Coral Reef Fish of the Bahamas and Florida Keys Final
This topic submitted by Ryan Purcell (
purcelrm@muohio.edu) at 11:51 PM on 5/15/09.
The views are spectacular at the wall break,
25 m deep, San Salvador, Bahamas.
Ryan Purcell
GLG 413
Dr. Hays Cummins
5/15/09
Coral Reef Fish of the Bahamas and Florida Keys
The Coral Reefs are an explosion of color and all that look at them feel the same sense of wonder and amazement. When most people think of the reefs, they imagine an alien landscape of coral that is swarming with a multitude of fantastically colored fish of every shape ad size. Each fish is unique in itÕs own right, with different coloration and body shape, and each plays an important role in the upkeep of the reef. These fish include, but are not limited to the angelfish, pufferfish, parrotfish, wrasse, anemonefish, surgeonfish, butterflyfish, grouper, and triggerfish. Most of the fish I will be discussing are ones that can be seen in the reefs in the Bahamas and the Florida Keys. I will also be talking about ways that fish on the reef protect themselves from predators. Such defense mechanisms allow fish to keep themselves alive and many fish have developed unique methods. On the other hand, these fish face ever decreasing odds for survival due to global warming and death of the coral that they inhabit.
To start off, I would like to take a look at the angelfish. The angelfish is part of the family Pomacanthidae and is composed of 8 different genera: Apolemichthys, Centropyge, Chaetodontoplus, Genicanthus, Holacanthus, Pomacanthus, and Pygoplites. One in particular I would like to focus on is the Queen Angelfish. It is found most often in the Caribbean near the lower levels of coral structures. Some people have argued that Holacanthus ciliarus, the Queen Angelfish, is the most beautiful specimen on the reef (Florida Museum of Natural History). This is due to the unique coloration that this particular angelfish posses. Composed of bright blue and yellow scales with tinges of orange and black here and there and a completely yellow tale, there is little doubt that the creature is a spectacular site. At the top of the head lies what gives this angelfish its royal lineage. Placed there is a ring of black with blue spots that resembles a jeweled crown. A young Queen Angelfish however, does not have the coloration as the adult counterpart. In fact, it is dark blue with yellow and has dark bars running vertical across its bodies. Physically the Queen Angelfish has a slender body with long a dorsal fin and a blunt face, which houses a mouth that contains a row of thin teeth resembling a brush. Its primary diet consists of sponges and algae but also includes tunicates, jellyfish, coral and plankton. Juvenile specimens are know to set up cleaning stations and eat parasites off compliant, larger fish.
Next of the list is the parrotfish. The parrotfish appears in a wide variety of colors, shapes, and sizes and can be found in tropical waters all over the world. There are 80 known species of parrotfish that range anywhere from less than one foot up to four feet in length (National Geographic). It was given the name of parrotfish because its mouth resembles the beak of the bird of the same name. The beak is actually a fusion of protruding teeth (Florida Natural History). Seeing this unusual assemblage on a fish seems odd, but the parrotfish uses this highly specialized beak to scrape off coral in order to feed on algae. At the back of the parrotfishÕs throat is a set of pharyngeal teeth that crush and grind the coral into bits. After the coral passes through the digestive system and the nutrients are absorbed, the coral is disposed as waste in the form of sand. Parrotfish can be distinguished from one another according to how their front teeth are arranged (Florida Natural History). Parrotfish have moderately compressed bodies with blunt faces and are protected by large, heavy scales covering their bodies. Another defense mechanism that the parrotfish possesses is the ability to secrete a mucous membrane that can cover their entire body. Scientists believe this cocoon masks the fish from predators that hunt by smell and touch, allowing it to sleep easy at night. However, the membrane takes a long time to produce and remove and is not used every night for reasons unknown to scientists (Animal Bytes). An unusual practice that we humans think is odd, but one that is quite common among fish is the practice of sex change. Parrotfish happen to be able to pull this feat off quite well. Often, a group of parrotfish is led by a suepermale that defends his territory aggressively from other males. The rest of the group is composed of females, an if the lead male dies, the biggest female changes sex and coloration and takes over. Decreased numbers of either males or females also stimulates sex change, and the parrotfish will adapt to counteract the imbalance (Florida Natural History). The parrotfish is also not limited to a mating season and therefore can mate all year round.
The surgeonfish is also and interesting creature inhabiting the reefs. There are about 80 known species of surgeonfish that range in coloration and size, and they can be found all over the tropical waters of the world. The family of surgeonfish includes tang, doctorfish, and unicornfish. Their name is derived from the scalpel-like spine located near the caudal fin. This spine, which is very sharp, can cut like a knife and is used to defend the surgeonfish against enemies. The spine is either retractable or fixed, depending on the species, and the number of spines ranges from between one or two to 6 per side. Surgeonfish generally keep to shallower waters around the reefs with clear water and lots of sunlight. This kind of habitat is good for algae growth, with is the surgeonfishÕs main food supply. Surgeonfish play a big role in keeping algae levels from getting out of control and killing the coral. Their bodies are thin and oval shaped and in some cases are know to grow up to 3 feet in length. Their mouths are designed to scrape and sift algae from rocks. Often the can be found in small groups and they are sometimes territorial. Some species, however, can be found inhabiting more open waters, but they reside in slightly larger groups and are often larger in size themselves.
Another fish that can be found in the Bahamas and the Florida Keys is Epinephelus striatus, the Nassau Grouper. Groupers are often fished for food and have even been banned from commercial use in the US and are being considered put on the endangered species list. The grouper usually keeps to the bottom of the reef and can be found up to 90 meters underwater. Typically they keep to themselves, but the do sometimes form small groups, especially during times of mating. The Nassau Grouper can grow up to 4 feet long and weigh around 50 pounds. The grouper is football shaped with big eyes and somewhat spiny fins. It is also a carnivore and feeds mainly on other fish, crabs, lobster, shrimp, and octopuses. The grouper catches its prey by swallowing it whole after ambushing it. The grouper utilizes changing camouflage to blend in with the rocks around to hide from predators and prey alike. Normally the Nassau Grouper is brownish-red to black with bands of white along the length of the body. The Nassau Grouper also frequents things called cleaning stations, where small fish like wrasse, clean parasites and other things off of the bigger fish. The grouper remains motionless as to not pose as a threat and the small fish approach and begin cleaning, allowing the small fish to eat and the grouper to remain clean.
Many fish on the reefs have developed unique defense mechanisms and other techniques in order to protect themselves from prey and ensure their survival to the next generation. Such techniques include camouflage, bad taste, false coloration and patterns, spines, and larger than life appearances. Predators have also developed similar tactics in order to catch their intended prey off-guard. Other defense mechanisms are quite unique and are not as wide spread as some of the other, including the anemonefishÕs relationship with the anemone. I have already discussed a couple of techniques, such as the parrotfish excreting a mucous membrane to hide it scent from predators while it sleeps and the surgeonfishÕs sharp spines which can be used to fend off attackers. Another defense utilized by many fish is the concept of moving as groups. Large groups confuse predators since they arenÕt able to focus on a single victim. Instead, when they strike, they end up scattering the group and end up empty-handed. Another technique is camouflage, which allows the fish to blend in with its surroundings. Though many fish are brightly colored, it actually helps them to blend in with the colorful coral and vegetation around them. Predators also employ this tactic, and blend in with the rock around them and lie in wait until their prey swims by, and then they strike. Another coloring pattern that confuses predatory fish is a false eye located near the back of the victim. Some butterflyfish are know to use this technique and it works by making the predator think that the tail is the head and they end up striking the least vulnerable part of the fish, giving it valuable time to escape. Another type of butterflyfish has thin bands of color arrayed vertically along its body, which confuses predators as to which end is the head. Porcupinefish and pufferfish, though closely related are not the same thing, share some of the same defensive maneuvers. When they feel threatened, they have the ability to suck in water and expand their bodies, making them appear much bigger than they actually are. This makes them look to big for a predator to eat and attempts to scare them away. The porcupinefish, unlike the pufferfish, has thick spines that protrude from its body during expansion to further deter enemies. The anemonefish has a very close symbiotic relationship with the anemones it lives around. Anemonefish, such as the clown fish, have developed protection against the painful stings of the anemones, and when a predator is near, the fish hides among the tentacles. At other times, it clears away dead tentacles by eating them, and keeps the anemone clean by eating the scraps of food left behind after the anemoneÕs meal.
There are many more fish on the reef and each is important in its own right. All of the creatures on the reefs work together to keep the delicate coral environment in tact and without each one, the reef may suffer in unknown ways. This has become a problem recently with the rise of coral bleaching and over-fishing. The bleaching of the coral is due to the rise of ocean temperatures due to global warming. When the coral is bleached the fish begin to die off because their main source of food and habitat has been taken away from them. Over-fishing is also a big problem, because greedy fishermen have nearly fished some species into oblivion. This disrupts the natural order of the environment and can have negative affects on both the coral and other fish populations. Depending on the type of fish, it can take several years for fish to recover from decreased number. That is, if they are left to themselves and are free from human interference. Most of the problems fish are facing are due to human activity, and if we do not reform our way, then we may end up losing some of the most exotic and beautiful creatures on the planet.
Works Cited
"ANIMAL BYTES." SeaWorld/Busch Gardens ANIMALS - HOME. 15 May 2009 .Byatt, Andrew, Alastair Fothergill, Martha Holmes, and Dk Publishing. Blue Planet. New York: DK ADULT, 2002.
"Coral Reef Fish Need Decades Or Longer To Recover." Science Daily: News & Articles in Science, Health, Environment & Technology. 15 May 2009 ."Evolution: Survival: Coral Reef Connections." PBS. 15 May 2009 ."Fish Pictures, Photos, Facts, Information, Sounds, Habitats, Reports, News - National Geographic." Animals - Facts, Information, Photos, Pictures, Sounds, Habitats, Reports, News - National Geographic. 15 May 2009 .
"Florida Museum of Natural History Ichthyology Department." Florida Museum of Natural
History. 15 May 2009 .Magurran, Anne E.. "The Adaptive Significance of Schooling as an Anti-Predator Defense in Fish." Ann. Zool. Finnici 27 (1990): 51-66.
"Pufferfish Inflation." Biomechanics at UCI. 15 May 2009 .Stafford-Deitsch, Jeremy. Reef : A Safari Through the Coral World. San Francisco: Sierra Club Books, San Francisco, Ca, U.S.A., 1991.
"Fishy Trivia: Defence and Offense." Habitatnews. 15 May 2009 .
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