SURVIVAL PROBABILITY ESTIMATES FOR LARGE JUVENILE AND ADULT GREEN TURTLES (CHELONIA MYDAS) EXPOSED TO AN ARTISANAL MARINE TURTLE FISHERY IN THE WESTERN CARIBBEAN

AbstractDietary studies provide key insights into threats and changes within ecosystems and subsequent impacts on focal species. Diet is particularly challenging to study within marine environments and therefore is often poorly understood. Here, we examined the diet of stranded and bycaught loggerhead (Caretta caretta) and green turtles (Chelonia mydas) in North Cyprus (35.33° N, 33.47° E) between 2011 and 2019. A total of 129 taxa were recorded in the diet of loggerhead turtles (n = 45), which were predominantly carnivorous (on average 72.1% of dietary biomass), foraging on a large variety of invertebrates, macroalgae, seagrasses and bony fish in low frequencies. Despite this opportunistic foraging strategy, one species was particularly dominant, the sponge Chondrosia reniformis (21.5%). Consumption of this sponge decreased with increasing turtle size. A greater degree of herbivory was found in green turtles (n = 40) which predominantly consumed seagrasses and macroalgae (88.8%) with a total of 101 taxa recorded. The most dominant species was a Lessepsian invasive seagrass, Halophila stipulacea (31.1%). This is the highest percentage recorded for this species in green turtle diet in the Mediterranean thus far. With increasing turtle size, the percentage of seagrass consumed increased with a concomitant decrease in macroalgae. Seagrass was consumed year-round. Omnivory occurred in all green turtle size classes but reduced in larger turtles (> 75 cm CCL) suggesting a slow ontogenetic dietary shift. Macroplastic ingestion was more common in green (31.6% of individuals) than loggerhead turtles (5.7%). This study provides the most complete dietary list for marine turtles in the eastern Mediterranean.

Download Full-text

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.

Download Full-text

Some of them came home: the Cayman Turtle Farm headstarting project for the green turtle Chelonia mydas

Oryx ◽

10.1017/s0030605305000372 ◽

2005 ◽

Vol 39 (2) ◽

pp. 137-148 ◽

Cited By ~ 38

Author(s):

Catherine D.L. Bell ◽

Joe Parsons ◽

Timothy J. Austin ◽

Annette C. Broderick ◽

Gina Ebanks-Petrie ◽

...

Keyword(s):

Chelonia Mydas ◽

Breeding Population ◽

Marine Turtle ◽

Management Technique ◽

Cayman Islands ◽

Age At Maturity ◽

Green Turtles ◽

Local Breeding ◽

The Caribbean ◽

Cayman Turtle Farm

Headstarting is a management technique employed to enhance recruitment of turtles into diminished or extirpated marine turtle populations. Although there have been numerous projects worldwide, there has been a paucity of detailed investigations into its efficacy. Between 1980 and 2001, 16,422 captive-raised hatchlings and 14,347 yearling green marine turtles Chelonia mydas were released from the Cayman Turtle Farm. Approximately 80% of all turtles released were subject to some form of tagging, including living tags. A total of 392 tagged animals have been recaptured at intervals of up to 19 years. Of this total, 160 individuals were captured in the Cayman Islands and 232 were recorded from other locations within the wider Caribbean and southeastern USA. There was significant variation in the release-recapture intervals at the three countries with most returns (Cayman, Cuba and Nicaragua). A positive relationship exists between time at large and size at recapture and data suggest growth rates comparable to those of wild green turtles in the region. There have been at least six living tag returns, four involving turtles released as yearlings and two involving turtles released as hatchlings. This demonstrates an age at maturity that may be as short as 15–19 years, depending on stage of release. Results show that some headstarted turtles are moving around the Caribbean, surviving for long periods of time, contributing to the local breeding population, and are possibly displaying shifts in habitat utilization with age similar to those recorded by wild individuals.

Download Full-text

The nesting success of green turtles on beaches at Kazanli, Turkey

Oryx ◽

10.1017/s0030605300023607 ◽

1992 ◽

Vol 26 (3) ◽

pp. 165-171 ◽

Cited By ~ 1

Author(s):

Stephanie J. Coley ◽

Andrew C. Smart

Keyword(s):

Nest Site ◽

Chelonia Mydas ◽

Nesting Success ◽

Beach Erosion ◽

Marine Turtle ◽

Chemical Pollution ◽

Turtle Species ◽

Green Turtles ◽

Nesting Beaches ◽

Turkish Society

The green turtle Chelonia mydas is one of two marine turtle species to nest in Turkey. Its three main nesting beaches are in eastern Turkey, with possibly the densest congregation of nesting turtles in the Mediterranean being found at Kazanli. However, beach erosion, hatchling predation, agricultural encroachment and chemical pollution mean that the future of the Kazanli nest site is uncertain. The Turkish Society for the Protection of Nature (Dogal Hayati Koruma Dernegi) is making valiant efforts to protect all the turtle nesting beaches in Turkey but lacks detailed information on the numbers of nesting turtles on many beaches. This paper describes a short study of nesting turtles at Kazanli during 1990 and makes recommendations for the conservation of the nesting beach.

Download Full-text

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.

Download Full-text

ANALYSIS 16S RDNA OF THE TURTLES IN FORECLOSURE CAGES AT PADEI LAUT, CENTRAL SULAWESI, INDONESIA

Indonesian Fisheries Research Journal ◽

10.15578/ifrj.23.1.2017.39-44 ◽

2017 ◽

Vol 23 (1) ◽

pp. 39

Author(s):

Adriani Sri Nastiti ◽

Masayu Rahmia Anwar Putri ◽

Joni Haryadi ◽

Arif Wibowo ◽

Ngurah N Wiadnyana

Keyword(s):

Carapace Length ◽

Genetic Relationships ◽

Chelonia Mydas ◽

Iucn Red List ◽

Red List ◽

Marine Turtle ◽

Green Turtles ◽

Illegal Fishing ◽

Central Sulawesi

Marine turtle is one of the protected aquatic animals as listed in CITES Appendix and IUCN red list. However, illegal fishing of marine turtle is still occurred Padei Laut Village, in Morowali Regency, Central Sulawesi Province, Indonesia. The research aims to study the population of marine turtle based on the carapace length and the genetic relationships. Data of carapace length was measured in-situ and genetic analysis was used mitochondrial DNA. The results showed that the carapace (ten samples which was green turtles/Chelonia mydas) was ranges between 42-102 cm; 91% of samples was immature and 9% was mature. Moreover, it also revealed that those turtles resembled by 99.98% of genetic similarity.

Download Full-text

Use of Baculovirus-Expressed Glycoprotein H in an Enzyme-Linked Immunosorbent Assay Developed To Assess Exposure to Chelonid Fibropapillomatosis-Associated Herpesvirus and Its Relationship to the Prevalence of Fibropapillomatosis in Sea Turtles

Clinical and Vaccine Immunology ◽

10.1128/cvi.00438-07 ◽

2008 ◽

Vol 15 (5) ◽

pp. 843-851 ◽

Cited By ~ 18

Author(s):

Lawrence H. Herbst ◽

Shefali Lemaire ◽

Ada R. Ene ◽

David J. Heslin ◽

Llewellyn M. Ehrhart ◽

...

Keyword(s):

Immunosorbent Assay ◽

Recombinant Baculovirus ◽

Chelonia Mydas ◽

Sea Turtle ◽

Marine Turtle ◽

Enzyme Linked Immunosorbent Assay ◽

Green Turtles ◽

Glycoprotein H ◽

History Of ◽

Experimentally Induced

ABSTRACT Chelonid fibropapillomatosis-associated herpesvirus (CFPHV) is an alphaherpesvirus believed to cause marine turtle fibropapillomatosis (FP). A serodiagnostic assay was developed for monitoring sea turtle populations for CFPHV exposure. CFPHV glycoprotein H (gH) expressed in recombinant baculovirus was used in an enzyme-linked immunosorbent assay (ELISA) to detect virus-specific 7S turtle antibodies. Using captive-reared green turtles (Chelonia mydas) with no history of virus exposure as “known negatives” and others with experimentally induced FP as “known positives,” the assay had 100% specificity but low sensitivity, as seroconversion was detected in only half of the turtles bearing experimentally induced tumors. Antibodies were detected only in samples collected after cutaneous fibropapillomas appeared, consistent with observations that tumors are significant sites of virion production and antigen expression and the possibility that prolonged/repeated virus shedding may be required for adequate stimulation of 7S antibody responses to gH. Natural routes of infection, however, may produce higher seroconversion rates. High gH antibody seroprevalences (∼80%) were found among wild green turtles in three Florida localities with different FP prevalences, including one site with no history of FP. In addition, all eight loggerhead turtles (Caretta caretta) tested were seropositive despite FP being uncommon in this species. The possibility that CFPHV infection may be common relative to disease suggests roles for environmental and host factors as modulators of disease expression. Alternatively, the possibility of other antigenically similar herpesviruses present in wild populations cannot be excluded, although antibody cross-reactivity with the lung/eye/trachea disease-associated herpesvirus was ruled out in this study.

Download Full-text

Assessing tag loss and survival probabilities in green turtles (Chelonia mydas) nesting in Malaysia

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315417000224 ◽

2017 ◽

Vol 98 (4) ◽

pp. 961-972 ◽

Cited By ~ 2

Author(s):

Hideaki Nishizawa ◽

Juanita Joseph ◽

Vicki Yii-Ching Chew ◽

Hock-Chark Liew ◽

Eng-Heng Chan

Keyword(s):

Confidence Interval ◽

Survival Probability ◽

Loss Rate ◽

Chelonia Mydas ◽

Loss Probability ◽

Population Status ◽

Mark Recapture ◽

Survival Probabilities ◽

Green Turtles ◽

Tag Loss

The loss of external tags is one of the biggest problems in mark-recapture research. An evaluation of tag loss is therefore required to improve tagging methodology, select appropriate tag types, and accurately estimate population status and dynamics. We estimated tag loss probability of double-tagged green turtles (Chelonia mydas) nesting at Redang Island, Malaysia (05°49′ N 103°00′ E), from 1993–2014. For both titanium and Inconel tags, we found a tag loss pattern with a high initial tag loss rate that decreased to an asymptote near a constant value above zero. The initial tag loss probability for titanium tags was higher than for Inconel tags, and titanium tags were lost earlier than Inconel tags in more individuals when both types of tags were attached. In addition, comparison of the tag loss probability of Inconel tags attached during the period when tagging staff changed every year to that when senior tagging staff were not changed, indicated that lack of consistency in tagging staff affected the application of at least one of two Inconel tags. Estimated tag loss probability was incorporated into a recapture model, and annual survival probability was estimated to be 0.893 (95% confidence interval: 0.857–0.921).

Download Full-text

Estimating the number of green and loggerhead turtles nesting annually in the Mediterranean

Oryx ◽

10.1017/s0030605302000431 ◽

2002 ◽

Vol 36 (3) ◽

pp. 227-235 ◽

Cited By ~ 108

Author(s):

Annette C. Broderick ◽

Fiona Glen ◽

Brendan J. Godley ◽

Graeme C. Hays

Keyword(s):

Chelonia Mydas ◽

Marine Turtle ◽

Green Turtles ◽

Northern Cyprus ◽

Loggerhead Turtles ◽

The Status ◽

The Mediterranean ◽

Endangered Status ◽

Breeding Seasons ◽

Median Interval

Most species of marine turtle breed every two or more years and it is the norm for females to lay more than one clutch of eggs within a nesting season. Knowing the interval between breeding seasons and the clutch frequency (number of clutches laid by an individual in a breeding season) of females allows us to assess the status of a nesting population. At Alagadi Beach, Northern Cyprus, over a period of 6 years (1995–2000), we attributed 96% of green Chelonia mydas and 80% of loggerhead Caretta caretta turtle clutches to known individual females. This intensive level of monitoring enabled us to estimate the clutch frequency for both species. Using four different methods we estimated clutch frequency to be 2.9–3.1 clutches per female for green turtles and 1.8–2.2 clutches per female for loggerhead turtles. The median interval between nesting seasons for green turtles was 3 years, and for loggerhead turtles it was 2 years. Utilizing these parameters and available data from other beaches that are monitored regularly, we estimate that there are 2,280–2,787 logger-head and 339–360 green turtles nesting annually at these sites in the Mediterranean. This highlights the Critically Endangered status of this population of green turtles. Furthermore, as conventional beach patrols underestimate clutch frequency, these population estimates are likely to be optimistic.

Download Full-text