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The
“head-start” procedure, where turtles are raised in
captivity through very vulnerable early months of life and then
released, is a somewhat controversial and much debated issue.
After
ensuring maximum hatch of eggs, the young are permitted to crawl
down the beach from which the eggs came, in an attempt to
“imprint” the natal beach on the young turtle’s biological
memory. They are then allowed to either swim from shore or
gathered for release in water where turtles of the same
size-range occur naturally.
Some
programs have kept the young turtles for only a few days or up
to two weeks, just enough time for them to absorb the yolk sac
and acquire the ability to dive easily. Such brief captivity,
however, presents the risk that the turtle will exhaust both its
“infantile swimming frenzy” and the neonatal food reserves
needed to reach the open sea and its feeding habitat in good
condition.
To
prove head-starting to be a useful conservation tool, it must be
shown that a greater percentage of hatchlings will reach
maturity and reproduce successfully if they are head-started
than if they develop naturally.
It
can be 20 years before the turtles mature and the females return
to their natal beach to lay their eggs. Also, the mechanism that
allows the female to locate its natal beach is not yet
understood, so a deficiency in the treatment of the young
turtles may interfere with this process. The concern is that
they might not migrate to appropriate locations nor come ashore
to nest when mature.
 If
a significant number of turtles are to be kept for more than a
year, extremely spacious facilities
and abundant regular food supplies are necessary. Most
head-started turtles are released after 6 to 15 months, and
head-start programs are expensive and demanding.
As
with all wild creatures reared in captivity, inappropriate
relationships with humans, unnatural feeding patterns, and
impaired foraging abilities may develop. The potential
introduction of disease and parasites from released captives
into wild populations is also a serious concern (Jacobson,
1996), and there are further concerns about releasing turtles
from different genetic stocks into wild populations (Dodd,
1982). The aberrant behavior and movements of some newly
released turtles have been widely documented.
In
certain parts of the world there are commercial sea turtle
farms. Their market is restricted by the CITES Convention which
bans international trade in sea turtles, and they are frowned on
by environmentalists and generally considered commercially
non-viable. The farms have,  however,
provided a unique opportunity to study some aspects of the
biology of sea turtles, allowing manipulation and
experimentation that is not possible in the wild. They have
successfully solved numerous husbandry problems involving
nutrition, disease, and reproductive physiology. Most
commentators concede that these research activities have been
broadly beneficial to our general understanding of sea turtle
biology.
For
many years head-started ridley turtles were tossed into the Gulf
of Mexico after one year in captivity without any attempt to
monitor results. In 1993, a Kemp’s ridley head-start project
was abruptly terminated mainly because it lacked a methodical
evaluation. During the early 1980s a lot of live and dead
year-old head-started ridleys were washed ashore, some within
hours and up to weeks after being released a few miles off the
Texas coast. There were also a number of reports of ridleys
“bumping into” fishermen in the surf as well as out on
boats. It appeared that there was high mortality after release,
and that the project was not very successful.
Recent
evidence suggests that green turtles and Kemp’s ridleys
released from a head-start
program can function normally and integrate themselves into wild
populations of sub-adults.
There are documented cases of long-term survival of released
turtles, with growth and movements suggesting that they have
successfully adapted to the wild (Wood and Wood, 1993).
Scientists
at Texas A&M University in Galveston, Texas, have been
capturing head-started ridleys in the wild and have shown that
many do survive, are healthy and grow substantially after their
release.
At
Padre Island, Texas, and other surrounding islands Dr. Donna
Shaver Miller has recorded nesting by a dozen or so head-started
ridleys that had been “imprinted” to Padre Island sand and
water as eggs/hatchlings. Similarly at Rancho Nuevo in Mexico
several have been found nesting.
Perhaps,
as more head-started turtles reach maturity, sufficient data
will accumulate to justify the hopes of the proponents of the
procedure, adding a vitally needed new tool for the sea turtle
conservationists.
Acknowledgements:
--
Pritchard, P.; P. Bacon; F. Berry; A. Carr; J. Fletemeyer; R.
Gallagher; S. Hopkins; R. Lankford; R. Marquez M.; L. Ogren; W.
Pringle, Jr.; H. Reichart and R. Witham. 1983. Manual of sea
turtle research and conservation techniques, Second Edition.
K. A. Bjorndal and G. H. Balazs, editors. Center for
Environmental Education, Washington, D.C.
-- James
Perran Ross. In Research and Management Techniques for the
Conservation of Sea Turtles, K. L. Eckert, K. A. Bjorndal,
F. A. Abreu-Grobois, M. Donnelly, editors. IUCN Marine Turtle
Specialist Group Publication No. 4, 1999.
-- George
H. Balazs
-- Wallace
J. Nichols, Ph.D. Director WILDCOAST International conservation
team.
-- Pamela
Plotkin, Ph.D. Frostburg State University: Regional Vice-chair
for the Northwest Atlantic /SSC/Marine Turtle Specialist
Group.
Clips:
In
June 2001, a fishing vessel off the Mediterranean coast of Spain
was reported as incidentally capturing 400 sea turtles in its
nets, in one single day. No information is available regarding
survival of the turtles.
The
Kromsan Chrome factory at Kazanli in Turkey, on one of the few
remaining Mediterranean green turtle nesting beaches, and under
fire for the effects of its toxic waste on the local
environment, now appears willing to participate in an
independent assessment.
A
search is in progress in the Nile Delta, Egypt, hoping to
establish that isolated pockets of the brackish water Nile Soft
Shelled turtle, previously thought to be extinct, still survive
there.
After
a police crackdown on the sale of sea turtle meat in the
Alexandria Fish Market, Egypt, latest reports indicate that
although much reduced, the trade persists with the slaughter
being carried out behind the scenes in a back room.
In
Zakynthos, Greece, during the first full summer of the
Management body for the Zakynthos National Marine Park, on
probably the most important loggerhead turtle nesting beaches in
the Mediterranean, horse riding has been rife on the nesting
beaches; speedboats race across the Bay; stray dogs roam the
dunes; garbage bins are full and overflowing; people are seen
fishing from the beach; and beach furniture litters the beaches
at double the amount allowed by law. Quite a list for a
so-called protected area!!
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