Basking shark (Cetorhinus maximus) in Canadian Pacific Waters: recovery strategy: chapter 17

9. Measuring Progress

Studies to determine current population structure and species distribution are important components necessary to assess future impacts to population growth and recovery. While it is unlikely that these information gaps will be addressed completely prior to action planning, these studies will contribute to an improved understanding of anthropogenic and ecological processes affecting the Pacific population of Basking Shark. Because of the long-term nature of this recovery strategy, and particularly the population and distribution objectives, the timelines in the performance measures listed below represent benchmarks at which evaluations of progress towards meeting the objectives will be undertaken. Performance measures for each population and distribution objective are outlined in Table 5 below.

Table 5: Performance Measures

Population & Distribution Objective Performance Measures
Objective 1: Maintain the current abundance of Basking Sharks.
  • Proven maintenance, promotion, and utilization of the Basking Shark Sightings Network and Database.
  • Within five years, observe, at a minimum, the current annual average number of reliable sightings11.
Objective 2: Attain positive population growth of Basking Sharks within 15-20 years.
  • Proven maintenance, promotion, and utilization of the Basking Shark Sightings Network and Database.
  • Within five years, observe an increase in annual average number of reliable sightings throughout species distribution range.
  • Within 15-20 years, established Canadian, U.S. and Mexican overflights observe higher numbers of Basking Sharks annually.
Objective 3: Attain increase in Basking Shark aggregations (two or more sharks).
  • Proven maintenance, promotion, and utilization of the Basking Shark Sightings Network and Database.
  • Within five years, see an increase in reliable sightings of aggregations of two or more sharks.
Objective 4: Maintain distribution of Basking Sharks.
  • Proven maintenance, promotion, and utilization of the Basking Shark Sightings Network and Database.
  • Within five years, observe an increase in annual average number of reliable sightings throughout species distribution range.

11 Reliable sightings would include those from aerial surveys as well as confirmed sightings reported to the Basking Shark Sightings Network.

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