An ideal combination for marine turtle conservation: exceptional nesting season, with low nest predation resulting from effective low-cost predator management

AbstractWe examined impacts from effective predator management on nesting success of marine turtles in an exceptional nesting year at Hobe Sound National Wildlife Refuge, Florida, USA, a beach with a high density of nesting marine turtles that has a history of severe nest predation. Historically up to 95% of nests were predated, primarily by raccoons Procyon lotor and, more recently, armadillos Dasypus novemcinctus. Predator control was identified as the most important conservation tool for marine turtle reproduction. Predator management by refuge staff as ancillary duties typically only held predation levels to c. 50%. However, when experts in predator control were employed predation was substantially reduced. An extraordinary opportunity to evaluate the biological and economic benefits of this management approach occurred in 2008, a year with exceptionally heavy nesting. Loggerhead turtle Caretta caretta nesting resurged, green Chelonia mydas and leatherback Dermochelys coriacea turtles nested in record numbers, producing twice or more than their median number of nests, and the first Kemp’s ridley Lepidochelys kempii nest was observed. Overall predation was 14.7%, resulting in an estimated > 128,000 additional hatchlings emerging compared to estimates had no predator management been in place and historical predation rates occurred, and > 56,000 hatchlings more than expected had predator management been conducted as ancillary duties rather than by experts. The USD 12,000 investment for expert predator management equated to only USD 0.09 spent for each additional hatchling produced compared to the scenario of no predator control and only USD 0.21 compared to the scenario of predator control as ancillary duties.

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Status of Marine Turtles in British Columbia Waters: A Reassessment

The Canadian Field-Naturalist ◽

10.22621/cfn.v118i1.885 ◽

2004 ◽

Vol 118 (1) ◽

pp. 72 ◽

Cited By ~ 3

Author(s):

Donald F. McAlpine ◽

Stan A. Orchard ◽

Kelly A. Sendall ◽

Rod Palm

Keyword(s):

British Columbia ◽

Marine Environment ◽

Chelonia Mydas ◽

Marine Turtle ◽

Dermochelys Coriacea ◽

Concerted Effort ◽

Leatherback Turtles ◽

Marine Turtles ◽

Green Turtles

Marine turtles in British Columbia have previously been considered off course stragglers. Here we document 20 new reports for Green Turtles, Chelonia mydas, and Leatherback Turtles, Dermochelys coriacea, for the province. Until recently there had been no concerted effort to acquire data on marine turtle abundance or frequency off British Columbia. Observations presented here allow a reassessment of marine turtle status in British Columbia waters. We suggest Green Turtles and Leatherbacks should be considered rare vagrants and uncommon seasonal residents, respectively, off British Columbia and that they are a natural part of the British Columbia marine environment.

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Defending against disparate marine turtle nest predators: nesting success benefits from eradicating invasive feral swine and caging nests from raccoons

Oryx ◽

10.1017/s0030605314000805 ◽

2014 ◽

Vol 50 (2) ◽

pp. 289-295 ◽

Cited By ~ 18

Author(s):

Richard M. Engeman ◽

David Addison ◽

J.C. Griffin

Keyword(s):

Nest Predation ◽

Sus Scrofa ◽

Nesting Success ◽

Marine Turtle ◽

Financial Cost ◽

Feral Swine ◽

Predator Species ◽

Marine Turtles ◽

Nest Protection ◽

Nesting Season

AbstractNest predation can threaten marine turtle nesting success, and having to address dissimilar predator species complicates nest protection efforts. On Florida's Keewaydin Island predation by raccoons Procyon lotor and invasive feral swine Sus scrofa are disparate, significant threats to marine turtle nests. Using 6 years of nesting data (mostly for loggerhead marine turtles Caretta caretta) we examined the impacts of swine predation on nests and the benefits of swine eradication, caging nests to protect them from raccoon predation, and the effects of nest caging on swine predation. Nest predation by swine began in mid nesting season 2007, after which swine quickly annihilated all remaining marine turtle nests. During 2005–2010 raccoon predation rates for caged nests (0.7–20.4%) were significantly lower than for uncaged nests (5.6–68.8%) in every year except 2009, when little raccoon predation occurred. The proportions of eggs lost from raccoon-predated nests did not differ between caged and uncaged nests. Caging did not prevent destruction by swine but median survival time for caged nests was 11.5 days longer than for uncaged nests, indicating that caged eggs in nests have a greater chance of hatching before being predated by swine. The financial cost of the eradication of swine greatly outweighed the value of hatchlings lost to swine predation in 2007.

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Two hundred years after a commercial marine turtle fishery: the current status of marine turtles nesting in the Cayman Islands

Oryx ◽

10.1046/j.1365-3008.2001.00168.x ◽

2001 ◽

Vol 35 (2) ◽

pp. 145-151 ◽

Cited By ~ 3

Author(s):

Jonathan J. Aiken ◽

Brendan J. Godley ◽

Annette C. Broderick ◽

Timothy Austin ◽

Gina Ebanks-Petrie ◽

...

Keyword(s):

Chelonia Mydas ◽

Marine Turtle ◽

Current Status ◽

Cayman Islands ◽

Eretmochelys Imbricata ◽

Marine Turtles ◽

Mature Adults ◽

Large Populations ◽

Sexually Mature ◽

Insight Into

AbstractLarge populations of marine turtles breeding in the Cayman Islands were drastically reduced in the early 1800s. However, marine turtle nesting still occurs in the islands. The present-day status of this nesting population provides insight into the conservation of marine turtles, a long-lived species. In 1998 and 1999, the first systematic survey of marine turtle nesting in the Cayman Islands found 38 nests on 22 beaches scattered through the three islands. Three species were found: the green Chelonia mydas, hawksbill Eretmochelys imbricata and loggerhead Caretta caretta turtles. Comparison with other rookeries suggests that the small number of sexually mature adults surviving Cayman's huge perturbations may be impeding population recovery. This shows the need to implement conservation measures prior to massive reductions in population size.

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The value of long-term, community-based monitoring of marine turtle nesting: a study in the Lamu archipelago, Kenya

Oryx ◽

10.1017/s0030605317000771 ◽

2017 ◽

Vol 53 (1) ◽

pp. 71-80 ◽

Cited By ~ 4

Author(s):

Mike I. Olendo ◽

Gladys M. Okemwa ◽

Cosmas N. Munga ◽

Lilian K. Mulupi ◽

Lily D. Mwasi ◽

...

Keyword(s):

Green Turtle ◽

Low Cost ◽

Western Indian Ocean ◽

Chelonia Mydas ◽

Sea Turtle ◽

Marine Turtle ◽

Olive Ridley ◽

Community Based ◽

Green Turtles ◽

Incubation Duration

AbstractMonitoring of nesting beaches is often the only feasible and low-cost approach for assessing sea turtle populations. We investigated spatio-temporal patterns of sea turtle nesting activity monitored over 17 successive years in the Lamu archipelago, Kenya. Community-based patrols were conducted on 26 stretches of beach clustered in five major locations. A total of 2,021 nests were recorded: 1,971 (97.5%) green turtleChelonia mydasnests, 31 (1.5%) hawksbillEretmochelys imbricatanests, 8 (0.4%) olive ridleyLepidochelys olivaceanests and 11 (0.5%) unidentified nests. Nesting occurred year-round, increasing during March–July, when 74% of nests were recorded. A stable trend in mean annual nesting densities was observed in all locations. Mean clutch sizes were 117.7 ± SE 1 eggs (range 20–189) for green turtles, 103±SE 6 eggs (range 37–150) for hawksbill turtles, and 103±SE 6 eggs (range 80–133) for olive ridley turtles. Curved carapace length for green turtles was 65–125 cm, and mean annual incubation duration was 55.5±SE 0.05 days. The mean incubation duration for green turtle nests differed significantly between months and seasons but not locations. The hatching success (pooled data) was 81.3% (n = 1,841) and was higher for in situ nests (81.0±SE 1.5%) compared to relocated nests (77.8±SE 1.4%). The results highlight the important contribution of community-based monitoring in Kenya to sustaining the sea turtle populations of the Western Indian Ocean region.

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Chelonia mydas fibropapillomatosis in Baie Blanche, Tintamarre Island Saint Martin (FWI), an environmental sciences and veterinary cross-analysis

10.21203/rs.3.rs-876743/v1 ◽

2021 ◽

Author(s):

Claire SALADIN

Keyword(s):

Early Stage ◽

Health Assessment ◽

Environmental Parameters ◽

Chelonia Mydas ◽

Marine Turtle ◽

Neoplastic Disease ◽

Environmental Pressures ◽

Marine Turtles ◽

Key West ◽

Saint Martin

Abstract Chelonia mydas’s fibropapillomatosis is a panzootic neoplastic disease that has been affecting the species since 1930’s, starting in Key West Florida USA. Most likely induced by the Chelonian HerpesVirus 5 (ChHV5), fibropapillomatosis has been recorded as affecting all species of marine turtles, provoking the growth of malignant external and internal round shaped tumors to marine turtles, that share numerous genomic similarities with human cancers. This research focuses on the two pristine bays of Tintamarre island in Saint Martin (French West Indies), Baie Blanche and Lagon, where the early stage of fibropapillomatosis has been observed affecting juvenile Chelonia mydas resident of Tintamarre. The results obtained when cross-analyzing the environmental monitoring and studies performed of Tintamarre island and a veterinary health assessment of Chelonia mydas juvenile and sub-adult marine turtles of Baie Blanche, bring a different perspective to the environmental pressures that may be responsible of the expression of the disease in Chelonia mydas. Macro-algae and Cadmium (Cd) contamination of marine turtles habitat and foraging grounds are environmental parameters that are found as possibly inducing fibropapillomatosis clinical expression in Tintamarre in this research, concurring with previous publications findings. Tintamarre island in Saint Martin (FWI) is a key site to study pertaining to marine turtle fibropapillomatosis.

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Dramatic reduction in predation on marine turtle nests through improved predator monitoring and management

Oryx ◽

10.1017/s0030605305000876 ◽

2005 ◽

Vol 39 (3) ◽

pp. 318-326 ◽

Cited By ~ 40

Author(s):

Richard M. Engeman ◽

R. Erik Martin ◽

Henry T. Smith ◽

John Woolard ◽

Carrie K. Crady ◽

...

Keyword(s):

Nest Predation ◽

Management Strategies ◽

Predation Rate ◽

Marine Turtle ◽

Conservation Implications ◽

Turtle Conservation ◽

Predator Management ◽

Successful Design ◽

Patterns Of Behavior ◽

Tracking Plot

We describe improvements to monitoring/indexing methodology for predators of marine turtle nests on the east coast of Florida, and the resulting marine turtle conservation implications from integrating the methodology into predator management. A strip transect from dune line to the shore improved an already successful design for monitoring raccoons, and was also sensitive for armadillos. The data were integrated into predator management operations to effectively and efficiently remove the species responsible for turtle nest predation. Tracking plot data also served to validate predator patterns of behavior relative to turtle nesting and improve prospects for preventive predator management strategies. Perhaps the most important finding is that predation at a beach historically suffering nearly complete losses (95%) of marine turtle nests had nest predation reduced to nominal levels (9.4%). For 2002 this predation level represents an estimated 69,000 additional hatchling turtles produced over historical predation rates, and 16,700 additional hatchlings over the previous lowest predation rate.

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Natural beaches confer fitness benefits to nesting marine turtles

Biology Letters ◽

10.1098/rsbl.2008.0359 ◽

2008 ◽

Vol 4 (6) ◽

pp. 704-706 ◽

Cited By ~ 16

Author(s):

David A Pike

Keyword(s):

Chelonia Mydas ◽

Coastal Development ◽

Marine Turtle ◽

Population Declines ◽

Negative Effects ◽

Marine Turtles ◽

Green Turtles ◽

Offspring Production ◽

Coastal Species ◽

Terrestrial Habitats

Coastal ecosystems provide vital linkages between aquatic and terrestrial habitats and thus support extremely high levels of biodiversity. However, coastlines also contain the highest densities of human development anywhere on the planet and are favoured destinations for tourists, creating a situation where the potential for negative effects on coastal species is extremely high. I gathered data on marine turtle reproductive output from the literature to determine whether coastal development negatively influences offspring production. Female loggerhead ( Caretta caretta ) and green turtles ( Chelonia mydas ) nesting on natural beaches (as opposed to beaches with permanent development) produce significantly more hatchling turtles per nest; all else being equal, females that successfully produce more offspring will have higher fitness than conspecifics producing fewer offspring. Thus, female marine turtles nesting on natural beaches probably have higher fitness than turtles nesting on developed beaches. Consequently, populations nesting on natural beaches may be able to recover more quickly from the historic population declines that have plagued marine turtles, and some species may recover more quickly than others.

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Using Aerial Photogrammetry to Assess Stock-Wide Marine Turtle Nesting Distribution, Abundance and Cumulative Exposure to Industrial Activity

Remote Sensing ◽

10.3390/rs13061116 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1116

Author(s):

Sabrina Fossette ◽

Graham Loewenthal ◽

Lauren R. Peel ◽

Anna Vitenbergs ◽

Melanie A. Hamel ◽

...

Keyword(s):

Protected Areas ◽

Large Scale ◽

Chelonia Mydas ◽

Marine Turtle ◽

Cumulative Exposure ◽

Cumulative Impact ◽

Industrial Activity ◽

Marine Turtles ◽

Aerial Photogrammetry ◽

Nesting Activity

The lack of accurate distribution maps and reliable abundance estimates for marine species can limit the ability of managers to design scale-appropriate management measures for a stock or population. Here, we tested the utility of aerial photogrammetry for conducting large-scale surveys of nesting marine turtles at remote locations, with a focus on the flatback turtle (Natator depressus) in the Pilbara region of Western Australia. Aerial surveys were conducted between 29 November and 6 December 2016 to overlap with the peak nesting season for flatback turtles and collected imagery was used to examine marine turtle distribution, abundance, and cumulative exposure to industrial activity relative to overlap with protected areas. Two observers independently reviewed aerial georeferenced photographs of 644 beaches and recorded turtle tracks and other evidence of turtle nesting activity. A total of 375 beaches showed signs of nesting activity by either flatback, green (Chelonia mydas) or hawksbill (Eretmochelys imbricata) turtles. Most of these beaches (85.3%) were located on islands, and the rest (14.7%) on the mainland. Half (n = 174) of the active beaches showed evidence of fresh (0–36 h. old) flatback nesting activity, with track abundance varying from 1.0 to 222.0 tracks·night−1. Six rookeries accounted for 62% of the Pilbara flatback stock. Remarkably, 77% of identified flatback rookeries occurred within protected areas. However, one-third (34%) of those were also located within 5 km of a major industrial site, including eight of the highest abundance beaches (50–250 tracks·night−1). Several key rookeries were also identified as being relatively unexposed to industry-related pressures but currently unprotected, highlighting the need for a cumulative impact assessment to be completed for this flatback stock. Finally, our aerial tallies and multiple ground-survey flatback track tallies were highly correlated and together with low intra- and inter-observer errors suggested that reliable data can be collected via aerial photogrammetry for nesting marine turtles. Such large-scale digitized surveys can therefore be used to assess the cumulative exposure of marine turtles to pressures, and to reveal new conservation opportunities.

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A Systematic Review of Acoustic Telemetry as a Tool to Gain Insights Into Marine Turtle Ecology and Aid Their Conservation

Frontiers in Marine Science ◽

10.3389/fmars.2021.765418 ◽

2021 ◽

Vol 8 ◽

Author(s):

Emily E. Hardin ◽

Mariana M. P. B. Fuentes

Keyword(s):

Systematic Review ◽

Spatial Data ◽

Acoustic Telemetry ◽

Low Cost ◽

Research Priorities ◽

Marine Species ◽

Marine Turtle ◽

Home Ranges ◽

Turtle Species ◽

Marine Turtles

While widely applied in fisheries science, acoustic telemetry remains an underutilized method in the field of marine turtle biotelemetry. However, with the ability to provide fine-scale spatial data (tens to hundreds of meters, depending on array setup and receiver range) at a low cost, acoustic telemetry presents an important tool for obtaining key information on marine turtle ecology. We present a comprehensive and systematic review acknowledging how acoustic telemetry has been used to advance the field of marine turtle ecology and conservation. We identify the extent of current studies and discuss common and novel research approaches while addressing specific limitations of acoustic telemetry. Forty-eight studies were reviewed, representing six of the seven marine turtle species and all life stages, with most individuals identified as juveniles (45%) and hatchlings (36%). Most studies (83%) focused on the spatial distribution of marine turtles, including estimating home ranges, investigating drivers of habitat use, and identifying horizontal movement patterns and vertical space use. Additionally, acoustic telemetry has been used to study hatchling dispersal and marine turtle exposure and response to threats, as well as to monitor physiological parameters. We identified that acoustic telemetry directly or indirectly informs 60% of the top questions and research priorities related to marine turtles identified by experts in the field. With an increase in acoustic telemetry receiver networks and collaborations across taxa, the applicability of acoustic telemetry is growing, not only for marine turtles but for a wide array of marine species. Although there are limitations that need to be considered at a site/project-level, acoustic telemetry is an important, low-cost technology able to address key questions related to marine turtle ecology that can aid in their conservation, and therefore should be considered by researchers as they develop their projects.

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Genomic Variation of the Fibropapilloma-Associated Marine Turtle Herpesvirus across Seven Geographic Areas and Three Host Species

Journal of Virology ◽

10.1128/jvi.79.2.1125-1132.2005 ◽

2005 ◽

Vol 79 (2) ◽

pp. 1125-1132 ◽

Cited By ~ 44

Author(s):

Rebecca J. Greenblatt ◽

Sandra L. Quackenbush ◽

Rufina N. Casey ◽

Joel Rovnak ◽

George H. Balazs ◽

...

Keyword(s):

Chelonia Mydas ◽

Genomic Variation ◽

Open Reading Frames ◽

Marine Turtle ◽

Neoplastic Disease ◽

Geographic Variations ◽

Turtle Species ◽

Marine Turtles ◽

Simplex Virus ◽

Reading Frames

ABSTRACT Fibropapillomatosis (FP) of marine turtles is an emerging neoplastic disease associated with infection by a novel turtle herpesvirus, fibropapilloma-associated turtle herpesvirus (FPTHV). This report presents 23 kb of the genome of an FPTHV infecting a Hawaiian green turtle (Chelonia mydas). By sequence homology, the open reading frames in this contig correspond to herpes simplex virus genes UL23 through UL36. The order, orientation, and homology of these putative genes indicate that FPTHV is a member of the Alphaherpesvirinae. The UL27-, UL30-, and UL34-homologous open reading frames from FPTHVs infecting nine FP-affected marine turtles from seven geographic areas and three turtle species (C. mydas, Caretta caretta, and Lepidochelys olivacea) were compared. A high degree of nucleotide sequence conservation was found among these virus variants. However, geographic variations were also found: the FPTHVs examined here form four groups, corresponding to the Atlantic Ocean, West pacific, mid-Pacific, and east Pacific. Our results indicate that FPTHV was established in marine turtle populations prior to the emergence of FP as it is currently known.

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