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Date: Wed, 18 Jun 97 12:12:11 EDT
From: gopher@esdim.noaa.gov (ESDIM Gopher)
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Subject: Troubled Turtle
Apparently-To: cestvr@ces.iisc.ernet.in
Status: R
THE
TROUBLED TURTLE
By GERALD D. HILL, JR.
The turtle lives 'twixt plated decks
Which practically conceal its sex;
I think it clever of the turtle
In such a fix to be so fertile.
-Ogden Nash
Not clever enough, unfortunately. However ingenious its
solutions to short-term problems the sea turtle, at least, is in a
jam.
It may, in fact, be in danger of extinction.
Man has exploited the sea turtle for centuries. In addition
Nature, at times, has joined with man in what appears to be an
effort to wipe them from the face of the earth.
Nobody knows how many sea turtles there are, but the numbers
are declining at such a rate that some of the species will be extinct
in a few years if nothing is done to reverse the trend.
Historical records show great numbers of turtles caught as
early as the 17th century. Up to 800 turtles were taken by one man
in one month in Dry Tortugas, Fla. Off Cape Hatteras, N.C., 100
green turtles were taken per day per man. In the Cayman Islands,
1,000 to 2,000 turtles were taken in one night in 1603. Today,
turtles do not occur in these areas in anywhere near the numbers
that they used to.
However, something is being done, and if present efforts by
the National Marine Fisheries Service and others are successful,
one day the number of sea turtles may approach their original
numbers.
Seven kinds of sea turtles are found in the world:
Ieatherback, hawksbill, green loggerhead, Kerup or Atlantic ridley,
olive or Pacific ridley, and flatback.
The leatherback, the largest, grows to 650 - 1,200 pounds. It
is found throughout the tropical seas of the world, with the
largest concentration in the South China Sea. The hawksbill grows
to 150-200 pounds. Little is known about the distribution or
nesting beaches of the hawksbill, but it has a wide range. The
green turtle grows to 250-450 pounds. It is estimated that the
world population of these turtles is between 100,000 and 400,000.
The largest concentration, about 100,000, is found off Queensland,
Australia, with the second most abundant stock of approximately
60,000 found in the western Caribbean. Less than a few hundred are
thought to nest along the Florida coast.
One of the largest populations of loggerhead, approximately
40,000, is found off the Florida and Carolina coasts, with another
30,000 thought to be in the vicinity of the Gulf of Oman in the
Mid-East. The largest population of Pacific ridley turtles,
450,000, is found in the waters of Costa Rica. The Atlantic and
Pacific ridleys are the smallest of the sea turtles and reach about
80-100 pounds when full grown.
Some of the sea turtles seem to have the nesting instincts
similar to those of the salmon. They appear to return to the same
beaches each year to lay their eggs. The green turtles can be
counted among this type, while the loggerhead doesn't seem to have
this drive to return to the same beach each nesting season.
Three theories concern the ability of the turtles to return to
their nesting beaches. Some scientists believe they navigate by
the stars. Others think they can sense the differential rotation
of the earth with changing latitudes. Finally, other scientists
believe they can taste or smell their routes to the nesting
beaches.
Turtles coming to nesting beaches number in the hundreds.
Usually during the night, they slowly drag themselves up on shore
and dig large holes in the warm, moist sand with their flippers,
there they lay their eggs. They cover the holes with sand and then
begin their slow trip back to the sea. The eggs remain in the sand for
approximately two months, and as they hatch, the small turtles dig
themselves out of the sand and scoot toward the water. The female often
lays as many as 200-300 eggs each nesting season, but all to many fail to
hatch, and most hatchlings die before reaching maturity.
Nobody seems to know what happens to the turtles during their
first year. Those that survive disappear for almost a year and are
believed to drift to sea and live in sargassum weeds that float in
large mats in the sea.
The main reasons for the decline in the sea turtle population
of the world are believed to be over exploitation, loss of habitat,
predation, and incidental killing.
Man has been the biggest factor in the reduction of the
numbers of turtles. The green turtle has been subjected to
tremendous commercial exploitation. The turtle is used for meat,
soup, leather, and cosmetics. Loggerheads are subject to less
intensive hunting because the meat does not taste as good as the
green. However, loss of habitat, predation on eggs by raccoons,
and incidental drownings by fishers are believed to have resulted
in the decline of this species. The Pacific ridley is hunted
intensively for its leather but seldom caught for its meat. The Pacific
Ridley is hunted most intensely on the Pacific coast of Mexico. Scientists
estimate that since the early 1960s, between 500,000 and 1,000,000 Pacific
ridleys have been taken. In Oaxaca State, Mexico, in 1977, 70,000
female Pacific ridleys were killed from a population of 150,000.
Action to save these and other species is in large part
dependent on the Endangered Species Act of 1973. The Departments of
Commerce and Interior are charged with the responsibility of
protecting endangered and threatened animals and plants.
The Department of the Interior, through its Fish and Wildlife
Service, has the responsibility for the protection of sea turtles
while the turtles are on land. The Department of Commerce, through
its National Oceanic and Atmospheric Administration's National
Marine Fisheries Service, has responsibility for sea turtles while
they are in the water.
Since the law was enacted, all species of sea turtles have
received some degree of protection under it. The law permits
turtles to be protected in two major ways.
A species may be declared endangered or it may be declared
threatened.
An endangered species is "any species which is in danger of
extinction throughout all or a significant part of its range." A
threatened species is" any species which is likely to become an
endangered species within the foreseeable future throughout all or
a significant part of its range."
The Atlantic ridley, leatherback. and hawksbill have been
listed as endangered for a number of years.
In August 1978, the loggerhead, Pacific ridley, and green were
listed as threatened for all populations worldwide. In addition,
the Pacific ridley was listed as endangered along the west coast of
Mexico, and the green was listed as endangered in Florida and along
the west coast of Mexico.
When a species is listed as endangered, it is illegal to take,
transport, or trade that species with limited exceptions.
When a species is listed threatened, regulations that are
necessary to conserve that species must be adopted.
One of the major threats to the loggerhead is the danger of
becoming entangled in the trawl nets of shrimpers. Under present
regulations, shrimp fishers are required to try to revive turtles
caught in their nets by laying the turtles on their backs and
pressing on their under sides until they are revived.
The National Marine Fisheries Service has been conducting
tests for over a year to develop "excluder panels," and has
chartered commercial shrimp vessels to support this work. The
excluder panel is a piece of large mesh net that is placed across
the front of the mouth of the shrimp trawl. As the trawl is
dragged along the bottom, the face of the net is held open by two
large wooden "trawl doors." The panel is stretched across the
opening and keeps the turtles from going into the net while at the
same time permitting the shrimp to go into the net through the
mesh.
Shrimp vessels from Georgia and northeast Florida and the Gulf
of Mexico have cooperated with the Service since the fall of 1977
in testing the panels under actual fishing conditions. Initial
panel designs have been effective in reducing sea turtle capture
and good progress is being made towards maintaining a shrimp catch
while using the excluder panel.
Other steps are being taken to stop the decline of sea turtle
population. The Service has proposed that the Cape Canaveral Ship
Channel, where loggerhead and Atlantic ridleys are known to
hibernate in the winter, be designated as critical habitat. Areas
off St. Croix in the Virgin Islands and the Mona Island in the
Caribbean are also being considered for possible designation as
critical habitat. When an area is designated a critical habitat, all
federal agencies are required to consult with the National Marine
Fisheries Service or the Fish and Wildlife Service to ensure that any
actions they may take in the area will not destroy or adversely modify
the habitat.
Because a critical habitat designation only affects actions of
the Federal Government, some areas of seasonal turtle
concentrations will probably have to be established under the Act
as restricted fishing areas, so as to minimize further the harmful
impact of fishing activities.
Information to support a proposed designation of Cape
Canaveral Channel, Florida, as a Restricted Fishing Area has been
obtained by a commercial shrimp vessel, chartered by NMFS to
conduct turtle excluder trawl research. The vessel found
loggerhead sea turtles hibernating in the Channel where commercial
shrimping was occurring. Several Atlantic ridleys were also found
in this area. This is the first known area of hibernation for
either species. If the area is proposed as an RFA, controls could
include use of the excluder panel, limitation of trawl-drag time to
one hour, and, possibly a closure of the Channel to bottom trawling
during the winter months.
Concentrations of sea turtles have been observed off South
Carolina and Georgia where shrimping occurs. However, the Service
does not have sufficient information to restrict these areas to
commercial shrimping at this time.
While the Endangered Species Act seeks to protect endangered
and threatened species worldwide, Federal control under the Act is
limited to persons subject to U.S. jurisdiction. Since sea turtles
are migratory species with circumglobal ranges, management and
restoration of sea turtles is an international problem. No
domestic program will succeed if it does not have international
cooperation.
Such an international program must encompass complementary
international controls on take, commercial trade, habitat
protection, research, and the reduction of incidental catch in
commercial fishing operations.
The United States will seek agreements with foreign nations which
have fisheries that take sea turtles incidentally to encourage those
nations to adopt conservation measures, such as the the excluder panel,
to reduce the incidental take. The United States is working with Mexico
on a bilateral agreement on the sea turtle management that could serve as
a model for similar agreements with other countries. The last surviving
breeding colony of Atlantic ridley turtles is in the Gulf of Mexico
at Rancho Nuevo. Cooperative efforts to preserve and protect this
colony have been initiated by Mexico, NMFS, FWS, the National Park
Service, and the Texas Parks and Wildlife Department. Similar
program should be developed for the green and Pacific ridley turtles on
the west coast of Mexico.