|
What
animals are you likely to encounter on the reefs off Key
Largo? Well, our reefs are home to over 260 species of
tropical fish and around 80 species of coral, not to mention
countless other invertebrates. In terms of fish, some
of the most commonly encountered are parrotfish, wrasses,
damselfish, snappers, grunts, and barracudas. Invertebrates
commonly seen on the reefs include lobster, sea cucumbers,
urchins, shrimp, and anemones. For most people, the most
impressive coral varieties are brain coral, mountainous
star coral, elkhorn coral, and sea fans. This variety
of marine life provides spectacular opportunities for
underwater photography!
PARROTFISH
occur in about 15 varieties that are frequently spotted
on the reefs of the Florida Keys Reef Tract. For most
of those species, however, the males and female are different
colors, and often the juveniles are at least one other
color, leading to somewhere around 50 different color
varieties, any color of the rainbow (and in the case of
Rainbow Parrotfish, all of them!). The fish tend to complicate
things by making an amazing change towards the end of
their life, too. Many parrotfish (along with wrasses and
groupers, among others) are protogynous sequential hermaphrodites.
This means that nearly all hatch out as females, and when
there is a shortage of reproductive males, each female
has the ability to change into a male! This involves a
major color and size change (among other things!) but
after about a week and a half, they are fully functioning
males. This means that most of the male fish sighted on
the reef used to be female! The parrotfish have a heavy
beak formed from their front teeth growing together, and
are primarily herbivorous, scraping reef-growing algae
off the rocks. In doing this, they grind a lot of the
limestone rock up in their stomach, which eventually travels
through the digestive tract. Parrotfish end up excreting
roughly 60% of our beach sand!
Close
relatives of the parrotfish, WRASSES even look like miniature
versions of their cousins. Like parrotfish, wrasse are
generally protogynous hermaphrodites, but unlike parrotfish,
most start out on the reef working as "cleaners".
These juvenile wrasse will form a "cleaning station"
around a coral head waiting for larger fish to approach
and indicate that they want to be cleaned. Upon the right
signal (frequently flaring gills and occasionally changing
color), the cleaners will approach the larger fish and
swarm all over its body, picking off parasites and removing
dead skin, a very important part of preventing disease
on the reef. Some cleaners are especially daring: juvenile
Spanish Hogfish (one of the largest wrasse species in
the Keys) are known for cleaning the mouths of Green Moray
Eels!
DAMSELFISH are found nearly everywhere on the reef, and
are sighted on every snorkel or dive. The most common
species include the zebra-striped Sergeant Major, the
colorful juvenile Cocoa Damsels, and the ubiquitous Bicolored
Damsel. Damsels are generally small (smaller than your
hand) but they don’t know it! To the contrary, these
are the only animals that are likely to "attack"
you while snorkeling! Damselfish fiercely defend garden
patches of algae on the reef, and if you get too close
to the bottom, they will come up and dance in front of
your mask to scare you away! Don’t worry, they’re
harmless; in fact, they put on quite a show if you stick
around to watch.
SNAPPERS
and GRUNTS are frequently confused with each other by
snorkelers and divers, and with good reason. They are
very similar in body shape and color; close enough, in
fact, that they are often found schooling together. These
schools can be very impressive, covering the entire sea
floor in between coral ridges. Both get their names from
fishermen; snappers tend to snap at fisherman when pulled
up in a net, whereas grunts will grate bony plates together
in their throats to make a loud, pig-like grunting noise.
Yes,
we do have GREAT BARRACUDAS here! They are seriously nasty-looking
predators, up to 7 feet in length, with a full mouth of
sharp teeth. The good news is, as far as we’re concerned…it’s
all just show. Barracudas primarily feed on fish about
two to three inches long, and rarely would go after anything
healthy (too much work for them!). If you head out on
the snorkel boats, you will often see people removing
jewelry before getting in the water. While this may be
a good idea to keep from losing anything, it won’t
have much impact on the barracudas (they can see A LOT
better than that, especially in our clear water). They
may be curious, but they are not a threat to snorkelers
or divers. Of course, you don’t have to tell your
friends that when you show them your pictures later!
SEA
CUCUMBERS, SEA URCHINS, and BRITTLE STARS are all members
of the Phylum Echinodermata, which are all animals with
spiny skins and a water vascular system. Sea cucumbers
are present on most reefs, but a good sighting is rare
during the day, because they usually hide within the cracks
of the reef. Sea urchins are more commonly sighted; although
numbers of the Caribbean Long-spined Urchin, Diadema antillarians,
greatly declined in the 80’s, they are making a
recovery on our reefs, and more commonly snorkelers see
the Rock-boring Urchin and Sea Egg (which frequently make
protective "sun hats" out of sea floor debris).
Brittle stars, relatives of the sea stars, are usually
reclusive, but can sometimes be found out during the day
by checking the mouth of tube sponges and looking under
ledges. They occur in any color imaginable, and at night
many divers discover that the hairs on their legs are
bioluminescent (glow in the dark)!
The
Class Crustacea in the Phylum Arthropoda contains the
CARIBBEAN SPINY LOBSTER, various types of CLEANER SHRIMP,
and ARROW CRABS, all of which can be found hiding under
ledges on our reefs. Spiny Lobster are protected on most
of the snorkel reefs, and so can grow to enormous size
there, topping two feet from rostrum to tail. On the other
end of the size spectrum, Arrow Crabs are usually no more
than three inches across and at first appear to be all
legs and no body! The cleaner shrimp, such as the Pederson’s
Cleaner Shrimp, are frequently found inside sea anemones
(such as the GIANT ANEMONE) from which they operate their
cleaning station. Divers and snorkelers have reported
having their fingers cleaned on several occasions.
If you come to the park to try your hand at underwater
photography, remember that the biggest and best-known
trick is to use the light to your advantage. Colors tend
to fade to blue over fairly short distances underwater
in the absence of bright lights. The best time of day
for natural-light photography is around 10:30 or 11:00,
when the sun is climbing and many of the larger animals
are still active. If you can, use a flash; doing so will
double the colors in your pictures! Otherwise, remember
the three rules: get CLOSE, get LOW, and shoot UP. Approach
your subject slowly, and don’t waste the film until
you get close enough to get those colors. Once you get
close, dive down below your subject (if possible) and
shoot at an upwards angle, with that beautiful blue water
forming the perfect backdrop. Remember these little tricks,
and you’ll be shooting some great pictures in no
time!
|