In 2015 in St. Kitts, 23 female leatherback sea turtles laid 59 nests. Hatch success was low at 5.8% due to high embryonic mortality. Autopsies were performed on 23 dead embryos and hatchlings from 10 nests. All turtles had pneumonia, which was a major factor in late embryonic death. Pneumonia may be caused by bacteria, though cultures were unsuccessful in identifying a predominant pathogen. The population also exhibited a predominance of females, which could be due to high nest temperatures or pollution. Additional research is needed to understand factors contributing to low hatch success in St. Kitts and the wider Caribbean.

1. In 2015, 23 females laid 59 nests in St. Kitts.
18 nests were followed to excavation and mean
hatch success was 5.8%. Embryonic mortality
was predominantly early stage (Figure 2). 23
turtles were evaluated (20 late stage embryos
and 3 dead-in-nest hatchlings). These
representative samples contained specimens
retrieved from a total of 10 different nests, 5
from Keys and 5 from North Friars.
Pneumonia affected
all turtles and was
grossly evident as
miliary white nodules
in 3 turtles (Figure 3).
It was mild (n=8),
moderate (n = 12), or
severe (n=3), and was
Predominately hetero-
philic, although there
were cases with hetero-
philic granulomas, and
the pattern varied from
Interstitial (n = 19, 82.6%) to
bronchopneumonia (n = 4, 17.4%) (Figures 4-
6). All cases of bronchopneumonia contained
intralesional rod-shaped bacteria. Bacteria were
not histologically evident in cases of interstitial
pneumonia. Aerobic and anaerobic cultures
(n=6) failed to identify a predominant isolate.
Furthermore, the developing gonad of all
turtles was female.
RESULTS
Pneumonia appears to be an important
contributing factor to late stage embryonal death
in St Kitts. This correlates with data obtained in a
study of leatherbacks in Florida where and 80%
of dead in nest hatchlings had pneumonia.6
Factors predisposing to fetal bacterial
bronchopneumonia could include maternal flora,
putrefaction of the nest environment,
immunosuppression due to pollutant exposure
among other causes, and/or primary viral
infection. It is unclear if interstitial pneumonia
represents an infectious inflammatory response,
or is a nonpathologic stage of extramedullary
granulopoiesis related to the developing fetal
immune system. Further study is warranted to
determine the impact of pneumonia on hatch
success in leatherbacks in the wider Caribbean
region.
Predominance of females in the population is
concerning and could reflect high nest
temperature or exposure to endocrine disrupting
chemicals.
Additional research in St. Kitts examines
environmental factors which may explain low
hatch success, particularly factors which
influence early embryonal mortality, including
temperature, conductivity, pH, sand grain size,
moisture, and contaminant exposure.
CONCLUSION
This work would not have been possible without the dedicated volunteers and staff of the SKSTMN,
especially Jenna Strapple, Joseph Keeton, Nahillyl Santiago, and Victoria Maroun. The authors also thank
David Hilchie and Maurice Matthew for assistance on histology and postmortem examinations.
Figure 5: Lung; late stage embryo.
Interstitial pneumonia exhibits
heterophils within edicular septae
(arrows) (Bar = 100µm).
Figure 4: Pneumonia
observed in 23 post
mortem evaluations
of dead in nest
leatherbacks.
Figure 6: Lung; late stage
embryo. Bronchopneumonia
features granulocytic
exudate filling airways (arrows)
(Bar = 100 µm).
Figure 3: Miliary white nodular foci
observed occasionally on lungs.
Figure 2: Mean proportion of embryo
stage mortality in 2015 leatherback sea
turtles nests.
ACKNOWLEDGEMENTS
HISTOPATHOLOGICAL SURVEY OF LATE STAGE EMBRYONAL MORTALITY
IN LEATHERBACK SEA TURTLES (DERMOCHELYS CORIACEA) IN ST KITTS, W.I.
K. Hill1, M.M. Dennis1, N. Lord1, K. Stewart1,2
1 Wallace, B.P., Tiwari, M. & Girondot, M. 2013. Dermochelys coriacea. The IUCN Red List of Threatened Species
2013: e.T6494A43526147.http://dx.doi.org/10.2305/IUCN.UK.2013-2.RLTS.T6494A43526147.en. Downloaded
on 18 January 2016.
2 Theodorakou C (2013) Factors affecting the reproductive output and hatching success of the leatherback sea turtle
Dermochelys coriacea in Tobago, West Indies.
3 Leslie AJ, Penick DN, Spotila JR, Paladino FV (1996) Leatherback turtle, Dermochelys coriacea,nesting and nest
success at Tortuguero, Costa Rica. Chelonian Conservation and Biology 2:159-168.
References
Leatherback sea turtles (Dermochelys
coriacea), classified as vulnerable by the IUCN,
have a low global hatch success of 50%, hence,
protection of eggs and successful hatching are
critical for population recovery.1
In St. Kitts, hatch success typically averages
from 5-10%. The Caribbean, as a whole, has a
49% success rate, based on studies conducted
in Tobago, Costa Rica, and St. Croix, indicating
St Kitts’ success is well below average.2,3,4
There are two main
Leatherback nesting
beaches on St. Kitts,
Keys and North Friars
(Figure 1). Historically,
Keys beach renders
lower success than
that of North Friars.
The aim of this study
Is to describe the
Pathology affecting
non-emergent
hatchlings and late
stage embryoson St. Kitts.
INTRODUCTION
METHODS
Nests were excavated within 48 hours of
any signs of emergence, or after a period of 61
days of incubation. At excavation, the
eggs/hatchlings were categorized; unhatched
eggs were opened and grouped according to
stage of mortality, following previous
methodology.5
Hatch success was determined as the
number of hatched eggs/number of eggs laid
(excluding SAGs). Where late stage embryos
and dead-in-nest hatchlings were present in a
nest, postmortem examinations and
histopathology were performed on at least two.
Giving preference to those with the least
postmortem decomposition.
Skin, muscle, brain, heart, lung, kidney, liver,
gonads, and gastrointestinal tract were
evaluated histologically.
©2015 Ross University School of Veterinary Medicine. All rights reserved.
1. Department of Biomedical Sciences, Ross University School of Veterinary Medicine, St. Kitts, West Indies
2. St. Kitts Sea Turtle Monitoring Network, St. Kitts, West Indies
4 Boulon RH, Dutton PH, McDonald DL (1996) Leatherback turtles (Dermochelys coriacea) on St Croix, U.S. Virgin Islands;
Fifteen years of conservation. Chelonian Conservation Biology 2:141-147.
5 Rafferty AR, Santidrian Tomillo P, Spotila JR, Paladine FV, Reina RD. Embryonic death is linked to maternal identity in
the leatherback turtle (Dermochelys coriacea).PLoS One 2011;6:e21038.
6 Miller DL, Wyneken J, Rajeev S, Perrault J, Mader DR, Weege J, and Baldwin CA. Pathologic findings in hatchlings and
posthatchling leatherback sea turtles(Dermochelys coriacea) from Florida. Journal of Wildlife Disease 2009.
Figure 1: St. Kitts’ primary
leatherback nesting beaches.