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Of the eight species
of sea turtles in the world, the Kemp's ridley, Lepidochelys
kempii, is the most endangered. It is also the
smallest sea turtle and the only species that nests
primarily during the daytime.
In 1978, a collaborative bi-national
program between Mexico and the United States was developed
to try and restore this species' population to a self
sustainable level, and in 1981, the U.S. Fish and
Wildlife Service asked the Gladys Porter Zoo to administer
the United States' field portion of the joint U.S./Mexico
effort to protect and increase the production of Kemp's
ridley sea turtles in their natal beaches located
in the State of Tamaulipas, Mexico. To date, the Zoo
still carries out that role.
Sea turtle research and conservation
in Mexico was formalized in 1962 with Instituto Nacional
de la Pesca (INP) then named Instituto Nacional de
Investigaciones Biologico-Pesqueras (INIBP) being
the lead agency. Conservation efforts for the Kemp's
ridley were initiated in 1966; when the National Program
for Research and Conservation began. The project field
station was located on the beach near the ranching
community of Rancho Nuevo, in the municipality of
Aldama, Tamaulipas. This locale is the only one in
the world where massive nesting aggregations of this
sea turtle were and are known to occur. Because it
is the only known major nesting beach for the Kemp's
ridley, this beach was declared the first National
Reserve for the Management and Conservation of Sea
Turtles in Mexico on July 4, 1977.
Historically speaking, the population
of the Kemp's ridley sea turtle declined at an alarming
rate from the 1940's to the 1980's. A film made in
1947 by Andres Herrera, an engineer from Tampico,
Tamaulipas, was presented by Dr. Henry Hildebrand
of the University of Corpus Christi, Texas, to the
American Society of Ichthyologists and Herpetologists
in 1961 at their annual conference. The film, fourteen
years old at the time, revealed an estimated 40,000
female Kemp's ridleys nesting on the beach at one
point in time. This was the first time scientists
had observed this type of massive synchronized nesting
behavior. This extraordinary phenomenon is termed
"arribada" or "arribazon" in Spanish.
It has two literal translations; "great arrival",
and "to put into port under stress", either
of which is equally appropriate in this case. What
could have appeared more stressful than thousands
of these turtles clambering over one anothers' shells
with flippers flailing and sand being tossed high
into the air in every direction? Many females actually
excavated the eggs off those that preceded them. The
result was that L. kempii was its own worst
"predator" at that point in time. That,
needless to say, was soon to change.
From 1966 to 1987, conservation efforts
focused on the area of Rancho Nuevo with the camp
located first at Barra Calabazas and then at Barra
Coma where it presently exists. In 1978, the U.S.
joined with Mexico at Rancho Nuevo. In 1988, the program,
now a bi-national one, expanded to the south to Barra
del Tordo with a camp at Playa Dos. In 1989 a third
camp was established to the north at Barra Ostionales
on Rancho Los Pericos. The north camp's location was
changed to 10 kilometers north of its original location,
near the town of Tepehuajes, in 1996 for logistical
reasons. In 1996, in coordination with the Tamaulipas
State Government, as in Tepehuajes, a camp was established
in La Pesca. In that same year, CRIP Tampico and CetMar
No. 9, as well as API Altamira, also expanded the
project to include Playa Miramar in Ciudad Madero
and Playa Tesoro in Altamira. In 1997, the area of
Lechuguillas, municipality of Vega de Alatorre, Veracruz,
started to be protected in cooperation with CRIP Veracruz.
Over the last twenty-eight years, the
Mexican and U.S. biologists working with the Kemp's
ridley sea turtle have learned a lot about the biology
of nesting sea turtles. When the project began, it
basically was at ground zero. We now know that although
some turtles nest in consecutive seasons, the majority
of them nest every other year. We know that nests
average 2.6-3.0 per female per season, each clutch
being one hundred or so eggs which require 42-62 days
incubation, depending on the temperatures. The Kemp's
ridley begins nesting around the second week in April.
We have now verified turtles which were
originally tagged on the eastern seaboard of the U.S.
as having returned to Mexico to lay their eggs. We
have recorded experimentally head-started turtles
nesting on Padre Island National Seashore, USA, and
the same turtles at Rancho Nuevo in Mexico during
the same nesting season. Apparently, the experimentally
imprinted head-started turtles were able to navigate
to Padre Island National Seashore and were also able
to socially facilitate with wild ridleys returning
to the Tamaulipan coastline's historic nesting grounds.
Kemp's ridley turtles will return to
nearly the same spot on the beach where they nested
in previous seasons; however, if they are disturbed,
they possess the behavioral "plasticity"
to move several kilometers up or down the beach to
a new nest site.
In past years we were unaware that a
few ridleys do nest at night even though the norm
for this species is diurnal (or daytime) nesting.
Our first beach patrol or "recorrido" as
it is called in Spanish, began at 8:00 am C.S.T.;
for years and years and that was early enough to find
the first nesting turtles of the day. Starting in
2001, our first beach patrol began encountering crawls
(tracks) and nests which were apparently from late
in the afternoon of the previous day or perhaps the
night time or early morning hours. The first and last
"recorridos" kept being moved to an earlier
and later hour respectively, and eventually, nesting
turtles (or the nests) were found at 5:30 am during
the cover of darkness and as late as 8:30 pm. This
has caused us to readjust our thinking and our patrol
schedules.
The United States field assistance group,
along with the Mexican Federal and State Government
crews, under the supervision of trained sea turtle
biologists, aid in beach patrols. Relevant data are
recorded and subsequently, most of the egg clutches
are translocated to facsimile nests within protective
corrals.
Two auxiliary corrals have been used
on the Rancho Nuevo beach since 2002. One is located
to the north at Barra Carrizo and the other was constructed
to the south at kilometer marker 5.1. The corrals
were constructed to facilitate the quick disposition
of the nests and to relieve the pressure at the main
corral at Rancho Nuevo. Patrols at the north and at
the south part of the beach would quickly transfer
the nests to their respective corrals during arribadas,
while those patrols nearest the main camp would use
the main corral. The auxiliary corrals were built
to exclude predators and had tent facilities to house
personnel who watched the area at night.
The fact that the fishing industry is
working with governmental agencies and environmentalists
in both Mexico and the United States is a big step
in the right direction and hopefully one which will
serve as a model for the other endangered species
programs where difficult economic and socioeconomic
issues exist. There are still problems, points of
contention and difficult issues to be resolved. By
working together for a common goal, "a Healthy
Gulf of Mexico", much needed resources may be
put where they are needed, and productive, versus
and endless array of litigation and mistrust.
Since 1978, there have been over
70k registered nests, and a little over 4.5 million
hatchlings have been released into the Gulf of Mexico.
At present, nesting aggregations (arribadas), number
in the hundreds, not the thousands which are necessary
for the species to survive without man's intervention.
Clearly we are going in the right direction but we
cannot diminish our present effort if we are to succeed.
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