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Recovery Strategy for the Leatherback Turtle

5.0 Identification of knowledge gaps [1]

There are a number of gaps in our knowledge about the Atlantic leatherback turtle in Canadian waters.  These gaps occur in areas of biology and ecology, habitat requirements, and potential threats.  The following is a list of efforts that are required in order to fill the knowledge gaps.

5.1 Ecology and Biology

  1. Conduct surveys to determine seasonal leatherback distribution and abundance and to identify foraging habitats that are of significant importance to the recovery of leatherback populations in Atlantic Canada.
  2. Identify and investigate distribution of prey/food sources to improve our understanding of leatherback/prey relationships.
  3. Model biotic and abiotic factors (e.g. oceanographic correlates) that may influence the seasonal distribution of leatherbacks in Canadian waters.
  4. Conduct research on the basic biology and physiology of the leatherback to better understand how these turtles function in relation to their environment.
  5. Investigate diving depth, duration, and frequency to provide dive correction factors for aerial survey assessments and to guide management measures pertaining to commercial fisheries.
  6. Determine the spatial and temporal overlap of commercial fisheries and leatherbacks to determine where and when leatherbacks may have the potential to interact with commercial fisheries.
  7. Analyse data from existing fishery observer programmes and identify where observer coverage may be needed to provide statistically valid bycatch estimates for leatherbacks taken in commercial fisheries.
  8. Fully capitalize on all opportunities for leatherback necropsy in Atlantic Canada to learn more about basic biology and disease, identify sources of mortality, and obtain samples for archiving and to support other studies.
  9. Investigate seasonal foraging and migratory movements of leatherbacks in Canadian and International waters.
  10. Establish long-term indices of leatherback abundance in Canadian waters.
  11. Conduct research to determine the nesting beach assemblages represented in the mixed foraging population that frequents Atlantic Canadian waters.

  5.2 Habitat

  1. Consolidate information from all jurisdictions on threats to habitats utilized by leatherback turtles.
  2. Continue to conduct studies that will identify habitats that are critical to leatherback turtles in Canadian waters.
  3. Use available oceanographic data to determine how sea surface temperature and chlorophyll are measures of primary productivity and proxies for leatherback prey, and can be correlated with leatherback distribution.
  4. Conduct research on the distribution and abundance of leatherback prey (jellyfish) and leatherback turtles in Atlantic Canadian waters.
  5. Identify leatherback turtle migration pathways by various means including satellite telemetry.
  6. Determine what activities are occurring or have potential to occur that impact the habitat utilized by the leatherback turtle.

  5.3 Threats

  1. Quantify known or potential threats to leatherback turtles on foraging grounds and along migratory routes.
  2. Estimate prospects for recovery at various levels of mortality based on knowledge of reproductive fitness.
  3. Estimate the bycatch associated with all fisheries known to incidentally take leatherback turtles.
  4. Recommend the adaptation of the current pelagic longline sampling protocol for the Canadian East Coast Observer Program to include turtle data collection in other gear sectors where observer coverage should be targeted.
  5. Evaluate the impact of all fishing gear types currently in use and rank according to impact (note gear types listed in U.S. plan).
  6. Evaluate/adopt the use of fishing gear modifications to reduce incidence of LBT-gear interactions/mortality.
  7. Investigate handling procedures to minimize harm to leatherback turtles incidentally taken in commercial fishing gear.
  8. Investigate post-release mortality from commercial fishing gear.
  9. Investigate the potential impact of seismic activities in foraging areas and migration pathways and evaluate the effectiveness of current or proposed mitigation measures for seismic activity.
  10. Investigate the potential impact of military activity on the leatherback turtle and its prey.
  11. Evaluate the impact of discharges associated with exploration and production drilling, particularly discharge of produced water (investigate Gulf of Mexico experience)
  12. Investigate the potential impact of contaminants and pollutants on the leatherback turtle.
  13. Determine the level of mortality and injury associated with marine debris (consider U.S. data).
  14. Evaluate vulnerability of leatherback turtles to vessel strikes and assess the incidence of vessel strikes as a cause of mortality in Canadian waters (consider U.S. data).
  15. Investigate options for mitigation of any gear related threats.

[1] SARA requires recovery strategies to include “a statement about whether additional information is required about the species” [SARA s.41(f)]. The following section outlines knowledge gaps needed to be addressed in order to achieve the recovery goal.