Low-Temperature Protection of Marine Turtle Eggs During Long-Distance Relocation

1989 ◽  
Vol 16 (3) ◽  
pp. 317 ◽  
Author(s):  
JL Harry ◽  
CJ Limpus
Keyword(s):  
Low Temperature ◽  
Sex Ratio ◽  
Embryonic Development ◽  
Incubation Period ◽  
Temperature Regime ◽  
Loggerhead Turtle ◽  
Caretta Caretta ◽  
Early Embryonic Development ◽  
Marine Turtle ◽  
Long Distance

Movement of marine turtle eggs, between about 3 hours and 3 weeks after oviposition, often results in substantial embryonic mortality. Eggs of the loggerhead turtle (Caretta caretta), which were cooled to 7-10�C within a few hours of oviposition, were relocated 1077 km in 14 h before being set at temperatures within the normal incubation range (26, 28 and 32�C). The percentage of viable embryos and hatchlings produced from these eggs was comparable to that of undisturbed eggs laid in natural nests. The incubation period and the sex ratio of the hatchlings, observed for each temperature regime, were unaffected by the initial cooling. Cooling C. caretta eggs effectively arrests early embryonic development, thereby extending the period during which eggs can be relocated without causing movement-induced mortality. This procedure is applicable in situations where turtle eggs must be transported for research or hatchery management purposes.

scholarly journals Out-foxing the red fox: how best to protect the nests of the Endangered loggerhead marine turtle Caretta caretta from mammalian predation?

Oryx ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 223-228 ◽  
Author(s):  
David J. Kurz ◽  
Katherine M. Straley ◽  
Brett A. DeGregorio
Keyword(s):  
Red Fox ◽  
Loggerhead Turtle ◽  
Caretta Caretta ◽  
Ease Of Use ◽  
Marine Turtle ◽  
Artificial Nests ◽  
Nest Protection ◽  
Mammalian Predators ◽  
Deployment Time ◽  
Level Of Motivation

AbstractRecovery plans for the Endangered loggerhead marine turtle Caretta caretta cite mammalian predation as a major threat, and recommend nest protection efforts, already present at many rookery beaches, to protect eggs and hatchlings. Nest protection techniques vary but wire box cages and plastic mesh screens are two common tools used to deter predation by a host of beach-foraging, opportunistic mammalian predators. We empirically tested the efficacy of wire cages and plastic mesh screens in preventing red fox Vulpes vulpes predation on artificial nests. Both techniques averted fox predation (0%), whereas unprotected control nests suffered 33% predation under conditions of normal predator motivation, or a level of motivation stimulated by loggerhead turtle egg scent. However, in side-by-side comparisons under conditions of presumed high predator motivation, 25% of mesh screens were breached whereas no cage-protected nests were successfully predated. In addition to effectiveness at preventing predation, factors such as cost, ease of use, deployment time, and magnetic disturbance were evaluated. Our study suggests that the efficacy of plastic screens and the potential disadvantages associated with galvanized wire should influence selection of mechanical barriers on beaches where fox predation threatens loggerhead nests.

Natural temperature regimes for loggerhead and green turtle nests in the eastern Mediterranean

1998 ◽  
Vol 76 (4) ◽  
pp. 723-729 ◽  
Author(s):  
Y Kaska ◽  
R Downie ◽  
R Tippett ◽  
R W Furness
Keyword(s):  
Sex Ratio ◽  
Incubation Period ◽  
Green Turtle ◽  
Eastern Mediterranean ◽  
Loggerhead Turtle ◽  
Chelonia Mydas ◽  
Maximum Temperature ◽  
Diel Cycles ◽  
Mean Temperature ◽  
The Mean

Temperatures of green turtle (Chelonia mydas) and loggerhead turtle (Caretta caretta) nests on the beaches of northern Cyprus and Turkey were examined. Electronic continuous-temperature recorders programmed by computer were placed at the top, middle, and bottom of the nests. The sex of 3-7 hatchlings from each level was determined from gonadal histology. The maximum temperature increase during the incubation period was 9.6oC for both species. The mean temperature during the middle third of the incubation period is a good indicator of the sex ratio of the clutch. The percentage of female embryos increased with temperature, 50% being female at 29°C. The mean temperature over the entire incubation period is not a good indicator of sex ratio but can be used to predict the duration of incubation period. The temperature differences within the clutch were larger in loggerhead than in green turtle nests. Eggs at the top of the nest experienced generally warmer (up to 1.4°C) conditions than eggs at the bottom of the same nest, and this caused variation in sex ratio within nests. Over all nests, the sex ratio (percent female) of hatchlings was 91% at the top, 83% at the middle, and 69% at the bottom. There was considerable interbeach thermal variation. Marked diel cycles of up to 1.5°C were detected in loggerhead turtle nests but not in the deeper nests of green turtles.

scholarly journals Protecting nests of the Critically Endangered South Pacific loggerhead turtle Caretta caretta from goanna Varanus spp. predation

Oryx ◽  
2019 ◽  
Vol 54 (3) ◽  
pp. 323-331 ◽  
Author(s):  
Christine A. Madden Hof ◽  
Gabriela Shuster ◽  
Nev McLachlan ◽  
Bev McLachlan ◽  
Saranne Giudice ◽  
...  
Keyword(s):  
Loggerhead Turtle ◽  
South Pacific ◽  
Caretta Caretta ◽  
Iucn Red List ◽  
Beach Erosion ◽  
Critically Endangered ◽  
Marine Turtle ◽  
Population Declines ◽  
The South ◽  
Cumulative Impact

AbstractThe South Pacific subpopulation of the loggerhead turtle Caretta caretta is categorized as Critically Endangered on the IUCN Red List because of significant population declines. Five Queensland beaches support high-density nesting of this subpopulation, but egg and hatchling survival are low at some beaches because of feral and native terrestrial predators. We quantified predation of loggerhead turtle eggs by two species of goanna, Varanus panoptes and Varanus varius, at Wreck Rock beach, one of the turtle's major nesting beaches. In addition, we conducted an experiment to determine the efficacy of a nest protection device. Predation rates at Wreck Rock beach were 15.2% for treatment and 45.8% for non-treatment clutches during the 2013–2014 nesting season. A higher probability of predation (64%) was predicted for the northern beach. Although nests were only partially predated (16.4% of the total number of eggs), nest loss to predators and beach erosion (caused by a cyclone) was 91.7%. If left unmanaged, the cumulative impact of predation and other threats, including those exacerbated by climate change, can cause unsustainable loss of loggerhead turtle nests. This study provides one of the first quantitative data sets on rates of loggerhead turtle clutch predation in the South Pacific. It enhances our understanding of goanna predation impacts and identifies an efficient predator exclusion device for mitigating the effects of terrestrial predators at Wreck Rock beach, and for protecting marine turtle nests across northern Australia and globally.

Study of the first reported nest of loggerhead sea turtle, Caretta caretta, in the Spanish Mediterranean coast

2002 ◽  
Vol 82 (6) ◽  
pp. 1005-1007 ◽  
Author(s):  
J. Tomás ◽  
J.L. Mons ◽  
J.J. Martín ◽  
J.J. Bellido ◽  
J.J. Castillo
Keyword(s):  
Incubation Period ◽  
Loggerhead Turtle ◽  
Caretta Caretta ◽  
Sea Turtle ◽  
Mediterranean Coast ◽  
Loggerhead Sea Turtle ◽  
Nest Placement

We summarize all the data of nest placement, incubation period, emergence of hatchlings and nest study of the first reported nesting event of a loggerhead turtle Caretta caretta (Reptilia: Cheloniidae) in the Spanish Mediterranean coast. The nest was laid in a beach of Almería province (south-east Spain) in July 2001. The incubation period was 58 days. Forty-two hatchlings emerged from a total of 97 eggs laid. Future beach surveys will determine whether this is a sporadic nesting event or whether loggerheads nest frequently in these coasts.

Population model analysis for the loggerhead sea turtle, Caretta caretta, in Queensland

1996 ◽  
Vol 23 (2) ◽  
pp. 143 ◽  
Author(s):  
SS Heppel ◽  
CJ Limpus ◽  
DT Crouse ◽  
NB Frazer ◽  
LB Crowder
Keyword(s):  
Population Decline ◽  
Survival Rates ◽  
Loggerhead Turtle ◽  
Caretta Caretta ◽  
Sea Turtle ◽  
Marine Turtle ◽  
Emergence Success ◽  
Eastern Australia ◽  
Loggerhead Turtles ◽  
The Usa

Worldwide declines of marine turtle populations have forced a need for sound conservation policies to prevent their extinction. Loggerhead turtles, Caretta caretta, are declining rapidly at eastern Australian nesting beaches, which are visited by females from all feeding areas for the stock. In some feeding areas of eastern Australia, loggerheads have been protected from deleterious anthropogenic effects. Using long-term mark-recapture data from one such protected group of turtles feeding on Heron Island Reef, Queensland, we created a matrix model to analyse loggerhead demography. We also produced a model for the females nesting at Mon Repos, Queensland, a major rookery where the annual nesting population has declined at rates approaching 8% per year. As indicated by a similar model for loggerheads in the USA, our models predicted that small declines in annual survival rates of adult and subadult loggerheads can have a profound impact on population dynamics. A loss of only a few hundred subadult and adult females each year could lead to extinction of the eastern Australian loggerheads in less than a century. Survival in the first year of life is relatively less important in these long-lived and slow-maturing animals. At Mon Repos, nesting female survival is apparently so low that even beach protection efforts resulting in 90% hatchling emergence success would not prevent population decline. Our research suggests that continued mortality pressure on subadult and adult turtles in their dispersed feeding areas of eastern and northern Australia is a major threat to the eastern Australian loggerhead turtle population. Measures that protect adult and subadult loggerhead turtles should be supported, including the use of turtle excluder devices (TEDs) on prawn trawls.

Cytological observations on fertilization and early embryonic development in sea cucumber Apostichopus japonicus

2012 ◽  
Vol 36 (2) ◽  
pp. 272 ◽  
Author(s):  
Jie TAN ◽  
Hui-ling SUN ◽  
Fei GAO ◽  
Jing-ping YAN ◽  
Ying-hui DONG ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Sea Cucumber ◽  
Apostichopus Japonicus ◽  
Early Embryonic Development
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