The following information is part of the text from the report "Status of killer whales in Canada", by R.W. Baird.
Introduction
Killer whales are found in all three of Canada's oceans (Figure 1). In the Pacific they are the most well-known cetacean both to the scientific community and to the general public. In fact, off the British Columbia (B.C.) coast long-term studies of killer whales have led to a greater understanding of these animals than of almost any other species of cetacean (Baird 1999). In the Canadian Arctic and Atlantic, killer whales are seen only occasionally and no in-depth scientific studies have been undertaken. Yet, because of their relatively large size, distinctive appearance, and the publicity this species has garnered in books, magazine articles, television, and in aquaria, killer whales are known by and recognizable by virtually everyone. In this report I review what is known of the general biology and ecology of killer whales in Canadian waters, including population discrimination, sizes and trends, behaviour, life history and limiting factors. Gaps in the available data are identified that may be relevant to their long-term status assessment. This review has been undertaken on behalf of the Fish and Marine Mammal Subcommittee of COSEWIC, the Committee on the Status of Endangered Wildlife in Canada.
The distinctive black and white pattern, blunt head, and tall dorsal fin in the middle of the back, are the primary identifying characteristics of killer whales (Figure 2). Adult males are substantially larger than females, although very few accurate measurements are available. Reports of maximum lengths of 9.75 m for males and 8.53 m for females given in the literature (e.g., Perrin and Reilly 1984) are actually estimates. The maximum length measured for males and females is 9.0 m and 7.7 m, respectively (Heyning and Brownell 1990). There is some suggestion of differences in size for individuals from different populations (cf. Berzin and Vladimirov 1983; Heyning and Brownell 1990), and more accurate measurements from different parts of their range are needed before average lengths of individuals from any one population can be characterized. From the few measurements available for adult individuals from British Columbia (e.g., Bigg and Wolman 1975), it is clear that the average length of adult individuals is much smaller than the maxima noted above. Adults are sexual dimorphic in appendage size, with adult males having a tall triangular dorsal fin which may reach up to 1.8 m in height, while in juvenile males and adult females it reaches 0.9 m or less and is generally more falcate (Figure 3). Pectoral fins and tail flukes are also sexually dimorphic, being much larger in adult males, with the fluke tips also bending downwards. As well, pigmentation in the genital area differs between males and females (Bigg et al. 1987).
Population Discrimination
The question of population segregation or division (fragmentation) is critical to any evaluation of status (IUCN 1996). If more than one distinct population exists, and factors which affect each population differ in any way, then each population must be monitored and managed independently.
"Residents" and "Transients"
In the case of killer whales in the Canadian Arctic and North Atlantic, no information is available to assess whether any population differentiation has occurred (Mitchell and Reeves 1988; Anonymous 1993). For the Pacific coast of Canada, clear evidence is available for differentiation of killer whales into two distinct "types" or "forms", termed "resident" and "transient" (Table 1; Figure 4; Bigg et al. 1976). The names "resident" and "transient" have become entrenched in the literature even though it has been demonstrated that they are not accurate as descriptions of the site fidelity and movement patterns of the two forms (Guinet 1990; Baird et al. 1992). As the names are frequently mis-interpreted as descriptive categorizations, they are referred to hereafter as resident and transient to try to prevent such confusion.
Several studies have documented a variety of behavioural, ecological, morphological and genetic differences between transients and residents (Table 1; Bigg et al. 1987; Baird and Stacey 1988; Morton 1990; Baird et al. 1992; Baird and Dill 1995, 1996; Barrett-Lennard et al. 1996; Hoelzel et al. 1998; Matkin et al. 1998; Ford et al. 1999). One of the most important differences is diet; residents appear to feed almost entirely on fish, while transients appear to feed almost entirely on marine mammals (for more detailed discussion, see Feeding Habits, below). Association patterns, in terms of observations of individuals traveling together in a group, and vocal dialects, are also used to discriminate residents from transients (Black et al. 1997). Interactions between residents and transients have only been reported on a small number of occasions (Jacobsen 1990; Morton 1990; Barrett-Lennard 1992; Baird and Dill 1995). On eight of those occasions no change was recorded in the behaviour of either form as they passed within a couple of kilometers of each other. Transients have been seen changing direction away from residents (avoiding them) on eight occasions, residents avoiding transients twice, and both avoiding each other twice. Since residents vocalize more frequently than transients (Morton 1990; Barrett-Lennard et al. 1996), transients may detect the presence of residents much sooner, and more frequently than the other way around (Baird and Dill 1995). Cases of residents showing no reaction when near transients may be due simply to them being unaware that transients were nearby. One observations of aggression between the two forms involved a large group of residents attacking a small group of transients (Ford and Ellis 1999), and one other observation of apparent aggression has also been observed (P. Spong, H. Symonds, personal communications).
The exact taxonomic relationship of these two forms is unclear. In 1987 Bigg et al. termed these two types of killer whales "races", and this term has been adopted, uncritically, by many investigators. "Races" are usually defined in a geographic sense, implying geographically isolated populations which are typically given subspecific designation (Mayr and Ashlock 1991).
Baird et al. (1992) outlined how these two forms may have evolved, and termed them incipient species. Baird (1994) subsequently argued that they should be considered separate species, although no formal description of each species has been presented. Heyning and Dahlheim (1993) have argued that insufficient information is available to determine the level of isolation between them. Hoelzel (personal communication) estimated genetic migration between these two forms at one male per five generations and one female per 20 generations (see Hoelzel et al. 1998).
Regardless of such disagreements and uncertainty in taxonomic relationship between these two forms, there is sufficient evidence to suggest that these forms or types should be treated as separate populations for management. Considering the differences in behaviour and ecology which have been documented (e.g., Table 1), it is also prudent not to apply behavioural or life history characters from one form to another, nor indeed from these populations of killer whales to killer whales elsewhere.
The suggestion that there may be more than one species in the genus Orcinus is not new. Mikhalev et al. (1981) and Berzin and Vladimirov (1983) described two species in the Southern Ocean, O. nanus and O. glacialis, respectively, both of which seem to refer to the same population of smaller individuals (Heyning and Dahlheim 1988). As well as differences in body size, other differences in morphology, behaviour and diet were noted, with one species feeding primarily on fish and the other feeding primarily on marine mammals, similar to the situation off Canada's west coast (Berzin and Vladimirov 1983). Neither of these species designations have been generally accepted (Perrin 1982; Heyning and Dahlheim 1988).
"Southern", "Northern" and "Offshore" Residents
A further level of population differentiation appears to exist within the resident form. Based on association patterns, pigmentation patterns and genetics, residents within British Columbia appear to be divided into three distinct, largely geographically based communities or populations (Bigg et al. 1987; Baird and Stacey 1988; Bain 1989; Ford et al. 1994a; Hoelzel et al. 1998; Matkin et al. 1998). One population, found generally around southern Vancouver Island and in Washington state, has been termed the "southern" resident community, one found generally off northern Vancouver Island and in southeast Alaska has been termed the "northern" resident community, and a third putative resident population is termed "offshore" killer whales, which appear to inhabit offshore waters along the entire coast. It should be noted that while based on mitochondrial DNA "offshore" killer whales are closely related to northern and southern residents (Hoelzel et al. 1998; Matkin et al. 1998), relatively little is known about other aspects of their biology, and it is unclear whether "offshore" killer whales share behavioural or ecological characteristics with northern or southern residents. British Columbia northern residents have been observed associating, and share the same mitochondrial DNA haplotype, with other resident-type killer whales in southeast Alaska (Dahlheim et al. 1997; Hoelzel et al. 1998). The resident-type whales from Alaska have not been documented in British Columbia, but based on both association patterns and genetics are likely part of the same population. These S.E. Alaska residents have in turn been observed interacting with residents in Prince William Sound, Alaska (Matkin et al. 1997), suggesting that gene-flow between northern residents and these other whales may exist. Similarly, both "offshore" killer whales and transients documented in British Columbia have also been seen off Alaska, Washington and/or California (Dahlheim et al. 1997; Black et al. 1997), suggesting that these individuals are part of larger populations. The U.S. National Marine Fisheries Service evaluates each of the resident populations, and the transient population, independently (Barlow et al. 1997; Hill et al. 1997).
The northern and southern resident communities have been reported to have ranges which do not overlap (e.g. Bigg et al. 1990; Felleman et al. 1991), but there are data which indicate their ranges overlap by over 120 km on both the east and west coasts of Vancouver Island (Bigg et al. 1976; M.A. Bigg, personal communication 1990; Ford et al. 1994a). "Offshore" killer whales similarly overlap in range with both northern and southern residents, though observations of "offshore" killer whales in or near the core areas of the other two groups are rare (e.g., Walters et al. 1992; Ford et al. 1994b). Regardless, behavioural interactions have not been observed between individuals from northern, southern and "offshore" resident communities, and differences in mitochondrial DNA and physical appearance suggest the communities are reproductively isolated (Baird and Stacey 1988; Stevens et al. 1989; Hoelzel and Dover 1991; Walters et al. 1992; Ford et al. 1994a; Hoelzel et al. 1998; Matkin et al. 1998). The northern and southern resident communities also appears to have distinct behavioural characteristics (Osborne 1986; Hoyt 1990); whether "offshore" killer whales exhibit such distinctive behavioural characteristics is unknown, simply due to the relative paucity of work that has been undertaken on that population. Regions identified as high use areas ("core areas" ) for northern and southern residents are separated by about 400 km (two and a half days of travel at 3.5 knots - Bigg 1982).
Distribution and Movements
Killer whales are cosmopolitan, having been observed in all oceans of the world (Leatherwood and Dahlheim 1978; Dahlheim and Heyning 1998). However, concentrations generally occur in colder regions and in areas of high productivity (Bigg et al. 1987; Heyning and Dahlheim 1988; Guinet and Jouventin 1990). In polar areas the occurrence of killer whales is thought to be limited by the presence of pack ice in winter months (Reeves and Mitchell 1988a), thus some north-south movements would have to occur in such areas. A recent sighting by Gill and Thiele (1997) of killer whales deep in Antarctic sea ice in winter indicates that not all individuals move away from the poles. Gill and Thiele (1997) suggest that the extreme seasonal differences in the number of observers in polar regions could be party responsible for the perception that killer whales do migrate. In general, no clear evidence of seasonal north-south migrations is available. In the southern hemisphere, based on sightings from whaling vessels, Mikhalev et al. (1981) described seasonal migrations from low-latitude areas in the winter months to higher latitude areas in summer. However, no information was presented on potential seasonal biases in effort, so it is difficult to judge the validity of such conclusions (Perrin 1982).
Within British Columbia, killer whales have been documented throughout virtually all salt-water (and some-fresh water) regions, including many long inlets, narrow channels and deep embayments. Both resident and transient killer whales have been recorded year-round in B.C. Presence of resident killer whales seems to be closely tied with peak abundance of various species of salmon, one of their primary prey (Heimlich-Boran 1986; Bigg et al. 1987; Nichol and Shackleton 1996). Several authors have suggested that residents are rare in the core study areas of Johnstone Strait and Haro Strait during winter months. However, in both areas one pod (A5 in Johnstone Strait, J1 in Haro Strait) is recorded during most winter months (D. Ellifrit, P. Spong, H. Symonds, personal communications). Broad scale shifts in distribution are apparent, though they are more conclusive for northern residents than southern residents, since there are two year-round land-based research projects being undertaken in or near the core area for northern residents (Morton 1990; P. Spong, H. Symonds, personal communications). There are several seasonal biases in effort which should be taken into account in terms of the seasonal distribution of southern residents, and the seasonal distribution of northern residents outside of the core area of Johnstone Strait. Inclement weather conditions and low daylight hours during winter months likely decrease the probability of visually detecting killer whales when they are present, and little winter work has ever been undertaken. Some evidence is available to suggest that northern residents decrease their frequency of vocalizing during winter months (Bain personal communication); this may confound examinations of winter occurrence using this method. Similarly, southern residents appear to travel further from shore during winter months (Baird unpublished; D. Ellifrit, personal communication), biasing detection based on shore-based observations. As such, more thorough examinations of seasonal movements (perhaps using satellite telemetry) and winter habitat use are warranted.
Seasonal influxes of killer whales into near-shore areas where pinnipeds are abundant have been noted at Marion Island, the Crozet Archipelago, and Punta Norte, Argentina (Condy et al. 1978; Guinet 1992; Hoelzel 1991). Baird and Dill (1995) showed that a strong seasonal peak in occurrence of transient killer whales in southern British Columbia coincided with the period when harbour seal pups were being weaned. However, only some pods appeared to preferentially use the area during that time, while others were seen regularly year-round (Baird and Dill 1995). Those pods which used the area year-round also tended to travel further from shore, where land-based observers or spotters were less likely to detect them. Because of this seasonal difference in use of near-shore areas, Baird and Dill (1995) and Baird (1995a) suggested that many studies which are shore-based may be biased when examining seasonal presence.
Killer whales have been documented moving long distances, with some individual transients and "offshore" killer whales identified both in central California and southeastern Alaska, a 2,660 km one-way distance (Goley and Straley 1994; Black et al. 1997). Actual home range sizes are unknown, since virtually no photo-identification work has been done in offshore areas (though see Black et al. 1997), and no animals have been satellite-tagged. Using the northern- and southern-most sightings of particular individuals, combined with the limited knowledge of onshore-offshore movements, the largest documented range for a transient in British Columbia is 140,000 km2, while the largest documented range for a resident is approximately 90,000 km2 (Baird 1999). Both residents and transients have been documented to move up to 160 km in one 24 hour period, but pods of both types also spend extended periods in small areas.
A comprehensive review of all records available for killer whales in the eastern Canadian Arctic and the western North Atlantic was last undertaken in the 1980s (see papers in Sigurjonsson and Leatherwood 1988). Sergeant and Fisher (1957) stated that killer whales migrated northwards in the spring along the coasts of Labrador and Newfoundland, though a more comprehensive review by Mitchell and Reeves (1988) concluded that biases in effort precluded the determination of any obvious pattern of distribution or movements. Killer whales are occasionally recorded in virtually all areas off eastern Canada, including Nova Scotia (Katona et al. 1988), in the Gulf of St. Lawrence (Wenzel and Sears 1988), off Newfoundland and Labrador (Lien et al. 1988), and in Hudson Bay and the Canadian Arctic (Reeves and Mitchell 1988), with one record from 81°N. Records from these compilations end in the early 1980s, thus another review incorporating more recent records is warranted. Based largely on records collected since the earlier review, it appears that there are only a couple of areas where killer whales appear to be somewhat regular in their occurrence. These include the Mingan Islands, Quebec, where R. Sears (Mingan Island Cetacean Study, personal communication) has observed the same small group of whales a number of times since 1984 (see Wenzel and Sears 1988), the western end of the Strait of Belle Isle (R. Sears, personal communication), off Battle Harbour, Labrador (S. Todd, College of the Atlantic, personal communication), and around Pond Inlet, Cumberland Sound, and the Lancaster Sound region, where regular, and possible annual visitation has been noted (Reeves and Mitchell 1988). In the western Canadian Arctic, some published distribution maps show the presence of killer whales (Jefferson et al. 1993; Dahlheim and Heyning 1998; Figure 1) in the Canadian side of the Beaufort Sea. According to two sources (T. Barry, L. Harwood, personal communications), native elders recall sightings of killer whales in the area in the 1940s or 50s, however numerous researchers who have undertaken surveys there in the last thirty years have never seen this species (M. Fraker, L. Harwood, D. Ljungblad, S. Moore, W.J. Richardson, personal communications). Any killer whales which do travel into the Canadian Beaufort Sea are likely part of the Bering Sea population (Dahlheim 1997).
Protection
Two factors are important in the legal protection of a species, the system that is in place to prohibit or regulate hunts or other threats, and the system for monitoring and enforcing regulations. Where information is available, each of these is discussed below.
International
Two international management measures/agencies are relevant to the protection of killer whales, CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora 1973) and the IWC (International Whaling Commission).
All species of cetaceans are listed by CITES under one of two appendices. Appendix I includes species threatened with extinction (and which may be affected by trade), while Appendix II includes species which may become threatened with extinction unless trade is regulated, as well as species which must be subject to regulation in order that trade in threatened species of similar appearance may be controlled (Klinowska 1991). Killer whales (and all species of cetaceans not listed under Appendix I) are listed under Appendix II for the latter of the above reasons. As such, international trade of killer whales or parts thereof by any countries which are Parties to CITES requires export permits from the country of origin. According to Klinowska (1991) the European Community treats all cetaceans as if they were listed in CITES Appendix I - thus trade requires permits from both exporting and importing countries and such trade must not be primarily for commercial purposes. Some other countries (e.g., USA) also have similar domestic rules, requiring both export and import permits for Appendix II species. As of October 1998 there were 144 Parties to CITES, leaving approximately 90 countries world-wide which were not members (CITES Secretariat statistics). This latter group includes Iceland, which has been actively involved in trade (see Limiting Factors below). Listing on CITES Appendix II does not provide protection per se, though it does mandate recording of international trade. In recent years, the only international trade of killer whales documented through CITES has been in small numbers of live animals between aquaria, a few scientific samples, and small numbers of teeth and carvings. Trade in teeth and carvings have primarily involved the transfer of these items between Greenland (a dependency of Denmark) and Denmark (CITES Secretariat statistics). Although all trade in Appendix II species from a CITES member should be documented, during a recent review of all killer whales kept in captivity (Hoyt 1992), E. Hoyt (personal communication) noted that some trade involving CITES countries had not been reported.
Killer whales are considered "small cetaceans" by the IWC, and there is currently considerable disagreement within the Commission as to whether small cetaceans are covered by the Convention. However, in 1980, in response to a large Russian take of killer whales in the Antarctic in the 1979/80 season, the IWC added a new sentence to Schedule paragraph 9(d), officially including killer whales in their moratorium on factory ship whaling (IWC 1981). Other IWC management measures (e.g., the Southern Ocean Sanctuary, moratorium on commercial whaling, etc) do not apply to killer whales.
National
Canada: Within Canada, management of killer whales has varied considerably over time, and both the federal government and one provincial government (B.C.) have been involved in management activities. Prior to 1970 no laws were in place to control or regulate captures or other interactions. Hoyt (1992) notes that news reports of deaths during captures and the out-of-country destinations of captured killer whales in the 1960s prompted wide-spread public pressure for the implementation of protective legislation. Such legislation was first introduced in 1970. Prior to 1982, killer whales were considered "wildlife" by the B.C. provincial government's Wildlife Branch, and possession permits could be issued for holding these animals in captivity. In 1982 the provincial Wildlife Branch re-wrote the "Wildlife Act", and deleted killer whales from the list of wildlife, in response to a federal move to include all cetaceans under the "Cetacean Protection Regulations" (under the Fisheries Act of Canada of 1867). These regulations prohibited "hunting" without a license. "Hunting" was defined as "to chase, shoot at, harpoon, take, kill, attempt to take or kill, or to harass cetaceans in any manner". No scheme, however, was in place to enforce such regulations, and aboriginal hunting could be undertaken without a license. In 1993, the federal government consolidated various marine mammal regulations, including the Cetacean Protection Regulations, under the new "Marine Mammal Regulations". These regulations stated that "no person should disturb a marine mammal except when under.... the authorities of these regulations", with "marine mammal" defined as all species listed under a particular appendix. However, many species of cetaceans, including killer whales, were not listed under that appendix, and thus no legal protection appears to have been in place. The definition of "marine mammal" was revoked in 1994, thus extending coverage to all species of marine mammals. Currently, hunting of killer whales can occur if a "Fishing License" is obtained (except for Aboriginals who can hunt without a license), but fees for such licenses are low ($5). However, no such licenses have been issued, and issuance is at the discretion of the federal Minister of Fisheries and Oceans. It is unlikely any would be issued in areas such as British Columbia, due to widespread public interest in these animals.
In terms of minimizing negative interactions between boats and killer whales, "whale watching guidelines" have been produced and disseminated by the Department of Fisheries and Oceans. There are also several ongoing efforts of self-regulation by the commercial whale watching industry in British Columbia, involving the production of guidelines and codes of conduct (Baird et al. 1998b). Among commercial operations in certain specific areas, the levels of awareness of and adherence to these guidelines is fairly high, though awareness and adherence by general members of the public (which make up the majority of boats with whales in some areas – see Figure 6) is currently unknown. As with the Cetacean Protection Regulations, virtually no official monitoring or enforcement activities take place, and enforcement itself is complicated by the difficulty in defining and measuring "harassment" in the field (see Limiting Factors, below). N. Bhaloo (DFO Conservation and Protection, Enforcement Unit, personal communication) notes that no violations of the Marine Mammal Regulations involving killer whales have been documented between 1993 and 1997, although there is one charge of harassment, involving a sports fishing operation outside of either of the two core areas for residents, pending from 1998 (E. Lochbaum, DFO, personal communication).
The 1997 Oceans Act provides for the establishment of marine protected areas (MPAs) in federal waters. One of the specific justifications listed for establishing MPAs is to conserve and protect marine mammals and their habitats. However, as with other federal legislation regarding marine mammals, establishment of marine protected areas and exclusion of activities which might jeopardize killer whales or other marine mammals are up to the discretion of the Minister of Fisheries and Oceans, rather than mandated. Regardless, there are general concerns about the efficacy of using MPAs to "protect" cetaceans (see below, as well as Phillips 1996; Whitehead et al. 1999), due primarily to the large range of most species and the lack of boundaries in the marine environment. Whitehead et al. (1999) note that most marine protected areas have provided little or no change in the level of threats faced by cetaceans in an area.
One example of an MPA specifically created to "protect" killer whales is the Robson Bight/Michael Bigg Ecological Reserve, a provincial designation in a core area for northern residents. This designation provides some protection to the shoreline habitat and limits human access by land. Its main relevance to killer whales is the protection of the terrestrial portion of several "rubbing beaches" which are regularly used by northern residents. However, its validity as a "whale sanctuary" has been questioned. Duffus and Dearden (1992) state that this designation "holds a fairly limited potential to protect a marine area", since it is the federal government that has jurisdiction over marine shipping and marine fisheries, and this is a provincial designation. They also note that the "boundary is highly permeable, and buffers of outside impacts are almost non-existent" (Duffus and Dearden 1992). They warn against the "fallacy of tokenism -- that is, giving the public the appearance of protecting an important whale habitat, when neither the importance of the site to the whales, nor the veracity of the protection is established -- creat[ing] a political "success" that may mask an ecological failure" (Duffus and Dearden 1992). Other than this effort by the B.C. provincial government, no other province or territory within Canada has legislated protection for this species.
Other Countries: Considering that killer whales regularly move between Canada and other countries (the U.S. on both coasts and almost certainly Greenland, see Heide-Jorgensen 1988, 1993; Mitchell and Reeves 1988), protection measures in these countries are directly relevant to the conservation of killer whales in Canada. In the United States, all cetaceans are protected through the Marine Mammal Protection Act of 1972, as well as through the Packwood-Magnuson Amendment of the Fisheries and Conservation Act and the Pelly Amendment of the Fisherman's Protective Act. These regulations allow for observers on fisheries that have a high probability of killing marine mammals, and also provide for limited monitoring and enforcement activities regarding boat/whale interactions. There are no management measures in Greenland that provide protection for killer whales, and kills in that area (see Limiting Factors, below) could affect Canadian populations.