Wyneken, Jeanette

Assessing the presence or absence of marine turtles in an open system poses both
observational and analytical challenges due to the migratory nature of marine turtles and their
use of large current systems. Concentrations can shift as turtles shift between oceanic and neritic
stages and migrate between breeding and foraging grounds. We conducted standard aerial
surveys monthly from 2011-2012 to capture seasonal snapshots of sea turtle presence. Each
survey covered the area from a northern boundary near West Palm Beach, Florida
26°43′N to a southern boundary near Miami, Florida 25°40′N, USA with
transects up to 20-50 km offshore. 218 turtles were observed during the course of this study
2011: n 79; 2012: n 139. We summarize our sightings by season: Winter December-February,
Spring March-May, Summer June-August, and Fall September-November to examine trends in
presence of sea turtles. A variety of sizes were observed throughout the year, indicating the
presence of several life stages of marine turtles in Florida’s waters during all four seasons. While
it is understood that marine turtles use the waters off the eastern coast of Florida, here we
document the magnitude of the shift in turtle presence each season throughout two years and
where the turtles occur most frequently. Our assessment of marine turtles in the waters off of
southeast Florida provide valuable metrics describing the in-water biology of these turtles and
for the first time, provide a quantitative assessment of annual and inter-annual fluctuations in
presence in the major current and along our coast.

Sea turtles are most vulnerable to predators during early growth when they are small and
relatively defenseless. Predation risk might be reduced by evolving effective behavioral as well
as morphological defenses. Loggerhead Caretta caretta and green turtle Chelonia mydas neonates
hide in weed lines. They also become wider faster than they increase in length, a pattern of
positive allometry that may function to minimize the time during growth when they are
vulnerable to gape-limited predators. Virtually nothing is known about how young leatherbacks
grow which might reduce their vulnerability to predators. To find out, we reared 30 hatchlings
from 10 nests in the laboratory for up to 14 weeks, post-emergence. Once weekly, each turtle’s
body proportions straight line carapace length, SCL; straight line carapace width, SCW were
measured to yield an observed pattern of growth. That observed growth pattern was compared to
an expected pattern in which the turtles retained their hatchling proportions as they grew larger
isometric growth. We found that all of the leatherbacks showed allometric growth as their SCW
increased more rapidly than their SCL. Thus as they grew, leatherbacks became proportionally
wider, though this growth was not as pronounced as seen in loggerheads and green turtles. We
also modeled vulnerability to gape-limited predators. Leatherbacks, like loggerhead and green
turtles, were less vulnerable to predation when growing allometrically. These results provide
insight into a little know sea turtle life stage and aids in understanding how morphology in early
development may reduce predation risk.

Loggerhead and leatherback sea turtles are often caught as longline bycatch in fisheries
worldwide. These species of sea turtle differ greatly in life history, morphology, and the ways
they are hooked. Leatherbacks tend to be “foul hooked,” externally in the shoulder or flippers,
while loggerheads tend to be hooked in the mouth or they swallow the bait so that hooking is
internal esophagus or stomach. The numbers of loggerheads and leatherbacks caught decreased
after changes in gear, bait and time of sets. However the proportion of leatherback mouth
hookings increased while foul hooking decreased. We described and compared prey approach
and attack behavior of both species in the presence and absence of visual targets. Waterborne
squid and jellyfish odors were used to elicit feeding behavior in the two species. Visual targets
were necessary to elicit biting. Loggerheads approach their prey with the mouth wide open, have
exceptionally good aim and usually bite their intended target. This accuracy is consistent with
the mouth and internal hooking. Leatherbacks frequently overshoot, miss their intended target
then have to re-approach the target multiple times before making contact. Leatherback feeding
behavior is disrupted easily if the body or flippers are touched during prey approach. This reapproach
behavior may make leatherbacks more prone snagging on lines rigged with J-hooks.
The shift by some fisheries to circle hooks, which are less prone to snagging, by give the
leatherbacks multiple chances to attack the bait and ingest it without getting hooked externally.

Worldwide, sea turtles are especially vulnerable immediately after emerging from
nests. Many monitoring programs measure hatchling production from nest inventories.
These inventories rarely account for mortality occurring post-emergence, leaving an
incomplete estimate of hatchling production. This study addresses the nest-to-surf data gap
for Florida’s east coast nesting assemblages of loggerhead sea turtles (Caretta caretta).
Five locations were surveyed during the 2016 nesting season by using infrared time-lapse
imagery, night vision optics, and track maps. Over all beaches, 7.6% of the observed
hatchlings did not survive to reach the water. Mortality sources varied by location.
Observed predators included: foxes, bobcats, yellow-crowned night herons, ghost crabs,
and gulls. Hatchling disorientation and misorientation occurred more frequently in urban
areas than natural areas. Factors including number of hatchlings emerging, nest-to-surf
distance, and urbanization may help managers estimate nest-to-surf mortality. This study
will improve life history models that serve as foundations of conservation management.

There are no modem anatomical studies of flipper development or particularly any
examining limb formation across distantly related taxa converging on similar flipper
morphology. This study compares and contrasts the development of flippers in sea turtle
(Caretta caretta) and penguin (Spheniscus demersus , Eudyptula minor) embryos.
Embryos were fixed, cleared and stained for cartilage anlagen, and prepared as whole
mounts. Skeletal elements forming the flipper and changes in their growth rates were
described across developmental stages. Results suggest skeletal elements contribute
differently to sea turtle and penguin flipper blades and there are significant differences in
bone shape and growth patterns. Greater proportional increases in lengths and areas were
found in sea turtles elements compared to penguins. Sea turtles appear to depend on a
pathway resulting in elongation of distal elements to build a flipper, whereas penguin
limbs undergo flattening and expansion of fewer elements to meet a similar structural
goal.

A phylogeny of Mexican Ambystoma salamanders was constructed using
larval morphology. Characters were scored for 19 ambystomatid species from
Mexico and North America Twenty-five continuous characters came from
external measurements of cranial and branchial features and ratios of
measurements. Twenty-six categorical characters were scored from internal and
external larval, branchial, and cranial features, as well as overall color and adult
life history. Cladograms constructed from individual character matrices lack
major resolution beyond individual species level. The consensus cladogram did
not resolve the majority of species, and was similar to consensus results from
previous cladistic analysis based on molecular characters. Convergent
morphology is evident in characters of geographically distant members of the
clade. However, species determination was possible for all examined taxa.
Neoteny is widespread in the A. tigrinum complex and, as an isolating
mechanism, may be the main driver of speciation in the complex.

From 2004 - 2007, the beach at Sandy Point National Wildlife Refuge (St. Croix,
USVI) experienced low summer erosion, which allowed native pioneer vegetation to
spread seaward and invade leatherback-nesting areas. The encroachment of vegetation
reduced nest survival. Here I describe the results of an experimental assessment of
vegetation control methods and of the effects of native vegetation on leatherback
hatching and emergence success. I tested four treatments: (i) naturally vegetated, (ii)
herbicide treated vegetation, (iii) mechanically removed above ground vegetation, and
(iv) non-vegetated (control) plots. Nests were relocated into each of the plot types then
left to incubate naturally. Hatching and emergence success was reduced when vegetation
was present. Vegetation was not adequately controlled by any of the methods tested. The
results identify future research needs for the development of appropriate management to
control the native vegetation and enhance leatherback nest productivity.

The Gopher Tortoise (Gopherus polyphemus) lives in upland habitats throughout its life.
Recent rapid urbanization of coastal Florida is resulting in large scale habitat fragmentation
that negatively affects this and other upland species. Losses of upland habitats result in
regulatory actions that include mitigation programs and animal relocations which currently
occur in the absence of understanding region-specific behavior and habitat needs. Gopher
Tortoise populations are similar to one another in that males have larger home ranges than
females, males defend burrows and mates during the breeding season, all have a high degree
of home range overlap, and forage on similar vegetation types. This study shows that
Southeastern Florida Gopher Tortoises differ from those elsewhere in that they maintain
relatively small home ranges, forage throughout the year, engage in social interactions yearround,
and have a bimodal (late winter-spring and late summer-fall) breeding season. My
study identifies differences in activity, behavior, and home ranges in a South Florida
population that may refine management strategies that include reconsideration of restocking
Northern populations with individuals from South Florida.

Characterizing a species mating system is integral to understanding its natural history and is critical to the development of effective conservation strategies. A mating system is typically described by examining a single population and subsequently drawing inferences on the whole of the species. Variation among populations and gaps in understanding of a species often are revealed when studies are compared between several locations. The majority of available marine turtle mating system data stem from nesting females or hatchlings scurrying off the beach. This practice left glaring holes in the understanding of these imperiled organisms in particular with respect to males. We use exclusion paternity analysis to compare the genotype of a nesting female with genotypes from a subset of her offspring and deduce male genotypes to identify and count the number of males contributing per clutch. Loggerheads Caretta caretta, green turtles Chelonia mydas and tleatherbacks Dermochelys coriacea are protected species with spatially and temporally overlapping nesting beaches. The genotypes of the three species nesting in southern Florida will be compared among clutches to define mating systems. Additionally, we will provide the first measure of operational population size for both males and females in southern Florida. Finally, by comparing results from several beaches, the interconnectedness of rookeries through male-mediated gene flow will be determined as well as the relatedness of males. Our approach to establishing the mating systems of hard-to access-life stages will have strong conservation value in strengthening the demographics that form the core of species assessment and management.

Assessing the spatial and temporal distributions of marine turtles in an open
system poses both observational and analytical challenges due to their migratory nature
and use of large current systems. Concentrations of animals can shift because turtles
undergo large-scale migrations and habitat shifts seasonally as well as a function of lifestage.
Surface counts of marine turtles in waters off Florida’s east coast were made in
and adjacent to the Florida Current using standard aerial surveys. While it is understood
that marine turtles use waters off the eastern coast of Florida, here we document the
magnitude of the shift in turtle presence each season throughout a two year study and
identify habitat characteristics where turtles occur most frequently. Our assessment of
marine turtles in the waters off southeast Florida provide valuable metrics describing the
in-water biology of sea turtles in this area to inform future management strategies of
these endangered species.