as there there were people. They had it curried, stewed, blackened, jerked, bisqued, fried or frittered, they had them on sticks and on waffles, in soups or on pizza. The choices were endless. Live music played on the stage adding the perfect eclectic sound to the feeling in the square. We feasted, we danced, we sang the night away until after a day of travel and diving and enjoying life to its fullest we had to call it a night. The short walk back to the hotel brought us ever further to our pillows and the Great Blue Hole in our dreams.

image

 

The journey and the destination

It was a dark and stormy night. No seriously, it was, and in the early hours of the morning we began to trickle into Logan international airport. By 3am we had all arrived, bags were packed and we were ready to go. Between the 11 of us we managed to figure out how to get our boarding passes, a task that should not have been nearly as complicated as it was. Within the hour and with little trouble, we had made it through security. Even professor Savage with his high speed low drag camera wasn’t detained. Eager to board we still had almost 2 hours to kill, and thankfully none of the restaurants would open till 15 minutes before we had to board. “Breakfast” snacks would have to be purchased quickly. The first flight was entirely uneventful with sleep being the main priority for most of us.

Miami international airport became a place to catch a few more hours of sleep before our flight at 1245. Originally we were leaving from gate D15, but just to keep us on our toes they changed to to D33 an hour before we had to go, rolling with the punches. The flight was delayed slightly, or more accurately the pilot decided he had better things to do then be there on time. Flight number 2 had a crash landing after what should have been a new ride at 6 flags. We had arrived in Belize City. Paperwork had been filled out on the plane, and we got through immigration smoothly. Bags were collected after watching the baggage wrangler wrestle with all the luggage. We were then off to a really long line to customs.  No troubles there either, however we were to encounter our first snag just through the next door.

image(1)

The last and final flight, just a short 15min to San Pedro, was over booked. Nine out of 11 were to make the flight. Abandoning our fellow travelers to find their own way. Or in reality just catch the next flight. A tiny 12 seater took us to our final destination. The first 9 of us disembarked grabbed our bags and avoided the dust off from the props of our plane turning around and taking off. A very short cab ride later and we were at the Thomas Hotel, our home for the next two weeks. Shorty thereafter the group was reunited, professor Patev and Riley had made it, alone and unafraid. Riley even was able to co-pilot the flight. It was time to enjoy Belize.

image(2)

The first order of business for many of us was to get in the water, food and unpacking were second to the call of the ocean. After a quick swim, some grocery shopping, and unpacking it was time for dinner. Caramba’s was the destination, and the food was divine. Conch fritters, blackened shrimp, and whole fish was on the menu, followed by fantastic key lime pie, and cheesecake. Far from home, and surrounded by new friends our first day was drawing to a close, heads hit the pillows as we all looked forward to exploring the octopus’s garden in the morning.