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Recovery Strategy for the Transient Killer Whale [Proposed]

2.6 Approaches Recommended to Meet Recovery Objectives

Approaches recommended to achieve the population, distribution and recovery objectives outlined in Section 2.3, 2.4 and 2.5 are detailed in Table 2 and are meant to serve as guidance to future Action Planning, as required by SARA and to recovery activities that will be undertaken by government and non-government organizations. Although the objectives are focused on a five-year term, the many approaches outlined below will likely extend past the term of this recovery strategy or be ongoing requirements.  

In addition to the lead role DFO has for this population’s recovery, there are several government agencies who have a key role in supporting transient killer whale protection and recovery including: Parks Canada, Environment Canada,  the Department of National Defence, Natural Resource Canada and the Province of British Columbia. 

While governments and agencies have legislative and program responsibilities to support transient recovery, the role of non-government organizations and the public in general cannot be underestimated with respect to effecting transient recovery.  Stewardship, education and outreach need to be considered in each of the following specific approaches for recovery.

2.6.1 Recovery planning

Table 2. Recovery Planning Table
Threats addressedBroad strategy to address threatRecommended approaches to meet recovery objectives
Objective P1 & P2: Population size and demographic monitoring
n/aPopulation censusDirected surveys
  Collaborations with other transient researchers
  Formal and informal sightings networks including opportunistic photo-identification
 Analytical modellingNumerical and demographic population modelling
Objective P3: Setting demographic and numerical population objectives
n/aAnalytical modellingNumerical and demographic population modelling
Objective D1 & D3: Monitoring of range utilization
n/a Population censusDirected surveys
  Collaborations with other transient researchers
  Formal and informal sightings networks including opportunistic photo-identification
Objective D2: Monitoring of prey distribution
n/aPopulation monitoringPinniped surveys
  Formal and informal sightings networks for small cetaceans
Objective R1: Reducing contaminants in Transient Killer Whales (TKW) and their prey
ContaminationRegulations & ProhibitionsMaintain and enforce existing prohibition on regulated PBTs and other non-PBT chemicals
  Evaluate the need for and efficacy of prohibitions on use of unregulated PBDEs and other non-PBTs that affect TKW or their prey and implement mitigation measures as necessary
  International cooperation and collaboration to reduce PBTs used outside Canada that contribute to Canadian contaminant levels
 Stewardship & EducationGovernment and non-government education and stewardship programs for industrial and private use of PBT and non-PBT compounds including currently used pesticides
 Contaminant Monitoring Dedicated sampling program for transient killer whales
  Dedicated sampling program for harbour seals
  Benchmark studies for other important prey species (other pinnipeds and cetaceans)
  Sediment sampling and monitoring (provides link to model food web bioaccumulation & link to sediment quality guidelines)
  Necropsy stranded TKW to evaluate possible exposure to contaminants,  biological pollutants & pathogens
Objective R2: Protecting Prey Populations
Prey limitationPinniped harvest protectionMaintain current harvest restrictions and ensure research, nuisance seal or other authorized removals do not cause pinniped population level reductions
 Small Cetacean protectionMaintain harvest restrictions and develop and/or maintain programs to protect small cetaceans from anthropomorphic threats
Objective R3: Protecting TKW from vessel disturbance
DisturbanceRegulationsImplement the proposed Marine Mammal Regulation amendments of the Fisheries Act
 Stewardship & EducationGovernment and non-government education and stewardship programs for stewardship and education programs aimed at reducing vessel disturbance
 GuidelinesAmend as necessary and/or develop species or area specific guidelines for viewing of transient killer whales
 Enforcement & MonitoringContinue and modify, as necessary, enforcement and monitoring programs directed to compliancy with guidelines and regulations
  Evaluate the efficacy of enforcement and education programs, and develop as necessary new approaches and protocols for TKW
Objective R4: Protecting TKW from harmful acute and chronic sound exposure
Disturbance & harmSeismic survey managementReview, develop and implement mitigation measures for all seismic surveys conducted throughout British Columbia TKW range to prevent disturbance or injury
 Sonar managementContinue development and implementation of adequate National Defence sonar protocols to minimize risk of exposure of transients to intense sound sources
Objective R5: Determining prey needs
Prey limitationStudies on foragingOpportunistic prey sampling during dedicated population census surveys

Directed surveys to determine diet of transients in offshore waters

Population abundance surveys of cetacean prey species

  Opportunistic observations through formal and informal sightings networks
Objective R6: Understanding the effects of contaminants and biological pollutants on TKW
Toxic ContaminationData collection, analysis & modellingDevelop methods to measure the contaminant effects on health of TKW using biopsy
  Demographic data exploration to evaluate possible population level impacts
 Studies on surrogate speciesControlled stuides on surrogate species (laboratory animals or other more abundant species auch as harbour seals) to predict effects of contaminants on TKW
Biological Pollutants & PathogensAnalysis of existing and new necropsy dataNecrospy, sample collection and analysis of samples
Objective R7: Understanding vessel disturbance effects
DisturbanceBehavioural studiesDedicated studies of foraging behaviour and predation rates in the presence of vessels
Objective R8: Understanding the effects of acute and chronic sound exposure
Disturbance & harmBehavioural studiesDetermine effect of high levels of chronic and acute industrial underwater noise on TKW behaviour and foraging success
 Data synthesisCompile existing data to evaluate the impact of chronic and acute sound exposure

2.7  Performance Measures

The performance measures that will be used to determine whether the objectives established within this recovery strategy are effective are explicitly stated within the objectives themselves. The evaluation of the performance of this recovery strategy will thus be addressed through the achievement of each objective.  Given our limited understanding of transient killer whale population dynamics, the role of prey limitation, the mechanisms and effects of anthropogenic threats and potential for synergistic effects between threats, completing the studies identified in this recovery strategy is a crucial first step towards achieving the long term goal of population viability.  However, it is uncertain whether these information gaps can be filled within a five-year time period and this will be considered in the overall evaluation at the end of this timeline.

2.8 Critical Habitat

“Critical habitat” is defined under SARA as “the habitat that is necessary for the survival or recovery of a listed wildlife species that is identified as the species’ critical habitat in the recovery strategy or in an action plan for the species” (SARA s.2 (1)).  Under SARA, defining critical habitat for transient killer whales to the extent possible is a legal requirement (SARA s.41 (1) (c)).  However, there are significant gaps in our knowledge of the habitat requirements of transient killer whales. 

Transients do not appear to be limited by specific physical features of the environment, other than features that may help them to successfully capture their prey.  They generally range widely over the coast, and although transients may be seen year-round, they rarely remain in any one area for extended periods, likely because their hunting tactics rely on being able to surprise their prey.  Once prey becomes alerted to the presence of transient killer whales in an area, they engage in anti-predator behaviours and become more difficult to capture.  Ambient noise is potentially an important factor influencing foraging success of transients, as they likely detect prey by passive listening (Barrett-Lennard et al. 1996, Ford and Ellis 1999).  Transients could potentially be displaced from foraging habitat if chronic anthropogenic noise interferes with prey detection.  Transients often return repeatedly to particular areas to forage (e.g. seal and sea lion haul-outs), but our understanding of which of these areas are important to transients on a population level is still very limited.  Consequently, it is necessary to develop a Schedule of Studies to better understand and identify critical habitat.  This is included in Section 2.8.1, Schedule of Studies to Identify Critical Habitat.

2.8.1 Schedule of Studies to Identify Critical Habitat

Table 3. Scheduleof Studies for the Identification of Critical Habitat
Description of ActivityOutcome/RationaleTimeline
Spatial analysis of existing sighting dataTo better understand habitat utilizationWithin one year of recovery strategy of acceptance
Spatial analysis of existing data with respect to the distribution of the prey of transient killer whalesTo better understand habitat utilization and whether transient distribution is correlated to prey abundanceWithin next five years
Spatial analysis of transient kill locations with respect to ambient noise environmentTo determine whether transient hunting success is influenced by anthropogenic noiseWithin next five years
Year-round surveys to determine range and seasonal movements of transientsTo better identify areas of occupancy Within next five years
Year-round surveys to determine the spatial and temporal distribution and abundance of small cetaceansTo better understand habitat utilization and whether transient distribution is correlated to prey abundanceWithin next five years
Formal and informal sightings network for TKW and small cetaceansAcquire better information on the distribution of transient prey and how it may influence transient distributionWithin next five years

2.9 Effects on Other Species

The collateral effects of protecting the habitat for transient killer whales through addressing contaminants and other sources of pollution are likely to be widespread, and will be beneficial to human health as well as to a wide variety of organisms including transient prey. However, if transient killer whale populations increase, a reduction from the current high levels of abundance of pinniped populations might be anticipated.  However, it would not be expected that these populations would be in jeopardy.  Not enough is known about the population status of cetacean prey species to predict an effect.  The strategies to protect transient killer whales from disturbance are complimentary to those recommended for resident killer whales and will have a positive effect on marine mammals in general.  

2.10 Recommended Approach for Recovery Implementation

A single species, single population approach is recommended for recovery of transient killer whales that encompasses a variety of strategies that focus on the threats to killer whales, their prey and their habitat.  However, because the strategies to address threats and some of the research needs are similar to those for resident killer whales, in practicality, it is likely that some activities will be conducted in a combined or complementary fashion.

2.11 Statement on when Action Plans will be Completed

Within two years of posting the final version of this recovery strategy, one or more action plans will be developed.  The plan(s) will include descriptions of programs, plus a timeline of programs with estimated budgets and will encompass a timeframe of at least five years.  The action plan(s) will complement the action plan(s) that are to be developed for resident killer whales, where appropriate, and may be coordinated for certain aspects if logistically feasible.  In the interim, many of the strategies in this document can be acted on and therefore, recovery implementation will be an ongoing activity that can occur in the absence of any formal action plan.