Not just Shark
Pictures: Elasmodiver contains photos of sharks, skates, rays, and
chimaera's from around the world. It began as a simple web based
field guide to help divers find the best places to encounter
different species of sharks and rays but it has slowly evolved into
a much larger project containing information on all aspects of shark
diving and photography. There are now more than a thousand shark
pictures and sections on shark evolution, biology, and
conservation. There is a large library of reviewed shark books, a
constantly outdated shark taxonomy page, a monster list of shark
links, and deeper in the site there are numerous articles and
stories about shark encounters. Elasmodiver is now so difficult to
check for updates, that new information and pictures are listed on
an Elasmodiver Updates Page that can be accessed here:
If you're looking
for a broader range of marine life pictures the following links
represent a new area of elasmodiver.com that contains pictures of
other marine organisms and of marine habitats. This expansion of
Elasmodiver is in its first stages but will eventually include pages
on all types of marine mammals, bony fishes and marine invertebrates
as well as coastal habitats, reefscapes and other imagess relating
to the ocean. Please return regularly to enjoy the progress.
Refugees of the Gulf Oil Spill
As I write this, the eyes of the world are focused on the mesmerizing river
of crude oil that is incredulously still pumping thousands of barrels a day
into the northern reaches of the Gulf of Mexico, enveloping and poisoning
everything it touches.
The headlines are filled with graphic images of oil clad sea birds, drowned
turtles, beaches covered in sticky black globules and marshlands clogged in
a reddish brown blanket of death. It is both a sad and angering picture.
Recriminations fueled by a collective feeling of helplessness, reverberate
from coffee shops to courtrooms, but to me the finger pointing is
irrelevant.
At every level, people and organizations have mobilized to contain the slick
and rescue as many air breathing animals as possible. The size and scope of
the terrestrial effort is comforting but below the surface there is little
that anyone can do.
The northern gulf is a critical deep sea habitat. Ironically, the oil rigs
that pepper the continental shelf and are now the cause of so much
devastation, are also oases of life that harbor complex and vibrant
ecosystems. Colonies of immobile invertebrates cling to every wire and
strut, feeding an army of crustaceans, mollusks and reef fishes. Enormous
clouds of tiny bait fish morph from one shadow to the next and are preyed
upon by schools of snappers and other teliost species which in turn support
large aggregations of silky and dusky sharks.
Perched between the apex predators and lesser life forms, small endemic
shark species such as the Gulf of Mexico Smoothhound Shark (Mustelus
sinusmexicanus) jockey for position in the food web.
The first and only time I encountered a Gulf of Mexico Smoothhound, I
initially thought that it was a smooth dogfish (M.canis) which is a closely
related, wide ranging resident of the eastern seaboard. When I later learned
that is was a virtually unknown species confined to a tiny patch of seafloor
in the northern gulf, I felt equally surprised and privileged to have had
the chance to encounter it.
I was aboard a research vessel at the time and the tiny shark was pulled
from the depths for study amidst a large assortment of other interesting
abyssal fishes. After the lab coats had taken fin clips for DNA analysis and
generally had their evil way with the hapless shark, I slipped into the
water and swam it over to the oilrig that we were tied off to. When I
released it into the shadowy depths, it swam tentatively at first as if not
trusting its liberty. Then, after eying me cautiously, it headed for a
barnacle encrusted crossbeam and began weaving its way down to the sea floor
six hundred feet below.
The images that I took of that little smoothhound shark have been haunting
me ever since I heard about the spill. I am optimistic that most pelagic
sharks had the wherewithal to swim south at the first bitter taste of oil.
But, what has become of vulnerable endemic species like the gulf smoothhound?
Did they all flee into open water like land animals running from a forest
fire or did they cling to the habitat they know, inadvertently exposing
their delicate gill structures and other organs to the viscose residue
floating around them in the water column like a giant toxic lava lamp?
After the Exxon Valdez disaster in Prince William Sound, the composition of
marine life within range of the spill was changed forever. Some species
quickly bounced back while other once plentiful creatures remained severely
depleted. Pink salmon populations displayed stunted growth and sea otters
and ducks showed higher than normal mortality rates in subsequent years
(partially because they ingested prey from contaminated soil). There were no
studies done on shark mortality in those isolated Alaskan waters because
dead sharks invariably sink. However, there must have been casualties up and
down the food chain.
Sharks are famous for their capacity to overcome almost all environmental
threats (other than overfishing). Female sharks held in isolation in
aquariums have even procreated without the aid of a mate. But for a small
endemic species like the gulf smoothhound whose entire habitat is under
siege, a dislocation of this magnitude could presage its demise.
There are no refugee camps or rehabilitation centers in the ocean but sharks
are resilient creatures. They are resistant to toxins and blessed with keen
spatial senses that will help them find their way back to ground zero once
the deluge is finally under control. But for those that fled and survived
the initial spill, the question remains, what kind of brave new world will
they be returning to?
