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HILDEBRAND (1963): A TRANSCRIPTION AND TRANSLATION

Charles W. Caillouet, Jr.1

1 119 Victoria Drive West, Montgomery, TX 77356-8446 USA, E-mail:

waxmanjr@aol.com

Hildebrand (1963) might be the single most important scientific contribution

to the historical literature concerning Kemp’s ridley sea turtle (Lepidochelys

kempii). In 1961, Henry H. Hildebrand attended the American Society of

Ichthyologists and Herpetologists meeting in Austin, Texas. There he presented a

movie taken by Andrés Herrera of an enormous arribada of Kemp’s ridley nesters

at Rancho Nuevo, Tamaulipas, Mexico, on 18 June 1947. Hildebrand (1963)

described this movie and estimated that the arribada contained 40,000 nesters.

His estimate became the benchmark against which subsequent changes in Kemp’s

ridley population status have been compared (U.S. Fish and Wildlife Service and

National Marine Fisheries Service, 1992).

Hildebrand (1963) was published in Spanish, but it also contains some

passages in English. Because of its historical importance, I transcribed the

original article, then translated the Spanish parts to English, so that both the

transcription and translation could be posted in the archives of Marine Turtle

Newsletter (http://www.seaturtle.org/mtn), thus making them more easily

available to all who might be interested.

Written permission to post the transcription and translation was granted by

Lic. Francisco Salvador Mora Gallegos, Apoderado Legal de la Academia

Mexicana de Ciencias A.C., on behalf of the Academia Mexicana de Ciencias and

the journal Ciencia as follows:

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I am grateful to Jaime Peña-V., Gladys Porter Zoo, Brownsville, Texas for his

important role in obtaining this written permission, and to Lic. Francisco Salvador

Mora Gallegos for granting it.

I scanned a xerographic copy of Hildebrand (1963) then converted it to rich

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text format (rtf) via optical character recognition (OCR) using Omnipage Pro 16.

The rtf version was converted into a Microsoft Word document (doc; with

language set to Spanish). I compared the Word document version to the

xerographic copy of Hildebrand (1963), word for word, and made corrections as

necessary. Some errors could remain, since the xerographic copy I worked from

was not sharp. I used Babylon 8 to translate the Spanish version to an English

version, which I also edited, word for word. Both the English and Spanish

versions are posted in the Marine Turtle Newsletter archives in searchable pdf

format. Line numbers are provided in case readers detect errors. I would greatly

appreciate being informed of errors so they might be corrected.

Hildebrand (1963) referred to Kemp’s ridley by its colloquial or vernacular

name, tortuga lora or just lora (meaning parrot, or tawny, or dark brown), but he

did not mentioned the name Kemp’s ridley, and I did not change this in my

translation. Place names also were not translated. Finally, the following terms

were not translated, but translations are attempted below:

veracruzanos persons whose origin is Veracruz

tortugueros turtlers, turtle egg collectors, turtle fishermen

chalupa nutshell, shallop, or sloop, a colloquial name used

for leatherback, Dermochelys coriacea

pargos snappers, Lutjanus sp.

guachinangos snappers, Lutjanus sp.

Hildebrand (1963) provided information about nesting of Kemp’s ridley, but

also described the method he used to estimate the 40,000-nester arribada. Such

information is especially useful because Márquez et al. (1999) acknowledged that

Hildebrand’s (1963) method of estimating the arribada had “recently come into

question.” Caillouet (2000) pointed out that some members of the Turtle Expert

Working Group suggested that Hildebrand’s (1963) methods be revisited and that

image analyses of the Herrera film might be a reasonable approach to re-

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estimating the arribada’s size.

Dickerson and Dickerson (2006) conducted image analyses of stitched

images taken from the Herrera film, and estimated mean counts for hypothetical

beach lengths ranging from 50 m to 1,000 m. Hildebrand (1963) interviewed

Andrés Herrera and others who indicated that the actual length and width of the

area of beach occupied by the nesters was “slightly more than a mile” (1,609 m)

and “in a strip some 20 meters wide along all the seashore” (65.6 ft), respectively.

Therefore, it should be possible to use Dickerson’s and Dickerson’s (2006)

estimated mean counts of nesters to re-estimate the total number of nesters in the

arribada.

Peter C. H. Pritchard (personal communication, November 2009) pointed out

to me that the various Rancho Nuevo area bocas (river or lagoon mouths)

mentioned by Hildebrand (1963) had silted and closed up by 1968 when Pritchard

began his work in the area in 1968. In other words, they became barras

(sandbars). He noted further that in 1968 the big estuary to the south of the camp

(Main Field Station, see below) was still recognized as Boca del Tordo, because

its mouth remained open. However, Boca Coma near the camp had closed and

was replaced by a small hill of sand, and was then known as Barra Coma. The

next landmark to the north was "Cementerio" (a small beachfront cemetery).

Then, the next estuary, Boca Calabazas, had become Barra Calabazas. Finally,

the former Boca San Vicente became Barra San Vicente. Jaime Peña-V.

(personal communication, November 2009) verified that the current landmarks

are all barras, except for Cementerio, and he provided the following list of place

names, in sequence from north to south:

Barra Carrizo

Barra Aparejo

Barra San Vicente

Barra Cachimbas

Barra Calabazas

Barra Jarcias

Cementerio

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Barra Coma (Main Field Station)

Barra Brasilito

Barra Brasil

Barra del Tordo

Most but not all of these landmarks are shown in Fig. 4 (p. 11) in Márquez-M. (1994), in which all were referred to as barras, except Cementerio.

CAILLOUET, C. W., JR. 2000. Letter to the editors: which Kemp’s ridley nest

numbers are correct? Marine Turtle Newsletter 87:13-14.

DICKERSON, V.A. & D.D. DICKERSON. 2006. Analysis of arribada in 1947

Herrera film at Rancho Nuevo, Mexico. In: Frick, M., A. Panagopoulou, A.F.

Rees & K. Williams (Compilers), Book of Abstracts, Twenty Sixth Annual

Symposium on Sea Turtle Biology and Conservation, International Sea Turtle

Society, Athens, Greece, p. 290-291.

HILDEBRAND, H. H. 1963. Hallazgo del area de anidacion de la tortuga marina,

“lora”, Lepidochelys kempi (Garman) en la costa occidental del Golfo de Mexico.

Ciencia, Méx. 22(4):105-112.

MÁRQUEZ, R., J. DÍAZ, M. SÁNCHEZ, P. BURCHFIELD, A. LEO, M.

CARRASCO, J. PEÑA, C. JIMÉNEZ, AND R. BRAVO. 1999. Results of the

Kemp's ridley nesting beach conservation efforts in México. Marine Turtle

Newsletter 85:2-4.

U.S. FISH AND WILDLIFE SERVICE AND NATIONAL MARINE

FISHERIES SERVICE. 1992. Recovery plan for the Kemp’s ridley sea turtle

Lepidochelys kempii. 40 p.

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HALLAZGO DEL AREA DE ANIDACION DE LA TORTUGA MARINA

“LORA”, LEPIDOCHELYS KEMPI (GARMAN), EN LA COSTA

OCCIDENTAL DEL GOLFO DE MEXICO

(Rept., Chel.)

INTRODUCCIÓN

Es posible que no exista ningún otro animal marino de gran talla cuya

abundancia y área de distribución hayan sido tan alteradas por el hombre, como

las de las tortugas. Esto parece corroborarlo el hecho de que desde más de

cincuenta años, desaparecieron las pesquerías organizadas de quelonios del

Noroeste del Golfo. Los escasos datos históricos de que se dispone sobre las

tortugas marinas de la zona que nos ocupa son difíciles de interpretar. Sin

embargo, el examen de tales escritos pone en claro los hechos siguientes:

1. La industria tortuguera se abastecía principalmente de la pesca con redes

en las bahías texanas [tejanas], aunque una cantidad desconocida, pero sin duda

muy pequeña, llegaba de México y de otras áreas del Golfo, transportada en

balandros.

2. Los datos disponibles sobre la existencia de nidos o huellas de tortugas

marinas en las playas son muy escasos para la totalidad del Estado de Texas. El

único dato histórico de que tengo conocimiento, es una afirmación en las notas de

viaje de Joutel (1713) sobre el malogrado establecimiento de LaSalle en la costa

de Texas, pero es tan ambigua que no aclara, si se refiere a las tortugas marinas o

a las terrestres.

3. Desde hace tiempo se sabe que las tortugas marinas anidan en abundancia

en las Costas de Tamaulipas, y de hecho, el historiador Alexandro Prieto (1873),

las consideró tanto a ellas como a sus huevos, un recurso importante de la costa.

Además, algunos viejos pescadores de Puerto Isabel (Texas), cuyos antepasados

estuvieron dedicados en Soto la Marina a la compra de pescado de agua salada,

me informaron que era un hecho conocido que las mayores concentraciones de

nidos se hallaban ubicadas en la región comprendida entre la boca del Río Soto la

Marina y Punta Jerez.

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Carr y Caldwell (1955) y Carr (1961), han resumido toda la información

disponible sobre la anidación de Lepidochelys kempi. Los lugares de puesta

citados son: Little Shell, en Isla Padre (Texas) y Nautla, Antón Lizardo, Alvarado

y Montepío, en el Estado de Veracruz. En el trabajo de 1961 (op. cit.) no se

mencionaron localidades en el Estado de Tamaulipas, pero el primero de los

artículos señalados cita una carta mía referente a un rumor sobre la recolección en

gran escala de huevos de tortuga lora cerca de Punta Jerez.

DATOS DISPONIBLES SOBRE EL DESOVE DE TORTUGAS MARINAS EN

EL SUROESTE DEL GOLFO DE MÉXICO

Veracruz. – Poco se puede agregar, a la información proporcionada por Carr

(1961), aunque una nueva área, la de Cabo Rojo, requiere estudio posterior. El Sr.

Virgil Mercer, que vivió allí con anterioridad y voló sobre las playas muchas

veces, escribe: “I have seen far more tracks on the beach from our camp

(Tampachichi) around Cabo Rojo to Tamiahua than in any other area. This may

be due to the fact that the beach is much softer there”. Mercer no logró ver

tortugas en la playa, pero indudablemente se debe a que no voló en días de viento

fuerte, que son los que prefieren las “loras” para salir del mar. En cualquier caso,

deberá hacerse rápidamente una investigación del área de Cabo Rojo, punto nodal

de los procesos costeros de acarreo, ya que el Sr. Mercer informa que la

recolección de huevos en esa zona es actualmente tan intensa que es sólo cuestión

de tiempo que las tortugas se extingan.

La región de playa comprendida entre Náutla y Tecolutla fue determinada

como región de puesta por Fugler y Webb (1957). De acuerdo con los

investigadores de la Estación de Biología Marina del Instituto Tecnológico de

Veracruz, se sabe que las tortugas desovan allí en cantidades “regulares”. El autor

desconoce el número de especies implicadas, pero probablemente la lora

represente el grueso de ellas.

Desde la Barra de Chachalacas hasta Alvarado, la playa es constantemente

recorrida por pescadores, turistas y otras personas, y por lo tanto, muy pocas

tortuga pueden conseguir un lugar para anidar antes de que hayan sido “viradas” o

volteadas. Aún en caso de que lograsen desovar es casi seguro que el nido sería

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encontrado y saqueado. He sido informado repetidamente por los pescadores de

Veracruz y Antón Lizardo que todas las tortugas anidan de noche, lo cual no es

correcto para el caso de la lora; en contraste con los informes previos de que las

tortugas eligen noches de luna para desovar, los veracruzanos aseguran que lo

hacen en noches oscuras y tormentosas. Sin duda, existe una fuerte presión

selectiva que favorece a las que se desvían de los hábitos “normales” conocidos

por los “tortugueros”. A diferencia de las bien conocidas localidades de anidación

de la tortuga carey, Eretmochelys imbricata, y las de las “tres quillas” o

“chalupa”, Dermochelys coriacea, los pescadores de Antón Lizardo afirman que

la lora no tiene lugares de anidación definidos y se la puede encontrar en

cualquier parte a lo largo de esa sección de la costa. Es probable que haya existido

hace muchos años una importante zona de anidación en la región de Antón

Lizardo, que desapareció con el tiempo.

Los guachinangueros de Veracruz me informan que las tortugas son comunes

en los bajos cercanos a Montepío, donde con frecuencia las arponean. Igual que

Carr (1958), el autor ha recibido informes frecuentes de “cantidades

considerables” de tortugas que anidan en Montepío. De hecho, este es el único

lugar, fuera de Tamaulipas, del cual el que escribe ha oído que las tortugas aniden

en número elevado. Evidentemente, las conclusiones de Carr (1961) en el sentido

de que ésta es una región de desove secundaria, no están justificadas en base de

nuestros conocimientos actuales sobre la biología de la lora, ni considerando la

reserva de los ribereños a proporcionar informes sobre animación de las tortugas.

Ni Carranza (1959), ni el autor encontraron evidencia del desove de la lora al

Oriente de los Tuxtlas, tanto en Veracruz como en la Península de Yucatán, o en

las islas de esa zona.

Tamaulipas. – Las playas tamaulipecas han experimentado menor desarrollo

que cualquier otra zona del Golfo de México; desde el Río Bravo, hasta Tampico,

no hay un solo puerto o aldea sobre la costa del Golfo. En las lagunas se efectúa la

pesca comercial en pequeña escala, empleándose ocasionalmente chinchorros

playeros y se explota algo de sal obtenida por evaporación solar. Debido a

dificultades de acceso, la playa ha sido visitada raras veces por los biólogos, pero

no así por los pescadores deportivos que la conocen bastante bien; así tenemos

que el Sr. Vincent Stevenson estableció un campamento de pesca deportiva en la

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Boca Jesús María en 1935 y el Sr. Francis McDonald otro, el Campo Andrés, en

Barra del Tordo, en 1948.

Sobre la base de los informes proporcionados por los señores Vincent y Kent

Stevenson parece que el número de tortugas que utilizan las playas entre Soto la

Marina y el Río Bravo, ha variado de año en año, y aún los sectores de la costa

favorecidos por las tortugas, cambiaron, lo que puede deberse a variaciones

producidas por la erosión y el acarreo de las corrientes litorales. No ha sido

posible identificar las tortugas observadas por V. Stevenson, pero dado que todas

fueron grandes o de tamaño medio y efectuaban el desove de noche, parece

adecuado concluir que la lora raras veces, o nunca, anida a lo largo de ese extenso

tramo de playa, ya que esta tortuga desova de día.

Texas. – Las entrevistas y correspondencia mantenidas con un cierto número

de personas, ha proporcionado muy escasa información sobre anidación de

tortugas marinas; excepto en dos casos, todos los informes se referían a tortugas

(la mayoría de las veces de especies dudosas), que desovaron en Big Shell y Little

Shell, o en sus inmediaciones, y casi todos ellos comprendían sólo uno o dos

ejemplares. Otro punto de interés consiste en que la mayor parte de estos informes

provinieron de pescadores deportivos y no de pescadores comerciales de

chinchorros playeros, que han trabajado durante muchos años en las costas de

Texas. Esto me indica que las zonas de anidación de las tortugas, y la

concentración de especies comerciales de peces, sobre todo la corvina, Sciaenops

occelata, no se corresponden en el tiempo. Un pescador me informó que las

tortugas recién avivadas son excelente carnada para la corvina.

Si bien hay algunas informes verbales y escritos (Joutel, 1713), relativos a la

presencia de tortugas marinas en las playas de Texas al norte de Port Aransas, no

hay buenas evidencias de que la lora anide allí. El 21 de mayo de 1962 la Sra. de

Dellenger, de Corpus Christi (Texas), fotografió con cámara de cine de 8 mm el

proceso de anidación de una lora en la playa de Port Aransas, aproximadamente a

3 Km de los rompeolas de acceso al puerto. Esta tortuga puso 104 huevos a las 11

de la mañana, en un nido situado a unos 25 m de las dunas y uno de los huevos

medía 37 mm de diámetro. Este constituye el dato más nórdico que se tiene sobre

la anidación de la lora.

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Sólo he identificado con certeza a la lora y a la “tres quillas” o “chalupa”

como anidadotas en Isla Padre. La utilización de este lugar por parte de la última

especie fue determinado por un ejemplar disecado y varios huevos conservados

por el taxidermista A. Brundrett, de Port Aransas. Un antiguo residente de Isla

Padre, el Sr. Lewis Rawalt, mostró al autor una fotografía tomada en mayo de

1932 de una “chalupa” arrastrándose por la playa y además describió en detalle

otros ejemplares de la misma especie en el momento de anidar, así como sus

huevos. En el curso de observaciones efectuadas durante 30 años en esa área,

nunca vio otras especies anidando, y sus observaciones fueron confirmadas

independientemente por otros pescadores.

John Werler (1951) publicó un artículo sobre el desove de una lora en Isla

Padre. Carr (1961) citó dos nidos de la Isla Padre, en la vecindad de Little Shell,

basado en fotografías de hembras anidando, tomadas por Jesse Laurence,

ingeniero del Condado de Nueces. Uno de esos nidos y había sido citado por

Werler. Sin duda, Isla Padre, no es una localidad importante de anidación de

tortugas marinas, puesto que sólo me ha sido posible señalar otros tres nidos de la

lora, sobre la base de mis entrevistas, verbales o por correspondencia. El Sr.

Laurence me ha hecho saber, que observó una tortuga semejante a las dos que

fotografió anidando a mediodía en la Barra de Corpus Christi, pero por desgracia

no anotó la fecha, ni tomó datos de este hecho. Rod Moore, un piloto local que ha

volado en aviones ligeros durante muchos años en el área de Corpus Christi,

recuerda haber visto dos pequeñas tortugas anidando en la playa, en un día

caluroso y de fuerte viento, aproximadamente en mayo de 1938, cuando volaba a

poca altura para localizar un automóvil entre Big Shell y Little Shell, en Isla

Padre.

Probablemente esta preferencia por ciertos sectores de la playa como lugares

de anidación sobre otros, puede explicarse por las características de los

sedimentos y de las corrientes litorales en estos puntos nodales. De acuerdo con

Alan Lohse (1959):

“Big and Little Shell are primary and secondary nodal points respectively of

coastal drifting processes acting along the Texas Gulf beaches. The areas of

accumulation of sand and shell detritus are shifted in short term seasonal

fluctuations and long term annual fluctuations.”

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Hay que hacer hincapié, en que las condiciones de la playa en estas

localidades son tan deficientes que los automóviles particulares raras veces

pueden atravesarlas. En consecuencia, también es posible que las tortugas hayan

sobrevivido en tales zonas debido a las escasas actividades humanas. Las

desovadoras actuales representarían por consiguiente, sólo el remanente de una

población de tortugas en otro tiempo más dispersa.

DESOVADEROS DE LA LORA EN EL SUR DE TAMAULIPAS

En 1958, cuando me hallaba visitando al Sr. Francis McDonald, me asombró

escuchar que cerca de su campo de pesca anidaban pequeñas tortugas durante

mayo y junio, en tal abundancia, que cada año venía un árabe con 40 ó 50 burros

y empacaba en sacos de yute grandes cantidades de huevos para venderlos en

Tampico. Al parecer, los ribereños emplean tanto el nombre de “tortuga” como el

de “cahuama”, para referirse a la lora.

El tamaño de los ejemplares era indicio de que éste constituía un desovadero

de Lora, pero la comprobación definitiva no fue posible hasta el otoño de 1960,

cuando logré obtener un caparazón de 59,5 cm de longitud, de una lora que fue

capturada al anidar. De acuerdo con Carr y Caldwell (1956) este ejemplar debe

haber pesado unos 25 Kg. El Sr. Juan González Galván, de Rancho Nuevo me

comunicó que el peso promedio de las hembras al anidar es de 35 Kg. He visco

fotografías de ejemplares grandes, con un peso de 45 Kg, capturados por Bob

Gulley frente a las costas de Texas.

Casi al mismo tiempo, la Sra. Eldridge, de Beaumont (Texas) me facilitó

amablemente, y me permitió copiar, una película de 8 mm sobre la secuencia del

desove de una lora. Con respecto a esta película, la Sra. Eldridge escribe:

“The pictures were made Friday, May 13, 1960 and it was between 10:00 and

11:00. When we first went out early in the morning to fish in the surf, we didn’t

notice any turtles but on our way back to camp (Campo Andrés) some time

between 9:30 and 10:00 one of the guides saw one, and then we saw two more.

We rushed to get our cameras at the camp and by the time we returned the turtles

had gone into the Gulf. We drove on and soon saw one just coming out of the

water. She went just below the sand dunes and started her nest. From the time

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she came out of the water, prepared her nest, laid her eggs and covered them, it

took no longer than 30 minutes. Earlier in the day it was calm, but around nine

o’clock it got extremely windy and Mr. McDonald, the camp owner, told us that

turtles always chose such weather so that the wind would blow the sand and cover

their tracks. We left the next day and from the plane, turtles could be seen all

along the Beach.”

Al interrogar al Sr. McDonald, se mostró reacio a estimar el número de

tortugas que anidaron, pero dijo que fueron varios miles, y afirmó que con

frecuencia desde 15 Km al norte de su campo, hasta unos 8 Km al sur, siempre

estarían a la vista por lo menos cinco tortugas anidando, entre las 9 de la mañana

y las 2 de la tarde. Uno de los guías de pesca, con experiencia de ocho años en

Campo Andrés, afirmó que las tortugas anidan por cientos en las proximidades

del Campo por miles cerca de Rancho Nuevo.

La ubicación y tamaño de la zona de anidación de la lora, fue probada sin

duda alguna por una asombrosa película de 16 mm tomada por el Ing. Andrés

Herrera, de Tampico; los biólogos marinos están en deuda con el por registrar este

espectacular suceso biológico del Golfo de México, antes de que sea diezmada la

población de tortugas por el hombre.

El Ing. Herrera permitió que se depositaran copias de su película en el

Departamento de Biología de la Universidad de Florida, en el Departamento de

Ciencias Marinas de la Universidad de Corpus Christi, y en la Estación de

Biología Marina del Instituto Tecnológico de Veracruz. En la película aparece una

enorme “arribada” de tortugas saturando la playa a plena luz del día, en tal

número, que con frecuencia las que llegaban después, cavaban los nidos de las del

primer grupo. En base de cuarteos efectuado sobre la película, e informes

proporcionados por Herrera, he estimado que había por lo menos 10 000 tortugas

en la playa en un momento dado y que probablemente 40 000 individuos anidaron

aquel día, entre las 9 de la mañana y la 1 de la tarde (fig. 1). Con respecto a la

película, los siguientes extractos de cartas y entrevistas con el Ing. Herrera,

representan observaciones de primera mano:

“20 de marzo de 1961. La arribada que tuve oportunidad de fotografiar tenía

una extensión de más de una milla totalmente llena de tortugas, al grado que

cuando regresé por mi avión no pude despegar porque estaban pasando debajo de

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él. Estos anímales depositan sus huevos (150 a 170) en un médano que tiene de un

metro a metro y medio de altura, en una faja de unos veinte metros de ancho a

toda la orilla de mar, y tal es la cantidad de tortugas poniendo a un mismo tiempo

que unas sacan los huevos que otras han puesto. Creo que dejan todo el subsuelo

de esa faja de terreno saturado de huevos, al grado que en cualquier lugar pueden

encontrar. Las arribadas salen de las nueve de la mañana hasta las doce o una de

la tarde…”

He comprobado estas notas con Juan González Galván, residente local que ha

estado observando las arribadas durante 25 años, y ha conocido detalles de las

arribadas anteriores por boca de viejos residentes de la localidad y ciertamente las

observaciones de Herrera no son exageradas. El Ing. Herrera presenció arribadas

el 18 de junio de 1947, el 30 de abril de 1948 y el 26 de abril de 1947. La película

fue tomada la primera de estas fechas. En una entrevista señaló que había volado

al lugar de anidación durante 25 días consecutivos con un fotógrafo de la RKO

Pathe News, sin haber visto señas de las tortugas. Al vigésimo sexto día, el

desilusionado fotógrafo permaneció en Tampico y Herrera tomó la película solo.

Todas las personas entrevistadas coincidieron en afirmar que la mayor parte de las

tortugas desovan en arribadas desde fines de abril hasta fines de junio y aún a

principios de julio en algunos años. Sin embargo, individuos aislados anidan

durante toda la temporada. También coincidieron en que cada tortuga anida tres

veces por temporada, pero sin los intervalos regulares de 12 a 15 días

característicos de otras especies de quelonias marinos (Carr, 1960). Una arribada

dura aproximadamente 4 horas, y puesto que hay 3 arribadas por temporada, se

dispone tan sólo de unas 12 horas al año para observarlas.

Como han indicado Herrera y Juan González (comunicación personal), la

gente de la región relaciona el arribo de las tortugas con la luna llena, es decir,

aparecen unos cuantos días antes o después del plenilunio. Aún más, creen que las

arribadas son influenciadas por las condiciones meteorológicas y siempre tienen

lugar en días de fuerte viento. González afirma que el viento ayuda a las tortugas

a salir del agua. Las creencias populares atribuyen a la lora considerable

inteligencia, suponiéndola conocedora de que ha elegido el momento más

propicio para emerger del mar, ya que la intensidad del viento va a cubrir sus

huellas, protegiendo al nido de su principal enemigo, el coyote (Canis latrans).

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Aunque es difícil concebir que una tortuga discierna con tan buen sentido, sí es

probable que este comportamiento sea consecuencia de la fuerte presión selectiva

impuesta a ella por el destructor coyote, efecto que también se manifiesta en los

hábitos diurnos de desove, en contraste con las costumbres nocturnas de este

predador.

Bob Gulley, A. Politis y R.Vaughn, revisaron la playa desde un avión

volando a poca altura los día, 17 y 24 de abril de 1961, desde Soto la Marina hasta

Punta Jerez, sin encontrar vestigios de tortugas, lo cual no es extraño, ya que las

huellas en la arena son tan superficiales que sólo una migración masiva podría

detectarse desde el aire. Ello no obstante, el primero de los días señalados se

localizaron cuatro tortugas por fuera de la línea de rompientes, entre Boca Carrizo

y Punta Jerez, y el 24 de abril se observaron tres tortugas juntas en Boca Carrizo.

El 20 de junio del mismo año, Politis, Gulley y el autor volaron a Barra del Tordo

desde Matamoros, observando una tortuga en Boca de San Vicente a las 11 de la

mañana, durante el viaje de ida, y 7 más en el de vuelta en la misma área, a eso de

las 2 de la tarde.

El mismo día, uno de los guías de Campo Andrés, nos comunicó haber

transplantado un grupo de huevas de lora hacia detrás de las dunas del Campo,

pero dijo que no habían nacido porque el tiempo había estado muy seco y

caluroso. A requerimiento nuestro desenterró el nido para que pudiésemos ver los

huevos: 94 de los 100 que había, acababan de nacer y las minúsculas tortuguitas

se encontraban aún a unos 35 cm de la superficie, por lo que las liberamos en el

mar y rápidamente se perdieron de vista. Los huevos de este grupo hicieron

eclosión en 50 días, en contraste con los 58 a 62 días que requirieron los que

trasplantó Laurence en Hábeas Christi, Texas (Carr, 1961).

El 26 de junio de 1961 regresé a Campo Andrés, para estar en las áreas de

puesta durante la luna llena del 28 de junio, y desde aquí fui a caballo a Rancho

Nuevo, Municipio de Aldama (Tamaulipas). La descripción de las zonas de

desove se basa en observaciones aéreas personales y en recorridos que realicé a lo

largo de la playa desde Boca Coma hasta aproximadamente 1 Km adelante de

Boca San Vicente (figs. 2 y 3).

No hay duda al presente de que la principal zona de anidación de

Lepidochelys kempi en Tamaulipas, y probablemente en el mundo, se encuentra

15

en las costas del Golfo, en Rancho Nuevo. Esta región estuvo aislada hasta hace

poco tiempo en que se comunicó por un camino de terracería con Aldama. Hay,

además, dos pistas de aterrizaje en Barra del Tordo y una más que se está

construyendo en Rancho Nuevo.

Las áreas de anidación se encuentran entre Boca Coma y unos 3,5 Km al

norte de la Boca San Vicente. Aparentemente una arribada rara vez cubre más de

dos kilómetros de playa, y cada uno de los 3 grupos que desovan en una

temporada, escarba porciones diferentes de la playa para depositar sus huevos. La

película del Ing. Herrera se refiere a una arribada que subió a la playa el 18 de

junio de 1947 en un tramo de menos de 2 Km de longitud, adyacente al lado norte

de la Boca San Vicente. En otros puntos, entre Boca Carrizo y Punta Jerez,

también desova la lora, en cantidades considerables, pero en apariencia no en

arribadas numerosas. Entre Boca Carrizo y Soto la Marina, también se encuentran

nidos, pero en menor cantidad.

He aceptado como nombres oficiales los que aparecen en el cuadrángulo de

Barra del Tordo [Hoja 14 Q-c (4) de la Comisión Cartográfica Militar, 2do ed.,

1952]. Estos nombres no coinciden con los empleados localmente en Barra del

Tordo o Rancho Nuevo. Boca Coma es nombre local que se emplea para la

desembocadura de un riachuelo muy pequeño, y no aparece en el mapa de la

Comisión. Boca San Vicente es llamada en el terreno, Boca Calabaza; Barra del

Tordo se encuentra en la desembocadura del Rió Carrizal, conocido en Campo

Andrés con el nombre de Rió San Rafael,

Rancho Nuevo se halla en la angosta planicie costera, entre las laderas de la

Sierra de Tamaulipas y el mar. Los ríos son muy cortos y corren sólo en la época

de lluvia. En muchos años secos el agua no basta para abrir las barras y los ríos se

hacen estuarios ciegos. La playa se intemperiza [intemperiaza] activamente por el

oleaje, es decir, es una playa de “alta energía” (Price, 1954).

Comparada con la costa de Texas, la playa es relativamente angosta, pero los

sedimentos son similares, excepto por trozos aplanados de roca que son llevados a

la playa, aquí o allá, por el oleaje. En un punto, aproximadamente un kilómetro al

sur de Boca San Vicente la base del reborde de la playa, se encuentra tapizada a lo

largo de unos 200 metros casi en totalidad por estas piedras aplanadas. La mayor

parte de ellas pueden considerarse de origen marino, como lo testifica la presencia

16

de organismos perforadores y sus impresiones, pero otras veces son calizas

arenosas quizá provenientes de alto ríos.

En cualquier caso, las tortugas no pueden cavar en estos puntos y por lo tanto

regresan al mar para emerger nuevamente en otros lugares. No hay dunas

propiamente dichas, sino un reborde de unos cinco metros de alto que corre

paralelo a la playa, excepto cerca de Boca Coma y Boca San Vicente, donde los

nortes han depositado arena adicional. La vegetación es dispersa. El reborde

arenoso mencionado se encuentra cubierto en la parte alta por crotos, Croton

punctatus, y cantidades menores de Ipomoea pescaprae y Uniola paniculata. En

el lado de tierra, crece en considerable cantidad un matorral espinoso, Rhandia

sp., y toda la zona sirve de pastoreo al ganado vacuno, cuyas huellas, junto con

los agujeros del cangrejo Ocypoda albicans, pueden verse por la playa ocultando

las huellas de los quelonios.

La mayor parte de las tortugas anidan entre la base del reborde arenoso y el

mar, en una franja angosta de unos 30 metros de ancho y aproximadamente a 1 ó

1,5 metros sobre la línea de alta mar. Durante el tiempo de mi visita, la playa al

sur de Boca Coma era angosta y sin duda estaba siendo erosionada, mientras que

en la sección cercana a la Boca de San Vicente, donde se encontraron huellas de

lora, se estaban depositando sedimentos. Indudablemente que los materiales de

origen terrestre, disponibles para transporte litoral por las corrientes, eran escasos,

ya que todos los arroyos, incluyendo los Ríos Carrizal y Soto la Marina, habían

permanecido parcial o totalmente cerrados por más de un año.

Se conoce muy poco la estructura y composición del fondo inmediato al

litoral. Según S. Fitzpatrick (comunicación personal) paralelo a la costa hay

depósitos calcáreos de origen fósil, con relieve hasta de 1 m de alto, y de 1,5 a 3

km de la playa, a profundidad de 5-8 m hay bancos arrecífales que soportan

poblaciones de pargos y guachinangos (Fam. Lutjanidae), explotadas al anzuelo

por los pescadores, pero no se ha estudiado hasta ahora la biología y composición

geológica de tales arrecifes.

A las 10 de la mañana del 27 de junio de 1951 localicé en Boca Coma una

cría de lora escapando hacia el mar. Según Juan González, las tortugas recién

nacidas emergen del nido tanto de día como de noche. Sus principales enemigos

en tierra, además del hombre, son, el coyote y el zopilote (Coragyps atratus),

17

mientras que al entrar al mar tienen que enfrentarse a cardúmenes de júreles

(Caranx hippos) y de corvinas (Sciaenops oce11ata) para sólo mencionar a dos de

sus principales predadores.

A unos dos o tres kilómetros de la Boca San Vicente, localizamos el mismo

día huellas de lora apenas perceptibles que habían sido hechas dos días antes.

Desde aquí, hasta la Boca San Vicente conté 82 huellas de este quelonio y una de

“caballera” (probablemente la cahuama, Caretta caretta). La lora dispone de la

playa para ella sola hasta fines de junio en que unas cuantas “caballeras” inician el

desove. Según informes proporcionados en la localidad, hace más de 25 años

también desovaba en esa zona otra tortuga, probablemente la chalupa

(Dermochelys coriacea), pero los actuales residentes no la conocieron. Con

respecto a la carey, (Eretmochelys imbricata), no se sabe que anide al norte de Isla

Lobos y ningún ribereño las ha visto en las playas de la lora.

En la misma zona localizarnos un nido con huevos de unos 3 cm de diámetro,

pero dado que el desarrollo embriológico estaba muy avanzado, lo cubrimos

nuevamente sin desenterrarlo por completo. Según el Sr. González, el primer

desove produce alrededor de 180 huevos, el segundo aproximadamente 150 y el

tercero de l00 a 110, pero los guías de Campo Andrés afirman que en el primero

se depositan de 120 a 130, en el segundo 100 y en el tercero de 60 a 70. Debido a

la rapidez con que se inicia el desarrollo embrionario, los huevos que han

permanecido más de dos días en el nido no son comestibles.

Dos de los nidos que observamos hablan sido destruidos por coyotes, pero no

se determinó el número de los que fueron saqueados por el hombre, ya que no era

posible investigar cada rastro individualmente. Por otra parte, los nidos son

robados muchas veces cuando la tortuga está desovando, y ya que el animal

instintivamente cubre de arena el agujero vacío, cualquier registro que se hiciera

de los nidos saqueados, podría ser desorientador. Sería conservador afirmar que

del 80 al 90% de los nidos en Boca de San Vicente, fueron destruidos el mismo

día que se hicieron. El grado de explotación de huevos de tortuga en esa zona es

indudablemente muy elevado para la sobrevivencia de la especie. Es imposible

tener cifras precisas del número de huevos que se expenden en los mercados, ya

que su venta está prohibida por las leyes de México, pero las estimaciones varían

desde unos cuantos utilizados como alimento fresco por los ribereños, hasta 20 a

18

24 camiones con 80 000 huevos cada uno que se llevaron a los mercados de

Aldama, Ciudad Mante, Valles y Tampico, provenientes de la primera arribada de

1961. Los huevos se venden a 50 centavos cada uno en las ciudades interiores,

donde son muy apreciados como afrodisíacos.

Aparentemente, sólo los habitantes de la costa comen carne de tortuga, pero

los informes son contradictorios. El aceite, que se emplea como remedio para

enfermedades de los pulmones, es aún más apreciado que aquélla, pero

desafortunadamente la lora sólo produce un litro y medio por ejemplar. En

cambio la “caballera” da unos 18 litros y otra tortuga que anidaba en la zona hace

muchos años – probablemente la chalupa – producía hasta 80 litros. El aceite es

también empleado para cocinar por personas que no pueden comprar manteca.

Con la modernización de la agricultura y el aumento constante de

comunicaciones en esa zona, se hace urgente dictar medidas conservacionistas

para evitar la extinción de las, hasta ahora numerosas arribadas de lora, pues

parece están disminuyendo considerablemente en número. Por desgracia,

carecemos de información biológica o estadística precisa sobre el tamaño de las

poblaciones de esta tortuga. Por ejemplo, la afirmación del Sr. González de que

“las crías van mar adentro” es desde luego incompleta, pero tan amplia como

cualquier explicación que pueden ofrecer los biólogos. Por fortuna, algo más se

sabe de la distribución de los adultos y subadultos en la plataforma continental,

como consecuencia de sus hábitos de permanecer en las inmediaciones de las

plataformas petroleras, lo que ofrece buenas posibilidades de estudio para dar

base al establecimiento de una legislación conservacionista adecuada.

SUMMARY

1. The principal existing Ridley rookery, Lepidoche1ys kempi Garman

(Rept., Chelonia), located at Rancho Nuevo, municipio de Aldama, Tamaulipas

(Mexico), is described for the first time. In this region, from Boca Coma to two

miles north of Boca San Vicente, the turtles come ashore in enormous

“arribadas”. Estimates made from movies indicate that 40,000 or more may nest

in a single day on slightly more than a mile of beach. There is considerable

nesting by isolated individuals and small groups in the remaining area from Soto

19

la Marina to Punta Jerez. Scattered nestings and possibly the remnants of other

rookeries occur in a long stretch of coastline from Port Aransas, Texas, to the

Tuxtlas in Veracruz.

2. The turtles nest in the daytime in Tamaulipas and Texas, usually in greatest

numbers from 9 o'clock in the morning to 1 o'clock in the afternoon. This may

have developed as a defense against the nocturnal coyote, principal natural

predator on eggs in this region.

3. The turtles nest three times during a season. They lay as many as l80 eggs

in the first clutch to as few as 80-1 l0 in the third.

4. There is no regular interval between nestings. It seems to be influenced

strongly by weather since most of the turtles reputedly come ashore during strong

winds.

5. At present, commercial utilization is intense but it is primarily directed to

the gathering of eggs. The oil is used as a medicine for lung and skin diseases.

6. Windy days which destroy the light trails in the hard packed sand, the short

time the “arribada” is on the Beach, and the isolation of the nestings grounds

explain the lapse of three quarters of a Century between the description of the

species and the discovery of its principal rookery.

HENRY H. HILDEBRAND

University of Corpus Christi,

Corpus Christi, Texas (EE. UU.),

Investigador Visitante,

Estación de Biología Marina,

Instituto Tecnológico de Veracruz,

Veracruz, México

BIBLIOGRAFÍA

CARR, A., The ridley mystery today. Animal Kingdom, 54(1):7-12, 1961.

CARR, A., y D. K. CALDWELL, The ecology and migrations of sea turtles.

1. Results of field work in Florida, 1955. Amer. Mus. Noviatates, no 1793:1-23,

1956.

20

CARR, A., y D. K. CALDWELL, The problem of the Atlantic ridley turtle

(Lepidochelys kempi) in 1958. Rev. Trop., 6(2):245-262, 1958.

CARR, A., y L. OGREN, Ecology and migrations of sea turtles. 4. The

green turtle in the Caribbean Sea. Bull. Amer. Mus. Nat. Hist. 121(1):1-48, 1960.

CARRANZA, J., Pesca y recursos pesqueros. En los recursos naturales del

sureste y su aprovechamiento. Ediciones del Instituto Mexicano de Recursos

Naturales Renovables, A. G. 3(2):151-238, 1959.

FUGLER, C. M. y R. O. WEBB, Some noteworthy reptiles and amphibians

from the states of Oaxaca and Veracruz. Herpetologica, 12(2)103-108, 1957.

JOUTEL, H., Journal Historique, Paris: Chez Estienne Robinot Libraire,

Quay et Attenant, 1713.

LOHSE, A., Geology. In development report on fish passes and water

interchange for the upper Laguna Madre and Corpus Christi Bay, coastal Texas.

Lithoprinted report prepared for Game and Fish Commission, State of Texas, pp.

17-25, 1959.

NOËL, T., Autobiography and reminiscentes of Theophilus Noël. Chicago:

Theo. Noël Company print, 1904.

PRICE, A., Dynamic environments: reconnaissance mapping, geologic and

geomorphic, of continental shelf of Gulf of Mexico. Gulf Coast Assn. Geol. Socs.

Trans. 4:75-107, 1954.

PRIETO, A., Historia y estadística del estado de Tamaulipas, núm. 13. Tlp.

Escalerillas, México, 1873.

WHERLER, J. E., Miscelaneous notes on the eggs and young of Texan and

Mexican reptiles. Zoologica, 36(1):37-48, 1951.

Ciencia, Méx., XXII (4):105-112.

21

Fig. 1. – Dibujo fiel basado en un cuadro de la película de 16 mm tomada por el

Ing. Andrés Herrera el 18 d junio de 1947, de una arribada de lora (Lepidochelys

kempi Garman), mostrando el momento de anidar (Dib. de H. Compton).

22

Fig. 2. – Costa occidental del Golfo de México, marcando los puntas citados en el

trabajo.

Fig. 3. – Sección, a mayor escala, del trozo de costa englobada en un rectángulo

en la Fig. 2.

DISCOVERY OF THE AREA OF NESTING OF THE MARINE TURTLE

“LORA”, LEPIDOCHELYS KEMPI (GARMAN), IN THE WEST COAST

OF THE GULF OF MEXICO

(Rept., Chel.)

INTRODUCTION

It is possible that there is no other marine animal of large size whose

abundance and area of distribution have been so altered by man, as those of the

23

turtles. This seems to be corroborated by the fact that for more than fifty years,

organized fisheries for chelonians have disappeared from the northwestern Gulf

[of Mexico]. The limited historical data that are available about marine turtles in

the area they occupy are difficult to interpret. Nevertheless, examination of such

writings makes clear the following facts:

1. The tortuguera industry is mainly supplied by fishing with nets in Texas

bays, although an unknown quantity, but without doubt very small, came from

Mexico and other areas of the Gulf, transported in sloops.

2. The available data on the existence of nests or tracks of marine turtles on

beaches are very scarce for the entire State of Texas. The only historical fact that I

have knowledge of is a statement in the travel notes of Joutel (1713) on the ill-

fated settlement of LaSalle on the Texas coast, but it is so ambiguous that it is not

clear whether it refers to marine turtles or to land [turtles].

3. It has long been known that marine turtles nest in abundance on the coasts

of Tamaulipas, and in fact, the historian Alexandro Prieto (1873) considered both

them and their eggs an important resource of the coast. Moreover, some old

fishermen of Port Isabel (Texas), whose ancestors were engaged in the purchase

of saltwater fish in Soto la Marina, informed me that it was a known fact that the

largest concentrations of nests were located in the region between the mouth of

the Río Soto la Marina and Punta Jerez.

Carr and Caldwell (1958) and Carr (1961), have summarized all the available

information on the nesting of Lepidochelys kempi. The laying places cited are:

Little Shell, on Padre Island (Texas) and Náutla, Antón Lizardo, Alvarado and

Montepío, in the State of Veracruz. In the work of 1961 (op. cit.), localities in the

State of Tamaulipas were not mentioned, but the first of the cited articles

identified my letter referring to a rumor about large-scale gathering of eggs of the

lora turtle near Punta Jerez.

DATA AVAILABLE ON NESTING OF MARINE TURTLES IN THE

SOUTHWEST GULF OF MEXICO

Veracruz. − Little can be added to the information provided by Carr (1961),

although one new area, Cabo Rojo, requires further study. Mr. Virgil Mercer,

24

who lived there before and flew over the beaches many times, writes: “I have seen

far more tracks on the beach from our camp (Tampachichi) around Cabo Rojo to

Tamiahua than in any other area. This may be due to the fact that the beach is

much softer there.” Mercer did not succeed in seeing turtles on the beach, but

undoubtedly it was because he did not fly on days of strong wind, which are those

the “loras” prefer on which to exit the sea. In any case, there must soon be an

investigation of the area of Cabo Rojo, a nodal point of coastal transport

processes, as Mr. Mercer said that the gathering of eggs in this area is now so

intense that it is just a matter of time before the turtles are extinguished.

The region of beach between Náutla and Tecolutla was determined to be a

nesting region by Fugler and Webb (1957). In accordance with researchers from

the Estación de Biología Marina del Instituto Tecnológico of Veracruz, it is

known that the turtles nest there in “regular” quantities. The number of species

involved is unknown to the author, but probably the lora represents the bulk of

them.

From Barra de Chachalacas to Alvarado, the beach is constantly travelled by

fishermen, tourists and other persons, and therefore very few turtles can obtain a

place to nest before being “redirected” or turned over. Even in the event that they

succeed in nesting it is almost certain that the nest will be found and looted. I

have been informed repeatedly by fishermen of Veracruz and Antón Lizardo that

all marine turtles nest at night, which is not correct in the case of the lora; in

contrast with previous reports that the turtles elect moonlit nights to nest, the

veracruzanos insist that they do on dark and stormy nights. Undoubtedly, there

exists a strong selective pressure that favors those that deviate from the “normal”

habits known by the “tortugueros”. Unlike the well-known locations of nesting of

the hawksbill turtle, Eretmochelys imbricata, and of the “three keels” or

“chalupa”, Dermochelys coriacea, the fishermen of Antón Lizardo assert that the

lora has no defined nesting sites and it can be found on any part along this section

of the coast. It is likely that a major area of nesting has existed for many years in

the region of Antón Lizardo, which has disappeared over time.

The snapper [Lutjanus spp.] fishermen of Veracruz informed me that the

turtles are common in the adjoining shoals at Montepío, where they are frequently

harpooned. Like Carr (1958), the author has received frequent reports of

25

“considerable quantities” of turtles that nest in Montepío. In fact, this is the only

place outside of Tamaulipas, about which the writer has heard that the turtles nest

in high number. Obviously, the conclusions of Carr (1961), in the sense that this

is a region of secondary nesting, are not justified on the basis of our current

knowledge of the biology of the lora, whereas neither do reports of the coastal

residents provide information about nesting turtles.

Neither Carranza (1959), nor the author found evidence of nesting of the lora

to the East of the Tuxtlas, both in Veracruz and likewise in the Yucatan Peninsula,

or in the islands in this area.

Tamaulipas. − The tamaulipan beaches have experienced less development

than any other zone of the Gulf of Mexico; from the Río Bravo to Tampico, there

is not a single port or village on the Gulf coast. In the lagunas small-scale

commercial fishing is carried out, occasionally employing beach seines, and some

salt obtained by solar evaporation is also exploited. Due to access difficulties, the

beach has rarely been visited by biologists, but this is not so for sport fishermen

who know [the beach] quite well; thus Mr. Vincent Stevenson established a sport

fishing camp in Boca Jesús María in 1935 and Mr. Francis McDonald another,

Campo Andrés, in Barra del Tordo, in 1948.

On the basis of reports provided by Messrs. Vincent and Kent Stevenson, it

seems that the number of turtles that use the beaches between Soto la Marina and

the Río Bravo has varied from year to year, and even the sectors of the coast

favored by the turtles changed, which may be due to changes produced by erosion

and accretion by littoral currents. It has not been possible to identify the turtles

observed by V. Stevenson, but given that all were large or medium in size and

nested at night, it seems appropriate to conclude that the lora rarely or never nests

along that vast stretch of beach, since this turtle nests during the day.

Texas. − Interviews and correspondence with a number of people have

provided very little information about nesting of marine turtles; except in two

cases, all reports referred to turtles (most times of dubious species), which nested

at Big Shell and Little Shell, or in their vicinity, and almost all of them included

only one or two specimens. Another point of interest is that most of these reports

came from sport fishermen and not from commercial beach seine fishermen, who

have worked for many years on the Texas coast. This suggests to me that nesting

26

areas of the turtles, and the concentration of commercial species of fish, especially

the redfish, Sciaenops occelata, do not coincide in time. A fisherman informed

me that hatchling turtles are excellent bait for redfish.

Although there are some verbal and written (Joutel, 1713) reports relating to

the presence of marine turtles on Texas beaches to the north of Port Aransas, there

is no good evidence that the lora nests there. On 21 May 1962, Mrs. de Dellenger,

of Corpus Christi (Texas), photographed with an 8 mm movie camera the process

of nesting of a lora at the beach in Port Aransas, approximately 3 km from the

breakwater bordering the entrance to the port. This turtle laid 104 eggs at 11 in the

morning, in a nest located some 25 m from the dunes and one of the eggs

measured 37 mm in diameter. This constitutes the most northerly data on lora

nesting.

I have identified with certainty only the lora and the “three keels” or

“chalupa” as nesting at Padre Island. The use of this place on the part of the last

species was determined by way of a dissected specimen and several eggs

preserved by taxidermist A. Brundrett, of Port Aransas. A former resident of

Padre Island, Mr. Lewis Rawalt, showed the author a photograph taken in May

1932 of a “chalupa” crawling along the beach and also described in detail other

examples of the same species at the moment of nesting, as well as their eggs. In

the course of observations made during 30 years in that area, he never saw other

species nesting, and his observations were independently confirmed by other

fishermen.

John Werler (1951) published an article on nesting of a lora on Padre Island.

Carr (1961) cited two nests at Padre Island, in the vicinity of Little Shell, based on

photographs of nesting females, taken by Jesse Laurence, an engineer of Nueces

County. One of those nests had been cited by Werler. Without doubt, Padre Island

is not an important nesting locality for marine turtles, since I have only been able

to identify three other nests of the lora, on the basis of my interviews, either

verbal or by correspondence. Mr. Laurence told me that he observed a turtle,

similar to the two that he photographed, nesting at noon in the Barra de Corpus

Christi, but unfortunately he did not note the date, nor keep data on this fact. Rod

Moore, a local pilot who has flown in light aircraft for many years in the area of

Corpus Christi, recalls having seen two small turtles nesting on the beach, on a

27

hot and strongly windy day, approximately in May 1938, when flying at low

altitude to locate an automobile between Big Shell and Little Shell, on Padre

Island.

Probably, this preference for certain sectors of the beach as nesting sites over

others can be explained by the characteristics of the sediment and coastal currents

in these nodal points. According to Alan Lohse (1959):

“Big and Little Shell are primary and secondary nodal points

respectively of coastal drifting processes acting along the Texas Gulf

beaches. The areas of accumulation of sand and shell detritus are

shifted in short term seasonal fluctuations and long term annual

fluctuations.”

It should be emphasized that the conditions of the beach in these localities are

so poor that private cars seldom can pass through. Accordingly, it is also possible

that the turtles have survived in such areas due to limited human activities.

Therefore, the current nesters would represent only a remnant of the turtle

population more dispersed at another time.

NESTING OF THE LORA IN THE SOUTH OF TAMAULIPAS

In 1958, when I was visiting Mr. Francis McDonald, I was amazed to hear

that small turtles nested around his fishing camp during May and June in such

abundance that, each year, an Arab came with 40 or 50 donkeys and packed large

quantities of eggs in jute sacks to sell in Tampico. Apparently, the coastal

residents use both the name “tortuga” and “cahuama”, to refer to the lora.

The size of these specimens indicated that this constituted lora nesting, but

the final verification was not possible until the autumn of 1960, when I was able

to obtain a carapace length of 59.5 cm, from a lora captured on the nest. In

accordance with Carr and Caldwell (1956) this specimen must have weighed

about 25 kg. Mr. Juan González Galván, of Rancho Nuevo, told me that the

average weight of the nesting females is 35 kg. I have seen photographs of large

specimens, with a weight of 45 kg, captured by Bob Gulley off the coast of Texas.

Almost at the same time, Mrs. Eldridge, of Beaumont (Texas), kindly

provided and allowed me to copy an 8 mm film of the sequence of nesting of a

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lora. With regard to this film, Mrs. Eldridge writes:

“The pictures were made Friday, May 13, 1960 and it was between

10:00 and 11:00. When we first went out early in the morning to fish

in the surf, we didn’t notice any turtles but on our way back to camp

(Campo Andrés) some time between 9:30 and 10:00 one of the guides

saw one, and then we saw two more. We rushed to get our cameras at

the camp and by the time we returned the turtles had gone into the

Gulf. We drove on and soon saw one just coming out of the water.

She went just below the sand dunes and started her nest. From the time

she came out of the water, prepared her nest, laid her eggs and covered

them, it took no longer than 30 minutes. Earlier in the day it was calm,

but around nine o’clock it got extremely windy and Mr. McDonald, the

camp owner, told us that turtles always chose such weather so that the

wind would blow the sand and cover their tracks. We left the next day

and from the plane, turtles could be seen all along the beach.”

Upon questioning, Mr. McDonald was reluctant to estimate the number of

turtles that nested, but said there were several thousand, and he stated that often,

from 15 km north of his camp to about 8 km south, he saw at least five turtles

nesting, always between 9 a.m. and 2 in the afternoon. One of the fishing guides,

with eight years experience at Campo Andrés, stated that the turtles nest by the

hundreds in the vicinity of the camp, and by the thousands near Rancho Nuevo.

The location and size of the lora nesting area were proven without doubt by

an astonishing 16 mm film taken by the Eng. Andrés Herrera, of Tampico; marine

biologists are in debt to him for recording this spectacular biological event of the

Gulf of Mexico, before the population of turtles is decimated by humans.

Eng. Herrera allowed copies of his film to be deposited in the Department of

Biology at the University of Florida, in the Department of Marine Sciences at the

University of Corpus Christi, and at the Estación de Biología Marina del Instituto

Tecnológico of Veracruz. In the film appears an enormous arribada of turtles

saturating the beach in broad daylight, in such numbers that those that came later

frequently dug up the nests of the earlier group. On the basis of numbers taken

from the film, and reports provided by Herrera, I estimated there were at least

10,000 turtles on the beach at a given time and that probably 40,000 individuals

29

nested on that day, between 9 in the morning and 1 in the afternoon (fig. 1). With

regard to the film, the following excerpts of letters and interviews with Eng.

Herrera, represent his first-hand observations:

“20 March 1961. The arribada that I had the opportunity to shoot was an

extension of more than one mile entirely full of turtles, to the degree that when I

came back to my plane I could not take off because they were passing below it.

These animals deposited their eggs (150-170) in a sand dune a meter to a meter

and a half high, in a strip some twenty meters wide along all the seashore, and the

number of turtles laying at the same time was such that some dug up the eggs that

others had laid. I believe that left the entire subsoil of the strip of land saturated

with eggs, to the extent they can be found in any place. The arribadas emerge

from nine in the morning to twelve or one in the afternoon ...”

I verified these notes with Juan González Galván, a local resident who has

been observing the arribadas for 25 years, and who has learned details of previous

arribadas by word of mouth from old local residents and the observations of

Herrera are certainly not exaggerated. Eng. Herrera witnessed arribadas on 18

June 1947, on 30 April 1948, and on 26 April 1947. The film was taken on the

first of these dates. In an interview he pointed out that he had flown over the place

of nesting during 25 consecutive days with a photographer from RKO Pathe

News, without having seen signs of the turtles. On the twenty-sixth day, the

disappointed photographer remained in Tampico and Herrera made the film alone.

All the people interviewed agreed that the majority of the turtles nest in arribadas

from the end of April through the end of June and even early July in some years.

However, isolated individuals nest throughout the season. They also agreed that

each turtle nests three times per season, but without the regular intervals of 12 to

15 days characteristic of other species of marine chelonians (Carr, 1960). An

arribada lasts about 4 hours, and since there are 3 arribadas per season, there are

only about 12 hours a year to observe them.

As indicated by Herrera and Juan González (personal communication), the

people of the region relate the arribadas of turtles to the full moon, i.e., they

appear a few days before or after the full moon. Further, they believe that the

arribadas are influenced by the weather and always take place during days of

strong wind. González said that the wind helps the turtles leave the water. Popular

30

beliefs attribute considerable intelligence to the lora, assuming it is aware that it

has chosen the more propitious time to emerge from the sea, since the intense

wind is going to cover its tracks, protecting the nest from its main enemy, the

coyote (Canis latrans). Although it is hard to imagine that a turtle discerns with

such good sense, it is likely that this behavior is the result of strong selective

pressure imposed on it by the destructive coyote, the effect of which is also

reflected in its diurnal nesting habit, in contrast to the nocturnal behavior of this

predator.

Bob Gulley, A. Politis, and R. Vaughn inspected the beach from a plane

flying at low altitude on days 17 and 24 April 1961, from Soto la Marina to Punta

Jerez, without finding traces of turtles, which is not surprising, since the tracks in

the sand are so superficial that only a massive migration could be detected from

the air. Nevertheless, on the first of the days noted, four turtles were located

outside the line of shoals, between Boca Carrizo and Punta Jerez, and on 24 April

three turtles were observed together in Boca Carrizo. On 20 June of the same

year, Politis, Gulley, and the author flew to Barra del Tordo from Matamoros,

noting one turtle in Boca San Vicente at 11 in the morning during the journey to,

and 7 more in the same area on the way back, around 2 in the afternoon.

The same day, one of the guides of Campo Andrés told us he had

transplanted a group of lora eggs behind the dunes of the camp, but said that they

had not hatched because it had been very dry and hot. At our request, he

unearthed the nest so that we could see the eggs; 94 of the 100 had just hatched

and the hatchlings were still about 35 cm from the surface, so they were liberated

into the sea and were quickly lost sight of. The eggs in this group hatched in 50

days, in contrast with the 58 to 62 days required by those transplanted by

Laurence in Corpus Christi, Texas (Carr, 1961).

On 26 June 1961 I returned to Campo Andrés, to be in the areas of nesting

during the full moon of 28 June, and from there went on horseback to Rancho

Nuevo, Municipality of Aldama (Tamaulipas). The description of the nesting

areas is based on aerial observations and personal tours which I made along the

beach from Boca Coma to about 1 km before Boca San Vicente (fig. 2 and 3).

There is presently no doubt that the main area of Lepidochelys kempi nesting

in Tamaulipas, and probably in the world, is located on the Gulf coast, at Rancho

31

Nuevo. This region was isolated until recently when it was connected to Aldama

by a dirt road. There are, in addition, two airstrips in Barra del Tordo and one

more being built at Rancho Nuevo.

Nesting areas are between Boca Coma and some 3.5 km north of Boca San

Vicente. Apparently, an arribada rarely covers more than two kilometers of beach,

and each of the 3 groups that nest in a season pick different portions of the beach

to deposit their eggs. The film by Eng. Herrera refers to an arribada that went up

on the beach on 18 June 1947 in a stretch of less than 2 km in length, adjacent to

the north side of Boca San Vicente. At other points, between Boca Carrizo and

Punta Jerez, the lora also nest in substantial quantities, but apparently not in

numerous arribadas. Between Boca Carrizo and Soto la Marina, also are nests, but

in lesser quantities.

I have accepted as official the names which appear in the Barra del Tordo

quadrangle [Sheet 14 Q-c (4) of the Military Mapping Commission, 2nd ed.,

1952]. These names do not coincide with those employed locally in Barra del

Tordo or Rancho Nuevo. Boca Coma is the local name used for the mouth of a

very small rivulet, and it does not appear on the map of the Commission. Boca

San Vicente is called Boca Calabaza in the field; Barra del Tordo is found at the

mouth of Río Carrizal, known in Campo Andrés as Río San Rafael.

Rancho Nuevo is in the narrow coastal plain, between the hillsides of the

Sierra de Tamaulipas and the sea. The rivers are very short and run only in the

rainy season. In many dry years water is insufficient to open the bars and rivers

become blind estuaries. The beach is actively weathered by the waves, that is, it is

a “high-energy” beach (Price, 1954).

Compared to the Texas coast, the beach is relatively narrow, but the

sediments are similar, except for pieces of flattened rock that are brought to the

beach, here or there, by the waves. At one point, approximately one kilometer

south of Boca San Vicente the base of the beach rim is carpeted along the course

of about 200 meters almost entirely by these flattened stones. Most of them can be

considered of marine origin, as testified by the presence of marine borers and their

holes, but others are sandy limestone perhaps from high rivers.

In any case, the turtles cannot dig in these locations and therefore return to

the sea to emerge again elsewhere. There are no dunes per se, but a rim of about

32

five meters high that runs parallel to the beach, except near the Boca Coma and

Boca San Vicente, where the northerlies [winds or currents] have deposited sand.

The vegetation is dispersed. The sandy rim mentioned is covered on the upper

part by crotons, Croton punctatus, and smaller quantities of Ipomoea pescaprae

and Uniola paniculata. On the land side grows a considerable amount of thorny

matorral, Rhandia sp., and all this area serves as pasture for grazing cattle, whose

hoof prints, together with crab Ocypoda albicans holes, can be seen on the beach

hiding the tracks of the chelonians.

Most of the turtles nest between the base of the sandy ridge and the sea, in a

narrow strip about 30 meters wide and about 1 or 1.5 meters above sea level.

During the time of my visit, the beach to the south of Boca Coma was narrow and

without doubt being eroded, while in the section near the Boca San Vicente,

where lora tracks were found, sediments were being deposited. There is no doubt

that materials of terrestrial origin, available for coastal transport by the currents,

were scarce, since all streams, including the Río Carrizal and Soto la Marina, had

remained partially or totally closed for more than a year.

Very little is known about the structure and composition of the sediment

immediate to the shore. According to S. Fitzpatrick (personal communication)

there are calcareous deposits of fossil origin parallel to the coast, with relief up to

1 m high, and of 1.5 to 3 km from the beach, at depths of 5-8 m there are reef

banks that support populations of pargos and guachinangos (Fam. Lutjanidae),

exploited by hook and line fishermen, but the biology and geological composition

of these reefs has not been studied before.

At 10 in the morning of 27 June 1951 a lora nester fleeing toward the sea was

located in Boca Coma. According to Juan González, hatchlings emerge from the

nest, equally during day and night. Their main terrestrial enemies, in addition to

man, are the coyote and black vulture (Coragyps atratus), and after they enter the

sea they have to deal with schools of jack crevalle (Caranx hippos) and redfish

(Sciaenops oce11ata) to mention only two of their top predators.

On the same day, some two or three kilometers from Boca San Vicente, I

located barely perceptible lora tracks that had been made two days before. From

there to Boca San Vicente I counted 82 tracks of this chelonian and one of a

“caballero” (probably the loggerhead turtle, Caretta caretta). The lora has the

33

entire beach at its sole disposal until the end of June at which time a few

“caballeras” begin nesting. According to reports provided in the locality, for more

than 25 years another turtle also nested in that area, probably the chalupa

(Dermochelys coriacea), but the current residents are not aware of it. With regard

to the hawksbill (Eretmochelys imbricata), it is not known to nest north of Isla

Lobos and no coastal resident has seen it on lora nesting beaches.

In the same area was found a nest of eggs approximately 3 cm in diameter,

but given that the embryological development was well advanced, it was covered

again without unearthing it completely. According to Mr. González, the first

nesting produces about 180 eggs, the second approximately 150 and the third l00

to 110, but the guides of Campo Andrés affirm that in the first are deposited from

120 to 130, in the second 100 and in the third in 60 to 70. Because of the speed

with which embryonic development starts, the eggs that have remained more than

two days in the nest are not edible.

Two of the nests observed had been destroyed by coyotes, but the number of

those that were looted by man was not determined, since it was not possible to

investigate every track individually. Moreover, many times the nests are robbed

when the turtle is laying, and because the animal instinctively covers the empty

hole with sand, any registration made of the looted nests would be misleading. It

would be conservative to say that 80 to 90 % of the nests in Boca de San Vicente

were destroyed the same day that were made. The degree of exploitation of turtle

eggs in that area is undoubtedly very high for the survival of the species. It is

impossible to have precise figures of the number of eggs that are being dispensed

in markets, because their sale is prohibited by the laws of Mexico, but estimates

vary from a few used as fresh food by coastal residents, up to 20 to 24 trucks with

80,000 eggs each that are taken to the markets of Aldama, Ciudad Mante, Valles

and Tampico, from the first arribada of 1961. The eggs are sold at 50 centavos

each in the interior cities, where they are very appreciated as aphrodisiacs.

Apparently, only the inhabitants of the coast eat turtle meat, but the reports

are contradictory. The oil, which is used as a remedy for lung disease, is even

more appreciated than the former, but unfortunately the lora produces only a liter

per specimen. In contrast, the “caballero” provides some 18 liters and another

turtle that nested in the area for many years, probably the “chalupa”, produced up

34

to 80 liters. The oil is also used for cooking by people who cannot buy butter.

With the modernization of agriculture and the steady increase in

communications in the area, it is urgent that conservation measures be

promulgated to prevent extinction of the, until now, numerous arribadas of lora,

which seem to be declining considerably in number. Unfortunately, biological

information or precise statistics on the size of the populations of this turtle are

lacking. For example, the affirmation of Mr. González that “the hatchlings go out

to sea” is certainly incomplete, but as broad as any explanation that biologists can

provide. Fortunately, more is known of the distribution of the adults and subadults

on the continental shelf, as a result of their habits of remaining in the vicinity of

petroleum platforms, which offers good opportunities for study so as to provide a

basis to establish proper conservation legislation.

SUMMARY

1. The principal existing Ridley rookery, Lepidoche1ys kempi

Garman (Rept., Chelonia), located at Rancho Nuevo, municipio de

Aldama, Tamaulipas (Mexico), is described for the first time. In this

region, from Boca Coma to two miles north of Boca San Vicente, the

turtles come ashore in enormous “arribadas”. Estimates made from

movies indicate that 40,000 or more may nest in a single day on

slightly more than a mile of beach. There is considerable nesting by

isolated individuals and small groups in the remaining area from Soto

la Marina to Punta Jerez. Scattered nestings and possibly the remnants

of other rookeries occur in a long stretch of coastline from Port

Aransas, Texas, to the Tuxtlas in Veracruz.

2. The turtles nest in the daytime in Tamaulipas and Texas, usually

in greatest numbers from 9 o'clock in the morning to 1 o'clock in the

afternoon. This may have developed as a defense against the nocturnal

coyote, principal natural predator on eggs in this region.

3. The turtles nest three times during a season. They lay as many as

180 eggs in the first clutch to as few as 80-110 in the third.

4. There is no regular interval between nestings. It seems to be

influenced strongly by weather since most of the turtles reputedly come

35

ashore during strong winds.

5. At present, commercial utilization is intense but it is primarily

directed to the gathering of eggs. The oil is used as a medicine for lung

and skin diseases.

6. Windy days which destroy the light trails in the hard packed

sand, the short time the “arribada” is on the beach, and the isolation of

the nestings grounds explain the lapse of three quarters of a century

between the description of the species and the discovery of its principal

rookery.

HENRY H. HILDEBRAND

University of Corpus Christi,

Corpus Christi, Texas (EE. UU.),

Investigador Visitante,

Estación de Biología Marina,

Instituto Tecnológico de Veracruz,

Veracruz, México

BIBLIOGRAFÍA

CARR, A., The ridley mystery today. Animal Kingdom, 54(1):7-

12, 1961.

CARR, A., y D. K. CALDWELL, The ecology and migrations of

sea turtles. 1. Results of field work in Florida, 1955. Amer. Mus.

Noviatates, no 1793:1-23, 1956.

CARR, A., y D. K. CALDWELL, The problem of the Atlantic

ridley turtle (Lepidochelys kempi) in 1958. Rev. Trop., 6(2):245-262,

1958.

CARR, A., y L. OGREN, Ecology and migrations of sea turtles. 4.

The green turtle in the Caribbean Sea. Bull. Amer. Mus. Nat. Hist.

121(1):1-48, 1960.

CARRANZA, J., Pesca y recursos pesqueros. En los recursos

naturales del sureste y su aprovechamiento. Ediciones del Instituto

Mexicano de Recursos Naturales Renovables, A. G. 3(2):151-238,

1959.

FUGLER, C. M. y R. O. WEBB, Some noteworthy reptiles and

36

amphibians from the states of Oaxaca and Veracruz. Herpetologica,

12(2)103-108, 1957.

JOUTEL, H., Journal Historique, Paris: Chez Estienne Robinot

Libraire, Quay et Attenant, 1713.

LOHSE, A., Geology. In development report on fish passes and

water interchange for the upper Laguna Madre and Corpus Christi Bay,

coastal Texas. Lithoprinted report prepared for Game and Fish

Commission, State of Texas, pp. 17-25, 1959.

NOËL, T., Autobiography and reminiscentes of Theophilus Noël.

Chicago: Theo. Noël Company print, 1904.

PRICE, A., Dynamic environments: reconnaissance mapping,

geologic and geomorphic, of continental shelf of Gulf of Mexico. Gulf

Coast Assn. Geol. Socs. Trans. 4:75-107, 1954.

PRIETO, A., Historia y estadística del estado de Tamaulipas, núm.

13. Tlp. Escalerillas, México, 1873.

WHERLER, J. E., Miscelaneous notes on the eggs and young of

Texan and Mexican reptiles. Zoologica, 36(1):37-48, 1951.

Ciencia, Méx., XXII (4):105-112.

FIGURES

Fig. 1. − Exact drawing based on one frame of the 16 mm film taken by Eng.

37

Andrés Herrera on18 June 1947, of an arribada of lora (Lepidochelys kempi

Garman), showing the moment of nesting (Drawing, H. Compton).

Fig. 2. − West Coast of the Gulf of Mexico, marking the points cited in this work.

38

Fig. 3. − Section, in larger scale, of the part of the coast included in the rectangle

on Fig. 2.