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Tropic news. Volume 9. Issue 8.

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Tropic news. Volume 9. Issue 8.
Series Title:
Tropic news
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United States Virgin Islands. Department of Planning and Natural Resources. Division of Fish and Wildlife.
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United States Virgin Islands. Department of Planning and Natural Resources. Division of Fish and Wildlife.
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Caribbean ( LCSH )
Newspapers -- Caribbean ( LCSH )
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North America -- United States Virgin Islands
Caribbean

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TROPIC NEWS
. PAPR7TrMNT OF PLANNING AND NATURAL DIVISION OF FISH AND WILDLIFE
RESOURCES
May 1997 Volume 9 Number 8
II


SAGA OF A SPONGIVORE:
The Ecology and Conservation of the Hawksbill Turtle


The hawksbill is the largest spongivore (sponge
eater) and the only reptile known to feed almost
exclusively on sponges. Fewer than a dozen verte-
brate animals are known to be dedicated
spongivores and those are predominantly angelfish
(including the gray; French; and queen angelfish),
filefish; trunkfish; and the Moorish idol.
Dr. Anne Meylan is one of the world's foremost
authorities on hawksbill turtles. Her studies indi-
cate that more than 95 percent of the stomach
contents of hawksbills consist of sponges. Dr.
Meylan's research and subsequent experiments by
other scientists indicate that male and female
hawksbills of all sizes depend on sponges as their
primary food source.
To better understand the "uniqueness" of a
sponge eater, you need to consider the structure,
defenses and nutritional qualities of sponges.
Sponges are multicelled animals which belong to
the phylum Porifera.
Most sponges eaten by hawksbills are charac-
terized by a dense matrix of spongin fibers and
siliceous spicules. Spicules resemble needle-thin
slivers of glass, many with multiple, hooklike tips.
Spicules are unaffected by the digestive processes
of hawksbills or other spongivores for that matter.
Some sponges consumed by hawksbills possess
noxious or toxic chemical compounds that in most
cases are effective deterrents against potential
predators. No one is sure how hawksbills overcome
the toxins that may be present in their prey
sponges.
Given the questionable gastronomic character of
sponges, why would hawksbills, angelfish, and
other spongivores want to eat sponges? Some
scientist have suggested that spongivory evolved in
response to increased competition for food among
animals on coral reefs. Sponges represent a wide-
spread, abundant, relatively underexploited food
source for any predator able to eat glass and not
become poisoned by toxins in the sponge. Little
information is available on how spongivores digest
their prey.
Hawksbills are influential inhabitants of coral
reefs. They not only maintain the size of sponge


populations on the reef but they enable other
animals to prey on sponges. As the turtle eats the
sponge, it exposes the soft inner parts of the sponge
which are fed on by other fish. This also exposes
many organisms that live within the sponge which
then are also preyed upon.
Just as hawksbills affect life on the reef, the
quality of the reef habitat affects them. Hawksbills
require a vibrant sponge community on which to
feed. Unfortunately, coral reefs worldwide are
deteriorating as a result of marine pollution, the
collection of reef life forms, other human distur-
bances, and natural catastrophes. If the conditions
of reefs and the food provided by reefs continue to
decline, the hawksbill will be affected.
As grim as the situation is for hawksbills, there
is hope. Legal international trade of tortoiseshell
has declined dramatically, although illegal trade
probably still continues. In 1992, Japan, histori-
cally the largest importer of tortoiseshell, agreed to
end its importation of tortoiseshell under the
Convention on International Trade of Endangered
Species (CITES). As recently as 1990, tortoiseshell
from some 12,200 hawksbills was exported from
the Caribbean into Japan. According to a report
published by Anne Meylan in 1989, the turtles
were taken from a region for which the maximum
estimate of nesting females is 5,000 each year.
Only through stringent enforcement of bans
on tortoiseshell trade, protection of coral reefs and
conservation of the beaches on which hawksbills
nest do we stand a chance to save this species. Loss
of the hawksbill turtle would be a terrible loss to
the biodiversity of the world's oceans.
Article partially excerpted from original story by Jeff
Ripple, Ocean Realm Magazine.

Quote
Like winds and sunsets, wild things were taken
for granted until progress began to do away with
them. Now we face the question whether a still
higher "standard of living" is worth its costs in
things natural, wild and free.







A Record Year At Sandy Point

The Sandy Point leatherback turtle project has
been running since 1981. Before the project was
started by the Division, nearly 50% of all nests laid
were lost to beach erosion each year. Those that
remained suffered poaching by humans. This left
very few nests to hatch and maintain the species.
As a result, numbers of turtles nesting each year at
Sandy Point was around 20 and probably declining.
For the first eight years of the project, we had an
average of 28 turtles nesting each year. For the
last eight years, we have averaged 41 turtles per
year with a high of 55 turtles in 1992 and 1994.
Starting in 1981, we began moving nests that
were laid in erosion prone parts of the beach to
"safe zones" We began patrolling the beach at
night, every night, from April 1 to the end of Au-
gust to try to encounter each and every turtle that
nested. As a result of these activities, poaching has
dropped to zero and loss to beach erosion is less
than 3% each year. This means more hatchlings
are successfully leaving Sandy Point than at any
time in the recent past. From genetic work we
know that the hatchlings return to Sandy Point to
nest once they mature. It is believed that leather-
backs take from ten to fifteen years to reach matu-
rity.
This year we may be seeing some exciting re-
sults of our nest protection efforts. As of the 18th of
May we have 100 individual turtles nesting on
Sandy Point. Thirty six of those are new, untagged
turtles, presumably young turtles coming to nest
for the first time. These may be turtles that
hatched from protected nests on Sandy Point ten to
fifteen years ago and have survived to maturity. It
is estimated that only about one in one- cont'd


~LrAT~t~


thousand eggs laid survives the perils of life and
lives long enough to reach maturity. When you
figure that half are probably males, it means that a
lot of eggs have to be protected to see one turtle
come back. Each turtle lays an average of 5.3 nests
per year, and 80 eggs per nest. If we exceed 100
turtles this year, which we easily may, we could
have over 500 nests and 40,000 eggs on the beach
this year, a monumental record for Sandy Point!
Article by Ralf H. Boulon, Jr., Chief of Environ-
mental Education Program.


Turtle Video now available
Just as promised, our latest video is now avail-
able. Third in the series, Our Natural Virgin Is-
lands: Sea Turtles: Our Endangered Mariners, is
really a treat for the sea turtle enthusiast. "Tessa
the Turtle", an animated turtle, shares interesting
information about her species. The 9.5 minute
video discusses Virgin Islands sea turtles; Leather-
backs, Green, and Hawksbills. The video is avail-
able at both DFW Offices in Redhook, St. Thomas
(809 775 6762) and Lagoon Street, St. Croix Office
(809 772 1955). Please give us a call if you are
interested. We request a $2.00 fee for postage per
video.
*SeO@@**OO@*Oe@@ee@@QOQQO@OeOOoe
Trees were saved by printing on recycled paper


t&?I This newsletter was funded by the US
1. Fish and Wildlife Service, Sport Fish and
SWildlife Restoration Acts, the Caribbean
-r\ o Fishery Management Council and the
Government of the VI.
Donna M. Griffin Editor
Ralf H. Boulon Jr. Chief of Environmental Education


GOVERNMENT OF THE VIRGIN ISLANDS
OF THE UNITED STATES
*******
Department of Planning and Natural Resources
Division of Fish and Wildlife
6291 Estate Nazareth 101
St. Thomas, USVI 00802-1104
(809)775-6762 (ST.T.), (809)772-1955 (ST.X.)


BULK RATE
U.S. POSTAGE PAID
CHARLOTTE AMALIE, V.
PERMIT NO. 35


Address Correction Requested


~i~L~aa~Pc~-r~9*;;~3liRnue~wrr~N~l~~aLz ~Y


-- ------ ---- ~---




Full Text

PAGE 1

] '~ ~! OF PLANNING AND NATURAL RESOURCES DIVISION OF FISH AND WILDLIFE May 1997 Volume 9 Number 8 SAGA OF A SPONGIVORE: The Ecology and Conservation of the Hawksbill Turtle populations on the reef but they enable other animals to prey on sponges. As the turtle eats the sponge, it exposes the soft inner parts of the sponge which are fed on by other fish. This also exposes many organisms that live within the sponge which then are also preyed upon. Just as hawksbills affect life on the reef, the quality of the reef habitat affects them. Hawksbills require a vibrant sponge community on which to feed. Unfortunately, coral reefs worldwide are deteriorating as a result of marine pollution, the collection of reef life forms, other human disturbances, and natural catastrophes. If the conditions of reefs and the food provided by reefs continue to decline, the hawksbill will be affected. As grim as the situation is for hawksbills, there is hope. Legal international trade of tortoiseshell has declined dramatically, although illegal trade probably still continues. In 1992, Japan, historically the largest importer of tortoiseshell, agreed to end its importation of tortoiseshell under the Convention on International Trade of Endangered Species (CITES). As recently as 1990, tortoiseshell from some 12,200 hawksbills was exported from the Caribbean into Japan. According to a report published by Anne Meylan in 1989, the turtles were taken from a region for which the maximum estimate of nesting females is 5,000 each year. Only through stringent enforcement of bans on tortoiseshell trade, protection of coral reefs and conservation of the beaches on which hawksbills nest do we stand a chance to save this species. Loss of the hawksbill turtle would be a terrible loss to the biodiversity of the world's oceans. Article partially excerpted from original story by Jeff Ripple, Ocean Realm Magazine. Quote Like winds and sunsets, wild things were taken for granted until progress began to do away with them. Now we face the question whether a still higher "standard of living" is worth its costs in things natural, wild and free. The hawksbill is the largest spongivore (sponge eater) and the only reptile known to feed almost exclusively on sponges. Fewer than a dozen vertebrate animals are known to be dedicated spongivores and those are predominantly angelfish (including the gray; French; and queen angelfish), filefish; trunkfish; and the Moorish idol. Dr. Anne Meylan is one of the world's foremost authorities on hawksbill turtles. Her studies indicate that more than 95 percent of the stomach contents of hawksbills consist of sponges. Dr. Meylan's research and subsequent experim-ents by other scientists indicate that male and female hawksbills of all sizes depend on sponges as their primary food source. To better understand the "uniqueness" of a sponge eater, you need to consider the structure, defenses and nutritional qualities of sponges. Sponges are multicelled animals which belong to the phylum Porifera. Most sponges eaten by hawksbills are characterized by a dense matrix of spongin fibers and siliceous spicules. Spicules resemble needle-thin slivers of glass, many with multiple, hooklike tips. Spicules are unaffected by the digestive processes of hawksbills or other spongivores for that matter. Some sponges consumed by hawksbills possess noxious or toxic chemical compounds that in most cases are effective deterrents against potential predators. No one is sure how hawksbills overcome the toxins that may be present in their prey sponges. Given the questionable gastronomic character of sponges, why would hawksbills, angelfish, and other spongivores want to eat sponges? Some scientist have suggested that spongivory evolved in response to increased competition for food among animals on coral reefs. Sponges represent a widespread, abundant, relatively underexploited food source for any predator able to eat glass and not become poisoned by toxins in the sponge. Little information is available on how spongivores digest their prey. Hawksbills are influential inhabitants of coral. reefs. They not only maintain the size of spong-e f.lrl" T ~~~~1.J

PAGE 2

A Record Year At Sandy Point thousand eggs laid survives the perils of life and lives long enough to reach maturity. When you figure that half are probably males, it means that a lot of eggs have to be protected to see one turtle come back. Each turtle lays an average of 5.3 nests per year, and 80 eggs per nest. If we exceed 100 turtles this year, which we easily may, we could have over 500 nests and 40,000 eggs on the beach this year, a monumental record for Sandy Point! Article by RalfH. Boulon, Jr., Chief of Environmental Education Program. Turtle Video now available Just as promised, our latest video is now available. Third in the series, Our Natural Virgin Islands: Sea Turtles: Our Endangered Mariners, is really a treat for the sea turtle enthusiast. "Tessa the Turtle", an animated turtle, shares interesting information about her species. The 9.5 minute video discusses Virgin Islands sea turtles; Leatherbacks, Green, and Hawksbills. The video is available at both DFW Offices in Redhook, St. Thomas (809 775 6762) and Lagoon Street, St. Croix Office (8097721955). Please give us a call if you are interested. We request a $2.00 fee for postage per video. Trees were saved by printing on recycled paper ~\9\"'I:f,. ~,p;~~ ~.. ~l~;r, ~D ~'{\O~ The Sandy Point leatherback turtle project has been running since 1981. Before the project was started by the Division, nearly 50% of all nests laid were lost to beach erosion each year. Those that remained suffered poaching by humans. This left very few nests to hatch and maintain the species. As a result, numbers of turtles nesting each year at Sandy Point was around 20 and probably declining. For the first eight years of the project, we had an average of 28 turtles nesting each year. For the last eight years, we have averaged 41 turtles per year with a high of 55 turtles in 1992 and 1994. Starting in 1981, we began moving nests that were laid in erosion prone parts of the beach to "safe zones" We began patrolling the beach at night, every night, from April 1 to the end of August to try to encounter each and every turtle that nested. As a result of these activities, poaching has dropped to zero and loss to beach erosion is less than 3% each year. This means more hatchlings are successfully leaving Sandy Point than at any time in the recent past. From genetic work we know that the hatchlings return to Sandy Point to nest once they mature. It is believed that leatherbacks take from ten to fifteen years to reach maturity. This year we may be seeing some exciting results of our nest protection efforts. As of the 18th of May we have 100 individual turtles nesting on Sandy Point. Thirty six of those are new, untagged turtles, presumably young turtles coming to nest for the first time. These may be turtles that hatched from protected nests on Sandy Point ten to fifteen years ago and have survived to maturity. It is estimated that only about one in onecont'd . This newsletter was funded by the US Fish and Wildlife Service, Sport Fish and Wildlife Restoration Acts, the Caribbean Fishery Management Council and the ~~~G<>vernment of the VI. Donna M. Griffin Editor RalfH. Boulon Jr. Chief of Environmental Education BULK RA1E U.S. POSTAGE PAID CHARLOTm AMALIE, V, PERMIT NO. 35 GOVERNMENT OF nm VIRGIN ISLANDS OF nm UNITED STATES ****** Department of Planning and Natural Resources Division of Fish and Wildlife 6291 Estate Nazareth 101 St Thomas, USVI 00802-1104 (809)775-6762 (ST .T.), (809)772-1955 (ST.X.) Address Correction Requested