Blue whale (Balaenoptera musculus) Atlantic population: COSEWIC status appraisal summary 2012

Endangered
2012

COSEWIC status appraisal summaries are working documents used in assigning the status of wildlife species suspected of being at risk in Canada. This document may be cited as follows:

COSEWIC. 2012. COSEWIC status appraisal summary on the Blue Whale Balaenoptera musculus, Atlantic population in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xii pp.

Production note: 
COSEWIC acknowledges Garry Stenson for writing the status appraisal summary on the Blue Whale Balaenoptera musculus, Atlantic population, in Canada. This status appraisal summary was overseen and edited by Jane Watson and Randall Reeves, Co-chairs of the COSEWIC Marine Mammals Specialist Subcommittee.

For additional copies contact:

COSEWIC Secretariat
c/o Canadian Wildlife Service
Environment Canada
Ottawa, ON
K1A 0H3

Tel.: 819-953-3215
Fax: 819-994-3684
Email: COSEWIC/COSEPAC@ec.gc.ca
Website: www.cosewic.gc.ca

Également disponible en français sous le titre Sommaire du statut de l’espèce du COSEPAC sur le Rorqual bleu (Balaenoptera musculus) (population de l’Atlantique) au Canada.

© Her Majesty the Queen in Right of Canada, 2012.
Catalogue No. CW69-14/2-23-2012E-PDF
ISBN 978-1-100-20728-5

COSEWIC Assessment Summary

Assessment Summary – May 2012

Common name
Blue Whale - Atlantic population

Scientific name
Balaenoptera musculus

Status
Endangered

Reason for designation
Whaling reduced the original population of this species. The population size is unknown but there are likely fewer than 250 mature individuals in Canada. There are also strong indications of a low calving rate and a low rate of recruitment into the population. The known causes of human-induced mortality of this species in Canada and elsewhere are ship strikes and entanglements in fishing gear. The species may also be vulnerable to disturbances due to increased noise in the marine environment and to changes in the abundance of its prey (zooplankton) through, for example, long-term changes in the climate.

Occurrence
Atlantic Ocean

Status history
The species was considered a single unit and designated Special Concern in April 1983. Split into two populations in May 2002. The Atlantic population was designated Endangered in May 2002. Status re-examined and confirmed in May 2012.

COSEWIC Status Appraisal Summary

Balaenoptera musculus

Blue Whale (Atlantic population) Rorqual bleu (Population de l’Atlantique)

Jurisdictions: Atlantic Ocean

Current COSEWIC Assessment:

Status category:

Date of last assessment: May 2002

Reason for designation at last assessment: Whaling reduced the original population. There are fewer than 250 mature individuals and strong indications of a low calving rate and a low rate of recruitment to the studied population. Today, the biggest threats for this species come from ship strikes, disturbance from increasing whale watch activity, entanglement in fishing gear, and pollution. They may also be vulnerable to long-term changes in climate, which could affect the abundance of their prey (zooplankton).

New reason for designation (only if different from above): Whaling reduced the original population of this species. The population size is unknown but there are likely fewer than 250 mature individuals in Canada. There are also strong indications of a low calving rate and a low rate of recruitment into the population. The known causes of human-induced mortality of this species in Canada and elsewhere are ship strikes and entanglements in fishing gear. The species may also be vulnerable to disturbances due to increased noise in the marine environment (e.g., shipping, seismic surveys) and to changes in the abundance of its prey (zooplankton) through, for example, long-term changes in the climate.

Criteria applied at last assessment: A1bd; D1

If earlier version of criteria was applied¹, provide correspondence to current criteria: Not applicable

If different criteria are proposed based on new information, provide explanation: A2abd, D1

A2abd: Meets Endangered under A2abd as over the past 3 generations (i.e. since ca. 1915) there has been a suspected decline of more than 50% in the total number of mature individuals based on the low numbers of individuals observed in recent surveys (a), the difficulty whalers had in finding and catching Blue Whales (preferred targets) in the last years of commercial whaling (b), and high levels of historic commercial exploitation (d). The cause of the reduction (commercial whaling) has ceased and is understood but the reduction may not be reversible. Although the cause of the reduction (commercial whaling) has ceased, its effects may not be fully understood and the reduction may not be reversible given the lack of evidence of strong recovery despite 45+ years of full protection from whaling.

D1. Meets Endangered under D1 as the number of mature animals is likely less than 250, based on the results of a DFO survey in 2007 covering waters from northern Labrador to the US border and including the Gulf of St Lawrence, in which only five Blue Whales were sighted off Newfoundland and 11 in the Gulf and Scotian Shelf.

If application of current specific criteria is not possible, provide explanation: Not applicable

Reason:

 sufficient information to conclude there has been no change in status category.
 not enough additional information available to warrant a fully updated status report.

Evidence (indicate as applicable):

Wildlife species: 

Change in eligibility, taxonomy or designatable units:  

Explanation:

There is no new information to indicate that the taxonomic or DU status of the Atlantic population of Blue Whales has changed.

Range:

Change in Extent of Occurrence (EO):

Change in Area of Occupancy (AO):

Change in number of known or inferred current locations:

Significant new survey information

Explanation:

No significant new data.

Population Information:

Change in number of mature individuals:

Change in total population trend: 

Change in severity of population fragmentation:

Change in trend in area and/or quality of habitat: 

Significant new survey information:

Explanation:

A total of 16 Blue Whales (5 off Newfoundland and 11 in the Gulf of St. Lawrence and Scotian Shelf) were sighted during a 2007 DFO survey of Atlantic Canadian shelf waters from northern Labrador (60°N) to the US border. The survey was designed to increase the likelihood of sighting Blue Whales by apportioning higher effort to areas where they had been sighted previously (Lawson and Gosselin 2009). Too few sightings were obtained to derive an estimate of abundance but the low number of sightings is consistent with previous estimates suggesting there are < 250 mature individuals.
 
There have been few sightings of Blue Whales in the Gully area of the Scotian Shelf over the past 20 years and no trend has been evident (Whitehead 2011).

Researchers in the Gulf of St. Lawrence report that only 21 calves have been recorded in over 32 years of annual sighting effort (Ramp 2011). Although Blue Whales are present off Newfoundland and Nova Scotia, no cow-calf pairs have been sighted there (Lawson 2011).

There are no new data on overall trends in abundance or habitat quality. The population is not considered to be fragmented.

Threats: 

Change in nature and/or severity of threats:

Explanation:

The threats identified during the 2002 assessment remain and the Blue Whale Recovery Team has identified additional threats and ranked them. There is no indication that the nature or severity of the threats has changed over the past ten years but perceptions and understanding have changed somewhat.

The main sources of human-induced mortality of Blue Whales in the North Atlantic are entanglement in fishing gear and ship strikes (documented in other populations; scars present in this population) although both types of events are rarely observed and reported for Blue Whales in the North Atlantic. Other potential limiting factors are changes in food availability (due, for example, to changes in trophic structure of the ecosystem or climate change through changes to hydrology) and behavioural changes due to increased noise in the marine environment (e.g., from shipping, seismic surveys; see Di Iorio and Clark 2010).

The Blue Whale Recovery Strategy team (Beauchamp et al. 2009) identified and ranked anthropogenic threats as follows.

1. High risk threats: 
   • Anthropogenic noise (resulting in environmental degradation and change in behaviour)
   • Food availability due to changes in the trophic structure and climate change
2. Medium risk threats:
   • Contaminants
   • Vessel collisions
   • Whale watching
3. Low risk threats:
   • Physical harm from anthropogenic noise
   • Entanglements in fishing gear
   • Epizootics and toxic algal blooms
   • Toxic spills.

Protection: 

Change in effective protection:

Explanation:

As of 2005, the Blue Whale (Atlantic population)is listed as Endangered on Schedule 1 of the Canadian Species at Risk Act and as such it is currently illegal to kill, harm, harass, capture or take individuals. COSEWIC also provides legal protection for the residence and critical habitat of listed species. However, the Recovery Strategy indicates that available information is insufficient for identifying critical habitat of Blue Whales in Canadian Atlantic waters (Beauchamp et al. 2009) and therefore no special protection is afforded in this regard at present.

Rescue Effect:

Evidence of rescue effect:  

Explanation:

It is difficult to determine if rescue is likely. Blue Whales appear to be increasing in the area around Iceland (Northeast Atlantic population) but are rare elsewhere in the North Atlantic.

Quantitative Analysis:

Change in estimated probability of extirpation:

Details:  No quantitative analyses are available.

Summary and Additional Considerations: [e.g., recovery efforts]

A Recovery Strategy for the Blue Whale in Atlantic Canada (Beauchamp et al. 2009) was finalized and published in December 2009. It identifies a recovery goal and outlines recovery objectives.

¹ An earlier version of the quantitative criteria was used by COSEWIC from October 1999 to May 2001 and is available on the COSEWIC website.

List of authorities contacted to review the status appraisal:

Marine Mammal SSC members

Lesage, V. March 2011. Research Scientist, Fisheries and Oceans, Canada, Mont Joli, QC

Lawson, J. March 2011. Research Scientist, Fisheries and Oceans, Canada, St. John’s, NL

Sears, R. April 2011. Researcher, Mingan Island Cetacean Study, Quebec

Ramp, C. April 2011. Researcher, Mingan Island Cetacean Study, Quebec

Sources of information:

Beauchamp, J., H. Bouchard, P. de Margerie, N. Otis, J.-Y. Savaria. 2009. Recovery strategy for the blue whale (Balaenoptera musculus), Northwest Atlantic population, in Canada [FINAL]. Species at Risk Act Recovery Strategy Series, Fisheries and Oceans Canada, Ottawa. 62 pp.

Comtois, S. C. Savenkoff, M.-N. Bourassa, J.-C. Brêthes and R. Sears. 2010. Regional distribution and abundance of blue and humpback whales in the Gulf of St. Lawrence. Canadian Technical Report of Fisheries and Aquatic Sciences 2877. 48 pp.

COSEWIC. 2002. COSEWIC assessment and update status report on the Blue Whale Balaenoptera musculus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 32 pp.

Di Iorio, L. and C.W. Clark. 2010. Exposure to seismic survey alters Blue Whale acoustic communication. Biology Letters 6:51-54.

Lawson, Jack. 2011. Personal Communications March/April 2011. Email correspondence and verbal communications with G. Stenson. Research Scientist, Fisheries and Oceans Canada, Mont Joli, QC.

Lawson, J. W. and J.-F. Gosselin. 2009. Distribution and preliminary abundance estimates for cetaceans seen during Canada’s marine megafauna survey – a component of the 2007 TNASS. Canadian Science Advisory Secretariat Research Document 2009/031. 28 pp.

Lesage, Veronique. 2011. Personal Communications March/April 2011. Email correspondence and verbal communications with G. Stenson. Research Scientist, Fisheries and Oceans Canada, Mont Joli, QC.

Ramp, C. 2006. Survival of adult blue whales Balaenoptera musculus in the Gulf of St. Lawrence, Canada. Marine Ecology Progress Series 319:287-295.

Ramp, Christian. 2011. Personal Communication, April 2011. Email correspondence with G. Stenson. Researcher, Mingan Island Cetacean Study, QC.

Sears, Richard. 2011. Personal Communication, April 2011. Email correspondence and verbal communications with G. Stenson. April 2011. Researcher, Mingan Island Cetacean Study, QC.

Whitehead, H. 2011. Personal Communications, April 2011. Email correspondence. Professor, Department of Biology, Dalhousie University, Halifax, NS.

Technical Summary

Balaenoptera musculus

Blue Whale (Atlantic population) Rorqual Bleu (Population de l’Atlantique)

Range of occurrence in Canada (province/territory/ocean): Atlantic Ocean

Demographic Information

Extent and Occupancy Information

^* See Definitions and Abbreviations on COSEWIC website and IUCN 2010 (PDF; 492 KB) for more information on this term.

Number of Mature Individuals (in each population)

Quantitative Analysis

Threats (actual or imminent, to populations or habitats)

Rescue Effect (immigration from outside Canada)

Current Status

Additional Sources of Information:

Beauchamp, J., H. Bouchard, P. de Margerie, N. Otis, J.-Y. Savaria. 2009. Recovery strategy for the Blue Whale (Balaenoptera musculus), Northwest Atlantic population, in Canada [FINAL]. Species at Risk Act Recovery Strategy Series, Fisheries and Oceans Canada, Ottawa. 62 pp.

Taylor, B.L., Chivers, S.J., Larese, J. and Perrin, W.F. 2007. Generation length and percent mature estimates for IUCN assessments of cetaceans. Southwest Fisheries Science Center, National Marine Fisheries Service, La Jolla Laboratory, Administrative Report LJ-07-01. 18 pp.

Status and Reasons for Designation

Applicability of Criteria

COSEWIC History

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as sa result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC Mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC Membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions
(2012)

Wildlife Species
A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)
A wildlife species that no longer exists.

Extirpated (XT)
A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)
A wildlife species facing imminent extirpation or extinction.

Threatened (T)
A wildlife species likely to become endangered if limiting factors are not reversed.

Special Concern (SC)*
A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at Risk (NAR)**
A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data Deficient (DD)***
A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

* Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.
** Formerly described as “Not In Any Category”, or “No Designation Required.”
*** Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” (insufficient scientific information on which to base a designation) prior to 1994. Definition of the (DD) category revised in 2006.

The Canadian Wildlife Service, Environment Canada, provides full administrative and financial support to the COSEWIC Secretariat.