Mechanistic modeling of the effects of climate change on sea turtle migration to nesting beaches

2021 ◽  
Author(s):  
Noga Neeman
2018 ◽  
Vol 25 (2) ◽  
pp. 753-762 ◽  
Author(s):  
Miguel R. Varela ◽  
Ana R. Patrício ◽  
Karen Anderson ◽  
Annette C. Broderick ◽  
Leon DeBell ◽  
...  

Behaviour ◽  
2013 ◽  
Vol 150 (8) ◽  
pp. 863-893 ◽  
Author(s):  
Col Limpus ◽  
Ruth L. Kamrowski

Sea finding behaviour in hatchling sea turtles is widely believed to be guided by orientation towards the brightest horizon and away from high silhouettes. We propose that the horizon profile at the lowest angle of elevation is a more important cue for ocean finding than light intensity. Examples of hatchling orientation occurring at natural nest sites, at preselected beach release sites, and within a walled wooden arena under various conditions in the field, are presented. We conclude that hatchlings orient as follows: (1) Hatchlings move towards the horizon line at the lowest angle of elevation; (2) Hatchlings move away from high silhouettes, in a direction that remains close to the horizon line at the lowest angle of elevation; (3) Should a conflict exist regarding the direction of lowest horizon elevation, hatchlings move towards the brightest lowest horizon. This refinement to current theory explains numerous instances of natural non-ocean-finding behaviour in marine turtles, which occur both by day and by night, and in the absence of artificial lighting. We propose that the disruption caused to hatchling orientation by artificial lighting close to nesting beaches occurs because bright lights mask the horizon line as a cue by making it impossible to discern, causing the hatchlings to move towards the only visible “horizon” — the artificial lights. Consequently, we recommend that managers of sea turtle rookeries where turtles have an ocean-finding problem should manipulate the beach profile to ensure the direction of the ocean matches the lowest angle of elevation, in combination with light reduction strategies — as the most effective means of preventing disrupted orientation.


2015 ◽  
Vol 104 ◽  
pp. 9-15 ◽  
Author(s):  
Kristina H. Yamamoto ◽  
Sharolyn J. Anderson ◽  
Paul C. Sutton

PLoS ONE ◽  
2015 ◽  
Vol 10 (6) ◽  
pp. e0129528 ◽  
Author(s):  
Jacob E. Hill ◽  
Frank V. Paladino ◽  
James R. Spotila ◽  
Pilar Santidrián Tomillo

2017 ◽  
Vol 44 (2) ◽  
pp. 127 ◽  
Author(s):  
Zoe Truscott ◽  
David T. Booth ◽  
Colin J. Limpus

Context Off-shore recruitment impairment of sea-turtle hatchlings because of light pollution is a growing concern to conservation of sea-turtle population throughout the world. Studies have focussed on sea-turtle hatchling sea-finding behaviour, and ignored the possible effect that on-shore lighting might have on hatchlings after they have entered the sea. Aims We experimentally evaluated the effect that on-shore light pollution has on the swimming behaviour of green turtle hatchlings once they have entered the sea and begun swimming off-shore. We also estimated the decrease in off-shore recruitment of hatchlings as a result of light pollution disruption of the off-shore swim. Methods Hatchling misorientation rates were quantified by releasing marked hatchlings to the sea from different land-based locations adjacent to light-polluted beach areas under a variety of environmental conditions. The beach in light-polluted regions was then searched for marked hatchlings returning to shore from the sea. Key results Misorientation rates were highest in trials conducted during moonless nights (66.7% of trials had some hatchlings return to shore) and lowest during trials conducted during moonlit nights (no trials had hatchlings return to shore). Green turtle hatchling off-shore recruitment for the entire 2014–15 nesting season at Heron Island was estimated to decrease 1.0 –2.4% as a result of on-shore lights disrupting hatchling off-shore swimming behaviour. Conclusions On moonless nights, sea-turtle hatchlings after having successfully completed their journey from nest to sea and entered the sea can be lured back to shore again by shore-based light pollution and, this will decrease their off-shore recruitment success. Implications To ensure maximum off-shore recruitment of sea-turtle hatchlings, on-shore light pollution adjacent to nesting beaches needs to be minimised so as to minimise misorientation and disorientation of hatchlings while on the beach and in near-shore waters.


2010 ◽  
Vol 61 (4) ◽  
pp. 464 ◽  
Author(s):  
M. M. P. B. Fuentes ◽  
J. L. Dawson ◽  
S. G. Smithers ◽  
M. Hamann ◽  
C. J. Limpus

Sea turtles rely on reef islands for key parts of their reproductive cycle and require specific sediment characteristics to incubate their eggs and dig their nests. However, little is known about the sedimentological characteristics of sea turtle rookeries, how these sediment characteristics affect the vulnerability of rookeries to climate change, and the ecological implications of different sediment or altered sediment characteristics to sea turtles. Therefore, we described the sediment and identified the reef-building organisms of the seven most important rookeries used by the northern Great Barrier Reef (nGBR) green turtle population. We then reviewed the literature on the vulnerability of each identified reef-building organism to climate change and how various sediment characteristics ecologically affect sea turtles. Sediments from the studied rookeries are predominantly composed of well-sorted medium-grained to coarse-grained sands and are either dominated by Foraminifera, molluscs or both. Dissimilarities in the contemporary sedimentology of the rookeries suggest that each may respond differently to projected climate change. Potential ecological impacts from climate change include: (1) changes in nesting and hatchling emergence success and (2) reduction of optimal nesting habitat. Each of these factors will decrease the annual reproductive output of sea turtles and thus have significant conservation ramifications.


2020 ◽  
Vol 41 ◽  
pp. 339-347
Author(s):  
HE Smith ◽  
SR Hoover ◽  
M Salmon ◽  
H Seaman ◽  
CM Coppenrath ◽  
...  

Invasive fire ants prey on a variety of organisms in the southeastern USA, including the pipped eggs and hatchlings within sea turtle nests. The granular fire ant bait AMDRO® (active ingredient hydramethylnon) is currently used at some rookeries to protect nests, but no studies have been conducted to determine if the pesticide negatively impacts the eggs or the hatchlings. We examined the pesticide’s effect on loggerhead (Caretta caretta) nests at Juno Beach, Florida, USA, specifically targeting how exposure affected hatching success, hatchling emergence success, and the ability of the turtles to orient visually from the nest to the sea. Pesticide granules were placed within a 30 cm diameter circle on the sand directly above the nest during the final 5-10 days of incubation, representative of its typical application at nesting beaches. Cornmeal granules in soybean oil and untreated natural nests served as controls. AMDRO had no significant effect on hatching success or emergence success, nor did it result in any deficiencies in hatchling orientation accuracy. However, the pesticide and cornmeal control attracted other predators (Atlantic ghost crabs and avian species), in addition to fire ants, to the nest site, thus revealing the nest’s location and potentially increasing its vulnerability. Consequently, we suggest that its usage may not be beneficial at sites where predators other than ants are especially abundant.


2021 ◽  
Vol 17 (5) ◽  
Author(s):  
Graeme C. Hays ◽  
William J. Chivers ◽  
Jacques-Olivier Laloë ◽  
Charles Sheppard ◽  
Nicole Esteban

There are major concerns about the ecological impact of extreme weather events. In the oceans, marine heatwaves (MHWs) are an increasing threat causing, for example, recent devastation to coral reefs around the world. We show that these impacts extend to adjacent terrestrial systems and could negatively affect the breeding of endangered species. We demonstrate that during an MHW that resulted in major coral bleaching and mortality in a large, remote marine protected area, anomalously warm temperatures also occurred on sea turtle nesting beaches. Granger causality testing showed that variations in sea surface temperature strongly influenced sand temperatures on beaches. We estimate that the warm conditions on both coral reefs and sandy beaches during the MHW were unprecedented in the last 70 years. Model predictions suggest that the most extreme female-biased hatchling sex ratio and the lowest hatchling survival in nests in the last 70 years both occurred during the heatwave. Our work shows that predicted increases in the frequency and intensity of MHWs will likely have growing impacts on sea turtle nesting beaches as well as other terrestrial coastal environments.


2020 ◽  
Vol 41 ◽  
pp. 329-338
Author(s):  
AD Phillott ◽  
MH Godfrey

There is increasing concern about feminization of sea turtle populations resulting from female-biased production of hatchlings due to climate change and selective loss of males from other anthropogenic drivers. Extreme female-biased breeding populations would reduce the likelihood of successful mating and potentially result in high rates of infertile eggs. Infertile eggs are those in which none of the events between sperm penetration of the ovum and syngamy have occurred. Distinguishing between fertile and infertile eggs is challenging, especially in field conditions, and researchers often have relied on physical evidence gathered from unhatched eggs at the end of the incubation period, which likely have experienced tissue decomposition. We argue that infertility in sea turtle eggs can be demonstrated only by the absence of holes caused by sperm penetration of the inner perivitelline membrane; sperm bound between the inner and outer perivitelline membranes; nuclei in the blastodisc; embryonic tissue or membranes in egg contents; and/or the characteristic white spot on the egg exterior. Unhatched eggs can be examined at the end of the incubation period, but we recommend that studies specifically investigating infertility examine at least 20 oviposited eggs each from clutches laid by at least 20 different turtles at the peak of the nesting season.


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