Leatherback Sea turtle (depleted or rare species) within the PBGB LOMA

Transcription

1 Leatherback Sea turtle (depleted or rare species) within the PBGB LOMA Potentially Harmful Activity (X) Potentially Harmful Stressor (X) Bottom trawl Oil pollution X Fishing Scallop dredges Marine Industrial effluent pollution Clam dredges Fishplant effluent Midwater trawl Sewage Gillnets (bottom) X Historic military waste Gillnets (pelagic) X Long range transport of nutrients Longline X Acid rain Seine (pelagic) Persistent Organic Pollutants X Recreational cod fishery ( Eutrophication ) Crab pots X Ghost nets X Lobster pots Litter X Whelk pots X Other contaminants (specify) Other (specify) Ice distribution Otter trapping Climate Temperature change Other Change Seal hunt Sea-level rise harvest Seabird hunt Ocean acidification Seaweed harvest Current shifts Anchor drops/drags Increased storm events Seabed Ore spill Increased UV light alteration Fish offal dumping Oxygen depletion Finfish aquaculture Changes in freshwater runoff Dredge spoil dumping Other (specify) Dredging Green crab Mining/Oil & gas drilling Harmful Membranipora species Cables Golden Star Tunicate Freshwater diversion Violet Tunicate Coastal Subtidal construction Vase Tunicate alteration Intertidal/coastal Codium fragile construction Clubbed Tunicate Other (specify) Didemnum Vessel traffic X Harmful Algal Blooms Disturbance Ship strikes X Disease organisms (human waste) Ecotourism Disease organisms (aquaculture) Marine construction Other (specify) Seismic surveys Navy sonar Other Other (specify)

2 Background Information The leatherback turtle is the most widely distributed of all sea turtles, with individuals undertaking extensive migrations between tropical and temperate waters. At-sea field research confirms that leatherbacks from multiple nesting colonies aggregate annually off Canada s Atlantic coast. Therefore, Canadian efforts to promote recovery of this endangered reptile have global implications. Coastal and slope waters of the NW Atlantic provide high-use foraging habitat for leatherbacks. Fisheries interactions are an important source of injury and mortality for leatherbacks in temperate waters.(james, M. C., Sherrill-Mix, S. A., & Myers, R. A., 2007) 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. The global decline of leatherbacks has also been largely attributed to incidental capture in fisheries, with pelagic longlines proposed as a key threat. However, leatherbacks caught in pelagic longlines are normally entangled or hooked externally by this mobile gear, and are usually capable of swimming to the surface to breathe. Therefore, for leatherback turtles, entanglement in pelagic longlines does not necessarily lead to mortality. In fact, observer data reveals that very few turtles are discovered dead on pelagic longlines, although post-release mortality remains unknown. Of 323 leatherbacks observed interacting with US pelagic longline gear in 2001 and 2002, only one (0.3%) was found dead (Garrison 2003). In contrast, as our data suggest, fishing gear anchored to the bottom (fixed gear) in shelf waters may lead to higher mortality per interaction because turtles entangled at depth or at the surface at low tide will almost certainly drown. As fixed gear fisheries receive relatively little observer coverage, the magnitude of the threat they pose to leatherbacks has not been adequately recognized nor addressed. As in Canadian waters, leatherbacks are regularly entangled in fixed gear in US waters off New York through Maine (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005) Feeding behavior may also put leatherbacks at risk more indirectly. Since the horizontal movement of jellyfish is largely passive (van der Spoel, 1991). They tend to concentrate where currents converge. These same currents concentrate other buoyant objects, including marine debris (e.g., plastic bags, discarded and lost fishing gear, etc.). Therefore, leatherbacks foraging in areas where jellyfish are concentrated may encounter significant amounts of potentially harmful materials of anthropogenic origin (Carr, 1987). These convergence zones and other areas of high productivity also attract commercially valuable species of fish inadvertently bringing leatherbacks into contact with fishing gear (James, M. C. & Herman, T. B., 2001). When dead leatherbacks wash ashore, plastics are commonly found in their digestive tracts. Leatherbacks are known to ingest plastic sheeting, tar halls, monofilament, styrofoam, and other marine debris of anthropogenic origin. These materials can directly affect the survival of marine turtles by causing fatal blockages in the digestive tract. Moreover, the potential toxic effects of such ingestion, while poorly understood, may be significant.

3 While in Canadian waters, leatherbacks forage on large jellyfish species which mainly occur in northern coastal areas. Seasonal increases in water temperature have been shown to be important to both sexual development and the onset of reproduction in Cyanea and related species. Rapid spring increases in coastal water temperatures linked to exponential growth in C. capillata and A. aurita first occur in southern parts of eastern Canada, with more northerly areas reaching peak seasonal temperatures later in the season. The spatio-temporal seasonal patterns in leatherback distributions inferred from sightings data likely parallel the seasonal cycles of C. capillata and other gelatinous leatherback prey, with turtles exploiting emerging food resources and then departing northern waters when prey densities decline. Similarly, variation in the temporal distribution of leatherback sightings between years may reflect inter-annual differences in the timing of various stages of development of Cyanea and other scyphomedusae (for details, see Brewer and Feingold, 1991). The present findings, satellite telemetry studies and data from pelagic fisheries observer programs all point to coastal and slope waters of the western Atlantic north of 38_N as preferred summer and fall foraging habitat for leatherbacks.(james, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A., 2006) Scoping Gillnet (bottom): Leatherbacks are highly prone to entanglement in fishing gear, especially gillnets. Incidental capture in fisheries is considered a leading cause of leatherback population decline (James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A., 2006). The susceptibility of leatherbacks to entanglements may result from their large body size, long pectoral flippers and soft shell. Leatherbacks are unable to swim backwards, and this reduces their ability to avoid entanglement or free themselves once they become entangled (Fisheries and Oceans Canada, 2004). Gillnets are used widely within the LOMA, inshore and offshore, focusing on areas of high productivity which are also areas where whales aggregate. Screened in. Gillnets (pelagic): Pelagic gillnets were traditionally used in inshore waters to target Atlantic salmon and other pelagics such as herring and mackerel, and were responsible for significant bycatch of seabirds and cetaceans. In 1992, a moratorium and voluntary license buyout program was introduced for Atlantic salmon in Newfoundland as a conservation measure, and use of pelagic gillnets within the LOMA is greatly reduced. Herring is currently the dominant pelagic species landed, and accounts for less than 2% of the total landings in the LOMA, and purse seine and traps are responsible for the majority of the catch (Fisheries and Oceans Canada, 2008). As a result, pelagic gillnets are not considered a key activity or stressor within the LOMA. Screened out. Longlines: The recovery strategy for leatherbacks in Atlantic Canadian waters identifies both pelagic and demersal longlines as gear with a high potential to entangle leatherback turtles (Atlantic Leatherback Turtle Recovery Team, 2006). Turtle interactions are well

4 documented in pelagic longline fisheries targeting swordfish and tuna in Atlantic Canadian waters. For example 28 interactions were recorded in 2001, and 37 in 2002 with 20% observer coverage (Atlantic Leatherback Turtle Recovery Team, 2006). Leatherback entanglement in the vertical lines of the demersal longline fishery has also been recorded (Atlantic Leatherback Turtle Recovery Team, 2006). Screened in. Crab pots: There issignificant use of crab pots (Fisheries and Oceans Canada, 2007) within the LOMA, particularly off the south coast, northeastern areas of the LOMA and areas of the shelf edge and slope. Crab pots may be set singly or in strings, and are attached by ropes to surface buoys. In Newfoundland waters, crab pots are generally linked together in a long chain by groundlines which float in the water column many meters off the bottom. The Newfoundland and Labrador Whale Release and Strandings Program reported significant entanglement of leatherbacks in crab pots (Ledwell, W. & Huntington, J., 2007). Both ground lines and lines to surface buoys are responsible for frequent entanglement. The use of lead (heavy) groundlines can minimize entanglement in crab pots, but this mitigation is not widely adopted. Screened in. Whelk pots: Whelk pots can be set singly or in strings, and are attached by ropes to surface buoys. Both ground lines and lines to surface buoys are responsible for entanglement of large marine mammals and leatherback turtles. The whelk fishery within the LOMA is currently focused on St. Pierre Bank and average annual landings ( ) amount to 571t or about 0.7% of the total landings for the LOMA (Fisheries and Oceans Canada, 2008). Given the relatively low level of effort in the LOMA using this gear, whelk pots are not considered a key stressor within the LOMA. Screened out Ship strikes: Leatherback turtles breathe air, and feed on planktonic jellyfish, and so spend much of their time near the sea surface where they are vulnerable to ship strikes. Historical records suggest that fatal ship strikes involving whales first began in the late 1800s when ships began to reach speeds of knots, and increased over the last 50 years as the number and speed of ships increased, but little information is available in relation to leatherbacks. A number of major shipping routes traverse the LOMA, and leatherbacks may be particularly vulnerable to ship strikes due to their large size and habitat of feeding and basking on the sea surface. Screened in. Oil pollution: The LOMA has a moderate risk of oil pollution with numerous sources of chronic oil (ports, urban runoff, ballast bilge and production water) and sources of accidental spills (tanker traffic, shipping, fishing, oil storage, refining and transhipment). The leatherback is relatively resistant to the effects of oil due to its thick leathery hide and lack of sensitive features such as fur, feathers or gills, and its high mobility. However, at times, oil can foul the skin or be ingested through breathing or feeding at the site of a spill, or through ingestion of contaminated prey, causing soft tissue irritation and acute or chronic toxicity. Since leatherbacks are not particularly sensitive to oil pollution, and the risk of

5 interaction between a leatherback and an oil spill within the LOMA is relatively low, this is not considered a key stressor. Screened out. Ghost nets: Since the 1960s when non-biodegradable synthetic ropes, buoys and netting gradually replaced traditional biodegradable materials, lost fishing nets known as ghost nets, have become a serious threat to marine ecosystem health. Due to the high intensity of fishing activity in the LOMA and the dynamic nature of the environment, loss of gear is likely significant, and leatherback turtles may be vulnerable to this stressor. Screened in. Litter: Leatherbacks depend on prey with very little nutritive content and since this species diet of jellyfish is high in water and low in organic content, they must consume large quantities of food to fulfill their food energy requirements. This is the only known biological limiting factor in Canadian waters (Atlantic Leatherback Turtle Recovery Team, 2006). Their specialized diet may make leatherbacks vulnerable to ingestion of plastics and other buoyant marine debris. This behaviour is adaptive in exploiting large concentrations of jellyfish, and leatherbacks will readily consume a variety of inedible buoyant objects such as plastic bags, styrofoam, balloons, condoms and plastic sheeting. Since marine debris accumulates at convergence zones where prey is also naturally concentrated, the magnitude of the threat that ingestion of marine debris poses may be grossly underestimated (Barreiros, J. & Barcelos, J., 2001; James, M. C. & Herman, T. B., 2001). Sources of plastic debris within the LOMA include fishing vessels and shipping as well as land-based sources. Ocean gyres are known to accumulate plastic debris from distant sources, and although there is no data on densities of plastic debris in gyres within the LOMA, data showing high accumulations of debris on beaches of isolated island such as Sable island indicates that there is a significant problem in the northwest Atlantic. This is supported by data from leatherback mortalities retrieved in the LOMA with accumulations of ingested plastic. Screened in. Persistent organic pollutants (POPs): Leatherback turtles are large reptiles, but feed very low on the food chain, with jellyfish being their preferred prey. As a result, they are not likely to accumulate POPs to any significant extent, unlike the smaller piscivorous whales and fish such as belugas and tunas. Screened out. Key Activities/Stressors: Gillnets (groundfish) Long Lines Crab pots Ship strikes Ghost nets Litter

6 Reference List 1. Atlantic Leatherback Turtle Recovery Team (2006). Recovery Strategy for Leatherback Turtle (Dermochelys coriacea) in Atlantic Canada (Rep. No. Species at Risk Act Recovery Strategy Series ). Ottawa: Fisheries and Oceans Canada. 2. Barreiros, J. & Barcelos, J. (2001). Plastic Ingestion by a Leatherback Turtle Dermochelys coriacea from the Azores (NE Atlantic). Marine Pollution Bulletin, 42, Fisheries and Oceans Canada. Underwater World Aquatic Species at Risk - The Leatherback Turtle Ottawa, Ont. Ref Type: Pamphlet 4. Fisheries and Oceans Canada. The Grand Banks of Newfoundland: Atlas of Human Activities. The Grand Banks of Newfoundland: Atlas of Human Activities Fisheries and Oceans Canada. Ref Type: Map 5. Fisheries and Oceans Canada LMNOP4R Effort and Catch. Policy and Economics Branch. [Newfoundland and Labrador Region Catch and Effort] Fisheries and Oceans Canada. Ref Type: Data File 6. James, M. C. & Herman, T. B. (2001). Feeding of Dermochelys coriacea on Medusae in the Northwest Atlantic. Chelonian Conservation and Biology, 4, James, M. C., Ottensmeyer, C. A., & Myers, R. A. (2005). Identification of high-use habitat and threats to leatherback sea turtles in northern waters: new directions for conservation. Ecology Letters, 8, James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A. (2006). Canadian waters provide critical foraging habitat for leatherback sea turtles. Biological Conservation, 133, James, M. C., Sherrill-Mix, S. A., & Myers, R. A. (2007). Population characteristics and seasonal migrations of leatherback sea turtles at high latitudes. Marine Ecology Progress Series, 337, Ledwell, W. & Huntington, J. (2007). Whale and leatherback sea turtles incidental entrapment in fishing gear in Newfoundland and Labrador and a summary of the Whale Release and Strandings Program during 2006 A Report to the Department of Fisheries and Oceans, St. John's, Newfoundland and Labrador, Canada.

7 Leatherback Seaturtle in Placentia Bay Grand Banks LOMA Gillnet (bottom) Magnitude of Interaction Areal extent: Leatherback turtles have not been systematically surveyed around Newfoundland and distribution maps rely largely on opportunistic reporting and tracking of small numbers of individual leatherbacks. The primary determinant of movement and behaviour of leatherbacks is the spatial and temporal distribution of their primary prey, gelatinous plankton generally known as jellyfish. In general jellyfish abundance is highest in coastal waters (James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A., 2006) James et al. identified spatial use of leatherbacks in the western Atlantic through satellite tracking tags on 38 turtles (Fig. 1, below): Figure 1. Spatial use of Leatherbacks in the Western Atlantic (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005). This data was updated by the Turtle Expert Working Group in 2007 and is shown in Fig. 2 below:: Figure 2. Habitat use by Leatherback Turtles on foraging Grounds in the northwest Atlantic (Turtle Expert Working Group, 2007). 1

8 The Atlantic Leatherback Turtle Recovery Team mapped leatherback occurrence and areas of concentrations which are shown in Fig. 3 below: Figure 3. Occurrence of the leatherback turtle, Dermochelys coriacea, off eastern Canada. Shaded areas show the location of concentrations of observations (Atlantic Leatherback Turtle Recovery Team, 2006). This information indicates that leatherbacks are broadly distributed throughout southern, and coastal areas of the LOMA, including areas outside the 200 mile limit where gillnet fishing is minimal. Geo-referenced demersal gillnet fishing locations are available for vessels over 35ft (Fig 4 below) with major demersal gillnet fisheries in the LOMA targeting American plaice, Atlantic cod, grey sole, witch flounder, haddock, white hake, halibut, lumpfish, pollock, redfish Greenland halibut, skate, winter flounder and yellowtail flounder. Figure 4. Areal extent of gillnet fisheries (vessels > 35ft), Newfoundland Region fisheries, (Fisheries and Oceans Canada, 2008). Areal extent of gillnet (108,000km 2 ). 2

9 There is also a significant inshore gillnet fishery, largely targeting cod (3Ps), lumpfish and winter flounder. Based on this information we have estimated an area of overlap of 80% Score 8 Contact: Quantitative Fishing Gear Score (Fisheries and Oceans Canada, 2007) for contact between bottom gillnets and leatherback are low (0-25%). Turtle fishery interactions represent a greater threat to leatherback turtles than previously recognized. Data suggests that fishing gear anchored to the bottom (fixed gear) may lead to higher mortality per interaction because turtles entangled at depth or at the surface at low tide, will almost certainly drown. As fixed gear fisheries receive relatively little observer coverage, the magnitude of the threat they pose to leatherbacks has not been adequately recognized. Leatherbacks are regularly entangled in fixed gear in Canadian waters (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005). Since entanglement in fishing gear has been identified as a significant threat to leatherbacks in the region (Atlantic Leatherback Turtle Recovery Team, 2006; Griffin, E., Miller, K. L., Harris, S., & Allison, D., 2008; Ledwell, W. & Huntington, J., 2007), have selected a score at the high end of the low range Score 3.5 Duration: Leatherbacks are typically present in the LOMA from June to October (Atlantic Leatherback Turtle Recovery Team, 2006) Gillnet fishing occurs from May 1 to Feb 28 or 100% of the time occupied by the CP. Score 10 Intensity: Global maps (Halpern et al., 2008) for demersal non-destructive fisheries with high bycatch, which include gillnets, shows medium (light blue) to high (orange) intensity relative to global levels, for a score range of 20% to 80% (see figure below). Map colour Red Orange Yellow Light Blue Dark Blue Intensity % 60-80% 40-60% 20-40% 0-20% Figure 5. Global intensity of demersal non-destructive fisheries (adapted from (Halpern et al., 2008)). 3

10 This map can be used to provide guidance in scoring the intensity of a stressor in relation to maximum (100%) intensity in a global context, in accordance with the scale provided below. Halpern s fishing maps are based on ( ) data, and best represent NAFO fisheries. Halpern s map indicates a moderate intensity of gillnet fishing within the LOMA Gillnet fisheries within the LOMA represented an average of 9% of the landings from , however, in the Southwest Shelf Edge and Slope EBSA, gillnets accounted for 30% of landings from (Fisheries and Oceans Canada, 2008). We have selected an intermediate score of 50% as suggested by Halpern s map. Score 5 Magnitude of Interaction: (8 x 3.5 x 10 x 5)/1000 = 1.4 Sensitivity: Sensitivity of the CP to acute impacts: Quantitative Fishing Gear Scores (Fisheries and Oceans Canada, 2007) for harm resulting from an interaction between bottom gillnets and sea turtles range from 0 (rarely) to high (> 75% of the time). Fisheries where scores for harm is high include Atlantic wide vessels , and Greenland Halibut vessels less than 65 for 2GHJ3KLMNO. Incidental capture in fisheries is considered a leading cause of leatherback population decline (James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A., 2006). The susceptibility of leatherbacks to entanglements may result from their large body size, long pectoral flippers and soft shell. Leatherbacks are unable to swim backwards, and this reduces their ability to avoid entanglement or free themselves once they become entangled (Fisheries and Oceans Canada, 2004). Acute impacts due to entanglement may vary in severity from trivial to lethal depending on the extent of the entanglement. Entanglement of leatherbacks beneath the surface generally leads to death through drowning since the turtle is unable to reach the surface to breath. Even if the turtle is able to free themselves, serious injuries may be sustained, or gear may remain attached to the turtle leading to chronic impacts (Atlantic Leatherback Turtle Recovery Team, 2006). Data suggests that fishing gear anchored to the bottom (fixed gear) may lead to higher mortality per interaction because turtles entangled at depth or at the surface at low tide will almost certainly drown. As fixed gear fisheries receive relatively little observer coverage, the magnitude of the threat they pose to leatherbacks has not been adequately recognized nor addressed. Leatherbacks are regularly entangled in Canadian waters (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005). Since entanglement in fishing gear has been identified as a significant stressor to leatherbacks in the region (Atlantic Leatherback Turtle Recovery Team, 2006; Griffin, E., Miller, K. L., Harris, S., & Allison, D., 2008; Ledwell, W. & Huntington, J., 2007), we have selected a score at the high end of the moderate range. Score 7 4

11 Sensitivity of the CP to chronic impacts: A long lifespan, very high rates of egg and hatchling mortality, and a late age of maturity makes this species unusually vulnerable to even small increases in rates of mortality of adults and older juveniles. Generation time is estimated at <30 years (COSEWIC & James, M. C., 2001). The leatherback turtle is classified as critically endangered by the International Union for the Conservation of Nature and as endangered by the Committee on the Status of Endangered Wildlife in Canada. Leatherbacks have experienced a dramatic population decline of more than 60 per cent since Currently, the total number of nesting females is thought to be less than 35,000 worldwide (Fisheries and Oceans Canada, 2004). The Atlantic population appears to be more stable, but shows dramatic fluctuations from year to year. The relative density of leatherbacks in Canadian waters has been estimated at turtles (during summer), but this is likely low, as there are no accurate population estimates for leatherbacks in Canadian waters (COSEWIC & James, M. C., 2001). Chronic impacts of entanglement may include population decline or morbidity ranging from minor rope cuts, to debilitating impacts due to severe injuries or gear remaining attached and/or imbedded in the turtle. In these cases, the ability of the animal to move and feed may be compromised by injuries, infection, and interference with vital body functions (rope/netting confining limb, neck or mouth movement) or by the weight of gear. In severe cases death may occur months or even years later as a result of starvation or chronic infection (Atlantic Leatherback Turtle Recovery Team, 2006) Turtles towing gear for any length of time are unlikely to free themselves, and are more likely to become entangled again. Given the poor recovery rate for serious interactions, low reproductive rates and depleted status of the CP, we have selected a moderate score (5.5) for chronic sensitivity. Leatherbacks are listed as a depleted species for the LOMA (add 1 point) Score 6.5 Sensitivity of ecosystem to harmful impacts to the CP: Leatherbacks depend on prey with very little nutritive content and since this species diet of jellyfish is high in water and low in organic content, they must consume large quantities of food to fulfill their food energy requirements (Atlantic Leatherback Turtle Recovery Team, 2006). Jellyfish are generally considered a nuisance species, which can foul fishing gear and force the closure of swimming beaches. Jellyfish also compete with larval fish for food (both eat zooplankton), and are also known predators of larval fish (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005). Leatherbacks help keep the jellyfish population under control, and may therefore help conserve fish species. Despite their relatively small numbers, leatherbacks represent a significant biomass due to their large size, and contribute significantly to the energetics of the marine ecosystem. Leatherbacks are highly mobile, and their large scale movements contribute to the 5

12 Due to their large size and habit of basking on the sea surface, leatherbacks have long attracted interest, and their presence within the LOMA contributes to ecotourism opportunities. Canadian waters support one of the highest summer and fall densities of leatherbacks in the North Atlantic, and should be considered critical foraging habitat for this endangered species (James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A., 2006). Although areas within the LOMA have been identified as important areas for leatherback aggregation and feeding, leatherbacks are widely distributed within the Northwest Atlantic during the summer months and other areas may be of equal or greater importance. Based on this information we have selected a score in the medium range to reflect the importance of the leatherback within the LOMA. Score 6 Sensitivity: ( )/3 = 6.5 Risk of Harm: 1.4 x 6.5 = 9.1 6

13 Certainty Checklist Answer yes or no to all of the following questions. Record the number of NO s to the 9 questions, and record certainty according to the scale provided below: 1 No s = High certainty 2-3 No s = Medium certainty > 4 No s = Low certainty Y/N Y Is the score supported by a large body of information? N Is the score supported by general expert agreement? N Is the interaction well understood, without major information gaps/sources of error? Y Is the current level of understanding based on empirical data rather than models, anecdotal information or probable scenarios? Y Is the score supported by data which is specific to the region, (EBSA, LOMA, NW Atlantic? Y Is the score supported by recent data or research (the last 10 years or less)? N Is the score supported by long-term data sets (ten years or more) from multiple surveys (5 years or more)? Y Do you have a reasonable level of comfort in the scoring/conclusions? N Do you have a high level of confidence in the scoring/conclusions? Score: Low For interactions with Low certainty, underline the main factor(s) contributing to the uncertainty Lack of comprehensive data Lack of expert agreement Predictions based of future scenarios which are difficult to predict Other (provide explanation) Suggest possible research to address uncertainty: Improved observer coverage of gillnet fisheries 7

14 Reference List 1. Atlantic Leatherback Turtle Recovery Team (2006). Recovery Strategy for Leatherback Turtle (Dermochelys coriacea) in Atlantic Canada (Rep. No. Species at Risk Act Recovery Strategy Series ). Ottawa: Fisheries and Oceans Canada. 2. COSEWIC & James, M. C. (2001). COSEWIC Assessment and Update Status Report on the Leatherback Turtle Dermochelys coriacea in Canada Ottawa: Committee on the Status of Endangered Wildlife in Canada. 3. Fisheries and Oceans Canada. Underwater World Aquatic Species at Risk - The Leatherback Turtle Ottawa, Ont. Ref Type: Pamphlet 4. Fisheries and Oceans Canada (2007). Placentia Bay-Grand Banks Large Ocean Management Area Conservation Objectives (Rep. No. 2007/042). Canadian Science Advisory Secretariat Science Advisory Report. 5. Fisheries and Oceans Canada LMNOP4R Effort and Catch. Policy and Economics Branch. [Newfoundland and Labrador Region Catch and Effort] Fisheries and Oceans Canada. Ref Type: Data File 6. Griffin, E., Miller, K. L., Harris, S., & Allison, D. (2008). Trouble for Turtles: Trawl Fishing in the Atlantic Ocean and Gulf of Mexico Washington, DC: Oceana. 7. Halpern, B. S., Walbridge, S., Selkoe, K. A., Kappel, C. V., Micheli, F., D'Agrosa, C., Bruno, J. F., Casey, K. S., Ebert, C., Fox, H. E., Fujita, R., Heinemann, D., Lenihan, H. S., Madin, E. M. P., Perry, M. T., Selig, E. R., Spalding, M., Steneck, R., & Watson, R. (2008). A Global Map of Human Impact on Marine Ecosystems. Science, 319, James, M. C., Ottensmeyer, C. A., & Myers, R. A. (2005). Identification of high-use habitat and threats to leatherback sea turtles in northern waters: new directions for conservation. Ecology Letters, 8, James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A. (2006). Canadian waters provide critical foraging habitat for leatherback sea turtles. Biological Conservation, 133, Ledwell, W. & Huntington, J. (2007). Whale and leatherback sea turtles incidental entrapment in fishing gear in Newfoundland and Labrador and a summary of the Whale Release and Strandings Program during 2006 A Report to the Department of Fisheries and Oceans, St. John's, Newfoundland and Labrador, Canada. 8

15 11. Turtle Expert Working Group (2007). An Assessment of the Leatherback Turtle Population in the Atlantic Ocean (Rep. No. NOAA Technical Memorandum NMFS-SEFSC-555). U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Southeast Fisheries Science Center. 9

16 Leatherback Seaturtles in the Placentia Bay Grand Banks LOMA Longline Magnitude of Interaction Areal extent: Leatherback turtles have not been systematically surveyed around Newfoundland and distribution maps rely largely on opportunistic reporting and tracking of small numbers of individual leatherbacks. The primary determinant of movement and behaviour of leatherbacks is the spatial and temporal distribution of their primary prey, gelatinous plankton generally known as jellyfish. In general jellyfish abundance is highest in coastal waters (James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A., 2006) James et al. identified spatial use of leatherbacks in the western Atlantic through satellite tracking tags on 38 turtles (Figure 1, below): Figure 1. Spatial use of Leatherbacks in the Western Atlantic (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005). This data was updated by the Turtle Expert Working Group in 2007: Figure 2. Habitat use by Leatherback Turtles on foraging Grounds in the northwest Atlantic (Turtle Expert Working Group, 2007). 1

17 Figure 3. Occurrence of the leatherback turtle, Dermochelys coriacea, off eastern Canada. Shaded areas show the location of concentrations of observations and are taken from Goff and Lien (1988; A), Witzell (1999 and DFO, 2005; B), and James (2000; C).(Atlantic Leatherback Turtle Recovery Team, 2006) This information indicates that leatherbacks are broadly distributed throughout southern, and coastal areas the LOMA. Geo-referenced fishing locations for longlines are available for vessels over 35ft are shown on Fig 4 below. Figure 4. Areal extent of longline fisheries (vessels > 35ft), Newfoundland Region fisheries, (Fisheries and Oceans Canada, 2008). Areal extent (219,494km 2 ). 2

18 The longline fishery (vessels over 35ft) is conducted in an area (219,494 km 2 / 617,700km 2 ) encompassing 35.5% of the LOMA, largely within the southern LOMA and coastal areas (area occupied by the CP). Based on this information we have estimated an area of overlap of 60%. Score 6 Contact: Quantitative Fishing Gear Scores (DFO 2007) for contact between longline fisheries and leatherbacks are rare (< 1% of the time) or occasional (1-25% of the time) depending on the fishery. The recovery strategy for leatherbacks in Atlantic Canadian waters identifies both pelagic and demersal longlines as gear with a high potential to entangle leatherback turtles (Atlantic Leatherback Turtle Recovery Team, 2006). Turtle interactions are well documented in pelagic longline fisheries targeting swordfish and tuna in Atlantic Canadian waters. For example 28 interactions were recorded in 2001, and 37 in 2002 with 20% observer coverage (Atlantic Leatherback Turtle Recovery Team, 2006). Leatherback entanglement in the vertical lines of the demersal longline fishery has also been recorded (Atlantic Leatherback Turtle Recovery Team, 2006). Based on this information we have selected a score at the high end of the low range. Score 3.5 Duration: Leatherbacks are typically present in the LOMA from June to October (Atlantic Leatherback Turtle Recovery Team, 2006) Various longline fisheries open within different areas of the LOMA at slightly different times but are generally open throughout the entire time that the CP is present in the LOMA (Fisheries and Oceans Canada, 2008) Score 10 Intensity: Halpern et al. (2008) have developed maps showing the global intensity of several anthropogenic stressors including a range of fisheries. These maps can be used to provide guidance in scoring the intensity of a stressor in relation to maximum (100%) intensity in a global context, in accordance with the scale provided below. Halpern s map of demersal non-destructive fisheries with low bycatch, which include longlines is shown in Fig. 5 below: 3

19 Map colour Intensity Red % Orange 60-80% Yellow 40-60% Light Blue 20-40% Dark Blue 0-20% Figure 5. Global Intensity for demersal non-destructive fisheries (Halpern, B. S. et al., 2008) Fig 5 shows a highly variable intensity relative to global levels but is generally low for a score range of 20% to 40%. Longline fisheries within the LOMA represent an average of 2% of the Newfoundland landings from (Appendix A, Table 13) (Fisheries and Oceans Canada, 2008). There are also some landings of large pelagics (swordfish, tuna, and shark) by the Canadian longline fleet, largely focused in the southern portion of the LOMA in deep water, but these fisheries represent less than 1% of the total landings in the LOMA (Fisheries and Oceans Canada, 2007b). Since longline landings represent a low percent of the total landings in the LOMA we have selected the lowest score in the global range. Score 2 Magnitude of Interaction: (6x 3.5 x 10 x 2)/1000 = 0. 4 Sensitivity: Sensitivity of the CP to acute impacts: Quantitative Fishing Gear Scores (Fisheries and Oceans Canada, 2007a) for harm resulting from an interaction between longlines and leatherbacks are rare (< 1% of the time) or high (>75% of the time) depending on the fishery. Both pelagic and demersal longlines are identified as gear with a high potential to entangle leatherback turtles (Atlantic Leatherback Turtle Recovery Team, 2006). Turtle interactions are well documented in pelagic longline fisheries targeting swordfish and tuna in Atlantic Canadian waters. For example 28 interactions were recorded in 2001, and 37 in 2002 with 20% observer coverage (Atlantic Leatherback Turtle Recovery Team, 2006). Leatherback entanglement in the vertical lines of the demersal longline fishery has also been recorded (Atlantic Leatherback Turtle Recovery Team, 2006). Live release was observed in all cases for leatherback turtles in the pelagic longline fisheries (Atlantic Leatherback Turtle Recovery Team, 2006). Leatherbacks are rare and occur in very low densities within the LOMA (COSEWIC & James, M. C., 2001), and ever encounter may be significant. Although incidents of turtle entanglement in longlines appear to be relatively high, we have selected a score in the low range, since all individuals were released alive. 4

20 Score 3 Sensitivity of the CP to chronic impacts: A long lifespan, very high rates of egg and hatchling mortality, and a late age of maturity makes this species unusually vulnerable to even small increases in rates of mortality of adults and older juveniles. Generation time is estimated at <30 years (COSEWIC & James, M. C., 2001) The leatherback turtle is classified as critically endangered by the International Union for the Conservation of Nature and as endangered by the Committee on the Status of Endangered Wildlife in Canada. Leatherbacks have experienced a dramatic population decline of more than 60 per cent since Because male turtles do not return to land, it is not possible to accurately count them. So, scientists determine the population of sea turtles by counting nesting females. Currently, the total number of nesting females is thought to be less than 35,000 worldwide (Fisheries and Oceans Canada, 2004). The Atlantic population appears to be more stable, but shows dramatic fluctuations from year to year. The relative density of leatherbacks in Canadian waters has been estimated at turtles (during summer), but this is likely low, as there are no accurate population estimates for leatherbacks in Canadian waters (COSEWIC & James, M. C., 2001). Acute mortality due to longline entanglement is unlikely to contribute to population decline, but chronic impacts are of greater concern. From observations in the swordfish fishery, both hooks and line remained attached to released turtles in 48.8% of all cases in 2001, and 74.5% of all cases in Just hooks remained attached in another 5.5% of all cases in 2001 and 24.1% of all cases in Post-release mortality is unknown, but significant morbidity is likely, and therefore we have selected a moderate score (6) Leatherbacks are listed as a depleted species for the LOMA (add 1 point) Score 7 Sensitivity of ecosystem to harmful impacts to the CP: Leatherbacks depend on prey with very little nutritive content and since this species diet of jellyfish is high in water and low in organic content, they must consume large quantities of food to fulfill their food energy requirements (Atlantic Leatherback Turtle Recovery Team, 2006). Jellyfish are generally considered a nuisance species, which can foul fishing gear and force the closure of swimming beaches. Jellyfish also compete with larval fish for food (both eat zooplankton), and are also known predators of larval fish (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005). Leatherbacks help keep the jellyfish population under control, and may therefore help conserve fish species. Despite their relatively small numbers, leatherbacks represent a significant biomass due to their large size, and contribute significantly to the energetics of the marine ecosystem. Leatherbacks are highly mobile, and their large scale movements contribute to the transfer of energy and biomass from seasonally productive areas to distance marine systems. 5

21 Due to their large size and habit of basking on the sea surface, leatherbacks have long attracted interest, and their presence within the LOMA contributes to ecotourism opportunities. Canadian waters support one of the highest summer and fall densities of leatherbacks in the North Atlantic, and should be considered critical foraging habitat for this endangered species (James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A., 2006). Based on this information we have selected a score in the medium range to reflect the importance of the leatherback within the LOMA. Score 6 Sensitivity: ( )/3 = 5.3 Risk of Harm: 0.4 x 5.3 = 2.1 6

22 Certainty Checklist Answer yes or no to all of the following questions. Record the number of NO s to the 9 questions, and record certainty according to the scale provided below: 1 No s = High certainty 2-3 No s = Medium certainty > 4 No s = Low certainty Y/N Y Is the score supported by a large body of information? N Is the score supported by general expert agreement? N Is the interaction well understood, without major information gaps/sources of error? Y Is the current level of understanding based on empirical data rather than models, anecdotal information or probable scenarios? Y Is the score supported by data which is specific to the region, (EBSA, LOMA, NW Atlantic? N Is the score supported by recent data or research (the last 10 years or less)? N Is the score supported by long-term data sets (ten years or more) from multiple surveys (5 years or more)? N Do you have a reasonable level of comfort in the scoring/conclusions? N Do you have a high level of confidence in the scoring/conclusions? Score: Low For interactions with Low certainty, underline the main factor(s) contributing to the uncertainty Lack of comprehensive data Lack of expert agreement Predictions based of future scenarios which are difficult to predict Other (provide explanation) Suggest possible research to address uncertainty: Improved observer coverage 7

23 Reference List 1. Atlantic Leatherback Turtle Recovery Team (2006). Recovery Strategy for Leatherback Turtle (Dermochelys coriacea) in Atlantic Canada (Rep. No. Species at Risk Act Recovery Strategy Series ). Ottawa: Fisheries and Oceans Canada. 2. COSEWIC & James, M. C. (2001). COSEWIC Assessment and Update Status Report on the Leatherback Turtle Dermochelys coriacea in Canada Ottawa: Committee on the Status of Endangered Wildlife in Canada. 3. Fisheries and Oceans Canada. Underwater World Aquatic Species at Risk - The Leatherback Turtle Ottawa, Ont. Ref Type: Pamphlet 4. Fisheries and Oceans Canada (2007a). Placentia Bay-Grand Banks Large Ocean Management Area Conservation Objectives (Rep. No. 2007/042). Canadian Science Advisory Secretariat Science Advisory Report. 5. Fisheries and Oceans Canada The Grand Banks of Newfoundland: Atlas of Human Activities. The Grand Banks of Newfoundland: Atlas of Human Activities (in press). 6. Fisheries and Oceans Canada LMNOP4R Effort and Catch. Policy and Economics Branch. [Newfoundland and Labrador Region Catch and Effort] Fisheries and Oceans Canada. 7. Halpern, B. S., Walbridge, S., Selkoe, K. A., Kappel, C. V., Micheli, F., D'Agrosa, C., Bruno, J. F., Casey, K. S., Ebert, C., Fox, H. E., Fujita, R., Heinemann, D., Lenihan, H. S., Madin, E. M. P., Perry, M. T., Selig, E. R., Spalding, M., Steneck, R., & Watson, R. (2008). A Global Map of Human Impact on Marine Ecosystems. Science, 319, James, M. C., Ottensmeyer, C. A., & Myers, R. A. (2005). Identification of high-use habitat and threats to leatherback sea turtles in northern waters: new directions for conservation. Ecology Letters, 8, James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A. (2006). Canadian waters provide critical foraging habitat for leatherback sea turtles. Biological Conservation, 133, Turtle Expert Working Group (2007). An Assessment of the Leatherback Turtle Population in the Atlantic Ocean (Rep. No. NOAA Technical Memorandum NMFS-SEFSC-555). U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Southeast Fisheries Science Center. 8

24 Leatherback Sea Turtles in Placentia Bay Grand Banks LOMA Crab pots Magnitude of Interaction Areal extent: Leatherback turtles have not been systematically surveyed around Newfoundland and distribution maps rely largely on opportunistic reporting and tracking of small numbers of individual leatherbacks. The primary determinant of movement and behaviour of leatherbacks is the spatial and temporal distribution of their primary prey, gelatinous plankton generally known as jellyfish. In general jellyfish abundance is highest in coastal waters (James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A., 2006) James et al. identified spatial use of leatherbacks in the western Atlantic through satellite tracking tags on 38 turtles (Figure 1, below): Figure 1. Spatial use of Leatherbacks in the Western Atlantic (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005). This data was updated by the Turtle Expert Working Group in 2007: Figure 2. Habitat use by Leatherback Turtles on foraging Grounds in the northwest Atlantic (Turtle Expert Working Group, 2007).

25 Fiure 3. Occurrence of the leatherback turtle, Dermochelys coriacea, off eastern Canada. Shaded areas show the location of concentrations of observations and are taken from Goff and Lien (1988; A), Witzell (1999 and DFO, 2005; B), and James (2000; C).(Atlantic Leatherback Turtle Recovery Team, 2006) This information indicates that leatherbacks are broadly distributed throughout southern, and coastal areas the LOMA. Geo-referenced fishing locations for crab pots are available for vessels over 35ft are shown on Fig 4 below. Figure 4. Areal extent of Snow Crab Pots (vessels > 35ft) in Placentia Bay Grand Banks LOMA, (Fisheries and Oceans Canada, 2008). Areal extent (274,600km 2 )

26 The snow crab fishery (vessels over 35ft) is conducted in an area (274,600 km 2 / 617,700km 2 ) encompassing 44.5% of the LOMA, including a significant portion of the southern LOMA. There is also a significant inshore crab fishery (vessels under 35 ), accounting for a significant portion of the total landings for the LOMA from The distribution of the inshore fisheries is shown on Fig 4 below: Figure 5. Distribution of Snow Crab Fisheries in Placentia Bay from (Community Resource Services Ltd & Jacques Whitford Environment Ltd, 2001). Based on this information we have estimated an area of overlap of 60%. Score 6 Contact: Quantitative Fishing Gear Score (DFO 2007) scores for contact between snow crab pots and leatherbacks are rare (< 1% of the time), but scores are higher for other types of pots such as hagfish, rock crab and toad crab. Of all Atlantic seaturtle species, leatherback seem to be most vulnerable to entanglement in fishing gear such as pelagic longlines, lines associated with fixed ear (pots, traps, gillnets), buoy anchor lines and other ropes and cables (Atlantic Leatherback Turtle Recovery Team, 2006). Surface buoy lines appear to be most problematic (Atlantic Leatherback Turtle Recovery Team, 2006). The Newfoundland and Labrador Whale Release and Strandings Program (Ledwell, W. & Huntington, J., 2007) and other researchers report significant entrapment of leatherbacks in crab pot gear (COSEWIC & James, M. C., 2001);(Atlantic Leatherback Turtle Recovery Team, 2006). The leatherback s insatiable appetite and foraging curiosity also may lead to entanglement in fishing gear. Front flipper entanglement in ropes and cables are common, and this may result from turtles approaching buoys and biting at them. (COSEWIC & James, M. C., 2001). Based on this information we have selected a score at the high end of the low range. Score 3.5

27 Duration: Leatherbacks are typically present in the LOMA from June to October (Atlantic Leatherback Turtle Recovery Team, 2006) Snow crab fishing is open within different areas of the LOMA at slightly different times between early April to the end of July (Fisheries and Oceans Canada, 2008) or 15days/ 150days. This amounts to 10% of the time occupied by the CP. Score 1 Intensity: Halpern et al. (2008) have developed maps showing the global intensity of several anthropogenic stressors including a range of fisheries. These maps can be used to provide guidance in scoring the intensity of a stressor in relation to maximum (100%) intensity in a global context, in accordance with the scale provided below. Halpern s map of demersal non-destructive fisheries with low bycatch, which include crab pots is shown in Fig. 6 below: Figure 6. Global Intensity of demersal non-destructive fisheries with low bycatch, which include crab pots (adapted from (Halpern, B. S. et al., 2008). Fig. 6 shows a highly variable intensity relative to global levels but is generally low for a score range of 20% to 40%. Since the snow crab fishery accounts for 36% of the landings in the LOMA, excluding vessels less than 35 we have selected a high score in this range. Score 4 Magnitude of Interaction: (6x 3.5 x 1 x 4)/1000 = 0.1

28 Sensitivity: Sensitivity of the CP to acute impacts: Quantitative Fishing Gear Scores (Fisheries and Oceans Canada, 2007) for harm resulting from an interaction between crab pots and leatherbacks are low (occasionally 1-25%), but scores are higher for other types of pots such as hagfish, rock crab and toad crab. The Newfoundland and Labrador Whale Release and Strandings Program reported significant entanglement of leatherbacks in crab pots (Ledwell, W. & Huntington, J., 2007). Prior to 1990 most reported entanglements of humpback and minke whales were in inshore cod traps and groundfish gillnets (Lien, J., 1994), but entanglement in gear such as snow crab pots has became more common (Ledwell, W. & Huntington, J., 2007) as the shellfish fisheries became more dominant. Acute impacts due to entrapment may vary in severity from trivial to lethal depending on the species, and the extent of the entanglement. Data suggests that entanglement in fixed gear may lead to higher mortality per interaction because turtles entangled at depth or at the surface at low tide will almost certainly drown. As fixed gear fisheries receive relatively little observer coverage, the magnitude of the threat they pose to leatherbacks has not been adequately recognized nor addressed. As in Canadian waters, leatherbacks are regularly entangled in fixed gear in US waters off New York through Maine (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005) Based on this information we have selected the highest score within the low range. Score 3.5 Sensitivity of the CP to chronic impacts: A long lifespan, very high rates of egg and hatchling mortality, and a late age of maturity makes this species unusually vulnerable to even small increases in rates of mortality of adults and older juveniles. Generation time is estimated at <30 years (COSEWIC & James, M. C., 2001) The leatherback turtle is classified as critically endangered by the International Union for the Conservation of Nature and as endangered by the Committee on the Status of Endangered Wildlife in Canada. Leatherbacks have experienced a dramatic population decline of more than 60 per cent since Because male turtles do not return to land, it is not possible to accurately count them. So, scientists determine the population of sea turtles by counting nesting females. Currently, the total number of nesting females is thought to be less than 35,000 worldwide (Fisheries and Oceans Canada, 2004). The Atlantic population appears to be more stable, but shows dramatic fluctuations from year to year. The relative density of leatherbacks in Canadian waters has been estimated at turtles (during summer), but this is likely low, as there are no accurate population estimates for leatherbacks in Canadian waters (COSEWIC & James, M. C., 2001). Chronic impacts of entanglement can range from minor rope scars, to debilitating injuries, or moderate to severe morbidity due to gear remaining attached or imbedded in the turtle. In these cases, the ability of the animal to move and feed may be compromised by injuries, infection, interference with vital body functions (rope/netting confining limb, neck or mouth movement) or by the weight of gear. In severe cases death may occur

29 months or even years later as a result of starvation or chronic infection (Atlantic Leatherback Turtle Recovery Team, 2006) Turtles towing gear for any length of time are unlikely to free themselves, and are more likely to become entangled again. Given the poor recovery rate for serious interactions, and low reproductive rates of leatherbacks, we have selected a moderate score (5.5) for chronic sensitivity. Leatherbacks are listed as a depleted species for the LOMA (add 1 point) Score 6.5 Sensitivity of ecosystem to harmful impacts to the CP: Leatherbacks depend on prey with very little nutritive content and since this species diet of jellyfish is high in water and low in organic content, they must consume large quantities of food to fulfill their food energy requirements (Atlantic Leatherback Turtle Recovery Team, 2006). Jellyfish are generally considered a nuisance species, which can foul fishing gear and force the closure of swimming beaches. Jellyfish also compete with larval fish for food (both eat zooplankton), and are also known predators of larval fish (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005). Leatherbacks help keep the jellyfish population under control, and may therefore help conserve fish species. Despite their relatively small numbers, leatherbacks represent a significant biomass due to their large size, and contribute significantly to the energetics of the marine ecosystem. Leatherbacks are highly mobile, and their large scale movements contribute to the transfer of energy and biomass from seasonally productive areas to distance marine systems. Due to their large size and habit of basking on the sea surface, leatherbacks have long attracted interest, and their presence within the LOMA contributes to ecotourism opportunities. Canadian waters support one of the highest summer and fall densities of leatherbacks in the North Atlantic, and should be considered critical foraging habitat for this endangered species (James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A., 2006). Based on this information we have selected a score in the medium range to reflect the importance of the leatherback within the LOMA. Score 6 Sensitivity: ( )/3= 5.3 Risk of Harm: 0.1x5.3=0.5

30 Certainty Checklist Answer yes or no to all of the following questions. Record the number of NO s to the 9 questions, and record certainty according to the scale provided below: 1 No s = High certainty 2-3 No s = Medium certainty > 4 No s = Low certainty Y/N Y Is the score supported by a large body of information? N Is the score supported by general expert agreement? N Is the interaction well understood, without major information gaps/sources of error? Y Is the current level of understanding based on empirical data rather than models, anecdotal information or probable scenarios? Y Is the score supported by data which is specific to the region, (EBSA, LOMA, NW Atlantic? Y Is the score supported by recent data or research (the last 10 years or less)? Y Is the score supported by long-term data sets (ten years or more) from multiple surveys (5 years or more)? N Do you have a reasonable level of comfort in the scoring/conclusions? N Do you have a high level of confidence in the scoring/conclusions? Score: Low For interactions with Low certainty, underline the main factor(s) contributing to the uncertainty Lack of comprehensive data Lack of expert agreement Predictions based of future scenarios which are difficult to predict Other (provide explanation) Suggest possible research to address uncertainty: Improved observer coverage

31 Reference List 1. Atlantic Leatherback Turtle Recovery Team (2006). Recovery Strategy for Leatherback Turtle (Dermochelys coriacea) in Atlantic Canada (Rep. No. Species at Risk Act Recovery Strategy Series ). Ottawa: Fisheries and Oceans Canada. 2. Community Resource Services Ltd & Jacques Whitford Environment Ltd (2001). Socio-Economic Overview of Placentia Bay, Newfoundland. 3. COSEWIC & James, M. C. (2001). COSEWIC Assessment and Update Status Report on the Leatherback Turtle Dermochelys coriacea in Canada Ottawa: Committee on the Status of Endangered Wildlife in Canada. 4. Fisheries and Oceans Canada. Underwater World Aquatic Species at Risk - The Leatherback Turtle Ottawa, Ont. Ref Type: Pamphlet 5. Fisheries and Oceans Canada (2007). Placentia Bay-Grand Banks Large Ocean Management Area Conservation Objectives (Rep. No. 2007/042). Canadian Science Advisory Secretariat Science Advisory Report. 6. Fisheries and Oceans Canada LMNOP4R Effort and Catch. Policy and Economics Branch. [Newfoundland and Labrador Region Catch and Effort] Fisheries and Oceans Canada. Ref Type: Data File 7. Halpern, B. S., Walbridge, S., Selkoe, K. A., Kappel, C. V., Micheli, F., D'Agrosa, C., Bruno, J. F., Casey, K. S., Ebert, C., Fox, H. E., Fujita, R., Heinemann, D., Lenihan, H. S., Madin, E. M. P., Perry, M. T., Selig, E. R., Spalding, M., Steneck, R., & Watson, R. (2008). A Global Map of Human Impact on Marine Ecosystems. Science, 319, James, M. C., Ottensmeyer, C. A., & Myers, R. A. (2005). Identification of high-use habitat and threats to leatherback sea turtles in northern waters: new directions for conservation. Ecology Letters, 8, James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A. (2006). Canadian waters provide critical foraging habitat for leatherback sea turtles. Biological Conservation, 133, Ledwell, W. & Huntington, J. (2007). Whale and leatherback sea turtles incidental entrapment in fishing gear in Newfoundland and Labrador and a summary of the Whale Release and Strandings Program during 2006 A Report to the Department of Fisheries and Oceans, St. John's, Newfoundland and Labrador, Canada.

32 11. Lien, J. (1994). Entrapments of large cetaceans in passive inshore fishing gear in Newfoundland and Labrador ( ). (Rep. No. Reports of the International Whaling Commission, Special Issue 15). 12. Turtle Expert Working Group (2007). An Assessment of the Leatherback Turtle Population in the Atlantic Ocean (Rep. No. NOAA Technical Memorandum NMFS-SEFSC-555). U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Southeast Fisheries Science Center.

33 Leatherback Turtle in Placentia Bay Grand Banks LOMA Ship strikes Magnitude of Interaction Areal extent: Leatherback turtles have not been systematically surveyed around Newfoundland and distribution maps rely largely on opportunistic reporting and tracking of small numbers of individual leatherbacks. The primary determinant of movement and behaviour of leatherbacks is the spatial and temporal distribution of their primary prey, gelatinous plankton generally known as jellyfish. In general jellyfish abundance is highest in coastal waters (James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A., 2006) James et al. identified spatial use of leatherbacks in the western Atlantic through satellite tracking tags on 38 turtles (Figure 1, below): Figure 1. Spatial use of Leatherbacks in the Western Atlantic (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005). This data was updated by the Turtle Expert Working Group in 2007: Figure 2. Habitat use by Leatherback Turtles on foraging Grounds in the northwest Atlantic (Turtle Expert Working Group, 2007). 1

34 Figure 3. Occurrence of the leatherback turtle, Dermochelys coriacea, off eastern Canada. Shaded areas show the location of concentrations of observations and are taken from Goff and Lien (1988; A), Witzell (1999 and DFO, 2005; B), and James (2000; C).(Atlantic Leatherback Turtle Recovery Team, 2006) This information indicates that leatherbacks are broadly (but sparsely) distributed throughout southern, and coastal areas the LOMA, including areas outside the 200 mile limit. The primary source of detailed local data on marine traffic for the LOMA is maintained by the Canadian Coast Guard (CCG), and is based on a mandatory reporting system for all commercial vessels over 500t (or carrying pollutants or dangerous cargo) transiting within Canada s 12 nautical mile territorial sea (fig. 4 below). Figure 4. Commercial shipping, traffic density (from ECAREG data) (Fisheries and Oceans Canada, 2007). 2

35 The ECAREG system does not include information on vessels transiting through Canada s Exclusive Economic Zone (EEZ), and since significant foreign vessel traffic transits the outer edges of the LOMA en route between northern Europe and the US Eastern Seaboard (without entering territorial waters), we have also consulted the MARIN database (Pelot, R. & Wootton, D., 2004). This includes ECAREG data from 2001, but also includes merchant vessel movement data (2001) acquired from Lloyds of London, Marine Intelligence Unit, which records other ships transiting waters off the coast of Canada, primarily between the USA and Europe. Fishing data (1999) were drawn from each of the four Eastern Canada reporting regions: Laurentian, Gulf, Scotia- Fundy and Newfoundland. The individual GIS track files for each region and year were merged together into one layer where darker shades correspond to greater concentrations of vessel traffic. We have overlaid our own EBSA boundaries to determine the frequency of marine traffic in each area, shown in the Figure 3 below. Figure 5. Annual vessel transits for all vessel types combined (merchant, fishing, cruise ships) (Pelot, R. & Wootton, D., 2004). Based on this information, the annual vessel traffic is for the LOMA is considered to be moderate, with moderate to high in most coastal areas and moderate to low in most offshore areas. Since leatherbacks appear to be most common in southern, and coastal areas the LOMA where vessel traffic is highest, we have selected a score at the high end of the moderate range. Score 7 Contact: While incidents of collisions with leatherbacks have not been documented in Atlantic Canada, they have been known to occur in US waters (Atlantic Leatherback Turtle Recovery Team, 2006), and collisions with cetaceans are well documented (Elvina, S. S. & Taggart, C. T., 2008; Jensen, A. S. & Silber, G. K., 2004; Laist, D. W., Knowton, A. R., Meade, J. G., Collet, A. S., & Podesta, M., 2001; Vanderlaan, A. S., Taggart, C. T., Serdynska, A. R., Kenney, R. D., & Brown, M. W., 2008) 3

36 Leatherbacks breathe air, and also spend time resting and feeding at the sea surface (James, M. C., Myers, R. A., & Ottensmeyer, C. A., 2005). Diving behaviour of leatherbacks in continental slope waters of the northeastern US and eastern Canada suggests that they spend 43 to 50% of their time at the water surface (Transport Canada & RMRI (Canada), 2007). Leatherback turtles are known to bask at the surface for extended periods of time when foraging in temperate waters and, therefore, may be vulnerable to collisions with marine traffic. In areas where recreational boating, commercial fishing and ship traffic are concentrated, propeller and collision-related injuries may represent a source of mortality (Atlantic Leatherback Turtle Recovery Team, 2006). The likelihood of contact is therefore considered high. Score 8 Duration: Leatherbacks are typically present in the LOMA from June to October (Atlantic Leatherback Turtle Recovery Team, 2006) Most vessel traffic is relatively consistent throughout the year, with the exception of fishing and passenger vessels which are greatly reduced in the winter (December to March) (Pelot, R. & Wootton, D., 2004). Since peak vessel traffic coincides with leatherback occurrence in the LOMA, duration is 100% Score 10 Intensity: Detailed maps of shipping density have been published, which enable us to gauge intensity in relation to the global max (100%). Intensity of ship traffic is displayed in the following map by Halpern et al. in Fig. 6 below: Map colour Red Orange Yellow Light Blue Dark Blue Intensity % 60-80% 40-60% 20-40% 0-20% Figure 6. Commercial Shipping Activity in PBGB LOMA (Halpern, B. S. et al., 2008). Therefore commercial shipping within the LOMA can be considered moderate (40-60%) on a global scale, as the shipping density is predominantly yellow in colour. Score 5 4

37 Magnitude of Interaction: (7 x 8 x 10 x 5)/1000 = 2.8 Sensitivity: Sensitivity of the CP to acute impacts: Leatherbacks breathe air, and also spend time resting and feeding at the sea surface (James, M. C., Myers, R. A., & Ottensmeyer, C. A., 2005). Leatherback turtles are known to bask at the surface for extended periods of time when foraging in temperate waters and, therefore, may be vulnerable to collisions with marine traffic. In areas where recreational boating, commercial fishing and ship traffic are concentrated, propeller and collision-related injuries may represent a source of mortality (Atlantic Leatherback Turtle Recovery Team, 2006). While incidents of collisions with leatherbacks have not been documented in Atlantic Canada, they have been known to occur in US waters (Atlantic Leatherback Turtle Recovery Team, 2006), and collisions with cetaceans are well documented (Elvina, S. S. & Taggart, C. T., 2008; Jensen, A. S. & Silber, G. K., 2004; Laist, D. W., Knowton, A. R., Meade, J. G., Collet, A. S., & Podesta, M., 2001; Vanderlaan, A. S., Taggart, C. T., Serdynska, A. R., Kenney, R. D., & Brown, M. W., 2008) The highest incidents of vessel strikes to large whales in North American waters occurred in the US east coast, and was nearly 5 times higher than the frequency reported in Eastern Canada (Jensen, A. S. & Silber, G. K., 2004). While all sizes and types of vessels can collide with whales, most lethal or severe injuries are caused by vessels >80 m in length (Laist et al. 2001).Historical records suggest that fatal ship strikes involving marine mammals first began in the late 1800s when ships began to reach speeds of knots, and increased over the last 50 years as the number and speed of ships increased (Laist, D. W., Knowton, A. R., Meade, J. G., Collet, A. S., & Podesta, M., 2001). Jensen and Silber found that the range of speeds at which vessels were operating when a whale was hit was 2 51 knots, and the mean speed was 18.1 knots. The mean vessel speed which resulted in serious injury or mortality to the whale was 18.6 knots (Jensen, A. S. & Silber, G. K., 2004). The high occurrence of Navy reports may reflect military and government reporting practice rather than an actual higher frequency of collisions relative to other ship types (Jensen, A. S. & Silber, G. K., 2004), and suggests that incidents may be significantly under-reported by commercial vessels. Large vessel traffic within the LOMA include tankers (oil, chemical), cargo vessels (bulk, general, container), and passenger vessels (ferries, cruise ships, tour boats) (Fisheries and Oceans Canada, 2002). Acute impacts from ship strikes are likely low, but this may be largely the result of the low density of leatherbacks in the LOMA and globally. Based on this information we have selected a score at the high end of the low range. Score 3 Sensitivity of the CP to chronic impacts: A long lifespan, very high rates of egg and hatchling mortality, and a late age of maturity makes this species unusually vulnerable to even small increases in rates of mortality of 5

38 The leatherback turtle is classified as critically endangered by the International Union for the Conservation of Nature and as endangered by the Committee on the Status of Endangered Wildlife in Canada. Leatherbacks have experienced a dramatic population decline of more than 60 per cent since Because male turtles do not return to land, it is not possible to accurately count them. So, scientists determine the population of sea turtles by counting nesting females. Currently, the total number of nesting females is thought to be less than 35,000 worldwide (Fisheries and Oceans Canada, 2004). The Atlantic population appears to be more stable, but shows dramatic fluctuations from year to year. The relative density of leatherbacks in Canadian waters has been estimated at turtles (during summer), but this is likely low, as there are no accurate population estimates for leatherbacks in Canadian waters (COSEWIC & James, M. C., 2001). Although ship collisions with leatherbacks have not been recorded within the LOMA, and are likely rare, even the occasional death of a leatherback is a concern due to their depleted status. Non-lethal incidents and propeller injuries may also occur, and are much less likely to be reported. Since small inshore fishing boats (<35 ) make up close to 90% of fishing vessels in the region (Fisheries and Oceans Canada, 2002), and small boat traffic hugs the coast (Pelot, R. & Wootton, D., 2004) where leatherbacks tend to be concentrated, minor collisions and propeller injuries are an additional concern. Chronic sensitivity is considered to be in the low range (2) Leatherbacks are listed as a depleted species for the LOMA (add 1 point) Score 3 Sensitivity of ecosystem to harmful impacts to the CP: Leatherbacks depend on prey with very little nutritive content and since this species diet of jellyfish is high in water and low in organic content, they must consume large quantities of food to fulfill their food energy requirements (Atlantic Leatherback Turtle Recovery Team, 2006). Jellyfish are generally considered a nuisance species, which can foul fishing gear and force the closure of swimming beaches. Jellyfish also compete with larval fish for food (both eat zooplankton), and are also known predators of larval fish (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005). Leatherbacks help keep the jellyfish population under control, and may therefore help conserve fish species. Despite their relatively small numbers, leatherbacks represent a significant biomass due to their large size, and contribute significantly to the energetics of the marine ecosystem. Leatherbacks are highly mobile, and their large scale movements contribute to the transfer of energy and biomass from seasonally productive areas to distance marine systems. Due to their large size and habit of basking on the sea surface, leatherbacks have long attracted interest, and their presence within the LOMA contributes to ecotourism opportunities. 6

39 Based on this information we have selected a score in the medium range to reflect the importance of the leatherback within the LOMA. Score 6 Sensitivity: (3+3+6)/3=4.0 Risk of Harm: 2.8 x 4.0 =11.2 7

40 Certainty Checklist Answer yes or no to all of the following questions. Record the number of NO s to the 9 questions, and record certainty according to the scale provided below: 1 No s = High certainty 2-3 No s = Medium certainty > 4 No s = Low certainty Y/N N Is the score supported by a large body of information? N Is the score supported by general expert agreement? N Is the interaction well understood, without major information gaps/sources of error? Y Is the current level of understanding based on empirical data rather than models, anecdotal information or probable scenarios? N Is the score supported by data which is specific to the region, (EBSA, LOMA, NW Atlantic? Y Is the score supported by recent data or research (the last 10 years or less)? Y Is the score supported by long-term data sets (ten years or more) from multiple surveys (5 years or more)? N Do you have a reasonable level of comfort in the scoring/conclusions? N Do you have a high level of confidence in the scoring/conclusions? Score: Low For interactions with Low certainty, underline the main factor(s) contributing to the uncertainty Lack of comprehensive data Lack of expert agreement Predictions based of future scenarios which are difficult to predict Other (provide explanation) Suggest possible research to address uncertainty: 8

41 Reference List 1. Atlantic Leatherback Turtle Recovery Team (2006). Recovery Strategy for Leatherback Turtle (Dermochelys coriacea) in Atlantic Canada (Rep. No. Species at Risk Act Recovery Strategy Series ). Ottawa: Fisheries and Oceans Canada. 2. COSEWIC & James, M. C. (2001). COSEWIC Assessment and Update Status Report on the Leatherback Turtle Dermochelys coriacea in Canada Ottawa: Committee on the Status of Endangered Wildlife in Canada. 3. Elvina, S. S. & Taggart, C. T. (2008). Right whales and vessels in Canadian waters. Marine Policy, 32, Fisheries and Oceans Canada (2002). Statistical Services - Commercial Licenses - Vessels Information. Fisheries and Oceans Canada [Announcement posted on the World Wide Web]. from the World Wide Web: 5. Fisheries and Oceans Canada. Underwater World Aquatic Species at Risk - The Leatherback Turtle Ottawa, Ont. Ref Type: Pamphlet 6. Fisheries and Oceans Canada The Grand Banks of Newfoundland: Atlas of Human Activities. The Grand Banks of Newfoundland: Atlas of Human Activities (in press). 7. Halpern, B. S., Walbridge, S., Selkoe, K. A., Kappel, C. V., Micheli, F., D'Agrosa, C., Bruno, J. F., Casey, K. S., Ebert, C., Fox, H. E., Fujita, R., Heinemann, D., Lenihan, H. S., Madin, E. M. P., Perry, M. T., Selig, E. R., Spalding, M., Steneck, R., & Watson, R. (2008). A Global Map of Human Impact on Marine Ecosystems. Science, 319, James, M. C., Myers, R. A., & Ottensmeyer, C. A. (2005). Behaviour of leatherback sea turtles, Dermochelys coriacea, during the migratory cycle. Proceedings of the Royal Society B, 272, James, M. C., Ottensmeyer, C. A., & Myers, R. A. (2005). Identification of high-use habitat and threats to leatherback sea turtles in northern waters: new directions for conservation. Ecology Letters, 8, James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A. (2006). Canadian waters provide critical foraging habitat for leatherback sea turtles. Biological Conservation, 133,

42 11. Jensen, A. S. & Silber, G. K. (2004). Large Whale Ship Strike Database (Rep. No. NMFS-OPR-25). U.S. Department of Commerce. 12. Laist, D. W., Knowton, A. R., Meade, J. G., Collet, A. S., & Podesta, M. (2001). Collisions Between Ships and Whales. Marine Mammal Science, 17, Pelot, R. & Wootton, D. (2004). Maritime traffic distribution in Atlantic Canada to support an evaluation of a Sensitive Sea Area proposal (Rep. No ). Maritime Activity & Risk Investigation Network. 14. Transport Canada & RMRI (Canada) (2007). Quantitative Assessment of Oil Spill Risk for the South Coast of Newfoundland and Labrador (Rep. No. CAN/0179/R003). Transport Canada. 15. Turtle Expert Working Group (2007). An Assessment of the Leatherback Turtle Population in the Atlantic Ocean (Rep. No. NOAA Technical Memorandum NMFS-SEFSC-555). U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Southeast Fisheries Science Center. 16. Vanderlaan, A. S., Taggart, C. T., Serdynska, A. R., Kenney, R. D., & Brown, M. W. (2008). Reducing the risk of lethal encounters: vessels and right whales in the Bay of Fundy and on the Scotian Shelf. Endangered Species Research, 4,

43 Leatherback Turtle in Placentia Bay Grand Banks LOMA Litter Magnitude of Interaction Areal extent: Leatherback turtles have not been systematically surveyed around Newfoundland and distribution maps rely largely on opportunistic reporting and tracking of small numbers of individual leatherbacks. The primary determinant of movement and behaviour of leatherbacks is the spatial and temporal distribution of their primary prey, gelatinous plankton generally known as jellyfish. In general jellyfish abundance is highest in coastal waters (James, M. C., Sherrill-Mix, S. A., Martin, K., & Myers, R. A., 2006) James et al. identified spatial use of leatherbacks in the western Atlantic through satellite tracking tags on 38 turtles (Figure 1, below): Figure 1. Spatial use of Leatherbacks in the Western Atlantic (James, M. C., Ottensmeyer, C. A., & Myers, R. A., 2005). This data was updated by the Turtle Expert Working Group in 2007: Figure 2. Habitat use by Leatherback Turtles on foraging Grounds in the northwest Atlantic (Turtle Expert Working Group, 2007).

44 Figure 3. Occurrence of the leatherback turtle, Dermochelys coriacea, off eastern Canada. Shaded areas show the location of concentrations of observations and are taken from Goff and Lien (1988; A), Witzell (1999 and DFO, 2005; B), and James (2000; C).(Atlantic Leatherback Turtle Recovery Team, 2006) This information indicates that leatherbacks are broadly (but sparsely) distributed throughout southern, and coastal areas the LOMA, including areas outside the 200 mile limit. It is estimated that 6.4 million tonnes of garbage go into the world s oceans every year (Keep Sweden Tidy Foundation, 2003). Plastic debris is of greatest concern due to its abundance, durability and buoyancy. There is no comprehensive data on marine litter available for the LOMA, although coastal surveys have identified significant accumulation of marine litter on coastal beaches in Placentia Bay, St. Mary s Bay and Conception Bay. In all areas, a high percentage of the debris was plastic. Domestic garbage was dominant in Conception Bay, while fishing-related debris dominated in Placentia Bay and St. Mary s Bay (Fisheries and Oceans Canada, 2005; Pink, D., 2004). Up to 80% of marine debris comes from the land, blowing and washing off beaches and carried to the sea by rivers, sewage systems, and storm drains. The remaining 20% is lost or discarded from boats and ships of all types and sizes (Federal-Provincial-Territorial Committee on NPA, 2000). Although little data is available on the concentration and distribution of marine litter in offshore areas of the LOMA, surface currents can carry significant quantities of floating litter, and floating debris is known to concentrate at convergence zones. Islands such as Sable Island accumulate significant quantities of plastic debris (Lucas, Z., 1992), and neuston net tows of surface waters of the Gully and surrounding areas off Nova Scotia found plastics in 80% of tows. The density of large debris inside the mouth of the Gully averaged almost three times that seen outside this area. Items included plastic grocery bags, nylon rope, potato chip bags, ice cream container lids, styrofoam, textile fibres, fishing line and fragments of plastic. Average densities in the entire study area were

45 greater than that reported by researchers in the North Sea, North Pacific and central Pacific, but less than the Mediterranean. (Dufault, S. & Whitehead, H., 1994). Major sources of marine litter include boat traffic (fishing and shipping) and ocean currents. Average annual marine traffic density (See Figure 4 below) in the LOMA are considered medium. Figure 4: Commercial Shipping Activity in PBGB LOMA (adapted from (Halpern, B. S. et al., 2008)). Based on the pollution potential of the area (moderate to high) and existing data for the area, we have estimated the areal extent at the high end of the medium range. Score 7 Contact: Leatherbacks breathe air, and also spend time basking, resting and feeding at the sea surface. Although there is evidence that leatherbacks do not feed exclusively at the surface (James, M. C., Myers, R. A., & Ottensmeyer, C. A., 2005), they feed mainly on planktonic jellyfish, and are generally thought of as surface feeders. Plastic particles and scraps of ropes, netting, six pack rings and related materials persist in the marine environment. Many plastics are buoyant in seawater, and float in surface waters where they interact with leatherbacks feeding at the sea surface. Since the horizontal movement of jellyfish is largely passive, they tend to concentrate where currents converge. These same currents concentrate other buoyant objects, including marine debris (e.g., plastic bags, discarded and lost fishing gear, etc.). Therefore, leatherbacks foraging in areas where jellyfish are concentrated may encounter significant amounts of potentially harmful materials of anthropogenic origin. (James, M. C. & Herman, T. B., 2001). Feeding behavior may also put leatherbacks at risk more indirectly. Leatherbacks depend on prey with very little nutritive content and must consume large quantities of food to fulfill their food energy requirements (Atlantic Leatherback Turtle Recovery Team, 2006). Possibly as a result of their insatiable appetite, leatherbacks will readily consume a variety of inedible buoyant objects such as plastic bags, styrofoam, balloons, condoms and plastic sheeting. The likelihood of contact is therefore considered high. Score 8

46 Duration: Leatherbacks are typically present in the LOMA from June to October (Atlantic Leatherback Turtle Recovery Team, 2006) Litter is considered a chronic stressor which occurs every year, and so is given a score in the medium range. Since marine litter is persistent, consisting largely of plastic debris, and sources of litter (land-based activities, fishing boats, ships and winds/currents) are present throughout the year, we have selected a score at the top of the medium range. Score 7 Intensity: Halpern et al. (2008) have developed maps showing the global intensity of several anthropogenic stressors including ocean pollution (see Fig. 5 below). This map can be used to provide guidance in scoring the intensity of a stressor in relation to maximum (100%) intensity in a global context, in accordance with the scale provided below. Map colour Intensity Red Orange Yellow % 60-80% 40-60% Light Blue 20-40% Dark Blue 0-20% Figure 5. Global Intensity of Ocean Pollution (adapted from (Halpern, B. S. et al., 2008) Fig. 4 shows a range of intensities within the LOMA from high (red) intensity to low relative to global levels for a score range of 20% to 100%. We have selected an average score between 20% and 100% for a score of 60%. Score 6 Magnitude of Interaction: (7 x 8 x 7 x 6)/1000 = 2.4 Sensitivity: Sensitivity of the CP to acute impacts: Leatherbacks depend on prey with very little nutritive content and since this species diet of jellyfish is high in water and low in organic content, they must consume large