Recovery Strategy for the North Pacific Right Whale in Pacific Canadian Waters [Final] 2011: Threats

Historic Threats

Commercial whaling

Right whales were once hunted extensively by commercial whalers because they are large, slow swimming, tend to congregate, and their thick layer of blubber usually prevents them from sinking when killed, making them an easy and profitable target. Commercial whaling for right whales began in the North Pacific in 1835 (Scarff 1991, 2001). Whaling was most intense during the decade 1839-1848 which accounts for approximately 80 percent of the total historic catch of right whales (Scarff 2001). The species was depleted throughout its range by 1900, at which point it ceased to be a principal target of commercial whaling (Scarff 2001). The recorded right whale catches by American whalers amounted to at least 14,500 animals (Best 1987, IWC 1986), and Scarff (2001) estimates that the total whaling-related mortality during the period 1839-1909, including mortality of struck-but-lost whales and non-American whalers, was in the range of 26,500-37,000 animals. Although right whales received international protection from commercial whaling by the 1931 Convention for the Regulation of Whaling, which took effect in 1935, important North Pacific whaling countries– Japan and the Soviet Union– did not sign the convention and continued whaling the North Pacific Right Whale through World War II (Scarff 1986). The first comprehensive prohibition on commercial whaling that was agreed to by all major North Pacific whaling nations was implemented by the IWC in 1949. However, “research whaling” was still permitted under this convention and Japan harvested 13 right whales and the Soviet Union harvested 10 right whales legally during the 1950s and 1960s (Brownell et al. 2001).

After the era of commercial whaling, illegal whaling in the North Pacific occurred on a much larger scale than once thought. Brownell et al. (2001) indicate that illegal hunting from 1961 to 1979 by the Soviet Union explains the current depleted status of North Pacific Right Whales. Hundreds of right whales were illegally hunted in the Kuril Islands and the Okhotsk Sea, and 372 were killed in the eastern North Pacific, notably the Gulf of Alaska and southeastern Bering Sea (Yablokov 1994, Zemsky et al. 1995, Tormosov et al. 1998, Doroshenko 2000, Ivashchenko et al. 2008). Remnant populations may have been gradually recovering from past commercial whaling until the 1960s, when illegal Soviet catches further compromised recovery (Brownell et al. 2001, Clapham and Ivashchenko 2009).

Subsistence/Aboriginal Harvest

North Pacific Right Whales were hunted historically by central and northern Nuu-chah-nulth (Nootkan) tribes off the west coast of Vancouver Island (Monks et al. 2001). Subsistence whaling may also have been conducted by the Haida off Haida Gwaii (Queen Charlotte Islands), but it is unknown whether right whales were taken (Acheson and Wigen 2002). Various aboriginal peoples from Washington State were also known to take this species (Mitchell 1979), although it was not usually the main target of their hunts, nor were they taken in great numbers (Brownell et al. 2001). Currently, subsistence hunters in Alaska and Russia do not report taking animals from the eastern North Pacific Right Whale population (Ferrero et al. 2000). In Canadian waters, a renewed interest in aboriginal whaling of the North Pacific Right Whale is unlikely given the extreme rarity of the species.

Current Potential Threats

Due to the lack of data on occurrence, distribution, habitat use, reproduction and genetics of the right whale in Pacific Canadian waters, current threats cannot be directly determined. However, it is important to consider all possible threats that may affect the survival of right whales occurring in Pacific Canadian waters and their habitat. Listed below are threats that are identified as having the potential to affect the North Pacific Right Whale based on information from other right whale populations around the world, as well as from other large whale species. At this time, the significance of these potential threats to the North Pacific Right Whale in Canadian waters cannot be assessed or prioritized.

Ship Strikes and Marine Traffic

In the North Atlantic, ship strikes are the most significant human-related source of injury and mortality for right whales (Kraus et al. 2005, Jensen and Silber 2004, Moore et al. 2007), with both small and large vessels causing injury and death (Knowlton and Brown 2007). Recent investigations suggest that vessel speeds of less than 13 knots (26 km/h) may increase the likelihood of right whales being able to avoid collisions (Knowlton and Brown 2007). At vessel speeds above 15 knots (28 km/h), mortality due to vessel strikes approaches 100%, and at vessel speeds below 11.8 knots (22 km/h), mortality dropped below 50% (Vanderlaan and Taggart 2007).

It is not known whether ship strikes are a significant source of injury or mortality of the North Pacific Right Whale. The Large Whale Ship Strike Database (Jensen and Silber 2004), which contains records of known large whale ship strikes worldwide from 1975 to 2002, does not include any record of North Pacific Right Whale strikes. However, ship strikes may be under-reported for right whales off the Pacific Canadian coast, due to the remoteness of most of the coast and because ship strikes can go undetected or unreported.

In the last 20 years, container and cruise ship traffic through B.C. ports has increased by 200% and is expected to continue to increase (Transport Canada 2005). This increase in marine traffic may disrupt right whales by displacing animals from important habitat, and increasing the risk of ship strikes. As information is gathered on the distribution and habitat-use of North Pacific Right Whales, their proximity to major shipping channels will determine whether ship strikes may pose a significant threat.

Entanglement in Fishing Gear

Entanglement in fishing gear is a major source of injury and mortality for the North Atlantic Right Whale (Kraus 1990, Clapham et al. 1999, IWC 2001a, Kraus et al. 2005), and it is possible that right whales in the North Pacific are also exposed to this threat. Entanglements that are not initially lethal may result in a gradual weakening of the entangled whale, making it more susceptible to other indirect causes of mortality, such as disease (Kenny and Kraus 1993). A recent analysis showed that more than 75% of North Atlantic Right Whales have scars that indicate past entanglement events (Knowlton et al. 2005 cited in Brown et al. 2009). Scar accumulation increased in the 1990s, and juvenile right whales were found to be more susceptible to entanglement than adults (Knowlton et al. 2005 cited in Brown et al. 2009). It has been shown that vertical and horizontal lines used in fixed gear fisheries (i.e., gillnets and pot gear) are the type of fishing gear most often implicated in right whale entanglements in Atlantic Canadian and U.S. waters (Johnson et al. 2005).

Due to the operation of Japanese salmon driftnet fisheries within the Russian Exclusive Economic Zone (EEZ) (inside the Okhotsk Sea and around Kamchatka) since 1991, entanglements in fishing gear may represent a threat to the western population of North Pacific Right Whales (Brownell et al. 2001). An entangled whale in the Okhotsk Sea was reported by T. Miyashita in 1992 (Brownell et al. 2001). The Russian gillnet fishery was implicated in the death of two right whales: one in 1983, and the other off the Kamchatka Peninsula (Russia) in 1989 (NMFS 1991, Kornev 1994). Although entangled whales have not been reported in the Bering Sea or Pacific Canadian waters, there are extensive fisheries in the eastern Bering Sea and entanglements should be considered a threat to right whales in this area, which may include individuals that also use Pacific Canadian waters.

Noise

Right whales, like all baleen whales, rely on sound for communication, navigation, and detection of predators and possibly prey (Clark 1994, Parks et al. 2006). Sound sources that interfere with these functions could thus result in disruption of migration, feeding, breeding, and other vital activities (Richardson et al.1995). The effects of noise on right whales might range from subtle changes in behaviour to physiological damage, such as permanent hearing loss and mortality due to inner ear blast injuries (Richardson et al. 1995).

Although the extent to which various noise sources affect the North Pacific Right Whale is unknown, anthropogenic activities in the marine environment do produce sound in the audible range of North Atlantic Right Whales (estimated to be 10 Hz to 22 kHz; Parks 2003), and therefore have the potential to affect these whales. These sources include seismic testing for oil and gas exploration, active and passive sonar and explosives testing by the military, fish-finding and bottom mapping sonar, acoustic deterrent devices, and increasing levels of noise from routine marine industrial activities (e.g., aquaculture, marine construction), commercial ships and small boats (Brown et al. 2009). Commercial shipping is the major contributor to chronic underwater noise (5 to 500 Hz). From 1950 to 2000, low frequency noise in the oceans increased 16 dB, corresponding to a doubling of noise power (3 dB) every decade, or a 7% annual increase in noise power (NRC 2003, IWC 2004).

Evidence of disturbance and displacement due to underwater noise has been observed in several baleen whale species (Richardson et al. 1995). Reactions have included avoidance of the noise area, interruption of feeding, movement away from the sound source, and changes in respiration and dive patterns (Anonymous 2005; Frankel and Clark 2000; McCauley et al. 2000; Richardson et al. 1995; Stone and Tasker 2006; Weir 2008).

The North Atlantic Right Whale produces vocalizations at frequencies primarily between 50 Hz and 2 kHz (Parks 2003), and similar vocalizations have been documented from the eastern North Pacific Right Whale (McDonald and Moore 2002, Mellinger et al. 2004, Munger et al. 2008). Right whale calls occur within the same frequency as anthropogenic noise, most notably noise from commercial shipping, so there is the potential for vocalizations to be masked by noise (Parks et al. 2007). Masking of right whale vocalizations could interfere with communication (Richardson et al. 1995), leading to a reduction in social communication (e.g., contact calls, mother-calf interaction), which could result in reduced mating opportunities (Richardson et al. 1995). It has been shown that changes in North Atlantic and Southern Right Whale calling behaviour varies with background noise levels, indicating that the whales may shift call frequency (Hz) in order to compensate for masking effects during periods of higher noise (Parks et al. 2007).

Underwater explosions from construction, military sonar exercises, and seismic surveys are known to directly affect the physiology of whales, and may result in mortality (Richardson et al. 1995, Ketten et al. 1993). In 1992, Humpback Whales off Newfoundland were found with damaged ear structures after underwater blasting was used in constructing oil installations (Ketten et al. 1993, Lien et al. 1995), and Todd et al. (1996) reported that acute noise was correlated with increased rates of entanglement in Humpbacks. The United States Navy released a report in which it took responsibility for the death of six beaked whales found beached with hemorrhaging after a sonar test in the Bahamas on March 15 and 16, 2000 (Anonymous 2001). In Pacific Canadian waters, noise from proposed activities such as oil and gas exploration, pipeline construction, military exercises, research studies, and wind-farm construction, may be of concern in the future. The Statement of Canadian Practice with respect to the Mitigation of Seismic Sound in the Marine Environment (DFO 2007) has been developed to provide guidance and marine mammal mitigation for seismic use in marine environments.

Pollution

Pollution may affect marine mammals in various ways. Contaminants can enter the tissues either directly (e.g., ingestion) from the environment or through bioaccumulation from prey. Non-food items or contaminants could be ingested directly during feeding (Katona and Kraus 1999). Right whales feed in convergent zones and slicks where surface currents concentrate flotsam, including contaminants, oil, and floating garbage (Carr 1985).

Organochlorine compounds (e.g., ∑DDT and PCBs) and metals are the contaminants of most concern for marine mammals. Despite high concentrations of PCBs in fish- and mammal-eating cetaceans (Béland et al. 1993, Ross et al. 2000, Addison and Ross 2001, Grant and Ross 2002, Ross 2002a, Ross 2002b, Ross 2006), right whales are low trophic level grazers, thus minimizing the concentrations of contaminants accumulating via their prey (Woodley et al. 1991). O’Shea and Brownell (1994) reported that concentrations of contaminants in baleen whales were generally much lower than in odontocetes; however, they emphasize that additional data would assist in addressing uncertainties. Baleen whales may also be affected through negative impacts of pollution on marine productivity (O’Shea and Brownell 1994), especially right whales due to their specialized copepod diet.

Until recently, no research was being conducted on the North Pacific Right Whale in Canadian waters. From 2002 to 2008, Fisheries and Oceans Canada conducted twenty-one multi-species, shipboard surveys (total of 28,725.33 km surveyed and 1,749.4 hours of effort, see App. A) to investigate the seasonal distribution and abundance of SARA-listed cetacean species (Ford et al. 2010a). These surveys were focused primarily in waters over the continental shelf and no right whales were sighted. Remote acoustical recording packages (ARPs) to monitor for the presence of right whales and other cetaceans off the Pacific Canadian coast have been deployed. One ARP was deployed for approximately six months in 2006 at Union Seamount and one ARP was deployed for approximately four months in 2007 at La Perouse Bank off the west coast of Vancouver Island⁶. No right whale vocalizations were detected in acoustic data collected during these deployments (Ford et al. 2010b). Future acoustic deployments are to focus on offshore locations with an emphasis on areas of historic whaling catches.

A conceptual framework has been developed to provide a near real-time prediction model for the distribution of large whale prey patches (i.e., zooplankton concentrations) (Gregr et al. 2005). The framework was then developed for North Pacific Right Whales as part of a multi-year North Pacific Research Board (NPRB)-funded project (Gregr et al. 2006). The project developed hypotheses about how patches of prey suitable for North Pacific Right Whale foraging might be formed in the eastern North Pacific, based on (Gregr and Coyle 2009).

Status in Canada

The North Atlantic Right Whale and North Pacific Right Whale were formerly considered a single species (Eubalaena glacialis) by COSEWIC and were designated Endangered in 1980. The status of this species was re-examined and confirmed in April 1985 and in April 1990. Based on new scientific information, COSEWIC followed the lead of other international agencies and the species was split into two separate species in May 2003 (for further details, see Section 1.3 ‘Populations and Distribution – Nationally Significant Populations’). Status of the North Pacific Right Whale was re-examined and confirmed as Endangered in November 2004 based on an updated status report. This species was subsequently listed as Endangered under Schedule 1 of SARA in August 2006.

Status in the U.S.

In U.S. waters, the “northern right whale” (which included the North Pacific and North Atlantic Right Whale) was listed as Endangered under the Endangered Species Conservation Act in June 1970, and was subsequently listed as Endangered under the Endangered Species Act (ESA) in 1973. In 1973, the “northern right whale” was also designated as Depleted under the Marine Mammal Protection Act (MMPA) (NMFS 2009). In 2008, National Marine Fisheries Service (NMFS) officially listed the “northern right whale” as two separate, endangered species under the ESA: the North Pacific Right Whale (E. japonica) and North Atlantic Right Whale (E. glacialis) (Federal Register 2008b).

International Status

An international assessment of the conservation status of right whales was completed in 1996 by the International Union for Conservation of Nature (IUCN). This assessment delineated three “populations”- North Pacific, North Atlantic and Southern. However, it did not distinguish these populations as separate species. The North Pacific and North Atlantic populations were listed as Endangered, and the Southern population was listed as Lower Risk.

In most of the scientific literature prior to 2000, including previous Red Lists, all northern hemisphere right whales were treated as the single species E. glacialis. Currently, the taxonomy used by the IUCN follows that of the IWC Scientific Committee (IWC 2001b) and the Convention on Migratory Species, which now recognize right whales in the North Atlantic, North Pacific and southern hemisphere as three distinct species. A 2008 assessment by the IUCN listed the North Pacific Right Whale as Endangered (Reilly et al. 2008a), the North Atlantic Right Whale as Endangered (Reilly et al. 2008b), and the Southern Right Whale as Least Concern (Reilly et al. 2008c).

Protection in Canada

North Pacific Right Whales in Canada are protected under the Species at Risk Act (SARA) as well as under the Marine Mammal Regulations (MMR). The MMR, made pursuant to the Fisheries Act, apply in respect of the management and control of fishing for marine mammals and related activities and, therefore, provide a legislative framework for the conservation and protection of marine mammals in Canada. SARA prohibits killing, harming and harassing a threatened, endangered, or extirpated species⁷ and protects their critical habitat from destruction⁸.

Protection in the U.S.

In U.S. waters, right whales were first protected by the Endangered Species Conservation Act (precursor to ESA) in 1970. Since 1973 right whales have been protected under the Marine Mammal Protection Act (MMPA), which prohibits, with certain exceptions, the "take" of marine mammals in U.S. waters and by U.S. citizens on the high seas, and the importation of marine mammals and marine mammal products into the U.S. The Endangered Species Act (ESA) protects endangered and threatened species and their habitats by prohibiting the “take” of listed animals and the interstate or international trade in listed plants and animals, including their parts and products, except under Federal permit.

International Protection

Right whales were first protected internationally from commercial whaling by the 1931 Convention for the Regulation of Whaling, which took effect in 1935. However, protection was not complete since neither Japan nor the Soviet Union signed the Convention (Scarff 1986, Donovan 1992). All right whales worldwide were protected under the International Convention for the Regulation of Whaling, implemented by the IWC when Japan and the Soviet Union joined in 1949.

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is an international agreement between governments. Its goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival. Right whales were listed by CITES in 1975 in Appendix 1, which lists species that are the most endangered among CITES-listed animals and plants. Trade in specimens of these species is tightly monitored, and permitted only in exceptional circumstances.

There is an urgent need for information on the distribution, biology, ecology and threats to the North Pacific Right Whale. Knowledge of the species is not yet adequate to clearly define recovery objectives or approaches.

Current Presence, Abundance, Distribution, Habitat Use, and Critical Habitat in Pacific Canadian Waters

Information on the occurrence, distribution and migration patterns of right whales in the North Pacific is critical to identifying the key factors affecting the recovery of this species. Feeding grounds remain unknown in Pacific Canadian waters, yet right whales may exist in Pacific Canadian waters, though in very low numbers. Without current data on distribution, it is not possible to identify if a conflict exists between shipping channels and important habitats, or whether a decrease in reproductive success is a result of shifts in prey availability. Determining habitat use is necessary in order to determine the abundance and distribution of right whales in Pacific Canadian waters. Critical habitat has not been identified for the right whale in Pacific Canadian waters (see Section 1.4.1 ‘Habitat and Biological Needs’ and Section 2.7 ‘Critical Habitat’).

Population Structure and Genetics

There are uncertainties about population structure and number of populations for the North Pacific Right Whale. Genetic investigations would delineate populations, perhaps providing further support for the two-population hypothesis (see Section 1.3 ‘Populations and Distribution- Nationally Significant Populations’). Analyses using both mitochondrial and microsatellite DNA would address the question of genetic exchange between populations in high latitudes or on offshore breeding grounds (Brownell et al. 2001). These analyses would provide information on genetic diversity and determine whether a bottleneck has occurred in these populations, as found in the North Atlantic Right Whale. A genetic “bottleneck” could limit the recovery of the North Pacific Right Whale through reduced reproduction and recruitment resulting from reduced fecundity, decreased neonate and juvenile survival, or lowered resistance to disease (Ralls et al. 1988, Haebler and Moeller 1993) (see Section 1.4.3 ‘Limiting Factors’). However, as Brownell et al. (2001) noted, the major obstacle to these genetic studies is finding a sufficient sample size of right whales.

Life History Parameters and Population Dynamics

The life history parameters and population dynamics of the North Pacific Right Whale need further investigation. Data on the abundance and population dynamics (e.g., birth rate, growth rate, and mortality) of right whales in the North Pacific need to be collected and analysed. For example, if evidence exists for delayed onset of sexual maturity, then potential causes such as insufficient food supply, low genetic diversity or depensation could be investigated.

Clarification of Threats and Human Influences

Due to the general lack of knowledge of the North Pacific Right Whale, particularly for Pacific Canadian waters, current threats to the species, or the significance of potential threats, cannot be directly determined. However, it is important to consider potential threats, so that they can be assessed and addressed when the presence of right whales has been confirmed in Pacific Canadian waters. Clarification on the extent to which marine projects or developments (e.g., shipping lanes, underwater explosives) pose direct and/or indirect threats to the North Pacific Right Whale is required. A thorough investigation of the potential for conflict between shipping lanes and right whale distribution may be critical to the survival of right whales, as illustrated in the North Atlantic (Brown et al. 2009). Preferred habitat and genetic delineation of populations must also be clarified. Information regarding the population structure of North Pacific Right Whales and their habitats is needed to determine the potential effects of human actions and whether future management actions are effective.

⁵ SARA requires that the recovery strategy identify “…threats to the survival of the species and threats to its habitat that is consistent with information provided by COSEWIC.” [SARA s.41(1)(b)].

⁶ Passive acoustic monitoring began in 2003 however reliable data was not collected until 2006 and 2007. 1915 hours over 160 days were recorded in 2006 at Union Seamount and 1437 hours over 120 days were recorded in 2007 at La Perouse Bank (Ford et al. 2010b).

⁷ SARA s. 32(1): No person shall kill, harm, harass, capture or take an individual of a wildlife species that is listed as an extirpated species, endangered species or a threatened species.

⁸SARA s. 58(1): Subject to this section, no person shall destroy any part of the critical habitat of any listed endangered species or of any listed threatened species.

⁹ SARA requires that the recovery strategy include “a statement about whether additional information is required about the species [SARA, s.41(1)(f)].