Cause and Call for Modification of the Bi-National
Recovery Plan for the Kemp’s Ridley Sea Turtle
(Lepidochelys kempii) - Second Revision
Charles W. Caillouet, Jr.1, Benny J. Gallaway2 & André M.
Landry, Jr.3
1
119 Victoria Drive West, Montgomery, TX 77356-8446 USA (Email: waxmanjr@aol.com); 2LGL Ecological Research
Associates, Inc., Bryan, TX 70802 USA (E-mail:
bjg@lgltex.com); 3Departments of Marine Biology, Wildlife
and Fisheries Sciences, and Marine Sciences, Texas A&M
University at Galveston, Galveston, TX 77553 USA (E-mail:
landrya@tamug.edu)
We propose that the Bi-national Recovery Plan for the
Kemp’s Ridley Sea Turtle (Lepidochelys kempii) - Second
Revision (NMFS et al. 2011) be revisited and modified in
2015. NMFS (2010) and NMFS et al. (2011) state that
approved recovery plans are subject to modification as
dictated by new findings, changes in species status, and
completion of recovery actions. Although Kemp’s ridley
recovery actions have not been completed, many new findings
and observed changes in its species status after 2009 warrant
modification of the recovery plan. Kemp’s ridley’s “species
status” was described in the Executive Summary of NMFS et
al. (2011) as “Current Status: The Kemp’s ridley nesting
population is exponentially increasing, which may indicate a
similar increase in the population as a whole.” However, its
exponential growth was unexpectedly interrupted in 2010
(Caillouet 2010, 2011, 2014; Crowder & Heppell 2011;
Gallaway et al. 2013; Gallaway & Caillouet 2014; Gallaway
& Gazey 2014; Heppell 2014, In press).
The ESA of 1973 (as amended) requires review of all listed
species at least once every 5 years. According to NMFS (2010),
an approved recovery plan should be reviewed immediately
following a 5-yr review, to determine whether it needs to be
brought up to date. The required 5-yr review for Kemp’s ridley
is almost three years overdue (see NMFS & USFWS 2007).
Approved recovery plans can be modified by an update,
revision, or addendum, the choice among which depends upon
various criteria, including background information, recovery
strategy, recovery objectives and criteria, and recovery actions
and implementation schedule (NMFS 2010).
Many new findings (e.g., Seney & Landry 2008; Caillouet 2010,
2011; Putman et al. 2010; Bjorndal et al. 2011; Campagna et
al. 2011; Crowder & Heppell 2011; Finkbeiner et al. 2011;
Smith et al. 2011) were published before the recovery plan
(NMFS et al. 2011) was implemented, and more have been
published since (e.g., Antonio et al. 2011; Caillouet 2012a, b;
Garrison & Sasso 2012; Coleman 2013; Putman et al. 2012,
2013; Gallaway et al. 2013; Lewison et al. 2013; Belter 2014;
Bevan et al. 2014; Bjorndal et al. 2014; Gallaway & Caillouet
2014; Gallaway & Gazey 2014; Heppell 2014, In press; Valverde
2014). In our opinion, the most significant new findings were (1)
interruption of the Kemp’s ridley population’s pre-2010
exponential growth within the Gulf of Mexico in 2010
(Burchfield & Peña 2010; Caillouet 2011; Crowder &
Heppell 2011; Gallaway et al. 2013;
www.nps.gov/pais/naturescience/ kridley.htm), and (2) the
population’s decline in 2013 and 2014 (Caillouet 2014;
Gallaway & Caillouet 2014; Gallaway & Gazey 2014; Heppell
2014, In press). The conventional index of Kemp’s ridley
population size is the annual number of nests (i.e., clutches laid)
on three beach segments combined (Rancho Nuevo, Barra del
Tordo-Playa Dos, and Tepehuajes) in Tamaulipas, Mexico
(Caillouet 2014). Post-2010 changes in this index were
extraordinary (Caillouet 2014), compared to the recovery plan’s
optimistic prediction of 19% per year growth of the population
during years 2010-2020, under
an assumption that survival rates in 2009 remained constant
within each life stage (NMFS et al. 2011).
Investigations aimed at determining the cause or causes of post2009 changes in the Kemp’s ridley population have been
underway since the Deepwater Horizon (DWH) oil spill began
on 20 April 2010 (Bjorndal et al. 2011; Gallaway et al. 2013;
Fikes et al. 2014; www.gulfspillrestoration.noaa.gov;
www.publicnewsservice. org/2015-01-20/endangered-speciesand-wildlife/penalty-phase- begins-in-bp-oil-spill-disastertrial/a44038-1). NOAA’s Natural Resource Damage Assessment
(NRDA, www.gulfspillrestoration. noaa.gov) should provide
additional new findings.
Among other possible causes, mortality associated with incidental
capture of Kemp’s ridleys in shrimp trawls was examined and
estimated, but accounted for 21.6% or less of estimated
total mortality in 2010 (Gallaway et al. 2013; Gallaway & Caillouet
2014; Gallaway & Gazey 2014). The NMFS Southeast Regional
Office conducted ESA Section 7 consultations in 2012 and 2014,
regarding sea turtle regulations associated with Southeast U.S.
shrimp fisheries in Federal waters
(http://sero.nmfs.noaa.gov/protected_resources/
sea_turtles/documents/shrimp_biological_opinion_2014.pdf)
. Biological Opinions issued in May 2012 and April 2014
concluded that continued implementation of sea turtle conservation
regulations under the ESA and continued authorization of the
Southeast U.S. shrimp fisheries in federal waters under the
MSFCMA were not expected to cause an appreciable reduction in
likelihood of survival and recovery of Kemp’s ridleys in the
wild. In April 2012, a preliminary Kemp’s Ridley Stock
Assessment Model (KRSAM) was developed by the Planning
and Model Development Group (PMDG) of LGL Ecological
Research Associates, Inc. (Bryan, TX), presented for proof-ofconcept review at a stakeholders meeting held at Texas A&M
University in May 2012, and improved during a Kemp’s Ridley
Stock Assessment Workshop (KRSAW) held in Houston, TX
in November 2012 (Gallaway et al. 2013). The overarching
objectives of the KRSAW, funded by Gulf States Marine Fisheries
Commission (GSMFC), were to examine Kemp’s ridley
population’s status, trends and temporal-spatial distribution in
the Gulf of Mexico, to estimate mortality attributed to incidental
capture in shrimp trawls (under a working hypothesis that shrimp
trawling was the only source of anthropogenic mortality in postpelagic life stages), and to estimate total mortality (Gallaway et
al. 2013). The KRSAM raised the bar for demographic
modeling of the Kemp’s ridley population, primarily by
incorporating (1) a time series of annual shrimp trawling
mortality, estimated from a time series of annual shrimp
trawling effort by the U.S. shrimping fleet in the Gulf of
Mexico, and (2) a growth analysis based on a combination of
Marine Turtle Newsletter No. 145, 2015 - Page 2
mark-recapture and carapace length-frequency data combined.
No previous demographic model of a sea turtle population
had incorporated a time series of shrimp trawling mortality
(Gallaway et al. 2013; Caillouet 2014) despite the finding by
Magnuson etal. (1990) that incidental capture in shrimp
trawls was the most important source of mortality for postpelagic sea turtles. The KRSAM needs further improvement,
especially by combining a compatible time series of annual
shrimp trawling effort by Mexico's shrimping fleet with that of
the U.S. shrimping fleet, so that a time series of annual shrimp
trawling mortality throughout the Gulf of Mexico can be
estimated (Gallaway et al. 2013). For this purpose, we hope
that a compatible time series of annual shrimp trawling effort
by Mexico’s shrimping fleet can be provided by Mexico’s
Comisión Nacional de Acuacultura y Pesca (CONAPESCA;
www.conapesca.sagarpa.gob.mx/wb/cona/conapesca_english_v
ersion), within the Secretaría de Agricultura, Ganadería,
Desarrollo Rural, Pesca y Alimentación (SAGARPA; see
NMFS et al. 2011).
Demographic modeling has contributed to an understanding
of Kemp’s ridley population dynamics, and it may contribute
to elucidation of the cause(s) of interruption of exponential
growth of the population in 2010. Caillouet (2006, 2010,
2011, 2014) and Gallaway et al. (2013) discussed data and
analyses needed for demographic modeling of the Kemp’s ridley
population. However, proprietary issues surrounding data can
sometimes complicate, delay, constrain, or prevent timely access
to data essential to analyses and demographic modeling (Bjorndal
et al. 2011). NOAA’s Natural Resource Damage Assessment
(NRDA) may provide data relevant to demographic modeling.
Data archived in Mexico and the U.S., that heretofore may have
been too voluminous to enter into computer compatible media or
analyze, may also be useful to improving estimates of
population vital statistics needed for demographic modeling.
There is a continuing need to identify sources of data, to share
data, and to evaluate their usefulness and application to
demographic modeling (National Research Council 2010).
We suggest that modification of the recovery plan identify and
include requirements for data security, sharing, and evaluation
(see Bjorndal et al. 2011) as recovery priorities.
The National Research Council (2010) recommended that NMFS
and USFWS develop a coherent strategy for sea turtle assessments
to improve data collection methods, data quality, and data
availability, as well as a rigorous plan for external review of data
and models used to assess population status and trends. It also
recommended research emphasizing estimation of vital rates,
ecological or environmental mechanisms that drive vital rates,
anthropogenic mortality, and abundance. In-water abundance,
hatchling-cohort production, survival of immature turtles and
nesting females, age at maturity, breeding rates, and clutch
frequency were listed as the most serious demographic data
gaps. Identification and protection of migratory corridors and
critical habitats are also important to Kemp’s ridley recovery
(NMFS et al. 2011; www.nmfs.noaa.gov/pr/pdfs/petitions/
kempsridley_criticalhabitat_feb2010.pdf).
In April 2014, the 34th Annual Symposium on Sea Turtle
Biology and Conservation was held in New Orleans,
Louisiana (Valverde 2014). It included Kemp’s ridley
presentations or posters on assessment modeling, change in
population growth rate, strandings, migration corridors,
incidental hooking associated with recreational fishing in
Mississippi, genetic characteristics of feeding aggregations of
subadults, brevetoxin exposure, behavior related to red tide,
female-biased sex ratios, sex of hatchlings, monitoring and
protection of the Tecolutla (Mexico) beach, Tecolutla beach
temperatures, and climate change and reproduction. In
November 2014, the Second International Kemp’s Ridley Sea Turtle
Symposium, co-hosted by Texas Sea Grant and Gladys Porter
Zoo, was held in Brownville, Texas USA
(http://texasseagrant.org/assets/ uploads/resources/14101_SIKRSTS_program.pdf), to provide a forum for
presentation and discussion of the many recent advances in
Kemp’s ridley science, conservation, and management, and of
how these advances impact understanding of Kemp’s ridley
biology and conservation. During her presentation at this
symposium, Carole Allen stated that the recovery plan is
obsolete and should be rewritten (Carole Allen, pers. comm.,
January 2015). Gulf of Mexico ecosystem changes were among
the topics covered by the 2015 Oil Spill and Ecosystem Science
Conference, held in February 2015 in Houston, Texas
(http://texasseagrant.org/assets/uploads/ resources/15101_Monitoring_Status_program.pdf).
In recent years, USFWS has cut its annual funding for Kemp’s
ridley conservation in Tamaulipas, Mexico (Plotkin &
Bernardo 2014). NMFS et al. (2011) designated “lack of funding”
as a threat. The Kemp’s Ridley Recovery Team “felt strongly that
the lack of funds should be highlighted as a potential factor that
could reverse the population growth of the Kemp’s ridley”
(ibid.). Restoration of funding and increased funding are
urgently needed to support Kemp’s ridley conservation,
monitoring, research, and demographic modeling. Not only does
the recovery plan need modification in 2015, but consideration
should again be given to identifying and designating Kemp’s
ridley critical habitats, especially in light of the environmental
pollution catastrophe that occurred in the Gulf of Mexico in
2010 (http://www.nmfs.noaa.gov/pr/pdfs/petitions/
kempsridley_criticalhabitat_feb2010.pdf).
Acknowledgements. We are grateful for the contributions of
William Gazey, Pamela Plotkin, Scott Raborn, and John
Cole, who served with two of us (BJG & CWC) on LGL’s
PMDG, to all participants and observers at the KRSAM
stakeholders meeting, and to all participants in the KRSAW
(see Gallaway et al. 2013). We greatly appreciate
encouragement and support that led to the KRSAW, provided by
Louisiana Department of Wildlife and Fisheries (Mark
Schexnayder), Sea Grant programs of Texas, Louisiana,
Mississippi-Alabama, and Florida (Pamela Plotkin, Charles
Wilson, LaDon Swann, and Karl Havens, respectively), and for
funding of the KRSAW by GSMFC (Jeffrey Rester). Data for the
KRSAM and permission to use them were provided by the
NMFS Galveston Laboratory (James Nance), Mexico’s
CONANP and Secretaría de Desarrollo Urbano y Medio Ambiente
(SEDUMA) (coordinated by Jaime Peña and Patrick Burchfield,
Gladys Porter Zoo), the NMFS STSSN (Wendy Teas and
Sheryan Epperly), and the CMTTP (Peter Eliazar, Archie Carr
Center for Sea Turtle Research, University of Florida), for which
we are grateful. Mark Schexnayder, Julia Lightner, and Carole
Allen reviewed an early draft, and offered helpful comments.
Special thanks to Lisa Belskis for providing information related
to the sea turtle symposium in New Orleans.
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