Current Search: Sea turtles--Mortality (x)
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- Title
- The risk of hatchling loss to nearshore predators at a high-density loggerhead nesting beach in southeast Florida.
- Creator
- Stewart, Kelly Rhoda., Florida Atlantic University, Wyneken, Jeanette
- Abstract/Description
-
It has been recognized that mortality is high for juvenile stages of long-lived vertebrates such as sea turtles, however few studies have quantified mortality rates. The objective of this study was to assess the relative risk that hatchlings face in their first few minutes in the water, at the commencement of their offshore migration from a natural high-density nesting beach (Juno/Jupiter, FL). I followed 217 hatchlings at night by kayak, as they left the beach and documented the proportion...
Show moreIt has been recognized that mortality is high for juvenile stages of long-lived vertebrates such as sea turtles, however few studies have quantified mortality rates. The objective of this study was to assess the relative risk that hatchlings face in their first few minutes in the water, at the commencement of their offshore migration from a natural high-density nesting beach (Juno/Jupiter, FL). I followed 217 hatchlings at night by kayak, as they left the beach and documented the proportion surviving the initial 15 minutes in the water. Of these, 206 survived for an empirical survival rate of 95%. Tarpon were the most common predator observed. This survival rate is much higher than that previously observed at a hatchery (72%); this may be due to temporal and spatial variation in nest location at the natural beach. Juno and Jupiter beaches are therefore highly productive sea turtle rookeries.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12822
- Subject Headings
- Loggerhead turtle--Florida, Sea turtles--Mortality
- Format
- Document (PDF)
- Title
- Impact of the red imported fire ant (Solenopsis invicta ) on two species of sea turtle hatchlings.
- Creator
- Krahe, Holly B., Florida Atlantic University, Wetterer, James K.
- Abstract/Description
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Although the red imported fire ant (Solenopsis invicta ) is known to kill sea turtle hatchlings, little research has focused on sub-lethal effects of ant attacks on hatchlings emerging from nests. Sea turtle hatchlings of two species (Caretta caretta and Chelonia mydas) exposed to fire ants during incubation and emergence were collected on Juno Beach, Florida. Hatchlings were maintained for ten days in a common saltwater outdoor pool at the Marinelife Center, Juno Beach. Hatchlings showing...
Show moreAlthough the red imported fire ant (Solenopsis invicta ) is known to kill sea turtle hatchlings, little research has focused on sub-lethal effects of ant attacks on hatchlings emerging from nests. Sea turtle hatchlings of two species (Caretta caretta and Chelonia mydas) exposed to fire ants during incubation and emergence were collected on Juno Beach, Florida. Hatchlings were maintained for ten days in a common saltwater outdoor pool at the Marinelife Center, Juno Beach. Hatchlings showing pustules diagnostic of S. invicta stings were compared to non-stung controls in terms of survival, growth (mass and SCL) and initial crawling strength. Loggerhead hatchlings showed a significant decrease in survival, growth, and crawling strength when stung by fire ants. In contrast, no significant differences were seen in the survival, growth, and crawling strength of green turtle hatchlings when stung by fire ants.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/13252
- Subject Headings
- Fire ants--Venom--Physiological effect, Loggerhead turtle--Mortality, Green turtle--Mortality, Sea turtles--Florida
- Format
- Document (PDF)
- Title
- A comparison of body proportions in juvenile sea turtles: how shape may optimize survival in a vulnerable life stage.
- Creator
- Pate, Jessica Hope, Salmon, Michael, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Marine turtles produce many offspring which offsets the high mortality experienced by turtles during early development. Juvenile mortality might be reduced by evolving effective behavioral as well as morphological anti-predator defenses. Body proportions of three species (Caretta caretta, Chelonia mydas, Dermochelys coriacea) of turtles were measured in the first fourteen weeks of development to examine how growth may mitigate predation by gape-limited predators. Growth was categorized as...
Show moreMarine turtles produce many offspring which offsets the high mortality experienced by turtles during early development. Juvenile mortality might be reduced by evolving effective behavioral as well as morphological anti-predator defenses. Body proportions of three species (Caretta caretta, Chelonia mydas, Dermochelys coriacea) of turtles were measured in the first fourteen weeks of development to examine how growth may mitigate predation by gape-limited predators. Growth was categorized as isometric if shape did not change during development or allometric if body shape did change. All three species showed allometric growth in carapace width; however it was less pronounced in the larger D. coriacea turtles. Allometric growth in carapace width decreased as all three species grew in size. When high predation occurs in early development, many species will favor rapid growth into a size refuge. Juvenile sea turtles may optimize their survival by growing allometrically when predation risk is the greatest.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004223, http://purl.flvc.org/fau/fd/FA00004223
- Subject Headings
- Predation (Biology), Sea turtles -- Growth, Sea turtles -- Mortality, Sea turtles -- Population viability analysis
- Format
- Document (PDF)
- Title
- Brevetoxin Metabolism and Physiology - A Freshwater Model of Morbidity in Endangered Sea Turtles.
- Creator
- Cocilova, Courtney Christine, Milton, Sarah L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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The dinoflagellate Karenia brevis is one organism responsible for harmful algal blooms (HABs) that severely impact marine life. K. brevis produces a suite of neurotoxins referred to as brevetoxins (PbTx) which bind to voltage-gated sodium channels (VGSCs) in excitable tissues, affecting cellular permeability leading to a suite of symptoms and potentially cell death. Brevetoxicosis is difficult to treat in sea turtles as the physiological impacts have not been investigated and the magnitude...
Show moreThe dinoflagellate Karenia brevis is one organism responsible for harmful algal blooms (HABs) that severely impact marine life. K. brevis produces a suite of neurotoxins referred to as brevetoxins (PbTx) which bind to voltage-gated sodium channels (VGSCs) in excitable tissues, affecting cellular permeability leading to a suite of symptoms and potentially cell death. Brevetoxicosis is difficult to treat in sea turtles as the physiological impacts have not been investigated and the magnitude and duration of brevetoxin exposure are generally unknown. Due to their threatened and endangered status, experimental exposures cannot be performed to determine the fate of brevetoxin in sea turtle tissues, making it difficult to design appropriate treatments. The freshwater turtle, Trachemys scripta, was utilized as a model for brevetoxin exposure in turtles. Turtles were exposed to intratracheal instillation (10.53μg/kg) or oral dosing (33.48μg/kg) of PbTx-3 3x weekly over a period of 2-4 weeks. Tissues and fluids were collected for ELISA to determine PbTx-3 uptake and distribution, routes of excretion and rates of clearance (1h-1wk post-exposure). Tissues were also preserved for histopathology. Primary turtle neuronal cell cultures were exposed to PbTx-3 in the presence and absence of various agonists and antagonists to determine brevetoxin’s mode of action. PbTx-3 was widely distributed in all tissues and fluids following both intratracheal and oral exposures, but was largely cleared from the system within 24 hours; PbTx-3 moved into the bile and feces over 48h post exposure indicating that this is the main route of excretion. While exposed animals showed clear behavioral symptoms of toxicity including muscle twitching, swimming in circles, and ataxia, there was no evident tissue pathology. Despite the evident behavioral effects, turtle neurons are surprisingly resistant to PbTx-3, with an EC50 significantly higher than is seen in mammalian neurons. While PbTx-3 exposure resulted in significant Ca2+ influx, various antagonists prevented Ca2+ influx when added with PbTx-3 confirming the mechanism of action through VGSCs. Upregulation of Hsp72 in the turtle brain could be enhancing cell survival. Based on results, intralipid treatment post PbTx-3 exposure rapidly decreases symptoms and proves to be a suitable treatment for toxin exposure.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004812
- Subject Headings
- Sea turtles--Mortality., Sea turtles--Physiology., Marine toxins., Neurotoxic agents--Analysis.
- Format
- Document (PDF)
- Title
- Measuring Nest-to-Surf Mortality of Florida’s East and West Coast Loggerhead Sea Turtle (Caretta caretta) Hatchlings.
- Creator
- Villegas Vindiola, Brianna, Wyneken, Jeanette, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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Sea turtle hatchlings emerge from their nest and quickly crawl to the surf. During the crawl, hatchlings may encounter threats, biotic and abiotic, which can affect their ability to successfully reach the surf. The impact of these threats on hatchling survival during that crawl is largely undocumented. Current methods used to estimate cohort recruitment rely heavily on nest inventory data. This method, however, does not account for post-emergent hatchling mortality that occurs during the...
Show moreSea turtle hatchlings emerge from their nest and quickly crawl to the surf. During the crawl, hatchlings may encounter threats, biotic and abiotic, which can affect their ability to successfully reach the surf. The impact of these threats on hatchling survival during that crawl is largely undocumented. Current methods used to estimate cohort recruitment rely heavily on nest inventory data. This method, however, does not account for post-emergent hatchling mortality that occurs during the crawl. During the 2017-2018 nesting seasons, I quantified the fates of 1,379 loggerhead (Caretta caretta) hatchlings from 26 nest emergences during their crawl from the nest to the surf on the east and west coasts of Florida. I documented hatchling fates at 5 Florida nesting beaches: Wabasso, Boca Raton, Keewaydin Island, Naples, and Anna Maria Island. Overall, 6.5% of all emergent hatchlings died during the crawl from the nests to the surf. Ghost crabs, night herons, foxes, and coyotes killed hatchlings and photopollution and barriers on the beach (both abiotic threats) caused hatchling mortality. Anthropogenic (abiotic) threats accounted for more mortality than did predators. In order to assess how beach urbanization impacts hatchling mortality, I categorized each study site as urban (Wabasso and Naples), intermediate (Anna Maria Island and Boca Raton), or natural (Keewaydin Island) based on the relative levels of shoreline development and human activity at each beach. Sites with intermediate levels of urbanization accounted for greater levels of hatchling mortality than at other beaches due to the absolutely larger numbers of hatchlings lost to a disorientation event and to a beach barrier. Given the small numbers of emergences, at all sites, only a small proportion of the hatchlings mortalities (e.g., between 3 and 12 percent), site type could not be rigorously used as a discriminator. My results provide a better understanding of how specific environmental threats contribute to hatchling mortality. While nest-to-surf mortality is relatively low, its cumulative costs add up to several hundreds of thousands of hatchlings. Armed with this information, nesting beach managers can assess risks and focus their efforts to implement the most effective management practices to minimize losses of this imperiled species.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013277
- Subject Headings
- Loggerhead turtle--Florida, Caretta caretta, Sea turtles--Nests, Sea turtles--Mortality
- Format
- Document (PDF)
- Title
- Nest-to-surf mortality of loggerhead (Caretta caretta) sea turtle hatchlings on Florida’s east coast in 2016.
- Creator
- Erb, Victoria, Wyneken, Jeanette, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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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...
Show moreWorldwide, 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.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004934, http://purl.flvc.org/fau/fd/FA00004934
- Subject Headings
- Sea turtles--Mortality--Florida., Loggerhead turtle--Mortality., Predation (Biology), Sea turtles--Orientation., Animal navigation., Fire ants--Venom--Physiological effect.
- Format
- Document (PDF)
- Title
- Estimating predation levels and site-specific survival of hatchling loggerhead sea turtles (Caretta caretta) from south Florida beaches.
- Creator
- Whelan, Christie L., Florida Atlantic University, Wyneken, Jeanette
- Abstract/Description
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Few studies document mortality rates for hatchling sea turtles during their migration away from the nesting beach. This study quantifies and compares nearshore predation rates on loggerhead hatchlings (Caretta caretta) at several locations in southern Florida. Hatchlings were followed by observers in kayaks during the first 15 min of the migration away from the beach. The overall observed predation rate (4.6%) is similar to a previous estimate (5%) from a natural high density Florida nesting...
Show moreFew studies document mortality rates for hatchling sea turtles during their migration away from the nesting beach. This study quantifies and compares nearshore predation rates on loggerhead hatchlings (Caretta caretta) at several locations in southern Florida. Hatchlings were followed by observers in kayaks during the first 15 min of the migration away from the beach. The overall observed predation rate (4.6%) is similar to a previous estimate (5%) from a natural high density Florida nesting beach, and lower than at a hatchery site. Predation rates were higher on Florida's southeast coast than the southwest coast. Predation increased towards the end of the hatching season. Results suggest that currently, hatchling mortality rates are relative low in Florida's shallow nearshore waters. Given the lack of growth by loggerhead populations, the cumulative mortality must be high after hatchlings depart shallow coastal waters.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/13259
- Subject Headings
- Sea turtles--Florida--Atlantic Coast, Loggerhead turtle--Mortality, Predation (Biology)
- Format
- Document (PDF)
- Title
- Feeding behavior of loggerhead and leatherback sea turtles:a study to better understand longline bycatch.
- Creator
- Warraich, Natasha, Wyneken, Jeanette, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Two species of sea turtle, loggerheads (Caretta caretta) and leatherbacks (Dermochelys coriacea) are caught frequently as bycatch in longline fisheries. These fisheries use hooks baited with fish or squid. Yet, leatherbacks feed on gelatinous prey while loggerheads are carnivores. I investigated the responses of these two species to bait odors in controlled laboratory experiments to better understand their feeding behavior and why they interact with longlines. Both species initiated feeding...
Show moreTwo species of sea turtle, loggerheads (Caretta caretta) and leatherbacks (Dermochelys coriacea) are caught frequently as bycatch in longline fisheries. These fisheries use hooks baited with fish or squid. Yet, leatherbacks feed on gelatinous prey while loggerheads are carnivores. I investigated the responses of these two species to bait odors in controlled laboratory experiments to better understand their feeding behavior and why they interact with longlines. Both species initiated feeding behavior in the presence of squid bait odors and just C. caretta showed feeding behavior with sardine odors; neither responded to mackerel odors. The turtles are hooked differently on longlines. Loggerheads are usually hooked in the mouth while leatherbacks are usually hooked in the shoulder or flippers. Comparisons of prey attack behavior and accuracy in apprehending a stimulus in the presence of waterborne food odors identified speciesspecific differences that may predispose the turtles to particular kinds of hooking.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004171, http://purl.flvc.org/fau/fd/FA00004171
- Subject Headings
- Bycatches (Fisheries) -- Prevention, Longlining (Fisheries) -- Bycatches -- Prevention, Longlining (Fisheries) -- Environmental aspects, Sea turtles -- Effect of fishing on, Sea turtles -- Habitat -- Conservation, Sea turtles -- Mortality, Wildlife conservation
- Format
- Document (PDF)