Evaluating potential tagging effects on leatherback sea turtles

Sherrill-Mix, Scott; James, Michael C.

doi:10.3354/esr00070

Cited by 21 publications

(12 citation statements)

References 33 publications

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“…However, it is clear that the effects of any tagging technique should be carefully considered and weighed against the potential conservation benefits to make it justifiable. Particularly when involving endangered species, the fitness costs of tagging should be minimized as much as possible to ensure we are not contributing to their decline (Sherrill-Mix & James 2008).…”

Section: Discussionmentioning

confidence: 99%

Identification of high-use internesting habitats for eastern Pacific leatherback turtles: role of the environment and implications for conservation

Shillinger¹,

Swithenbank²,

Bograd³

et al. 2010

Endang. Species. Res.

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The numbers of leatherback turtles Dermochelys coriacea in the eastern Pacific Ocean have declined by up to 90% in the past 2 decades. Initially, egg harvesting was determined to be the largest causative factor, but now that this has been eliminated, high estimated adult mortality from fisheries bycatch poses the single greatest threat to this population. During the nesting season, adult female leatherback turtles nest multiple times and occupy coastal marine habitats near their nesting beaches. In this study, we characterize the interannual variability of high-use internesting habitats used by 44 (out of 46 total) female leatherback turtles that were satellite-tagged at Playa Grande, Costa Rica, from 2004 to 2007. A total of 1135 d of internesting movements were recorded across 3 tracking years. The core 25% utilization distribution (UD) remained predominantly centered within the marine protected area, Parque Nacional Marino Las Baulas (PNMB). The turtles generally dispersed in a northward or southward direction over the shallow continental shelf framing Costa Rica's Nicoya Peninsula. However, there was considerable interannual variation in the shape and area of the larger UD polygons, which was driven by variability in the thermal environment. The maximum swimming speeds and distance traveled from the nesting beach occurred during 2007. Significantly deeper and longer dive durations to cooler temperatures also occurred in this year, which may have been in response to the warming trend from the south driven by the strong Costa Rica Coastal Current. Our findings, therefore, validate the importance of PNMB as a critical habitat for internesting leatherback turtles, but also suggest that a latitudinal expansion of the park is warranted.

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Section: Discussionmentioning

confidence: 99%

Identification of high-use internesting habitats for eastern Pacific leatherback turtles: role of the environment and implications for conservation

Shillinger¹,

Swithenbank²,

Bograd³

et al. 2010

Endang. Species. Res.

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show abstract

“…This facilitates upfront hypothesis testing (e.g. behaviour of neophytes versus remigrants) and acts as post-hoc backup of identity following loss of satellite tags (Sherrill-Mix & James 2008).…”

Section: Seeking Outcomesmentioning

confidence: 99%

Satellite tracking of sea turtles: Where have we been and where do we go next?

Godley¹,

Blumenthal²,

Broderick³

et al. 2008

Endang. Species. Res.

310

298

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“…Wilson et al 1986, Ropert-Coudert et al 2007, Sherrill-Mix & James 2008. This may in turn influence the validity of findings from such studies; although many excellent population models exist to deal with incomplete or inadequate data sets (e.g.…”

Section: Introductionmentioning

confidence: 99%

Spotting the difference: towards fully-automated population monitoring of African penguins Spheniscus demersus

Sherley¹,

Burghardt²,

Barham³

et al. 2010

Endang. Species. Res.

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Placing external monitoring devices onto seabirds can have deleterious effects on welfare and performance, and even the most benign marking and identification methods return sparse population data at a huge time and effort cost. Consequently, there is growing interest in methods that minimise disturbance but still allow robust population monitoring. We have developed a computer vision system that automatically creates a unique biometric identifier for individual adult African penguins Spheniscus demersus using natural markings in the chest plumage and matches this against a population database. We tested this non-invasive system in the field at Robben Island, South Africa. False individual identifications of detected penguins occurred in less than 1 in 10 000 comparisons (n = 73 600, genuine acceptance rate = 96.7%) to known individuals. The monitoring capacity in the field was estimated to be above 13% of the birds that passed a camera (n = 1453). A significant increase in this lower bound was recorded under favourable conditions. We conclude that the system is suitable for population monitoring of this species: the demonstrated sensitivity is comparable to computer-aided animal biometric monitoring systems in the literature. A full deployment of the system would identify more penguins than is possible with a complete exploitation of the current levels of flipper banding at Robben Island. Our study illustrates the potential of fully-automated, non-invasive, complete population monitoring of wild animals.

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Evaluating potential tagging effects on leatherback sea turtles

Cited by 21 publications

References 33 publications

Identification of high-use internesting habitats for eastern Pacific leatherback turtles: role of the environment and implications for conservation

Identification of high-use internesting habitats for eastern Pacific leatherback turtles: role of the environment and implications for conservation

Satellite tracking of sea turtles: Where have we been and where do we go next?

Spotting the difference: towards fully-automated population monitoring of African penguins Spheniscus demersus

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