MEXICO / UNITED STATES OF AMERICA POPULATION

RESTORATION PROJECT FOR THE KEMP´S RIDLEY SEA

TURTLE, Lepidochelys kempii, ON THE COASTS OF

TAMAULIPAS, MEXICO

2014 Season

Summary Report on the 2014 Tagging Study as part of the

Kemp's Ridley Stock Assessment Project

Prepared for Benny Gallaway

President

LGL Ecological Research Associates, Inc.

Presented by Luis Jaime Peña

Curator of Conservation Programs

Gladys Porter Zoo

Javier Montaño Cuevas

Operations Director/Data Management Coordinator

Kemp's Ridley Project

Francisco Illescas Martínez

Project Leader

Conservación y Desarrollo de Espacios Naturales, S.C

INTRODUCTION

In response to a request from Gulf States Marine Fisheries Commission, a stock assessment was

conducted for the Kemp’s ridley sea turtle (Lepidochelys kempii) in the Gulf of Mexico. The

stock assessment was conducted in a workshop format led by LGL Ecological Research

Associates, Inc., Texas Sea Grant, and Charles W. Caillouet Jr., and was attended by 22 scientists

and 6 observers. The primary objectives were to examine Kemp’s ridley population status,

trends and temporal-spatial distribution in the Gulf of Mexico; estimate fishing mortality from

shrimp trawls, and estimate total mortality. Shrimp trawl mortality was identified in 1990 as the

greatest threat to sea turtles at sea, and widespread utilization of Turtle Excluder Devices

(TEDs) began in 1990 or shortly thereafter. The assessment also considered other factors that

may have had significant influence on the population.

The overarching purpose of the workshop was to conduct a Kemp’s ridley stock assessment

involving objective and quantitative examination and evaluation of relative contributions of

conservation efforts and other factors toward its population recovery trajectory. One of the

recommendations from this workshop was to prioritize expanded data collection at the nesting

beaches. A tagging study was proposed for the 2014 Kemp's ridley nesting season.

GOALS AND OBJECTIVES

Flipper tagging can provide information on population trends, habitat residency, movement

patterns (including international movements among range states), individual growth rates,

reproductive life history (e.g. remigration intervals, nesting frequency, clutch size, and/or

hatchlings produced per female), and strandings.

The main objective of the proposed tag-recapture study was as follows:

Develop a nest management plan that includes the adequate protection in corrals and in situ of

as many clutches as feasible at the Rancho Nuevo beach to meet established recovery criteria,

as well as the development of a tag-recapture protocol at the Rancho Nuevo sea turtle field

station. The Rancho Nuevo beach is the most important nesting site for the Kemp's ridley sea

turtle - over 80% of nesting occurs on this 30 km (18 miles) stretch of the Tamaulipas coast.

The tag-recapture protocol included recording morphometric data (carapace measurements),

and any tags present in as many Kemp's ridley nesting specimens (and stranded specimens)

that can be registered in the five month nesting period from April to August, as well as tagging

as many nesting females as possible.

The protocol developed at Rancho Nuevo may in turn be used as an indicator and a guide to

help in the development of a tag-recapture program with established logistics for each of the

sea turtle field stations in Tamaulipas including La Pesca, Tepehuajes, Barra Del Tordo, Altamira

and Ciudad Madero.

The data obtained from this tag-recapture project, in combination with historical data, has

followed the recommendation of the Stock Assessment Group of prioritizing expanded data

collection, and will have important implications for the development of improved conservation

strategies for the Kemp's ridley sea turtle, and an indication of the species' distribution and

migration behavior.

PROJECT ACTIVITIES AND METHODS

General monitoring and protection activities consist of daily beach patrols made by one team to

locate nesting females and protect clutches. When several females are counted in one trip, the

monitoring team alerts the camps of a possible arribada event. During the arribadas, several

teams patrol the beach on all-terrain vehicles, collecting biological data from females and

relocating clutches to the protected corrals. The clutches are collected and transported to the

corral as soon as possible, with the necessary precautions to avoid the early embryo mortality

caused by handling. Each clutch is reburied in a nest of similar size and depth as the in situ nest

and marked for monitoring over the incubation period. After incubation period, hatchlings are

counted, collected, and released in large groups in different spots on the beach. The content of

the nest is excavated after the hatchlings are released to determine hatch success.

Members of the tagging teams were on monitor duty on a daily basis and, during arribadas,

checked and/or tagged as many specimens as possible. The turtle was checked during the

nesting stages of egg-laying or during the early stages of nest covering. If the turtle did not

present any tags, it was tagged on the second scale of the left forefront flipper with an Inconel

style 1005-681 tag and a PIT tag. The Inconel tag series used was GPZ14. The tagging teams

used the established tagging methodologies prepared by WIDECAST. Relevant data, including

four curved carapace length measurements, were registered in a data card separate from the

nesting data card. An Excel database was created for this study.

ORGANIZATION

The Gladys Porter Zoo (GPZ) is a visitor-oriented zoological and botanical park, dedicated to the

preservation of nature through education, conservation and research. Since 1981,

GPZ has administered the United States' field portion of the joint U. S. / Mexico effort to

protect and increase the production of Kemp's ridley sea turtles at their natal beaches located

in the State of Tamaulipas, Mexico.

The main agency with which GPZ worked on this study was the Association for the Conservation

and Development of Natural Spaces (in Spanish: Conservación y Desarrollo de Espacios

Naturales, AC, CDEN), an NGO dedicated to providing professional environmental services and

assessments through which Tamaulipas's natural resources may be used efficiently and

adequately.

As part of a cooperative working agreement between the two organizations in 2012, CDEN

helps with the logistics of GPZ's portion of the Kemp's Ridley Binational Project.

SUMMARY DATA

During the 2014 nesting season, a total of 910 Kemp's ridley nesting females were checked for

tags and/or tagged. One turtle (with no tagging scars or tags), was measured, but not tagged.

89% of these turtles (810) were considered "neophytes" - that is, these turtles did not present

any type of tags or tagging scars. One turtle with a PIT tag from a previous season was

recorded nesting twice, and twenty-seven turtles tagged with 2014 Season tags were recorded

nesting twice. The following table lists the number of turtles that were checked for tags and/or

tagged by month, from April to August.

Included in these numbers are the twenty-eight turtles that were registered nesting twice and

the turtle that was measured but not tagged.

Month Number of

Turtles

April 87

May 82

June 639

July 126

August 5

MORPHOMETRIC DATA - Curved Carapace Lengths

CCL = Curved Carapace Length Maximum Minimum Average

CCL Tip to Tip 79.5 59.6 68.4

CCL Tip to Notch 79 59 67.7

CCL Notch to Notch 79.8 57.2 66.4

Curved Width 79 59.9 68.3

units are centimeters

As with the number of turtles per

month, these data include the

twenty-eight turtles that were

registered nesting twice and the

turtle that was measured but not

tagged.

Tip to Tip N Frequency

≤ 60 4 0.43%

60.1-64.9 85 9.04%

65-69.9 573 61.06%

70-74.9 260 27.66%

≥75 17 1.81%

Tip to Notch

≤ 60 8 0.85%

60.1-64.9 131 13.94%

65-69.9 626 66.70%

70-74.9 162 17.23%

≥75 12 1.28%

Notch to Notch

≤ 60 12 1.28%

60.1-64.9 240 25.64%

65-69.9 609 64.79%

70-74.9 63 6.70%

≥75 15 1.60%

Curved Width

≤ 60 6 0.64%

60.1-64.9 87 9.26%

65-69.9 558 59.47%

70-74.9 274 29.15%

≥75 14 1.49%

ACTUAL FREQUENCY TABLE

PHOTOS