Habitat use by immature loggerhead sea turtles in the Algerian Basin (western Mediterranean): swimming behaviour, seasonality and dispersal pattern

Revelles, M.; Cardona, Luís; Aguilar, Àlex; Félix, M. San; Fernández, Gloria L. Gallardo

doi:10.1007/s00227-006-0602-z

Cited by 64 publications

(68 citation statements)

References 39 publications

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“…Moreover, 8 of 11 turtles had . Furthermore, given the sizes of turtles in this study, this would also be consistent with a transition by juvenile loggerhead turtles from passive to active swimmers at ~40 to 60 cm straight carapace length, as has been reported in the Atlantic Ocean and Mediterranean Sea (Bolten 2003, Cardona et al 2005, Revelles et al 2007). However, 3 loggerhead turtles, nos.…”

Section: Environmental Factorssupporting

confidence: 90%

“…Our findings suggest that a similar scenario occurs in the waters off Peru and northern Chile. Moreover, as has been observed in several studies of juvenile loggerhead turtles in the Mediterranean Sea, the animals in our study appeared to avoid the waters of the continental shelf (Cardona et al 2005, Revelles et al 2007, Monzón-Argüello et al 2009). This observation is reinforced by similar findings by Donoso & Dutton (2010) who report loggerhead turtles in pelagic waters offshore from northern Chile.…”

Section: Environmental Factorssupporting

confidence: 85%

“…The findings of Howell et al (2010) that juvenile loggerhead turtles in the central North Pacific Ocean spent > 90% of their time in the upper 15 m of the water column supports the notion of a pelagic foraging lifestyle for this life history stage in this species. Furthermore, if these juvenile turtles have poorly developed diving abilities (Bolten 2003, Cardona et al 2005, Revelles et al 2007) then they would not be able to exploit benthic prey found over the shelf and may therefore specialize in pelagic prey, similar to Baja California where the loggerhead turtle population feeds primarily or exclusively upon pelagic red crab Pleuroncodes planipes (Nichols et al 2000.…”

Section: Environmental Factorsmentioning

confidence: 99%

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Post-capture movements of loggerhead turtles in the southeastern Pacific Ocean assessed by satellite tracking

Mangel

Alfaro‐Shigueto²,

Witt³

et al. 2011

Mar. Ecol. Prog. Ser.

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The post-capture movements made by loggerhead sea turtles Caretta caretta in the southeastern Pacific Ocean were monitored from 2003 to 2007. Fourteen loggerhead turtles were fitted with satellite transmitters and released off the coast of Peru. All turtles were juveniles (curved carapace length range: 40.5 to 68.5 cm) incidentally captured by small-scale longline fishing vessels from southern or central Peru. Track durations were highly variable (mean ± SD: 143 ± 90 d; range: 8 to 297 d) with no clear signs of immediate post-release mortality. Upon release, all turtles moved offshore beyond the continental shelf. Eight of 11 turtles tracked for > 60 d had final displacements of < 750 km, suggesting that loggerhead turtles often maintain extended residency in these waters and that this area is an important foraging zone for loggerhead turtles of southwest Pacific origin. Satellite tracks also showed a substantial overlap of areas used by turtles with known Peruvian longline fishing effort. Turtles spent 75% of their time within the area fished by this fleet (based upon observed sets). This suggests that turtles are vulnerable to fishery interactions and that bycatch mitigation measures should be employed to minimize fishery impacts on loggerhead turtles. The loggerhead turtles tracked during this study spent ca. 51% of their time in Peruvian waters, 39% in international waters and 9% in Chilean waters, which emphasizes the need for a multinational approach to sea turtle conservation and fisheries management in the region.KEY WORDS: Caretta caretta · Peru · Chile · Small-scale fisheries · Bycatch · Habitat · Governance Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 433: [261][262][263][264][265][266][267][268][269][270][271][272] 2011 been linked through genetic analyses and satellite tracking to aggregations of juveniles and subadults found in the central and eastern Pacific (Bowen 1995, Nichols et al. 2000, Polovina et al. 2006, Howell et al. 2010. In the South Pacific Ocean, decades of intense monitoring in eastern Australia has helped in defining many aspects of the nesting and oceanic ecology of loggerhead turtles in the western South Pacific region and in describing declining trends in abundance of that population (Limpus & Limpus 2003a). However, it was not until 2004 that the species was confirmed in the southeastern Pacific Ocean (SEP) through a combination of onboard and shore-based fisheries monitoring (Alfaro-Shigueto et al. 2004). Genetic studies have shown that the juvenile loggerhead turtles found in the SEP originate from Australian and New Caledonian rookeries (Alfaro-Shigueto et al. 2004, Boyle et al. 2009). Additional reports now also confirm the occurrence of loggerhead turtles off Ecuador and Columbia (Alava 2008) and Chile to a latitude of 32° S (Donoso & Dutton 2010). Alfaro-Shigueto et al. (2008) report primarily small-to medium-sized juveniles and subadultsized turtles found off the Peruvian coast (curved carapace length [CCL]...

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Section: Environmental Factorssupporting

confidence: 90%

Section: Environmental Factorssupporting

confidence: 85%

Section: Environmental Factorsmentioning

confidence: 99%

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Post-capture movements of loggerhead turtles in the southeastern Pacific Ocean assessed by satellite tracking

Mangel

Alfaro‐Shigueto²,

Witt³

et al. 2011

Mar. Ecol. Prog. Ser.

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“…A degree of permanence in the same area was indicated by tag returns in the western and eastern Mediterranean (Casale et al 2007a), and was directly observed through satellite tracking in some cases in the western Mediterranean (Revelles et al 2007a) but not in others, either in the western (Cardona et al 2005;Eckert et al 2008;Cardona et al 2009) or in the eastern Mediterranean (Bentivegna 2002). In general, resident areas of juveniles in oceanic zones are much wider than in neritic zones (Revelles et al 2007b;Cardona et al 2009;Casale et al 2012aCasale et al , 2012b (Figure 4), as also observed for adults in the Mediterranean and elsewhere (Hawkes et al 2006;Schofield et al 2010a).…”

Section: Large Juvenilesmentioning

confidence: 82%

“…Some just wandered across wide areas, with no sign of residence at any specific site (Bentivegna 2002;Casale et al 2007a;Eckert et al 2008;Cardona et al 2009;Hochscheid et al 2010) (Figure 3). Others frequented somewhat smaller areas (Cardona et al 2005;Revelles et al 2007aRevelles et al , 2007bEckert et al 2008;Cardona et al 2009;Hochscheid et al 2010;Casale et al 2012aCasale et al , 2012b (Figure 3), in some cases remaining for a long time in very restricted sites (Hochscheid et al 2010;Mencacci et al 2011). The areas frequented and the routes followed are the result of a combination of surface circulation patterns and the turtles' active swimming Revelles et al 2007b).…”

Section: Large Juvenilesmentioning

confidence: 98%

Movement patterns of marine turtles in the Mediterranean Sea: a review

Luschi

Casale

2014

Italian Journal of Zoology

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Understanding the at-sea spatial behaviour of sea turtles is a priority for their conservation. In the present paper, the current information on the distribution and movement patterns of the two species breeding in the Mediterranean, the loggerhead and the green turtle, is reviewed, focusing mainly on the 195 published routes of satellite-tracked turtles. A satisfactory level of knowledge about adults' migrations and other movements is reached only for loggerheads breeding at Zakynthos Island, Greece, and for green and loggerhead females nesting in Cyprus, while studies at foraging grounds are limited to loggerheads in the western and central parts of the basin. Adult males and females mostly show quite uniform post-breeding migratory patterns, typically moving towards individually specific neritic foraging grounds. A much higher variability is shown by loggerhead juveniles, which is probably associated with differences in their spatial behaviour while in oceanic or neritic waters. Evidence of seasonal migrations driven by lower temperatures in winter is available only for adult and juvenile loggerheads frequenting the two northernmost parts of the basin, i.e. the Ligurian and the northern Adriatic Sea. Current knowledge gaps and priorities for further research in the Mediterranean are discussed.

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Readaptation to the wild of rehabilitated loggerhead sea turtles (Caretta caretta) assessed by satellite telemetry

Cardona

Fernández²,

Revelles

et al. 2011

Aquatic Conservation

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ABSTRACT1. Satellite telemetry was used to assess the readaptation to the wild of six loggerhead sea turtles after a long and complicated rehabilitation process. Their behaviour in the wild after release was compared with that of 12 healthy control turtles captured in the same region and fitted with similar satellite tags.2. The behaviour of the rehabilitated turtles was more variable than that of the control turtles and an outlier analysis revealed that only two of the six rehabilitated turtles did not differ in their behaviour from that of the control turtles. For the other turtles, the following anomalies were detected: a higher speed of travel, a negative cosine of the turning angle (the turtle turns back very often), a higher percentage of shelf use, a longer time at the surface at night, a higher averaged latitude during tracking, a shorter total tracking time and lower percentage of good quality fixes. Nevertheless, none of the turtles exhibited simultaneously these anomalies and only one turtle exhibited more than two anomalies.3. These results suggest that most rehabilitated loggerhead sea turtles survive in the wild at least for several months after release, even after a long and complicated process of veterinarian treatment, but many may exhibit behavioural anomalies, which casts doubts on the success of readaptation in the long run.

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Habitat use by immature loggerhead sea turtles in the Algerian Basin (western Mediterranean): swimming behaviour, seasonality and dispersal pattern

Cited by 64 publications

References 39 publications

Post-capture movements of loggerhead turtles in the southeastern Pacific Ocean assessed by satellite tracking

Post-capture movements of loggerhead turtles in the southeastern Pacific Ocean assessed by satellite tracking

Movement patterns of marine turtles in the Mediterranean Sea: a review

Readaptation to the wild of rehabilitated loggerhead sea turtles (Caretta caretta) assessed by satellite telemetry

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