Identification of high‐use habitat and threats to leatherback sea turtles in northern waters: new directions for conservation

Abstract

Incidental capture in fisheries threatens many marine vertebrates, however, conservation cannot be effective without identifying major sources of mortality. For the critically endangered leatherback turtle (Dermochelys coriacea), a reliance on fisheries observer data and an absence of behavioural data sets corresponding to a large and diverse sample of animals have focused conservation efforts on a very limited part of the species marine habitat. Using the largest satellite telemetry data set for Atlantic leatherbacks, morphometrics from foraging animals and entanglement records, we show annual return migrations to key feeding areas by males, females and juveniles, and demonstrate the importance of northern latitudes to leatherbacks. We show that leatherbacks are vulnerable to entanglement in northern coastal and shelf waters, where turtle-fishery interactions represent a greater threat to this species than previously recognized. Unless conservation efforts expand to coastal and shelf areas, present efforts alone will not be sufficient to save the species.

Leatherback turtles: The menace of plastic

“…For instance, in the summer, in the NW Atlantic, leatherbacks migrate to foraging habitats off the Canadian Maritime Provinces. There the turtles become markedly fat, and these extra reserves are assumed to support the fall migration southwards to tropical waters, and the subsequent mating and egg laying (James et al, 2005). Whether decreased rates of energy assimilation delay departure southwards until cooler months, or whether departure occurs on time, but with smaller energy reserves, it might well reduce reproductive output.…”

Energy budget calculations indicate resource limitation in Eastern Pacific leatherback turtles

“…The recent dramatic decline in global leatherback populations is chiefly due to extensive egg-harvesting and adult mortality due to direct hunting and incidental fisheries interactions within the leatherbacks' extensive range (see analyses by Spotila et al 2000, Ferraroli et al 2004, Hays et al 2004, Lewison et al 2004, Troëng et al 2004, James et al 2005, Kaplan 2005). However, effects of climatically altered resource availability on energy acquisition, which have not been considered in these analyses, may also have significant impacts on the viability of leatherback populations.…”

“…Leatherbacks thermoregulate in varied thermal environments (Paladino et al 1990), make epic migrations (Morreale et al 1996, Eckert & Sarti 1997, Ferraroli et al 2004, Hays et al 2004, James et al 2005, have the fastest growth rate (Zug & Parham 1996) and largest reproductive output (Reina et al 2002) of any turtle, and are among the largest living reptile species (200 to 900 kg). Further, leatherbacks are specialist predators for gelatinous zooplankton prey (Bjorndal 1997).…”

Sea Turtles in Florida's Atlantic Waters

“…Eckert et al (2006) determined that the home-range of these animals was primarily along the continental shelf extending out to Gulf Stream waters east-southeast of Cape Canaveral and just off their nesting beaches. Adult female, adult male, and juvenile leatherback turtles tagged in waters off Nova Scotia, Canada, exhibited widely varied migration patterns throughout the western Atlantic Ocean (James et al, 2005). Individuals migrated to waters off nesting beaches as far south as the northeast coast of South America, Antilles, Panama, and Costa Rica, as well as continental shelf waters off the coast of the southeastern United States (James et al, 2005).…”

“…Leatherbacks primarily inhabit pelagic waters, make annual north-south migrations in the North Atlantic (Eckert, 1998;James et al, 2005;Eckert et al, 2006), and can swim over 10,000 km/yr often across entire ocean basins (Eckert, 1998;Hughes et al, 1998;Eckert et al, 2006). Post-nesting adult females were tracked from Florida's Atlantic beaches for durations of 38 to over 454 days (Eckert et al, 2006).…”