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In spite of the widespread occurrence of epibiotic turtle barnacles (Coronuloidea: Chelonibiidae and Platylepadidae) on extant marine turtles (Chelonioidea: Cheloniidae and Dermochelyidae), and although the association between these cirripedes and their chelonian hosts has existed for more than 30 million years, only a few studies have investigated the deep past of this iconic symbiotic relationship on palaeontological grounds. We describe probable platylepadid attachment scars in the form of hemispherical/hemiellipsoidal borings on an Upper Miocene (Tortonian) fragmentary turtle carapace, identified herein as belonging to Cheloniidae, from the Pisco Lagerstatte (East Pisco Basin, southern Peru). When coupled with the available molecular data, this and other similar ichnofossils allow for hypothesising that platylepadid symbionts were hosted by sea turtles as early as in early Oligocene times and became relatively widespread during the subsequent Miocene epoch. Chelonian fossils that preserve evidence of colonisation by platylepadid epibionts in the form of pits on the turtle shell should be regarded as fossil holobionts, i.e., palaeontological witnesses of discrete communal ecological units formed by a basibiont and the associated symbionts (including the epibiota). A greater attention to the bone modifications that may be detected on fossil turtle bones is expected to contribute significantly to the emerging field of palaeosymbiology.

The hawksbill turtle (Eretmochelys imbricata) is the most threatened sea turtle species in the world. An important aspect of the biology of sea turtles is the study of colonizing fauna, i.e., their epibiota. The aim of this study is a taxonomic determination on the epibiota found on 4 hawksbills turtles stranded in 2009 and 2011 on the coast of Rocha Department, Uruguay. The epibiota was composed by algae from the class Phaeophyceae (Sphacelaria sp. and Hincksia mitchelliae) and invertebrates from the classes Cirripedia (Platylepas hexastylos, Chelonibia testudinaria and Amphibalanus improvisus) and Hirudinea (Ozobranchus margoi), with greater predominance of P. hexastylos cirripeds (n= 365), a result that is consistent with other similar studies. Hincksia mitchelliae and A. improvisus are new reports as hawksbill turtles' epibiota.

This paper describes predation tactics used by the saltwater crocodile (Crocodylus porosus) on flatback (Natator depressus) and olive ridley (Lepidochelys olivacea) sea turtles on nesting beaches in northern Australia. For adult turtles, crocodiles used both a sit-and-wait tactic in which they attacked a turtle at the water's edge after it completed nesting and an active hunting strategy in which crocodiles followed turtle tracks into the dunes to attack turtles at nest sites. Saltwater crocodiles also hunted sea turtle hatchlings in the dunes and excavated a sea turtle nest and consumed the eggs. The protection of saltwater crocodiles in Australia starting in the early 1970s has led to increased population sizes and a greater proportion of larger individuals. This likely has resulted in increased predation rates on sea turtles over several decades, which should be considered as an important mortality component for some tropical nesting aggregations.

Field Island in Kakadu National Park, Northern Territory, Australia, supports a nesting population of flatback turtles (Natator depressus) monitored since 1990. We summarize 9 years of survey data for this location and make recommendations for future research. At least 221 nesting flatbacks were tagged at Field Island between 1990 and 2001. Nightly emergence rates indicate that Field Island is a locally and regionally important rookery for flatbacks with no other species recorded nesting. The mean interseasonal remigration period was 2.82 years. Female flatbacks laid clutches of similar sizes to those reported for other Australian rookeries, but nests tended to be deeper than those on nearby mainland beaches. No evidence of size decline (curved carapace length) occurred over the years, and mean curved carapace length was similar to those observed at other nesting rookeries. The amount of biological information now available for the Field Island rookery and the number of nesting turtles already tagged makes it valuable as an index site for flatback turtles in northern Australia.

Field Island in Kakadu National Park, Northern Territory, Australia, supports a nesting population of flatback turtles (Natator depressus) monitored since 1990. We summarize 9 years of survey data for this location and make recommendations for future research. At least 221 nesting flatbacks were tagged at Field Island between 1990 and 2001. Nightly emergence rates indicate that Field Island is a locally and regionally important rookery for flatbacks with no other species recorded nesting. The mean interseasonal remigration period was 2.82 years. Female flatbacks laid clutches of similar sizes to those reported for other Australian rookeries, but nests tended to be deeper than those on nearby mainland beaches. No evidence of size decline (curved carapace length) occurred over the years, and mean curved carapace length was similar to those observed at other nesting rookeries. The amount of biological information now available for the Field Island rookery and the number of nesting turtles already tagged makes it valuable as an index site for flatback turtles in northern Australia.

This report presents all registered catches of pelagic megafauna by the Dutch pelagic fleet in the Mauritanian Exclusive Economic Zone during the years 1999-2003. ‘By-catches’ incidentally include large species, notably cetaceans, sea turtles, sharks, rays, and some large pelagic fish such as swordfish and ocean sunfish. All observations were made in the framework of different projects of the Netherlands Institute for Fisheries Research (RIVO B.V.) in the area, financed by the Dutch Ministry of Agriculture, Nature Management, and Fisheries (LNV) and partly by the Redersvereniging voor Zeevisserij, part of the Pelagic Freezer-Trawler Association (PFA): “Assessment of Sardinella and other small pelagics in West Africa” (313-1230001), “Application of remote sensing data to analyse the distribution and recruitment of sardinella” (313-1230002), and “Preventing by-catches of protected or endangered species in the pelagic trawl fishery in West Africa” (313-1230003). The sampling procedures of incidentally caught pelagic megafauna on board of Dutch pelagic freezer-trawlers in Mauritania throughout the period 1999-2003 are evaluated in this report. The collected raw data on this by-catch of large species is whenever possible validated with an observation factor, shortcomings are discussed, and recommendations for improvements are given. This report presents raw data and explicitly avoids extrapolations up to mission or even fleet level.

De verspreiding van deze schildpad in Nederland en in Limburg en de vraag of dit een bedreiging vormt voor de inheemse herpetofauna. Geconcludeerd wordt dat er geen directe bedreiging is, maar dat de import van uitheemse diersoorten veel dierenleed veroorzaakt

The gut contents of five juvenile individuals of the loggerhead turtle Caretta caretta (L.) from waters around Madeira, Selvagem Grande (Selvagens Islands) and São Miguel (Azores) were analysed macro- and microscopically. Macroscopic investigations showed that epipelagic salps (e.g., Pyrosoma atlanticum Péron) and gastropods (e.g., Ianthina spp. and Pterotrachea spp.) constituted an important part of the food remains present in these loggerheads. To a lesser extent this also holds for organisms such as goose-barnacles (Lepas spp.). and Idotea metallica Bosc, which live on drifting materials, including algae. Microscopic examination revealed the presence in all turtles of large numbers of nematocysts, deriving mainly from Siphonophora and to a lesser extent from Scyphomedusae and Hydromedusae, indicating that pelagic coelenterates also formed an important, if not the most important part of the food consumed.

The gut contents of five juvenile individuals of the loggerhead turtle Caretta caretta (L.) from waters around Madeira, Selvagem Grande (Selvagens Islands) and São Miguel (Azores) were analysed macro- and microscopically. Macroscopic investigations showed that epipelagic salps (e.g., Pyrosoma atlanticum Péron) and gastropods (e.g., Ianthina spp. and Pterotrachea spp.) constituted an important part of the food remains present in these loggerheads. To a lesser extent this also holds for organisms such as goose-barnacles (Lepas spp.). and Idotea metallica Bosc, which live on drifting materials, including algae. Microscopic examination revealed the presence in all turtles of large numbers of nematocysts, deriving mainly from Siphonophora and to a lesser extent from Scyphomedusae and Hydromedusae, indicating that pelagic coelenterates also formed an important, if not the most important part of the food consumed.

The gut contents of five juvenile individuals of the loggerhead turtle Caretta caretta (L.) from waters around Madeira, Selvagem Grande (Selvagens Islands) and São Miguel (Azores) were analysed macro- and microscopically. Macroscopic investigations showed that epipelagic salps (e.g., Pyrosoma atlanticum Péron) and gastropods (e.g., Ianthina spp. and Pterotrachea spp.) constituted an important part of the food remains present in these loggerheads. To a lesser extent this also holds for organisms such as goose-barnacles (Lepas spp.). and Idotea metallica Bosc, which live on drifting materials, including algae. Microscopic examination revealed the presence in all turtles of large numbers of nematocysts, deriving mainly from Siphonophora and to a lesser extent from Scyphomedusae and Hydromedusae, indicating that pelagic coelenterates also formed an important, if not the most important part of the food consumed.