Offshore Killer Whale (Orcinus orca): management plan 2009

Official title: Management Plan for the Offshore Killer Whale (Orcinus orca) in Canada [Final Version]

Table of contents

 

the Offshore Killer Whale

December 2009

About the Species at Risk Act Management Plan Series

What is the Species at Risk Act (SARA)?

SARA is the Act developed by the federal government as a key contribution to the common national effort to protect and conserve species at risk in Canada. SARA came into force in 2003, and one of its purposes is “to manage species of special concern to prevent them from becoming endangered or threatened.”

What is a species of special concern?

Under SARA, a species of special concern is a wildlife species that could become threatened or endangered because of a combination of biological characteristics and identified threats. Species of special concern are included in the SARA List of Wildlife Species at Risk.

What is a management plan?

Under SARA, a management plan is an action-oriented planning document that identifies the conservation activities and land use measures needed to ensure, at a minimum, that a species of special concern does not become threatened or endangered.  For many species, the ultimate aim of the management plan will be to alleviate human threats and remove the species from the List of Wildlife Species at Risk. The plan sets goals and objectives, identifies threats, and indicates the main areas of activities to be undertaken to address those threats.

Management plan development is mandated under Sections 65–72 of SARA (http://www.sararegistry.gc.ca/approach/act/default_e.cfm).

A management plan has to be developed within three years after the species is added to the List of Wildlife Species at Risk. Five years is allowed for those species that were initially listed when SARA came into force.

What’s next?

Directions set in the management plan will enable jurisdictions, communities, land users, and conservationists to implement conservation activities that will have preventative or restorative benefits. Cost-effective measures to prevent the species from becoming further at risk should not be postponed for lack of full scientific certainty and may, in fact, result in significant cost savings in the future.

The series

This series presents the management plans prepared or adopted by the federal government under SARA. New documents will be added regularly as species get listed and as plans are updated.

To learn more

To learn more about the Species at Risk Act and conservation initiatives, please consult the SARA Public Registry (http://www.sararegistry.gc.ca/).

Recommended citation:

Fisheries and Oceans Canada. 2009. Management Plan for the Offshore Killer Whale (Orcinus orca) in Canada. Species at Risk Act Management Plan Series. Fisheries and Oceans Canada, Nanaimo. v + 49pp.

Additional copies:

Additional copies can be downloaded from the SARA Public Registry (http://www.sararegistry.gc.ca/).

Cover illustration: B. Lewis

Également disponible en français sous le titre
« Projet de plan de gestion des épaulards du large (Orcinus orca) au Canada»

© Her Majesty the Queen in Right of Canada, represented by the Minister of Fisheries and Oceans Canada, 2009. All rights reserved.
ISBN: 978-1-100-12128-4
Catalogue no. En3-5/4-2009E-PDF

Content (excluding the illustrations) may be used without permission, with appropriate credit to the source.

Preface

The Offshore Killer Whale is a marine mammal and is under the responsibility of the federal government.  The Species at Risk Act (SARA, Section 65) requires the competent minister to prepare management plans for species listed as special concern.  The Offshore Killer Whale was listed as a species of special concern under SARA in 2003.  The development of this management plan was led by Fisheries and Oceans Canada – Pacific Region, in cooperation and consultation with many individuals, organizations and government agencies, as indicated below.  The plan meets SARA requirements in terms of content and process (SARA sections 65-68).

Success in the conservation of this species depends on the commitment and cooperation of many different constituencies that will be involved in implementing the directions set out in this plan and will not be achieved by Fisheries and Oceans Canada or any other party alone. This plan provides advice to jurisdictions and organizations that may be involved or wish to become involved in activities to conserve this species.  In the spirit of the Accord for the Protection of Species at Risk, the Minister of Fisheries and Oceans invites all responsible jurisdictions and Canadians to join Fisheries and Oceans Canada in supporting and implementing this plan for the benefit of the Offshore Killer Whale and Canadian society as a whole.  The Minister will report on progress within five years.

Responsible Jurisdictions

Authors

The DFO Technical Team (Appendix III) prepared this document for Fisheries and Oceans Canada (DFO).

Acknowledgments

Fisheries and Oceans Canada would like to acknowledge all those who participated in the Cetacean Management Plan Technical Workshop (Appendix III), which provided valuable information on Offshore Killer Whale biology, and threats to the population; to support the generation of this management plan.

Strategic Environmental Assessment

A strategic environmental assessment (SEA) is conducted on all SARA recovery planning documents, in accordance with the Cabinet Directive on the Environmental Assessment of Policy, Plan and Program Proposals. The purpose of a SEA is to incorporate environmental considerations into the development of public policies, plans, and program proposals to support environmentally-sound decision making.

Management planning is intended to benefit species at risk and biodiversity in general. However, it is recognized that plans may also inadvertently lead to environmental effects beyond the intended benefits. The planning process based on national guidelines directly incorporates consideration of all environmental effects, with a particular focus on possible impacts on non-target species or habitats. The results of the SEA are incorporated directly into the plan itself, but are also summarized below.

Through the development of this plan numerous factors that jeopardize or have potential to jeopardize the management of this population were evaluated and are presented. Principal among the anthropogenic threats are reductions in the availability or quality of prey, environmental contamination, and acute acoustic disturbance. In some cases these factors threaten the population; in other cases they affect Offshore Killer Whales’ habitat. It was concluded that some threats can be mitigated through the use of existing legislation, policies and programs and, in fact, there are numerous examples of mitigation measures that are currently employed. However, in other cases the threat and/or the potential mitigation measure(s) require further research or evaluation before recommendations on specific actions or activities can be formulated. The general type of research, evaluation and approaches for mitigation are presented in this management plan (see Section 2.3 ‘Actions’).

Through the course of implementing actions, specific activities for management, recovery and mitigation will be evaluated and detailed for this population along with an evaluation of effects and costs for each activity or measure. Therefore, taking into account the multi-species nature of the recommendations for new mitigation to manage the population and that many of the recommendations to protect habitat fall under existing legislation and policies, this management plan will not entail any significant adverse effects.

Executive Summary

Killer Whales (Orcinus orca) are primarily black with a white-coloured abdomen, a large white patch behind each eye, and a grey saddle patch below and posterior to the black dorsal fin. The dorsal fin is large and distinctive in males, while small and curved in females and juvenile animals.  To the untrained eye, it is extremely difficult to distinguish between the three ‘assemblages’ of Killer Whales found on the west coast of North America; Resident, Transient and Offshore Killer Whales (also called ‘Offshores’).  Compared with those of Resident and Transient Killer Whales, the tips of Offshores’ dorsal fins tend to be rounded on the leading edge and over the apex of the fin, giving the dorsal fin a blunt appearance.  Dorsal fins tend to be less angled at the trailing edge and have many more nicks and notches than those of Resident Killer Whales.  The saddle patches are usually uniformly grey, although on some animals it may contain a black region (Black et al. 1997; Ford et al. 2000). 

Offshores are a genetically distinct group, thought to be most closely related to Resident rather than to Transient Killer Whales due to similarities in appearance, vocalizations and genetics (Barrett-Lennard and Ellis 2001).  They are most often observed in groups of 20 or more individuals (Barrett-Lennard and Ellis 2001) and based on photo-identification of these animals, there is believed to be a minimum of 288 animals in the British Columbia (B.C.) population (COSEWIC 2008).  Encounters with these whales have been few, and efforts to catalogue members of this population have been challenging given infrequent sightings, elusive behaviour, and their largely open ocean habitat.  In recent years, sightings of Offshores in coastal and inshore waters have increased (Fisheries and Oceans Canada-Cetacean Research Program (DFO-CRP) unpublished data) suggesting that usage of coastal habitat is higher than in the past and it may reflect a shift associated with oceanographic conditions and distribution of prey. 

Killer Whales in general appear to have naturally small population sizes and low potential rates of increase.  These intrinsic factors make this population vulnerable to threats. The most significant of identified threats are reduction in prey availability due to regime shift or fisheries competition, chronic and acute toxic contamination, and acute noise stress. Natural factors and periodic events such as mass strandings or entrapments in narrow inlets also have the potential to drastically reduce local numbers (COSEWIC 2008).

There are significant knowledge gaps in nearly all aspects of the general biology and ecology of Offshore Killer Whales, and an increase in research effort is necessary to address these deficiencies.  Continued efforts to clarify population abundance, prey requirements, and seasonal occurrence in Canadian waters are essential for effective management of this population.  The synchronization of multi-species management and research activities will facilitate comprehensive marine mammal conservation in B.C., and allow for effective use of available resources.

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