'drop off' at Clifton
First published in the 'Nassau Guardian'.
||The vast majority of
the Bahama Banks lie beneath the sea. Twelve thousand years ago,
when the sea level was lower and during that period known as the
Wisconsin Ice age, the whole area we know as the Bahama Banks was
dry land. But now the sea has risen once again to give the Bahamas
the greatest shallow water area suitable for reef development In the
The majority of the
banks are still covered with oolitic sand, and in many places the
dynamic process of carbonate formation is continuing. Here and
there, however, the coral has found a firm foundation and patch
reefs have formed.
It is these
patch reefs, and the more substantial fringing reefs, that make the
Bahamas famous in the world of SCUBA diving. Today the Bahamas has
more diving operations, and more people come here to dive than to
any other location in the Caribbean.
Bahamian reefs are one of our most beautiful natural resources and
certainly they are of tremendous economic benefit to the Bahamas.
This economic benefit will continue to increase in future years and
so the reefs must be protected in every way possible.
|The non-diver cannot really appreciate
the beauty of the reef environment and the diversity of its fauna.
From the surface the reefs are merely brownish patches. Even when a
water glass is used, a deep reef can only be seen in a bluish
monochrome, and then the three-dimensional aspect of the reef is
appreciation of the undersea world can only be attained by SCUBA
diving. Certainly many people can free dive a great distance down
into the sea, but they only have time to release a spear, free an
anchor or take the briefest glimpse at the reef around them.
Recently I had
the opportunity to explore one of the most beautiful and exciting
reef areas close to Nassau. At the western tip of New Providence,
shallow water extends only a short distance from the shore, a few
hundred yards out the seafloor plunges down to the great depths of
the Tongue of the Ocean in an almost vertical submarine cliff known
to divers as the drop-off. This drop-off is found along the
entire northern and western edge of New Providence, usually
beginning at depths in excess of 100 feet. Here though, in the
Clifton area, it starts its rapid descent into the depths at only
45 feet (15m).
||In those areas where the drop-off is
deep, coral growth is sparse for coral requires light for optimum
growth. Its tissues contain microscopic green plants called algae
that supply important nutrients to the coral. Without this light the
plant cells will die and the coral will no longer be able to
I was one of a group
of six divers towed out to the drop-off from the shore behind a
small boat. When we could see the deep blue of the ocean dropping
away beneath us we released the towline and swam down to the edge.
As we approached
the bottom the coral hummocks began to take shape. Shoals of small
fish divided before us and inquisitive damselfish came closer for a
better look at these invaders of their watery domain.
The lip of the
drop-off is covered with coral growths growing both upwards and
outwards. This is an ideal place for corals to grow. A constant
current brings along plankton upon which they feed. The water at
this point is clear and free from sediment, flowing in from the vast
depths of the Tongue of the Ocean. The only evidence of man’s
works to be seen is the yards and yards of monofilament and
stainless steel trace that festoons the reef in places, for when a
sports-fisherman loses his line it remains for years on the reef –
protected from the plastic-degrading effects of sunlight by the
depth of the water.
We checked our depth
gauges and swam out over the edge until we could see nothing below
us but the deep blue of very deep water. Looking back the edge of
the drop-off is a spectacular sight. The growth along the edge
becomes sparser with depth. We could probably see down more than 150
feet. At this depth the cliff is almost bare rock - only a few
sponges and whip corals break the monotony. We were not going down
there, however, for several reasons. Firstly because our air supply
would be rapidly used up, and secondly because we would be exposing
ourselves to several of the dangers of diving. A diver who stays
down too deep and too long may suffer from “the bends”, a
painful condition caused by bubbles of nitrogen in the blood.
Nitrogen may also become narcotic at depth and cause over-confidence
and euphoria. It is for these reasons and others that all divers
should undergo a proper course of training before
taking up the sport. Diving is like driving. If one follows the
rules it can be very safe, but if one doesn’t it can be very
|We continued down
until we reached our maximum depth of 80 feet. Now we could look up
at the coral cliff rising more than 30 feet above us. Huge shoals of
fish were silhouetted against the sunlight streaming down from
above. A solitary Spanish Mackerel
lazily finned his way and a huge and curious barracuda inspected us
from a distance of 15 feet.
The barracuda is an inquisitive fish; he
will always approach a diver and may follow him for some
considerable time, but will never come too close. He always looks more menacing than he is because of his habit
of opening and closing his mouth to continuously pass water
over his gills. To the diver it always seems as if he is gnashing
his teeth prior to a meal!
Such a place is
fascinating not for the grandeur of the terrain, or the spectacular
views of the teeming fish, but for the close-up sights animals and
fishes that few people have seen. Here the soft corals -
Gorgonians and Sea Whips form strange shapes. Stiff
Wire Coral juts out as much as six feet from the rock in single
filaments no more than a few millimeters in diameter. Giant tube
sponges are almost as large at these depths where no movement from
the surface waves disturbs the constant caress of the ocean
currents. Some of the corals are extraordinarily brittle. The
shallow cups of Agaricia coral are incredibly thin and break
at the slightest touch.
|The fish too are
largely different from those of the shallow reef. Here is the only
habitat of the Black-capped Basslet, Gramma melacara. This
little fish is almost identical in shape and behaviour with the
closely related Royal Gramma of shallower reefs. Its colouration
however, is totally different.
Described in the literature as magenta, it appears to be a
brilliant blue with a black cap extending from the mouth to the end
of the dorsal fin.
Within their narrow zone they are
extremely populous. Every niche or crevice in the rock is hideaway
of a Basslet when danger threatens. Like the Royal Gramma these
fascinating little fish spend much of their lives swimming upside
down beneath overhangs.
cliff is eroded to produce a cave. Seldom does such cave fail to
harbour some interesting animal. The smaller crevices contain Crinoids,
ancient relatives of the sea egg and starfish, their feathery arms
taking tiny planktonic animals from the passing currents.
caves may contain the giant Spider Crabs whose legs may stretch
three or four feet from one side to the other.
The larger caverns
often have a large population of fish and frequently provide homes
for the big Groupers found on the drop-off. The fish congregate
within the crevices and caves during the day and venture out onto
the exposed reef at night when they largely feed.
The scarcity of black
coral at Clifton disappointed me. Here and there could be seen small
bushes, but nothing large enough for commercial use. The law
prohibits the taking of black coral by SCUBA diving. Nevertheless
many people have been collecting this fairly valuable commodity for
use both in Nassau and for export. The large mature black coral
‘tree’ provides a habitat for many animals; sponges and molluscs
especially that live in its branches. The taking of the black coral
has thereby deprived these species of a suitable habitat.
|A fairly uncommon
sight, but one most likely, to be encountered by a diver on the
drop-off, is the enormous Manta Ray. The wingtips of this flattened
relative of the shark may stretch as much as 14 feet across. Usually
the rays swim in pairs parallel to the edge of the drop-off.
Despite their huge size they feed on tiny planktonic animals that
they filter out of the water passing through their gills.
occasions while SCUBA diving I have tried to follow them and hitch a
ride, for they are entirely harmless. However, although they appear
to be moving very slowly, they are usually moving a lot faster than
a diver with a cumbersome air tank on his back! My dive was coming to
its end. Glancing at my watch I could see that I only had a few more
minutes to remain safely at this depth, so reluctantly I signaled to
my “buddy” (a diver should never dive alone, but in a “buddy
pair”) and we began our ascent to the boat.
Although I had dived
here before, I’m always excited by the diversity of the Clifton
drop-off. On every dive there is the anticipation that some giant
creature of the deep may emerge. I am always fulfilled by having
been there, but at the same time disappointed that so few native
Bahamians will ever have the chance to visit this great natural