Figure 1. Dorsal view of Kemp's ridley sea turtle, Lepidochelys
kempi. From Brongersma (1972, Plate 10) with permission
of Rijksmuseum van Natuurlijke Historie, Leiden, the
Netherlands.

18



LITERATURE CITED

Bjorndal, Karen A. and George H. Balazs (editors). 1983. Manual of
sea turtle research and conservation techniques. Center for
Environmental Education, Washington, D.C., 126 p. (Second
Edition).

Brongersma, L. D. 1972. European Atlantic turtles. Zoologische
Verhandelingen 121:1-318.

Caillouet, Charles W., Jr. 1984, Essai de prevention de
l'extinction de la tortue de Kemp. Les Carnets de Zoologie
44(2):28-34.

Caillouet, Charles W., Jr. and Marcel J. Duronslet. 1985. Guest
editorial--sea turtle sex ratios and incubation temperature: are
we on the right track? Marine Turtle Newsletter 35:14-16.

Caillouet, Charles W., Clark T. Fontaine, Sharon A. Manzella, Theodore
D. Williams and Dickie B. Revera. 1986a. Scutes reserved for
living tags. Marine Turtle Newsletter 36:5-6.

Caillouet, Charles W., Jr., Clark T. Fontaine, Theodore D. Williams,
Sharon A. Manzella, Marcel J. Duronslet, Kathy L. W. Indelicato,
Dickie B. Revera, Andry M. Landry, Jr. and Pamela J. Howes. MSa.
The Kemp's ridley sea turtle head start research project: an
annual report for fiscal year 1986.

Caillouet, Charles W., Jr., Clark T. Fontaine, Theodore D. Williams,
Sharon A. Manzella, Dickie B. Revera, Dennis B. Koi, Kathy L. W.
Indelicato, Marty G. Tyree, Jorge K. Leong, Marcel J. Duronslet
and Kenneth T. Marvin. 1986b. The Kemp's ridley sea turtle head
start research project: an annual report for fiscal year 1985.
NOAA Technical Memorandum NMFS-SEFC—174, ii plus 37 p., 29
Tables, 1 Figure and 5 Appendices.

12



ridley) were captured and shipped alive from south Texas ports to markets
in New York (Gunter, 1981). Sea turtles are characteristically long-lived
and well suited for an oceanic existence (Carr, 1967). However, their
habit of nesting on beaches makes the adult females and their eggs par-
ticularly vulnerable to human exploitation and natural predation
(Hildebrand, 1963; Pritchard and Marquez, 1973; Doughty, 1984). In addi-
tion, the hatchlings are exposed to mammalian, avian and crustacean preda-
tors as they crawl down the beach to the water and to predatory fish after
they enter the shallow surf zone (ibid.). So little is known about the
habits and whereabouts of sea turtles during their first year of existence
in the wild that this period has been called the "lost year" (Carr, 1980).
Sea turtles are captured incidentally in the nets of shrimp trawlers, and
as a result thousands die annually (Watson and Seidel, 1980; Henwood and
Stuntz, in press). Sea turtles also are caught in shark nets (Chavez,
1969; Pritchard and Marquez, 1973).

Climatological changes may affect sex ratios in sea turtle populations.
Temperature during incubation of sea turtle eggs determines the sex ratio
of hatchlings in the clutch (Yntema and Mrosovsky, 1980; Morreale et al.,
1982; Standora and Spotila, 1985). Cooler incubation temperatures produce
a preponderance of males and warmer temperatures produce more females.
Thus, a warming trend in climate might possibly produce a preponderance of
females, while a cooling trend a preponderance of males. In any case, such
trends could lead to sex ratios too imbalanced for successful fertilization
of eggs. The effect of temperature on sex ratios of Kemp's ridleys from
artificially incubated eggs is being investigated, because it is of major
importance to the success of head starting (Caillovet and Duronslet, 1985;
Wibbels et al., 1985).

CONSERVATION EFFORTS

In January 1977, representatives of the Instituto Nacional de
la Pesca (INP) of Mexico, the United States Fish and Wildlife Service
(FWS), the National Park Service (NPS), the NMFS, and the Texas Parks
and Wildlife Department (TPWD) met in Austin, Texas USA to plan an
international program to save Kemp's ridley sea turtle from extinction



Figure 2, Head started yearling Kemp's ridley sea turtle,

Lepidochelys kempi, with metal tag on its left front
flipper. Photo by Daniel Patlan.

19



McVey, James P., and Thane Wibbels. 1984. The growth and movements
of captive-reared Kemp's ridley sea turtles, Lepidochelys kempi,
following their release in the Gulf of Mexico. NOAA Technical
Memorandum NMFS-SEFC-145, 25 p., 3 Figures, and 3 Tables.

Morreale, Stephen J., Georgita J. Ruiz, James R. Spotila, and Edward
A. Standora. 1982. Temperature-dependent sex determination:
current practices threaten conservation of sea turtles. Science
21621245-1247.

Mrosovsky, Nicholas. 1983. Conserving sea turtles. British
Herpetological Society, 176 p.

Owens, David W., Mark A. Grassman, and John R. Hendrickson. 1982.
The imprinting hypothesis and sea turtle reproduction.
Herpetologica 38(1):124-135.

Pritchard, Peter C. H. and Rene Marquez M. 1973. Kemp's ridley
turtle or Atlantic ridley, Lepidochelys kempi. International
Union for Conservation of Nature and Natural Resources Monograph
No. 2, 30 pe

Rabalais, Steven C. and Nancy N. Rabalais. 1980. The occurrence
of sea turtles on the south Texas coast. Contributions in Marine
Science 23:123-129.

Richard, Joseph D. 1983. Evidence for an African origin for green
turtles (Chelonia mydas) nesting on Ascension Island. American
Society of Ichthyologists and Herpetologists Conference, July,
1983. (Abstract only).

Standora, Edward A. and James R. Spotila. 1985. ‘Temperature depen-
dent sex determination in sea turtles. Copeia 1985(3):711-722.

16



OTHER CONSERVATION EFFORTS

Rearing Kemp's ridley in captivity has afforded an opportunity to deve-
lop a captive brood stock. Of the 264 Kemp's ridleys reared, tagged and
transferred to cooperating organizations, 110 survivors are now distributed
among Pan American University (South Padre Island, Texas), Sea-Arama Marine
World (Galveston, Texas), Dallas Aquarium (Dallas, Texas), Marine Life
Park, Inc. (Gulfport, Mississippi), Bass Pro Shops (Springfield,
Missouri), Gulfarium (Fort Walton Beach, Florida), Clearwater Marine
Science Center (Clearwater, Florida), Miami Seaquarium (Miami, Florida),
Theater of the Sea (Islamorada, Florida), Marineland, Inc. (St. Augustine,
Florida), Sea World of Florida (Orlando, Florida), North Carolina Marine
Resources Center (Kure Beach, NC), New England Aquarium (Boston,
Massachusetts), and Cayman Turtle Farm [1983] Ltd. (Grand Cayman Island,
BWI). Currently, they range in age from 2 to 8 years old.

In May 1984, eggs were laid by two of the captive-reared 5-year-old
females at the Cayman Turtle Farm [1983] Ltd. (Wood and Wood, 1984). Only
three eggs hatched, indicating that copulation with and fertilization by
captive-reared males had taken place, but the hatchlings died. No nestings
were reported for the 1985 season, but some of the 7-year-olds nested in
spring 1986, and viable hatchlings were produced (James Wood, Cayman Turtle
Farm, personal communication, September 1986). The nestings at age 5
represented the earliest documented age for nesting in the species, albeit
in captivity, and the successful hatches in captive 7-year-olds provided
the needed breakthrough to make captive propagation feasible.

Because sea turtles are caught incidentally in commercial shrimping
operations, methods have been developed to resuscitate and release turtles
that happen to get caught in this way (Watson and Seidel, 1980). The NMFS
SEFC Laboratories in Bay St. Louis and Pascagoula, Mississippi, developed a
Turtle Excluder Device (also Trawling Efficiency Device or TED; Fig. 3) for
shrimp trawls that allows captured turtles to escape from the nets during
trawling operations (Taylor et al., 1985). As fringe benefits, the "TED"
reduces the incidental catch of finfish without reducing the catch of
shrimp (Watson, Mitchell and Shah, 1986).



During the head starting of Kemp's ridley, special attention is given
to behavior, diet, water quality, water temperature, and sanitation (Klima
and McVey, 1981; Fontaine and Caillouet, 1985; Fontaine et al., 1985;
Caillouet et al., 1986c). Young Kemp's ridleys are very aggressive, and
when reared in groups, they bite and injure one another. The injuries
become infected and result in poor health and death in some cases (Clary
and Leong, 1984). However, the turtles thrive when reared individually. A
commercially-manufactured, dry, floating, pelletized diet manufactured by
PURINA has become the standard for head starting (see also Caillouet et
al., 1986b and 1986c), but the natural diet consists of crustaceans, fish,
jellyfish and molluscs (Pritchard and Marquez, 1973).

The first three years of head starting were exploratory (Klima and
Mevey, 1981; Fontaine et al., 1985). Thereafter, the rearing facilities
and methods were improved and became more or less standardized (Fontaine et
al., 1985). The number of live hatchlings received so far, representing
year-classes 1978-1986, has totaled 15,260. Currently, about 1,740 Kemp's
vidleys of the 1986 year-class are being head started. Plans are to expand
the annual rearing capacity to 2,700 turtles.

Survivors in good health and condition that have been tagged and
released so far into the Gulf of Mexico have totaled 10,792 (Caillovet et
al., MSa). Most of the tagged turtles were released off the coast of the
National Seashore (Caillovet et al., 1986b; Fontaine et al., MS). Some
were released off the upper coast of Texas, in Nueces and Copano Bays near
Corpus Christi, Texas, off the west coast and southern tip of Florida, and
in the Bay of Campeche, Mexico (Klima and McVey, 1981; McVey and Wibbels,
1984; Wibbels, 1984; Caillouet et al., MSa; Fontaine et al., MS). Of the
total released, 492 had been recovered as of 30 September 1986 (Caillouet
et al., MSa). Recoveries have been reported from the Gulf of Mexico, from
the east coast of the United States, and from the European Atlantic coast,
in a distribution comparable to that reported in the literature (e.g.,
Brongersma, 1972; Pritchard and Marquez, 1973) and as indicated by data
from the Sea Turtle Stranding and Salvage Network (Fontaine et al., MS).
One recovered from the coast of Morocco may be the first record of Kemp's
ridley for the northwest coast of Africa (ibid.). These recoveries show
that head started turtles survive, grow and migrate in the wild.



(Klima and McVey, 1981). The cooperative program was implemented in 1978
and has three objectives:

(1) Protection of the primary nesting area, the adult female turtles
and their eggs at the beach near Rancho Nuevo,

(2) evaluation of head starting, and

(3) establishment of a new nesting colony at the Padre Island National
Seashore near Corpus Christi, Texas.

Head starting involves rearing Kemp's ridley in captivity from newly-
hatched to yearling stages to increase survival during the critical first
year of life (Klima and McVey, 1981; Mrosovsky, 1983; Fontaine et al.,
1985). At the beach near Rancho Nuevo, plastic bags are used to collect
eggs as they emerge from the cloaca of the females in order to prevent the
eggs from coming in contact with the beach sand. Fewer than 5% of the
estimated 70,000-90,000 eggs laid each year at the Rancho Nuevo beach are
taken for head starting (Jack B. Woody, personal communication, July,
1984). The eggs are placed in polystyrene foam boxes containing beach
sand taken from the Padre Island National Seashore. The boxes are trans-
ported by single-engine aircraft to the National Seashore where the eggs
are incubated while still buried in the boxed sand.

When the hatchlings emerge, they are taken to the Padre Island beach
and allowed to crawl down the beach into the surf. It is hoped that they
become imprinted by exposure to the beach sand in the boxes during incuba-
tion and to the beach sand and surf after hatching. The hatchlings are
then netted from the surf, put into boxes, and transported by NPS vehicle
to Galveston, Texas. A few clutches, incubated, hatched and exposed to
sand and surf at the Rancho Nuevo beach, also have been transported to
Galveston for head starting.

Hatchlings received by the NMFS Galveston Laboratory are reared in
captivity for one year or less. Healthy survivors in good condition are
tagged and released into the Gulf of Mexico, in hopes that some will sur-
vive and instinctively return to Padre Island to nest as adults.



Taylor, Charles W., Anthony F. Serra, John F. Mitchell and Rodney Cc.
Sawyer. 1985. Construction and installation instructions for the
trawling efficiency device. NOAA Technical Memorandum
NMFS-SEFC-71, 22 p.

Watson, John W. and Wilber R. Seidel. 1980. Evaluation of techniques
to decrease sea turtle mortalities in the southeastern United
States shrimp fishery. International Council for the Exploration
of the Sea, Fish Capture Committee, C.M.1980/B:31, 8 Pp.

Watson, John W., John F. Mitchell and arvind K. Shah. 1986. Trawling
efficiency device: a new concept for selective shrimp trawling
gear. Marine Fisheries Review 48(1):1-9,

Werler, John E. 1951. Miscellaneous notes on the eggs and young of
Texan and Mexican reptiles. Zoologica 36(3):37-48 + plates,

Wibbels, Thane A. 1984. Orientation characteristics of immature
Kemp's ridley sea turtles, Lepidochelys kempi. NOAA Technical
Memorandum NMFS-SEFC-131, iv plus 67 p.

Wibbels, Thane, David Owens, Gayle Dienberg and Julia Noell. 1985.
Determination of sex ratios produced in the Kemp's ridley head
start program, Final Report to the National park Service,
Contract No. PX7490-5-0100, Department of Biology, Texas A&M
University, College Station, Texas.

Wood, James R. and Fern E. Wood. 1984, Captive breeding of the
Kemp's ridley. Marine Turtle Newsletter 30:12.

Woody, Jack B. 1986. Kemp's ridley sea turtle, p. 919-931. In:
Audubon Wildlife Report 1986.

Yntema, C. L. and Nicholas Mrosovsky. 1980. Sexual differentiation
in hatchling loggerheads (Caretta caretta) incubated at different
controlled temperatures. Herpetologica 36:33-36.

17



implanted near the distal end of a front flipper of all head started
turtles of the 1984 and 1985 year-classes. Multiple marking should
increase the probability of retention of at least one recognizable tag. As
an experiment, 50 ridleys of the 1984 year-class were “flipper-printed,"
by making plastic casts of potter's clay impressions of the flippers.
Plans are to use computer imagery to characterize and compare such "prints"
as a means of identifying individuals (Caillouet et al., MSb). Multiple-
marked Kemp's ridleys are being held in captivity beyond the first year, in
part to study tag retention and recognition of individuals.

Head started turtles unquestionably have a much higher survival during
their first year of life than those that must fend for themselves in the
wild from the time of hatching. However, after head started turtles are
Yeleased, the effects of prior human care and feeding may influence their
behavior in such a way that renders them more susceptible to natural preda-
tion or recapture by man, or less successful in obtaining food than their
completely wild counterparts. Conversely, perhaps some head started
turtles will overcome the hazards of the wild and survive, mature, and nest
successfully to form new colonies or bolster the existing one. The odds
against survival of thousands of head started turtles may be so great that
few if any may come ashore to nest in future years. Yet, the species is so
close to extinction that such risks seem insignificant in contrast to what
might be accomplished and learned by testing head starting. The turtles
are long-lived and could reproduce for a number of years, once they survive
to maturity. The hundreds of head started turtles tagged and released each
year are significant when compared to the current scarcity of nesters.

The primary objective of head starting will be fulfilled only when sur-
viving adults return to nest where they were "imprinted" as hatchlings.
Based upon successful reproduction of 7-year-olds in captivity, enough time
has elapsed for at least some of the head started survivors to have reached
the reproductive stage, but none have been observed on the nesting grounds
so far. In the interim, valuable knowledge has been gained by observing
Kemp's ridley in captivity and by monitoring its migrations, growth, and
survival in the wild.



WATIONA
S
of

Py

soo,

7 NOAA Technical Memorandum
y NMFS-SEFC- 188

Vrmenr oF

Report on Efforts to Prevent
Extinction of Kemp’s Ridley
Sea Turtle Through Head Starting

By

Charles Wax Caillouet, Jr.

U. S. DEPARTMENT OF COMMERCE
Malcolm Baldrige, Secretary

National Oceanic and Atmospheric Administration
Anthony J. Calio, Administrator

National Marine Fisheries Service
William E. Evans , Assistant Administrator for Fisheries

February 1987

This Technical Memorandum series is used for documentation
and timely communication of preliminary results, interim

reports, or similar special-purpose information. Although
the memoranda are not subject to complete formal review,

editorial control, or detailed editing, they are expected
to reflect sound professional work.



recruitment to the nesting population. Continued head starting, based on
a small fraction of the eggs produced at Rancho Nuevo each year, not only
can provide a steady flow of thousands of yearlings to the Gulf of Mexico,
but also a supply needed to maintain a captive stock of breeders as a
"safety net" for the species. Head starting also provides otherwise una-
vailable opportunities for research that contributes to a better under-
standing of the biology of Kemp's ridley sea turtle and the problems that
this species faces. Expansion of the use of the TED should increase the
survival of Kemp's ridleys caught incidentally during shrimping operations.
Further study of impacts of underwater explosions on sea turtles will be
required before it can be determined whether or not this is a significant
cause of mortality.

If Kemp's ridley sea turtles, marked or unmarked, begin showing up in
numbers to nest on the beach at the Padre Island National Seashore, or if
the nesters increase in numbers elsewhere, this will indicate that the com
bined conservation efforts are succeeding. Only time will tell how suc-
cessful these efforts will be.

ACKNOWLEDGMENTS

The Kemp's ridley sea turtle head start research project has been con-
ducted under Permits ABC-IV-0751/8676, ABC-IV-1258/4287, 242-0180-3794,
242.2-2610, 242.2-00026/1147, CG-115-900 (and Diplomatic Note No. 316502),
2534 (and Diplomatic Note No. 301976), 301271 (and Diplomatic Note No. 174)
and 150486-333-01-0750 (and Diplomatic Note No. 30132) from Mexico's
Departmento de Pesca (Instituto Nacional de la Pesca), Endangered and
Threatened Species Permits PRT 2-1770, PRT 2-4481, PRT-676379 and
PRT-689914 from the U. S. Fish and Wildlife Service, Scientific Permit No.
SP073 from the Texas Parks and Wildlife Department, Scientific Permit
7TP-015 from the Florida Department of Natural Resources, and Permits No.
US-701414, US-707274 and US-675990 from the Convention on International
Trade in Endangered Species of Wild Fauna and Flora (CITES).

Many individuals are playing important roles in the international
Kemp's ridley recovery program, including Rene Marquez Millan (INP), Jack

10



The Sea Turtle Stranding and Salvage Network has aided reporting of
sea turtles found stranded on beaches, either alive or dead. It provides
one useful index to sea turtle mortality. Because unauthorized possession
of sea turtles is punishable by law under the U.S. Endangered Species Act,
local, federal or state law enforcement agents should be contacted when a
stranded sea turtle is found. Large numbers of sea turtles found stranded
on beaches of the upper Texas Coast in 1985 and 1986 led to concerns that
the turtles might be injured or killed by underwater explosives used to
salvage petroleum platforms from depleted oil fields in the Gulf of Mexico.
As a result, NMFS entered into a Section 7 consultation with the Department
of Interior's Minerals Management Service (MMS), under the Endangered
Species Act, and 30-day advanced notice is now required before such salvage
Operations. This allows time for NMFS and MMS to Prepare for study of
impacts on protected species.

THE FUTURE

Restoring the population of Kemp's ridley will not be an easy task
(Mrosovsky, 1983). Conservation and management of Kemp's ridley and other
sea turtles require international cooperation among researchers and conser-
vationists (Bjorndal and Balazs, 1983). Of major importance is protection
of nesting turtles and their nests from poaching and predation. Oceanside
reserves and refuges have been created to insure that breeding colonies of
sea turtles and their nests are not further disturbed. Such protection of
the Rancho Nuevo beach by the Mexican government, including patrols during
the nesting seasons, has virtually eliminated poaching and dramatically
reduced predation on the beach to the extent that such losses are incon-
sequential and no longer prevent Kemp's ridley recovery (Jack Woody, FWS,
personal communication, January 1986), Marketing of sea turtles and their
products is being controlled to allow sea turtle populations to recover.
The United States and other nations prohibit capture of sea turtles and
have banned commercial uses, importation and exportation of sea turtles and
their products, whether caught or produced by turtle farms.

Continued protection of nesting areas and prohibitions on the pos-
session and sale of Kemp's ridley sea turtles, their eggs and other pro-
ducts should enhance the production and survival of young and increase

9



Carr (1980) believes that Kemp's ridleys that leave the Gulf of Mexico
and migrate along the Atlantic coasts of North America and Europe may be
strays doomed to die as hapless wanderers, never finding their way back
into the Gulf of Mexico to mate and nest. On the other hand, it seems
unlikely that such transoceanic migratory behavior would have evolved
without having some survival value to the species. Before the Rancho Nuevo
nesting colony became known to sea turtle biologists, Carr (1957) and Carr
and Caldwell (1958) suggested that the northwest coast of Africa might be
a possible nesting site. After the discovery of the Rancho Nuevo nesting
site was announced, interest in a search for a northwest African nesting
site waned. Based on examination of the literature, recoveries of tagged
Kemp's ridleys, and stranding records, Fontaine et al. (MS) speculated that
Carr (1957) and Carr and Caldwell (1958) may have been correct in proposing
a northwest African nesting site, but this remains unproven.

Head started turtles are tagged so that they can be identified if reco-
vered later on. According to Carr (1967), "a good tag is one that can be
quickly put on, that interferes little with the movements and peace-of-mind
of the animal; that will stay on a long time - if the animal is one that
lives a long time, as a turtle does; that is inscribed with clear direc-
tions for its return; and that offers a reward to the one who sends it
back." Unfortunately, no tag currently in use fulfills all these criteria.
To be successful in testing efficacy of head starting as a conservation
method, any tag used must be retained by the turtles at least for the
length of time it takes them to mature and nest. Furthermore, the tag must
be recognizable by those who examine nesting turtles. The standard tags
for head started Kemp's ridleys have been metal tags attached to the
trailing edge of a front flipper (Fig. 2). Some of the turtles also have
been marked with "living tags" formed by excision and transplantation of a
2-3 mm sliver of light-colored plastron tissue to a scute on the darker
carapace. This grafting technique was developed by Hendrickson and
Hendrickson (1981). All members of a year-class are marked on the same
carapace scute, and a different scute is selected to represent each year-
class (Caillovet et al., 1986a). A binary-coded, magnetic metal tag was



DOOR OPENING

FINFISH

DEFLECTOR DEFLECTOR GRID

FINFISH OPENING

Figure 3. Turtle Excluder Device (TED) or Trawling Efficiency Device
shown in cutaway diagram of a shrimp trawl and with
escaping sea turtle (from Watson et al., 1986).

20



(1958) suggested that sea turtles that have never nested encounter others
that have nested previously. Through such contacts, the novice turtles may
follow experienced ones to the nesting beach. This theory has been
referred to as "social facilitation" (Owens et al., 1982). Richard (1983)
proposed a theory called "random drift" through which sea turtles may be
conveyed passively to nesting beaches by oceanic currents. Recognition of
the nesting beach may involve a chemical sense (Carr, 1967), and Kemp's
ridley has a keen sense of smell (Grassman et al., 1984). This forms the
basis for the hypothesis of "imprinting" which assumes that Kemp's ridley
can "learn" and "remember" various odiferous substances characterizing the
nesting beach and its adjacent waters (ibid.).

Using the working hypothesis that “imprinting" takes place in the eggs
and/or hatchlings, biologists at the National Marine Fisheries Service's
(NMFS) Southeast Fisheries Center (SEFC) Laboratory in Galveston, Texas,
are giving Kemp's ridleys a head start by rearing them from hatchlings to
yearlings in captivity, tagging them and releasing them into the Gulf of
Mexico (Klima and McVey, 1981; Caillouet, 1984; Fontaine et al., 1985).
This paper describes the Kemp's ridley head start research project which is
part of an international program initiated in 1978 to prevent the possible
extinction of this species.

POPULATION STATUS

In June 1947, Andres Herrera of Tampico, Mexico, filmed on one day an
arvibada comprised of an estimated 40,000 Kemp's ridleys nesting on the
beach near Rancho Nuevo (Carr, 1963; Hildebrand, 1963). In 1960, there
were estimated to be about 10,000 nesting ridleys, and by the time the
Mexican Government began protective patrols of the beach in the mid-1960's,
the number had dwindled to 2,000 (Marquez, 1983). An estimated 600 Kemp's
vidleys nested in 1982 (ibid.), and now there are probably no more than 400
nesting females (Woody, 1986).

It is most likely that this spectacular decline in the Kemp's ridley
population is the result of excessive exploitation by man, although preda-
tion and other natural causes cannot. be ruled out as contributing factors.
Until the turn of the century, sea turtles (perhaps including Kemp's



Caillouet, Charles W., Jr., Dennis B. Koi, Clark T. Fontaine, Theodore
D. Williams, William J. Browning and Richard M. Harris. 1986c.
Growth and survival of Kemp's ridley sea turtle, Lepidochelys
kempi, in captivity. NOAA Technical Memorandum NMFS-SEFC-186, 34
p, 12 Tables and 7 Figures.

Caillouet, Charles W., Jr., Dickie B. Revera, Marcel J. Duronslet and
John Brucks. MSb. Dermatoglyphic patterns on Kemp's ridley sea
turtle flippers: can they be used to identify individuals?

Carr, Archie. 1957. Notes on the zoogeography of the Atlantic sea
turtles of the genus Lepidochelys. Revista de Biologia Tropical
5(1):45-61,

Carr, Archie F. 1961. The ridley mystery today. Animal Kingdom
64(1):7-12,

Carr, Archie F. 1963. Panspecific reproductive convergence in
Lepidochelys kempi. Ergebnisse der Biologie 26:298-303.

Carr, Archie. 1967. So excellent a fishe: A natural history of
sea turtles, Natural History Press, Garden City, New York,
248 p.

Carr, Archie. 1980. Some problems of sea turtle ecology. American
Zoologist 20:489-498,

Carr, Archie and David K. Caldwell. 1958. The problems of the
Atlantic ridley turtle (Lepidochelys kempi) in 1958. Revista de
Biologia Tropical 6(2):245-262.

Casas-Andreu, Gustavo. 1978. Analisis de la anidacion de las
tortugas marinas del genero Lepidochelys en Mexico. Anales del

Centro de Ciencias del Mar y Limnologia 5(1):141-158.

13



Fontaine, Clark T., Richard M. Harris, William J. Browning and
Theodore D. Williams. MS. Observations on distribution, growth
and survival of captive-reared, tagged and released Kemp's ridley
sea turtles (Lepidochelys kempi) from year-classes 1978-1983.

Grassman, Mark A., David W. Owens, James P, McVey, and Rene Marquez M.
1984, Olfactory-based orientation in artificially imprinted sea
turtles. Science 224:83-84,

Gunter, Gordon. 1981. Status of turtles on the Mississippi coast.
Gulf Research Reports 7(1):89-92,

Hendrickson, John R. 1958. The green sea turtle, Chelonia mydas
(Linn.) in Malaya and Sarawak. Proceedings of the Zoological
Society of London 130:455-535.

Hendrickson, John R. and Lupe Hendrickson. 1981. A new method for
marking sea turtles. Marine Turtle Newsletter 1926-7.

Henwood, Tyrrell A. and Warren E. Stuntz. In press. Analysis of sea
turtle captures and mortalities during commercial shrimp trawling.
Fishery Bulletin, U.S.

Hildebrand, Henry H. 1963. Hallazgo del area de anidacion de la
tortuga marina "lora", Lepidochelys kempi (Garman), en la costa
occidental del Golfo de Mexico. Ciencia 22(4):105-112.

Klima, Edward F. and James P. McVey. 1981. Headstarting the Kemp's
ridley turtle, Lepidochelys kempi, p. 481-487 In: Byjorndal,
Karen A. (editor). Biology and Conservation of Sea Turtles,
Smithsonian Institution Press, Washington, D.C.

Marquez, Rene. 1983. Current status of the Kemp's ridley population,
p. 6-11. In: Owens, David et al. (editors), Western Gulf of
Mexico Sea Turtle Workshop Proceedings, Texas A&M University Sea
Grant Program, College Station, Texas, TAMU-SG-84-105,

15



Kemp's ridley sea turtle, Lepidochelys kempi (Fig. 1), is one of eight
species of sea turtles (Bjorndal and Balazs, 1983). Kemp's ridley and the
olive ridley, L. olivacea, are the smallest of the sea turtles, reaching
an adult weight close to 45 kg. Sea turtles belong to the reptilian order
Testudines, a group that arose during the early Triassic more than 185
million years ago (Ernst and Barbour, 1972). Despite this remarkably long
and successful existence, many species of turtles are facing possible
extinction. Since 1973, Kemp's ridley, the rarest of the sea turtles, has
been classified as endangered under the U.S. Endangered Species Act and by
the Convention on International Trade in Endangered Species of Wild Fauna
and Flora.

The distribution of Kemp's ridley includes the Gulf of Mexico, the
Atlantic coast of North America to Nova Scotia, and European Atlantic
waters (Brongersma, 1972; Pritchard and Marquez, 1973). As far as is pre-
sently known, the principal nesting area for Kemp's ridley is a 20-km
stretch of oceanside beach bordering the Gulf of Mexico near Rancho Nuevo,
Tamaulipas, Mexico (Chavez et al., 1968). Each year, from April through
July, nesting events referred to in Spanish as “arribadas," meaning arri-
vals, occur during which large aggregations of ridleys nest over a period
of a few days (Chavez et al., 1968; Pritchard and Marquez, 1973;. Casas-
Andreu, 1978). Unlike other sea turtles, all of which nest at night,
Kemp's ridley nests during the day, so its arribadas are more frequently
observed. Single or scattered nestings have been reported for other
nesting localities (Werler, 1951; Carr, 1961; Chavez and Kaufmann, 1974;
Rabalais and Rabalais, 1980). It may take as many as 6-13 years of age
before Kemp's ridleys reach maturity (Brongersma, 1972; Pritchard and
Marquez, 1973). As shown from tagging studies at Rancho Nuevo, adult
females may nest more than once during a season (Chavez et al., 1968), but
all turtles at Rancho Nuevo do not nest every year (Marquez, 1983), which
suggests that some turtles may not nest at all in some years or that they
may nest elsewhere. Clutch size for Kemp's ridley at Rancho Nuevo averages
slightly more than 100 eggs (Chavez et al., 1968).

It is not known how sea turtles find their way to a beach to nest, but
several hypotheses have been proposed. Sea turtles may navigate by using
visual cues and/or other sensory mechanisms, such as an internal "compass"
which responds to the earth's magnetic field (Carr, 1967). Hendrickson



NOTICE

The National Marine Fisheries Service (NMFS) does not approve, recommend or
endorse any proprietary product or proprietary material mentioned in this
publication. No reference shall be made to NMFS, nor to this publication
furnished by NMFS, in any advertising or sales promotion which would indi-
cate or imply that NMFS approves, recommends or endorses any proprietary
product or proprietary material mentioned herein, or which has as its pur-
pose an intent to cause directly or indirectly the advertised product to
be used or purchased because of this NMFS publication.

A similar paper, in French (translation by Raymond Cayouette), has been
published elsewhere (Caillovet, 1984).

This report should be cited as follows:

Caillouet, Charles Wax, Jr. 1987. Report on efforts to prevent
extinction of Kemp's ridley sea turtle through head starting. NOAA
Technical Memorandum NMFS-SEFC-188, i plus 20 p.

Copies can be purchased from the National Technical Information Service,
5258 Port Royal Road, Springfield, VA 22161.



Woody (FWS), Milford Fletcher (NPS), Patrick Burchfield (Gladys Porter
200), Edward Klima (NMFS), Donna Shaver (NPS), Clark Fontaine (NMFS), and
their staffs. Carole Allen, Chairperson, and members of HEART (Help
Endangered Animals - Ridley Turtles), a special committee of the Piney
Woods Wildlife Society of North Harris County College, Houston, Texas,
deserve especial recognition for there perservering efforts in promoting
public awareness and support of the head start research project.

ll



Chavez, Humberto. 1969. Tagging and recapture of the lora turtle.
International Turtle & Tortoise Society Journal 3(4):14-19.

Chavez, Humberto, Martin Contreras G., and T. P. Eduardo Hernandez
D. 1968. On the coast of Tamaulipas. International Turtle &
Tortoise Society Journal 2(4):20-29, 37; 2(5):16-19, 27-34.

Chavez, Humberto and Reinhard Kaufmann. 1974. Informacion sobre
la tortuga marina Lepidochelys kempi (Garman), con referencia a un
ejemplar marcado en Mexico y Observado en Colombia. Bulletin of
Marine Science 24(2):372-377.

Clary, John C. III and Jorge K. Leong. 1984. Disease studies aid
Kemp's ridley sea turtle headstart research. Herpetological
Review 15(3):69-70.

Doughty, Robin W. 1984. Sea turtles in Texas: a forgotten commerce.
Southwestern Historical Quarterly LXXXVIII(1):43-70.

Ernst, Carl H. and Roger W. Barbour. 1972. Turtles of the United
States. The University Press of Kentucky, Lexington, Kentucky,
347 p.

Fontaine, Clark T. and Charles W. Caillouet, Jr. 1985. The Kemp's
ridley sea turtle head start research project: an annual report
for fiscal year 1984, NOAA Technical Memorandum NMFS-SEFC-152,
ii plus 13 p. and 3 Tables.

Fontaine, Clark T., Kenneth T. Marvin, Theodore D. Williams, William
J. Browning, Richard M. Harris, Kathy L. W. Indelicato, George A.
Shattuck, and Robert A. Sadler. 1985. The husbandry of hatchling
to yearling Kemp's ridley sea turtles (Lepidochelys kempi). NOAA
Technical Memorandum NMFS-SEFC-158, iv plus 34 p., 10 Tables, 22
Figures and 2 Appendices.

14