Foraging grounds, movement patterns and habitat connectivity of juvenile loggerhead turtles (Caretta caretta) tracked from the Adriatic Sea

Casale, Paolo; Affronte, Marco; Scaravelli, Dino; Lazar, Bojan; Vallini, Carola; Luschi, Paolo

doi:10.1007/s00227-012-1937-2

Cited by 55 publications

(82 citation statements)

References 46 publications

(81 reference statements)

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“…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). Long-term residence of juveniles in neritic foraging grounds seems more common than in oceanic areas and it has been observed in various locations through tag returns (Casale et al 2007a;Revelles et al 2008) and satellite tracking Cardona et al 2009;Hochscheid et al 2010;Casale et al 2012aCasale et al , 2012bHochscheid et al 2013) (Figure 3). The juvenile neritic foraging sites are, however, usually larger than the adult neritic sites, with juveniles showing a propensity to wander over quite large areas (e.g.…”

Section: Large Juvenilessupporting

confidence: 60%

“…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). Long-term residence of juveniles in neritic foraging grounds seems more common than in oceanic areas and it has been observed in various locations through tag returns (Casale et al 2007a;Revelles et al 2008) and satellite tracking Cardona et al 2009;Hochscheid et al 2010;Casale et al 2012aCasale et al , 2012bHochscheid et al 2013) (Figure 3).…”

Section: Large Juvenilesmentioning

confidence: 83%

“…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%

“…Finally, a few adult-sized turtles (CCL between 68 and 87 cm) have been tracked upon release after a rehabilitation period in turtle rescue centres in Italy (Bentivegna 2002;Mencacci et al 2006;Casale et al 2012a;Luschi et al 2013). These turtles displayed a variety of movements, including seasonal migrations over large spatial scales, often made independently and even against main surface currents ).…”

Section: Adult Loggerhead Turtlesmentioning

confidence: 99%

“…In contrast, individuals foraging in the north Adriatic have been found to move southwards in winter, as observed also in adults (see above), and in the Ligurian Sea (Lauriano et al 2011). For instance, Casale et al (2012a) tracked one individual during a complete migration cycle, with an autumn southwards migration along the Italian coast in the western Adriatic and a northwards spring return to the very same site following a route along the eastern Adriatic coast (Figure 2). However, the same study also showed that other individuals remained in the northernmost and coldest part of the basin during the whole winter (Casale et al 2012a).…”

Section: Large Juvenilesmentioning

confidence: 99%

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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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Section: Large Juvenilessupporting

confidence: 60%

Section: Large Juvenilesmentioning

confidence: 83%

Section: Large Juvenilesmentioning

confidence: 98%

Section: Adult Loggerhead Turtlesmentioning

confidence: 99%

Section: Large Juvenilesmentioning

confidence: 99%

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

Luschi

Casale

2014

Italian Journal of Zoology

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Annual survival probabilities of juvenile loggerhead sea turtles indicate high anthropogenic impact on Mediterranean populations

Casale

Freggi

Furii

et al. 2014

Aquatic Conservation

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One of the major gaps in the knowledge of sea turtle population dynamics is survival probability, in particular of juveniles, which represent the bulk of the population and whose survival has the greatest effect on population growth. One of the major global threats to sea turtles is incidental bycatch, although not all animals die in the process. This is particularly acute for the loggerhead sea turtle (Caretta caretta). Here fisheries-dependent monitoring is used to seek insights into patterns of survival at multiple Mediterranean foraging areas: north and south Adriatic, north Ionian, and the Tunisian shelf. Annual survival probability was estimated using the catch curve method. Size data of 2191 loggerhead turtles ranging from 19 to 92cm curved carapace length were converted to age according to eight age-size curves available from the Mediterranean Sea. The mean annual survival probabilities for the four areas were heterogeneous and ranged between 0.710 and 0.862. Results suggest that the survival probabilities for Mediterranean loggerheads, especially in some areas, are lower than would be expected from a healthy population. This is of particular concern for the Greek rookeries, which appear most affected by anthropogenic mortality occurring in the study areas. This supports the implementation in those areas of measures mitigating the main threats, notably bycatch

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Seasonal encounter rate, life stages and main threats to the loggerhead sea turtle (Caretta caretta) in the Aeolian Archipelago (southern Thyrrenian Sea)

Blasi¹,

Mattei²

2017

Aquatic Conservation

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1. Annual and seasonal encounter rates, life stages and the main threats to loggerhead sea turtles (Caretta caretta) in the Aeolian Archipelago (southern Italy) were studied. 2. Dedicated boat surveys resulted in 258 surface observations and 138 captures of healthy (n = 309), ailing (n = 66) and dead (n = 21) turtles from 2009 to 2013.3. Loggerheads were encountered at the sea water surface while resting (87%) or feeding on pelagic prey (13%).4. The loggerhead encounter rate (observations per km surveyed) was higher during the autumn, suggesting the presence of potential foraging/overwintering habitats in the area.5. The mean (± SD) curved carapace length (CCL) was 48.8 ± 10.7 cm, with 65% of the individuals ranging from 40-70 cm in size. Smaller turtles were encountered more frequently during the spring months, probably as a result of the abundant pelagic prey within the coastal area. During the colder season, larger turtles were more common in the afternoon than in the morning, suggesting that the time needed for rewarming might increase with turtle size.6. Ingestion of anthropogenic debris was reported in 48.5% of the rescued turtles. Individual mortality was mainly related to longline fishing (70.6%), with debris entanglements/ingestion frequently associated with these records. Longline bycatch and boat collisions were higher in summer, whereas debris ingestion was highest in spring. Different threats might affect particular life stages because the longline bycatch was more frequent for larger turtles, whereas boat collisions were more frequent with smaller individuals. 7. Migratory patterns, habitat characteristics and seasonal changes in sea temperature and currents might influence the seasonal occurrence of loggerhead turtles in this area.8. These results increase the current ecological knowledge of the factors driving loggerhead turtle life and are important for implementing management plans for its conservation in the Mediterranean Sea.

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Foraging grounds, movement patterns and habitat connectivity of juvenile loggerhead turtles (Caretta caretta) tracked from the Adriatic Sea

Cited by 55 publications

References 46 publications

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

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

Annual survival probabilities of juvenile loggerhead sea turtles indicate high anthropogenic impact on Mediterranean populations

Seasonal encounter rate, life stages and main threats to the loggerhead sea turtle (Caretta caretta) in the Aeolian Archipelago (southern Thyrrenian Sea)

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