COSEWIC Assessment and Status Report on the Leatherback Sea Turtle Dermochelys coriacea Atlantic population Pacific population in Canada ENDANGERED 2012 COSEWIC status reports are working documents used in assigning the status of wildlife species suspected of being at risk. This report may be cited as follows: COSEWIC. 2012. COSEWIC assessment and status report on the Leatherback Sea Turtle Dermochelys coriacea in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xv + 58 pp. (www.registrelep-sararegistry.gc.ca/default_e.cfm). Previous report(s): COSEWIC. 2001. COSEWIC assessment and update status report on the leatherback turtle Dermochelys coriacea in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 25 pp. James, M.C. 2001. Update COSEWIC status report on the leatherback turtle Dermochelys coriacea in Canada, in COSEWIC assessment and update status report on the leatherback turtle Dermochelys coriacea in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 1-25 pp. Look, F.R. 1981. COSEWIC status report on the leatherback turtle Dermochelys coriacea in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 20 pp. Production note: COSEWIC would like to acknowledge Kathleen Martin for writing the status report on Leatherback Sea Turtle Dermochelys coriacea in Canada, prepared under contract with Environment Canada. This report was overseen and edited by Ron Brooks, Co-chair of the COSEWIC Amphibians and Reptiles Specialist Subcommittee, with support from the Amphibians and Reptiles Specialist Subcommittee. For additional copies contact: COSEWIC Secretariat c/o Canadian Wildlife Service Environment Canada Ottawa, ON K1A 0H3 Tel.: 819-953-3215 Fax: 819-994-3684 E-mail: COSEWIC/[email protected] http://www.cosewic.gc.ca Également disponible en français sous le titre Ếvaluation et Rapport de situation du COSEPAC sur la Tortue luth (Dermochelys coriacea) au Canada. Cover illustration/photo: Leatherback Sea Turtle — Photo credit: Canadian Sea Turtle Network 2010. Her Majesty the Queen in Right of Canada, 2012. Catalogue No. CW69-14/116-2012E-PDF ISBN 978-1-100-20724-7 Recycled paper COSEWIC Assessment Summary Assessment Summary – May 2012 Common name Leatherback Sea Turtle - Atlantic population Scientific name Dermochelys coriacea Status Endangered Reason for designation Globally, this species is estimated to have declined by more than 70%. In the Atlantic, this species continues to be impacted by fisheries bycatch, coastal and offshore resource development, marine pollution, poaching of eggs, changes to nesting beaches and climate change. Canadian waters provide an important foraging area for these turtles. There they are threatened by entanglement in longline and fixed fishing gear. Occurrence Atlantic Ocean Status history The species was considered a single unit and designated Endangered in April 1981. Status re-examined and confirmed in May 2001. Split into two populations in May 2012. The Atlantic population was designated Endangered in May 2012. Assessment Summary – May 2012 Common name Leatherback Sea Turtle - Pacific population Scientific name Dermochelys coriacea Status Endangered Reason for designation The Pacific population of this species has collapsed by over 90% in the last generation. Continuing threats include fisheries bycatch, marine debris, coastal and offshore resource development, illegal harvest of eggs and turtles, and climate change. Occurrence Pacific Ocean Status history The species was considered a single unit and designated Endangered in April 1981. Status re-examined and confirmed in May 2001. Split into two populations in May 2012. The Pacific population was designated Endangered in May 2012. iii COSEWIC Executive Summary Leatherback Sea Turtle Dermochelys coriacea Atlantic population Pacific population Wildlife Species Description and Significance The Leatherback Sea Turtle (Dermochelys coriacea) is the largest of the seven extant species of marine turtles, and is the sole living member of the family Dermochelyidae. The leatherback has a shell covered by a leathery, slightly flexible, fibrous tissue embedded with tiny bones (osteoderms). The carapace is teardrop- shaped and has seven conspicuous longitudinal ridges. It is dark bluish-black, and the carapace, neck, head and front flippers are often covered with white, or bluish-white, blotches. The plastron is pinkish-white. Adults have a distinct pink spot on the top of the head. Adult Leatherback Sea Turtles attain a straight line carapace length of over 2 m, and a mass of 900 kg. Most individuals found in Atlantic Canadian waters are large sub- adults or adults. They can attain a body mass of 640 kg and reach a curved carapace length of 175 cm. Comparable data are not available from Pacific Canadian waters. Distribution The Leatherback Sea Turtle is found in the tropical and temperate waters of the Atlantic, Pacific and Indian oceans, with a range extending from approximately 71ºN to approximately 47ºS. The species nests, usually at tropical latitudes, on Caribbean and the Indo-Pacific islands, and along the shores of every continent except Europe and Antarctica. This species does not nest in Canada. iv Leatherbacks found in Atlantic Canada originate from nesting assemblages in the western North Atlantic and are widely distributed in Canadian waters, inhabiting both shelf and offshore waters between April and December where they forage on seasonally abundant gelatinous zooplankton (primarily jellyfish). Leatherback Sea Turtles are infrequently observed in Pacific Canadian waters. Observations are primarily in waters off Vancouver Island and Haida Gwaii from July to September. It is presumed that leatherbacks reach Pacific Canadian waters from California and Oregon either after crossing from Indonesia and the Solomon Islands or after swimming north from eastern Pacific nesting beaches in Mexico and Costa Rica. However, their origins have not been confirmed through DNA analysis. Habitat Leatherback Sea Turtles nest on land, but spend the rest of their lives at sea. After emerging from nests laid on sandy beaches, Leatherback Sea Turtle hatchlings move immediately to the marine environment. Male turtles never return to land. Female turtles return only to nest. Little is known about the movements or habitat needs of hatchling, juvenile and sub-adult Leatherback Sea Turtles. Adults make long-distance pelagic migrations sometimes over 10,000 km/year. Foraging grounds for turtles originating from western Atlantic nesting beaches are primarily located at temperate latitudes and include oceanic, coastal and continental shelf (neritic) habitats. Leatherbacks in Atlantic Canada occur in both offshore and coastal waters (range 2 to 5,033 m depth). Most sightings are from continental shelf (waters inside the 200 m isobath). Median depth of sightings is 113 m and mean sea surface temperature (SST) is 16.6ºC. Biology There are five stages in the Leatherback Sea Turtle life cycle: egg and hatchling; post-hatchling; juvenile; sub-adult; and adult. Age at maturity has still not been conclusively determined, and recent estimates range from 16-29 years. There are no estimates of age composition of populations and growth rates in the wild are unknown. The sex ratio is female-biased (1.86:1). Males linger offshore or travel among nesting beaches in advance of and until the peak of the nesting season. Females nest at 2- to 4-year intervals. The nesting season lasts 3 to 6 months and varies geographically. Females lay several clutches of approximately 80 eggs, typically at 8- to 12-day intervals. Incubation time is approximately 60 days. v Population Sizes and Trends The size of the seasonal Leatherback Sea Turtle foraging population in Canada is not known, but sightings data suggest that it numbers in the thousands in Atlantic waters but many fewer in Pacific waters. Population estimates are currently based on abundance of adult females encountered on nesting beaches. Recent estimates range from 34,000 to 94,000 adults (males and females) in the North Atlantic. Leatherback Sea Turtle sightings in Pacific Canadian waters are sparse and the number of turtles using these waters is not known. The beaches from which they likely originate have had their numbers of nesting females reduced by more than 90%. Current data on Leatherback Sea Turtles are insufficient to determine fluctuations and trends in the population in Canadian waters. Most major western Atlantic nesting populations may be stable or increasing slightly. In contrast, most nesting colonies in the Pacific are in steep decline, falling as much as 95% in less than one generation. Threats and Limiting Factors The primary threat to Leatherback Sea Turtles in Canadian waters is bycatch in fisheries. Individuals are vulnerable to entanglement in buoy lines, mooring lines, trip lines (or secondary buoy lines) and hi-flier lines, as well as in monofilament, cotton and polypropylene netting. Globally, the species faces a host of threats from fisheries bycatch, non-fisheries resource use (e.g., poaching), ship strikes, marine debris, construction and development, chemical pollution, ecosystem alterations, oil and gas exploration, and effects of climate change on nesting beaches and marine habitat. Protection, Status, and Ranks In Canada, Leatherback Sea Turtles are listed as “endangered” under the Species at Risk Act and also fall under the Fisheries Act and the Oceans Act. Since 2009, the species has been listed as Threatened