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Review of the Effectiveness of Recovery Measures for Southern Resident Killer Whales


Review of the Effectiveness of Recovery Measures for Southern Resident Killer Whales

Review of the Effectiveness of Recovery Measures for Southern Resident Killer Whales (PDF, 1.36 MB)

Table of Contents

9.0 Conclusions

The SRKW population is not recovering and in fact continues to decline. Some actions have been taken to date that have contributed to partially abating some of the threats to this population, but collectively they have not been sufficient to prevent a continued decline in the population trajectory. Positive steps taken to reducing threats to SRKWs include the development of whale watching guidelines in Canada and enforcement of whale watching regulations in the US, improved ocean disposal of sediment guidelines in Canada for PCBs, and bans on certain contaminants and restrictions on others in both countries. However, thus far no recovery measures have been implemented that directly aim to reduce shipping noise or improve prey availability for SRKWs. Some actions have been taken to reduce the input of contaminants into the marine environment, but more is clearly needed.

Going forward, concrete management-based measures to abate the threats of prey availability and acoustic disturbance should be paramount, and provide the best chance at seeing positive progress in the near term. Research and monitoring efforts to support potential management actions to reduce impacts from shipping are currently underway and have resulted in monitoring and acoustic modelling advances that could support mitigation of acoustic disturbance (e.g. work being coordinated by ECHO and undertaken by SMRU Consulting Canada, JASCO Applied Science, Oceans Network Canada and others). Progress in the abatement of the contaminant threat and resultant positive changes in the population will only become evident over much longer timeframes given the long life span of these animals, the high contaminant burdens they presently carry and the bio-accumulating nature of some contaminants. This highlights the need to begin the implementation of management based measures aimed at reducing contaminants as soon as possible.

Salmon management actions to address concerns about conservation of Fraser River Chinook have been implemented, though not specifically to address the needs of SRKWs, and measures to specifically address concerns about prey availability for SRKW in their key foraging habitats appear to be lacking or at best are in early stages of development. It is critical that SRKW be provided greater access to prey in their key foraging areas, either by increasing the abundance of the prey, by reducing underwater noise so they more effectively forage from the existing prey base, or a combination of both, because indicators of nutritional stress (links between body condition and subsequent mortality) are compelling (Matkin et al. 2017). Recovery Measures aligned with efforts to rebuild Chinook salmon stocks appear to be well captured in the draft Southern BC Chinook Strategic Plan. In the immediate future, however, Recovery Measures aimed at providing access to Chinook salmon through reduced competition from fishers and reductions in physical and acoustic disturbance should be of high priority to allow SRKWs to forage with greater efficiency in order to meet their energetic requirements with the available Chinook population abundance. To provide improved access to Chinook salmon, areas should be identified that can be set aside for periods of time for access by SRKWs to forage. Field research will be needed to measure foraging success rates (catch per unit effort) to be able to assess functioning of such reserves. Measures of increased prey availability (reduction of threat) could be inferred by regular monitoring of body condition and annual surveys. Surveys to monitor trends in survival and reproduction in the population should continue.

This review has also provided an opportunity to highlight a newly emerged threat (ship strikes) that was not recognized in the Recovery Strategy or Action Plan, as well as the identification of some modified and additional measures that should be implemented in the near term.

The identification of Critical Habitat for SRKW was an important achievement, although Critical Habitat identification alone does not necessarily result in direct reductions of threats. In order for threats to be reduced, Critical Habitat requirements need to be adequately enforced. Critical Habitat identification has brought greater scrutiny to development projects that are planned or approved in the Canadian portion of the Salish Sea, although there remains a need to assess their cumulative effects. The identification has also served to catalyze efforts to manage shipping noise and impacts on marine mammals, particularly SRKWs (Vancouver Port 2017). Additional important habitat off the southwest coast of Vancouver Island that adjoins the currently identified SRKW Critical Habitat has recently been identified. Designation and enforcement of this additional area should be implemented as soon as possible (DFO 2017b); however, challenges remain to effectively protect critical habitat from being destroyed.

Almost half of the Recovery Measures in the action plan (40 of 98) are related to addressing knowledge gaps to better understand impacts of threats to SRKW through research, modelling or monitoring, rather than directly reducing a threat. While these research-based activities have not directly reduced threats, they have and will continue to play a crucial role in informing management decisions and to help monitor the effectiveness of management actions. Some management decisions may be controversial or have socio-economic implications that may be weighed heavily. In such cases having a detailed understanding of the threats to SRKWs can help support decisions.

Management-based recovery actions often seem challenging to implement as there are typically trade-offs to reducing anthropogenic threats (otherwise we would have reduced or eliminated the threat already). To make progress on management-based Recovery Measures, there needs to be a commitment within the federal government to integrate across sectors within DFO (e.g. Fisheries Management and Science) to ensure these actions are incorporated and that measurable advances become requirements. This is also true, and perhaps more challenging, when the management-based Recovery Measure involves other government agencies with whom DFO would need to cooperate and collaborate. These other agencies would ideally need to commit to making progress on recovery of a SRKW through implementation of specific Recovery Measures.

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