Recovery strategy for the blue whale (Balaenoptera musculus), Northwest Atlantic population, in Canada
- 1.1 Species assessment information from COSEWIC
- 1.2 Description
- 1.3 Populations and distribution
- 1.4 Needs of the blue whale
- 1.5 Threats: Classification and description
- 1.5.1 Whaling
- 1.5.2 Natural mortality
- 1.5.3 High risk anthropogenic threats
- 1.5.4 Medium risk anthropogenic threats
- 1.5.5 Low risk anthropogenic threats
- 1.6 Actions already completed or under way
- 1.6.1 Blue whale protection
- 1.6.2 Habitat protection measures, awareness raising and other measures
- 220.127.116.11 The Saguenay–St. Lawrence Marine Park (SSLMP)
- 18.104.22.168 Marine Protected Areas
- 22.214.171.124 Awareness raising activities
- 126.96.36.199 Emergency response for Marine Mammals in Difficulty
- 188.8.131.52 Guidelines for best practices for watching marine mammals in Québec
- 184.108.40.206 Statement of Canadian Practice with respect to the mitigation of seismic sound in the marine environment
- 1.6.3 Research
- 1.7 Knowledge gaps
1.1 Species assessment information from COSEWIC
The following summary of the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assessment appears in the status report from Sears and Calambokidis (2002):
Common Name (population): Blue whale (Atlantic population)
Scientific Name: Balaenoptera musculus
Legal listing (Species at Risk Act (SARA)): January 2005 (Endangered)
COSEWIC Status: Endangered
Date of Assessment: May 2002
Reason for designation: 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).
Canadian Occurrence: Pacific and Atlantic Oceans
COSEWIC Status History: Entire Canadian range was designated as Special Concern in April 1983. Split into two populations in May 2002. The Atlantic population was up-listed to Endangered in May 2002. Last assessment based on an updated status report.
Blue whales (Balaenoptera musculus) have a tapered elongated shape and a varying blend of light and slated shades of gray with mottled pigmentation (Sears, 2002; Sears and Calambokidis, 2002). Some blue whales have very sparse mottling and appear uniformly pale or dark, while others have obvious mottling patterns, which are unique to them and stable throughout their lives. These differences in pigmentation and mottling patterns have allowed individuals to be identified and tracked through photo-identification (Sears, et al., 1987; Calambokidis, 1990; Sears, et al., 1990).
This cetacean has a large U-shaped head, which represents around 25% of its total body length and whalebones that can reach 1 m in length. The flippers measure around 4 m long. Their flukes are grey, broad and triangular with a straight or slightly curved trailing edge. Individual whales may have white patches (Sears, 2002; Sears and Calambokidis, 2002).
The blue whale is the largest animal known to have lived on Earth. Their weight varies between 73 000 and 136 000 kg (Sears, 2002; Sears and Calambokidis, 2002). Females are generally larger and longer than males and animals are larger on average in the southern hemisphere than in the northern hemisphere (Lockyer, 1984; Yochem and Leatherwood, 1985).
Figure 1. Illustration of a blue whale
Description of Figure 1
Figure 1 is an illustration of a blue whale by Daniel Grenier, courtesy of Mingan Islands Cetacean Study (MICS).
1.3 Populations and distribution
Blue whales are part of the Mysticeti group of baleen whales and more specifically the Balaenopteridae family. There are three blue whale subspecies spread out across most of the world’s oceans: 1) the northern blue whale, B. m. musculus (Linnaeus, 1758), occupies the northern hemisphere; 2) the southern blue whale, B. m. intermedia (Burmeister, 1871), lives in the waters around Antarctica; 3) the pygmy blue whale, B. m. brevicauda (Ichihara, 1966), is found from the sub-Antarctic zone of the southern Indian Ocean and southwestern Pacific Ocean (Yochem and Leatherwood, 1985; Sears, 2002). Using characteristics of the vocalizations produced by blue whales, McDonald et al. (2006b) divided blue whales into nine regions or populations, 4 in the Pacific, 3 in the Indian Ocean, 1 in the North Atlantic and 1 in the Southern Ocean.
Two geographically separated populations exist in Canadian waters, one in the North Atlantic and one in the North Pacific (Figure 2). The North Pacific population was part of a recovery strategy in 2005 (Gregr, et al., 2005). In the North Atlantic, blue whales have been split in two populations, one in the east and one in the west of the Atlantic, but this split has not been accepted by all authors (Gambell, 1979; Wenzel, et al., 1988; Sears, et al., 1990; Clark, 1994; Reeves, et al., 1998; Clapham, et al., 1999; Sears, 2002; Sears and Calambokidis, 2002; Sears and Larsen, 2002; Sears, 2003; Reeves, et al., 2004; McDonald, et al., 2006a). Photo-identification indicates that blue whales from the St. Lawrence, Newfoundland, Nova Scotia and New England would belong to the Northwest population, while blue whales photographed off Iceland and the Azores would belong to the Northeast population (Cetacean and Turtle Assessment Program (CETAP), 1982; Wenzel, et al., 1988; Sears, 2002; Sears and Larsen, 2002; Sears, 2003). Consequently, the Canadian blue whale population in the Atlantic, which is part of the current recovery strategy, belongs to the Northwest Atlantic population.
Figure 2. Geographical range of the blue whale, along the coast of North and Central America
Description of Figure 2
Figure 2 is a map showing the known areas of occurrence and the potential range of the blue whale. Adapted from Sears and Calambokidis (2002).
Every year, blue whales undertake long seasonal migrations, south to north, from their wintering areas in equatorial latitudes to summer feeding areas located in the productive waters of temperate to subarctic latitudes (Lockyer, 1984; Reeves, et al., 1998; Perry, et al., 1999; Sears and Calambokidis, 2002; Reeves, et al., 2004). This migration allows blue whales to feed during four to six months in very productive areas, to increase their body fat and store reserves for the months of the year when food is not as abundant in their wintering areas (Lockyer, 1984).
Little is known about the wintering and reproductive areas of blue whales in the North Atlantic, though some researchers suspect that they may travel south to Bermuda or Florida, while some whales remain in waters south of Iceland, and near Newfoundland and Nova Scotia (Sears, 2002; Sears and Calambokidis, 2002). Indeed, winter reports from various regions of the Estuary, northern Gulf of St. Lawrence and south and southwest of Newfoundland suggest that a proportion of the animals remain at our latitudes all year long (Sears and Williamson, 1982; Sergeant, 1982; Sears and Calambokidis, 2002; Lawson, 2003; Stenson, et al., 2003). In summer, blue whales from the Northwest Atlantic population probably range between Davis Strait, off the western coast of Greenland, and New England (Jonsgård, 1955, 1966; Sears, et al., 1990; Rice, 1998; Sears, 2002; Sears and Calambokidis, 2002).
Most of the recent sightings for the Northwest Atlantic population have been made in the Gulf of St. Lawrence (Sears, 1983; Sears, et al., 1990), more precisely in the area of the Mingan Islands, Anticosti Island, off the Gaspé Peninsula (Sears and Calambokidis, 2002; Sears, 2003), southwest and south coasts of Newfoundland (Sergeant, 1966; Mitchell, 1982; Lien, et al., 1987) and on the Scotian Shelf (Sutcliffe and Brodie, 1977; CETAP, 1982; Whitehead, et al., 1998; Reeves, 1999; Lawson and Gosselin, 2009). In the St. Lawrence Estuary, sightings have been made between Forestville and Tadoussac; in the Gulf, at the eastern tip of the Gaspé Peninsula, and on the North Shore, in the area of Sept-Îles and Port-Cartier. Observations have generally occurred from May to December, with peak sightings between June and August (Sears and Calambokidis, 2002). According to acoustical data, blue whales have been present on the Grand Banks between August and May, with a peak in vocal activities recorded from September to February (Clark, 1995). Furthermore, concentrations of individuals have also been sighted in the Laurentian channel, as well as south and northeast, in the Orphan Basin area, of Newfoundland (LGL, unpublished data).
Current global blue whale population estimates range between 5 000 and 12 000 individuals, although the accuracy of these estimates is uncertain (Carretta, et al., 2003). As for the Northeast Atlantic population, a survey conducted in 2001 indicated that summer abundance of blue whales in Iceland and in adjoining waters is estimated at 1159 individuals (Vikingsson, 2003). Furthermore, the number of blue whales in the Northwest Atlantic population is unknown, but it would be unlikely that this population comprises more than 250 individuals that have reached sexual maturity (Sears and Calambokidis, 2002).
From 1979 to the spring of 2007, a total of 405 blue whales were photo-identified mainly in the Estuary and northwest of the Gulf of St. Lawrence and biopsies were taken on nearly 40% of them (R. Sears, Mingan Island Cetacean Study (MICS), personal communication). Each year, from 20 to 105 blue whales are identified in this region. Approximately 40% of the identified blue whales frequently return to the study area, the others having been observed less than three seasons between 1979 and 2002, which suggests that these individuals range mostly outside the St. Lawrence, possibly in the waters at the edge of the continental shelf, north from the Labrador Sea and Davis Strait, east to the Flemish Cap and south to New England (Sears and Calambokidis, 2002). Photo-identification data from outside the Estuary and Gulf of St. Lawrence are limited. A few blue whales have been photographed along the coast of Newfoundland, on the Scotian Shelf and in the Gulf of Maine, and some are not included among the 405 blue whales that have been identified in the Estuary and northwest of the Gulf of St. Lawrence (Sears and Calambokidis, 2002; J. Lawson, Department of Fisheries and Oceans Canada (DFO), pers. comm.). Ramp et al. (2006) estimate the survival rate at 0.975 and the gender ratio of the 139 biopsy sampled individuals at 79 males for 67 females (Sears, 2003). Given the small proportion of blue whale distribution range that has been sampled until now and considering the low abundance of blue whales, the current data based on photo-identification do not allow for an estimate with a minimum degree of certainty the abundance of this species in the Northwest Atlantic (Hammond, et al., 1990; Sears and Calambokidis, 2002).
1.4 Needs of the blue whale
1.4.1 Habitat and biological needs in the Canadian Atlantic
According to available information, blue whales use coastal and pelagic waters in the Canadian Atlantic mainly in the summer, to feed primarily on euphausiids, commonly known as krill. These large whales are typically observed alone or in pairs (Sears, et al., 1990; Sears and Calambokidis, 2002). Some significant blue whale concentrations (up to 20 to 40 individuals, Sears, et al., 1990; R.Sears, MICS, unpublished data) have been observed in areas where their food is thought to be concentrated at certain times of the year. These areas are typically at the edges of the continental shelf, at topographic breaks, at the head of canyons or in deep channels where the interaction of currents with the landform often generates deep-water upwellings and a krill aggregation process (Sameoto, 1976, 1983; Simard, et al., 1986; Schoenherr, 1991; Lavoie, et al., 2000; Croll, et al., 2005; Sourisseau, et al., 2006; Simard, 2009).
No research has yet been carried out to simultaneously link krill concentrations with blue whale sightings. Nevertheless, several areas of high concentrations of krill, which may be potential feeding areas for the blue whale, have been pointed out, the most studied in the Northwest Atlantic being the area at the head of the Laurentian Channel, in the St. Lawrence maritime Estuary. There are also other significant areas in the Estuary, the Gulf and the Northwest Atlantic where concentrations of krill are found, in particular Honguedo Strait, the north shore of the Gaspé Peninsula and the Emerald Basin in Nova Scotia (Sameoto, 1976, 1983; Sameoto, et al., 1993; Cochrane, et al., 2000; I. McQuinn, DFO, unpublished data). Other areas with high concentrations of macrozooplankton, mainly krill, were sampled throughout the Gulf of St. Lawrence using an acoustic technique indicating other potential feeding areas of blue whale (I. McQuinn, DFO, unpublished data). These included the Gaspé current in the area off Sainte-Anne-des-Monts and Gaspé, in the Estuary, between Pointe aux Outardes and Pointe Mitis, at the western tip of Anticosti Island, around the Banc Parent, and off the west coast of Newfoundland, near the 150-m isobath.
Even though there is no systematic monitoring of these areas, the available data indicates that it is likely that krill aggregations form according to predictable patterns each year in these areas, as is the case in Honguedo Strait (Sameoto, 1983; I. McQuinn, DFO, unpublished data), in the St. Lawrence Estuary at the head of the Laurentian Channel (Simard and Lavoie, 1999; Cotté and Simard, 2005) and in several other locations. A numerical model supports the aggregation of particles with some similar behaviour patterns as krill in several of these areas (Sourisseau, et al., 2006). The basin’s topography coupled with its hydrodynamic circulationFootnote 3 seem to influence where blue whale food aggregations are likely to build up (Sourisseau, et al., 2006). At this time, it is not known to what extent krill aggregate in all of these areas, nor to what extent they are used by blue whales for feeding.
Blue whales have been sighted in several of these areas over the years and seasons, as well as in the Pointe-des-Monts area and between Sept-Iles and Blanc-Sablon, where deep-water upwellings occur that typically contain high concentrations of krill (see review in Lesage, et al., 2007). Present data are insufficient to determine the relative importance of krill and macrozooplankton aggregation areas for the blue whale. Even though there exists some connection between certain areas and the recurring occurrence of blue whales, a large yearly variation in summer sightings has been observed.
1.4.2 Ecological role and anthropogenic value
Blue whales are lower trophic level predators that ingest several tons of prey each day and could be prey for killer whales (Orcinus orca). The recovery of the Northwest Atlantic blue whale population will allow these animals--which historically were much more numerous--to fulfill their ecological role as predator and prey.
Blue whales are animals valued by whale watchers, scientists, and environmentalists. Recently, Olar et al. (2007) conducted a survey of 2000 Canadians to evaluate the economic benefits the recovery of marine mammals has in the St. Lawrence Estuary. They showed that Canadians are concerned about protecting marine mammals and that they agreed that Canada should spend more money for protecting the blue whale in the St. Lawrence Estuary.
1.4.3 Intrinsic limiting factors
Intrinsic characteristics of the blue whale’s life history and ecology can affect its recovery potential, specifically in terms of reproduction and dietary specialization.
In the northern hemisphere, blue whales mate and calve from late fall to mid-winter (Yochem and Leatherwood, 1985). Females usually give birth to a single calf every 2–3 years after a 10–11-month gestation period (Lockyer, 1984; Sears, 2002). At birth, calves measure 6–7 m and weigh over 2 tons (Sears, 2002; Sears and Calambokidis, 2002). Calves are dependant on their mothers during 7–9 months, until the weaning period (Lockyer, 1984; Tillman and Donovan, 1986). Weaning occurs in summer in feeding areas (Lockyer, 1984; Yochem and Leatherwood, 1985; Tillman and Donovan, 1986) where calves are taught to feed themselves (Lockyer, 1984). Sexual maturity in male and female blue whales is reached at 5-15 years of age (Yochem and Leatherwood, 1985; Perry, et al., 1999; Sears, 2002). In the northern hemisphere, females reach a length of 21–23 m, while males are 20–21 m long (Sears, 2002; Sears and Calambokidis, 2002). Blue whales are thought to live for more than 80 years. (Yochem and Leatherwood, 1985; Sears, 2002).
The Northwest Atlantic population’s annual growth rate is unknown. In the Antarctic, the annual growth rate has been estimated at 7.3% from 1968 to 2001 (Branch, et al., 2004), whereas the Northeast Atlantic population’s growth rate has been estimated at 5.2% between 1979 and 1988 (Sigurjònsson and Gunnlaugsson, 1990). In the Estuary and the Gulf of St. Lawrence, only 19 mother-calf pairs have been sighted over the last 30 seasons (R. Sears, MICS, J.-F. Gosselin, DFO, unpublished data). However, considering that only a small proportion of the range is surveyed in Canada, it is difficult to assess whether the low number of mother-calf pairs sighted is representative of the actual reproduction rate for the whole Northwest Atlantic blue whale population.
Another intrinsic limiting factor is that blue whales feed almost exclusively on krill (Jonsgård, 1955; Sergeant, 1966; Kawamura, 1980; Lockyer, 1984; Schoenherr, 1991) and display an individual consumption between 1800 and 3600 kg of krill every day (Yochem and Leatherwood, 1985). In the North Atlantic, their main prey are Thysanoessa inermis, T. longicaudata, T. raschii and Meganyctiphanes norvegica (Yochem and Leatherwood, 1985; Sears and Calambokidis, 2002). To meet their energy requirements, blue whales must feed exclusively in areas of very high concentrations of krill (Brodie, et al., 1978; Kawamura, 1980; Croll, et al., 2005). The areas where such densities of zooplankton exist are rare in the ocean; consequently, they are important for blue whale survival. The blue whales’ fat reserves accumulated during four or five months of intensive feeding are likely necessary for their winter migration and reproduction. The success of biological processes such as fertility, gestation, lactation, development, growth, sexual maturity and recruitment are all dependent on the blue whale’s capacity to store energy reserves (Lockyer, 1984).
Significant limiting factors that can affect the recovery potential of the species include a low birth rate combined with a late sexual maturity, resulting in a low population growth rate. Although there has been no whaling of the Northwest Atlantic blue whale population since 1966, its natural population growth is not fully understood. Furthermore, the blue whale population’s viability and recovery can been held back by factors that limit the availability of food resources (see section 220.127.116.11 Food availability).
1.5 Threats: classification and description
The most important factor responsible for the low numbers of blue whales in Canada is historical whaling, which decimated populations from the end of the 19th century until it was prohibited by the International Whaling Commission (IWC) in 1966. In the North Atlantic, 11 000 blue whales were likely captured prior to the 1960s (Sigurjònsson and Gunnlaugsson, 1990); 1 500 of them were captured in eastern Canadian waters from 1898 to 1915 (Sergeant, 1966; Mitchell, 1974a, b). It is estimated that whaling reduced the blue whale population by about 70%. Although the current size of the Northwest Atlantic population is unknown, it is very unlikely that the number of mature animals exceeds 250 individuals (Sears and Calambokidis, 2002). Consequently, the population could face reduced genetic diversity, which could in turn affect individuals (e.g., reduced fertility, reduced disease resistance) or the population (e.g., reduced population growth rate) (Lacy, 1997). The latter could also be subjected to the Allee effectFootnote 4, which could substantially disrupt this population’s recovery.
The authors of the COSEWIC status report (Sears and Calambokidis, 2002) mention several threats that are thought to hinder the recovery of the Northwest Atlantic blue whale population since the end of commercial whaling: shipping traffic, disturbance caused by whale-watching activities, entanglement in fishing gear, pollution, the effects of climate change on prey abundance, ice entrapments and predation. The current recovery strategy lists nine threats along with whaling and natural mortality (i.e., caused by ice entrapments and predation). Threats are divided into three risk categories based on their probability of occurrence or the severity of their theoretical effect on blue whales: high, medium and lower risk. This threat priority list (Appendix 1) was established based on current knowledge (which is limited and based mainly on blue whale sightings in the Estuary and Gulf of St. Lawrence area) and could change according to context or with the increase of knowledge. Because of the blue whale population’s small size in the Northwest Atlantic, even activities that affect a small number of individuals could have a serious impact on the population’s health.
Three types of whaling can threaten cetacean populations: commercial whaling, subsistence whaling and whaling for scientific purposes (Clapham, et al., 1999). Despite an international moratorium by the IWC on commercial whaling since 1966, some countries continue to whale, both for scientific research, such as Japan, or commercial purposes, such as Norway. According to genetic analysis of whale meat found on the Japanese and south Korean markets, meat from blue whales, fin whales (Balaenoptera physalus), humpback whales (Megaptera novaeangliae) and many other species protected under the IWC are still being sold (Baker, et al., 2000). In addition, the former Soviet Union continued to hunt certain species of whales, including blue whales, after the moratorium was introduced in 1966, killing approximately 8000 blue whales (Zemsky et al., 1995, 1996 in Clapham, et al., 1999; Yablokov et al., 1998 in Clapham, et al., 1999).
In Canada, according to the Marine Mammal Regulations of the Fisheries Act, hunting blue whales is prohibited within Canada’s exclusive economic zone. Moreover, blue whales are protected by article 32(1) of the Species at Risk Act (SARA), which states that “No person shall kill, harm, harass, capture or take an individual of a wildlife species that is listed as an extirpated species, an endangered species or a threatened species”. Subsistence whaling practised by aboriginal people would require permits or exemptions, but this type of hunting does not occur in Canada. Whaling remains a potentially significant human-induced source of mortality for large cetaceans. However, because it is unlikely that commercial whaling will resume in the near future in the Northwest Atlantic, whaling is not considered a current threat for blue whales in Canada.
1.5.2 Natural mortality
Ice carried by wind and currents in late winter or early spring can injure blue whales; they can even die by anoxia (lack of oxygenation) or be crushed by moving ice blocks. A small percentage of the individuals sighted in the St. Lawrence have dorsal scars caused by ice contact (Sears, et al., 1990; R. Sears, MICS, personal communication).
From 1868 to 1992, 23 ice entrapment events involving one to four blue whales were reported, affecting a total of 41 individuals, southeast of Newfoundland. Based on available information, these events occurred between March and April. Among the blue whales that were trapped, 28 died, five escaped and eight were unaccounted for. Most of the dead individuals that were examined were mature (i.e., 21-25 m in length). Two of the six blue whales that were examined for gender were females, one of which was pregnant (Stenson, et al., 2003).
The only known predator of blue whales is the killer whale (Perry, et al., 1999; Sears, 2002), but there is limited knowledge of the frequency of these attacks and the extent to which they are fatal (Reeves, et al., 1998). This predator attacks several cetacean species, including large whales (Jefferson, et al., 1991). Recent cases include mortal attacks on a group of sperm whales, Physeter macrocephalus and on minke whales, Balaenoptera acutorostrata (Pitman, et al., 2001; Ford, et al., 2005). There have been some reported cases for blue whales (Jefferson et al., 1991), such as the instance where almost 30 killer whales attacked and killed a young blue whale off Baja California (Tarpy, 1979).
Killer whales make specific rake-like markings with their teeth on their victims. Very few blue whales in the St. Lawrence carry such markings. In the Pacific, in the Sea of Cortez where killer whales are more abundant, 25% of the blue whales sighted carry marks caused by killer whale attacks (Sears and Calambokidis, 2002).
Knowledge of the Atlantic killer whale population is limited (Baird, 2001); they are not very abundant. Individuals have been sighted occasionally off the coasts of Labrador, Newfoundland, Nova Scotia and in the Gulf of St. Lawrence (Baird, 2001). The decline in the St. Lawrence beluga population (Delphinapterus leucas), a major prey for killer whales, could partly explain the low number of killer whales observed in the last decades (Mitchell and Reeves, 1988).
1.5.3 High-risk anthropogenic threats
18.104.22.168 Anthropogenic noise: acoustic environmental degradation and changes in blue whale behaviour
Blue whales produce very low frequency sounds (< 200 Hz) whose function is little understood (Ketten, 1998; Mellinger and Clark, 2003; Berchok, et al., 2006; McDonald, et al., 2006a). The whales could use the sounds to investigate the environment, locate feeding grounds, or to communicate with other individuals over short and long distances (Richardson, et al., 1995; Stafford, et al., 1998; McDonald, et al., 2001; Stafford, et al., 2007). Blue whales could also transmit information on their whereabouts and their reproductive status in order to coordinate reproductive activities (Richardson, et al., 1995). Some of these low-frequency sounds are difficult to detect when ambient noise levels are loud (Mouy, 2007; Stafford, et al., 2007; Simard and Roy, 2008; Simard, et al., 2008). Depending on the purpose of these sounds, making them difficult to hear may affect certain behaviours.
Anthropogenic noise levels, originating from seismic noise, shipping traffic, explosions, low frequency sonar, industrial and military activities in the oceans have been increasing over the last 50 years (Croll, et al., 2001; Andrew, et al., 2002; National Research Council, 2003; McDonald, et al., 2006b; Tyack, 2008). A 0.2 to 0.3 decrease in pH in the deep water in the St. Lawrence Estuary (M. Starr, DFO, personal communication), owing to climate change, combined with eutrophication, enable noise to carry over greater distances, possibly further affecting cetacean communication. Hester et al. (2008) have demonstrated that a pH decrease of 0.3 would result in a 40% decrease of noise absorption by water at frequencies lower than 10 kHz. Furthermore, the Intergovernmental Panel on Climate Change (IPCC) predicts that by the year 2050, oceanic surface waters will decrease in pH by 0.3 (Brewer, 1997). Noise propagation in the ocean would thus increase throughout the distribution area of the blue whale.
These anthropogenic noises could have a harmful impact on marine mammals by: 1) disrupting their ability to passively observe their environment, to detect the sounds emitted by other marine mammals or any other sounds; 2) causing behavioural changes; 3) altering hearing sensitivity or by causing injury which, in certain cases, are fatal (Richardson, et al., 1995; Southall, 2005; Nowacek, et al., 2007; Weilgart, 2007; Stockin, et al., 2008). This third point will be discussed in Section 22.214.171.124 “Anthropogenic noise: Physical harm”.
In the ocean before the Industrial Revolution, the call of a blue whale may have been heard over 100–1000 nautical miles, while in today’s noisier oceans it might be heard over only 10–100 nautical miles (Clark, 2003). Although the function of the sounds emitted is not well understood, it has been suggested that a decrease in communication range could affect blue whale reproduction by reducing the effectiveness of male communication with receptive females (Croll, et al., 2002). This harmful effect could be significant for a small-sized population such as the blue whale population (National Research Council, 2003). Based on the assumption that ambient noise has a significant impact on the capacity of the blue whales to communicate for reproduction or any other critical activity, anthropogenic noise could represent a factor that is likely to negatively affect this population’s recruitment and recovery (Croll, et al., 2002).
Moreover, in response to anthropogenic noise, blue whales can adopt a variety of reactions. Reactions can range from a brief interruption of normal activities, such as rest, feeding, social interaction, nurturing their calves, vocalizations, breaths, and dives, to avoiding noisy areas for a short or long period (McDonald, et al., 1995; Richardson, et al., 1995; National Research Council, 2003; DFO, 2004; Bejder, et al., 2006; Weilgart, 2007). There is a cost in terms of energy associated with these behavioural changes. The energy that would normally be used for vital activities, such as acquiring food or reproduction, is instead expended on avoidance behaviour. Although the effects of a behavioural change in response to anthropogenic noise on blue whales are unknown, they might not be negligible (Richardson, et al., 1995; National Research Council, 2003; DFO, 2004).
Among the anthropogenic noise occurring in Canadian waters, two are particularly significant: maritime shipping as well as seismic surveys and petroleum and gas development activities. As important shipping routes, the Estuary and Gulf of St. Lawrence offer a noisy aquatic environment, which could be a problem for marine mammals in certain areas, mainly in the Estuary and at the head of the Laurentian Channel (Scheifele, et al., 1997; Berchok, et al., 2006; Simard, et al., 2006; Stafford, et al., 2007; Simard and Roy, 2008; Simard, et al., 2008). In this area, blue whales emit sounds in a wider range of frequencies than those observed in other areas in the Northwest Atlantic (Mellinger and Clark, 2003; Nieukirk, et al., 2004; Berchok, et al., 2006). These authors have theorized that loud ambient noise in the St. Lawrence River could force blue whales to change the frequency of their signals in order to improve the likelihood that these signals will be heard by other blue whales (Berchok, et al., 2006). Changes in the vocalization pattern over time in response to ambient noise were also recorded for right whales (Parks, et al., 2007).
Seismic surveys and oil and gas development are conducted in several coastal areas around the world, including the east coast of Canada, east of Newfoundland and Labrador and on the Scotian Shelf (Lawson and McQuinn, 2004; Nieukirk, et al., 2004). Under conditions of low ambient noise and good propagation, noise produced by air gun arrays used in seismic surveys can be detected up to 3000 km away, sometimes masking the ability to detect vocalizations produced by blue whales in affected areas (Nieukirk, et al., 2004). Moreover, it was shown that seismic activities have consequences on cetacean behaviour in general; they can change navigation routes, alter their displacement speed, and modify their dive profiles and feeding (Stone, 2003). Because of the potential effects on the ecosystem and on blue whale behaviour, anthropogenic noise is a threat that is likely to jeopardize blue whale recovery in the Northwest Atlantic.
126.96.36.199 Food availability
With their restrictive diet (stenophagous) and their requirement for areas with high concentrations of prey, blue whales are particularly vulnerable to changes in prey abundance or distribution (Croll, et al., 1998; Clapham, et al., 1999; Acevedo-Gutièrrez, et al., 2002). A drop in food resources could have significant consequences on the population, and more specifically on recruitment. For example, Greene et al. (2003) showed that recruitment for the North Atlantic right whale (Eubalaena glacialis) was affected by the availability of food resources. In a context where food resources are limited, a post-lactating female blue whale may not accumulate enough energy for its subsequent conception or for the subsequent nursing period, and consequently abort the pregnancy or give birth to a calf that is unable to survive (Lockyer, 1984).
In addition to natural variability in the ocean’s climate, three anthropogenic factors could have an effect on krill availability for blue whales. Firstly, an increase in pelagic fish that feed on krill such as capelin (Mallotus villosus) and Atlantic herring (Clupea harengus) could limit the availability of this resource for blue whales (i.e., interspecific competition). In recent decades, the abundance and distribution of pelagic fish has changed considerably in the Estuary and Gulf of St. Lawrence following the decline of their predators, Atlantic cod (Gadus morhua) and redfish (Sebastes spp.), caused in part by the commercial fishery (Canadian Atlantic Fisheries Scientific Advisory Committee (CAFSAC), 1994; Gascon, 2003). Cetaceans and seals have gradually replaced them as principal predators for pelagic fish (Savenkoff, et al., 2004; Savenkoff, et al., 2006), but they exert weaker predatory pressure than the groundfish did (Savenkoff, et al., 2007). Although the effect on pelagic fish of having fewer predators is unknown, it could have increased their numbers (Worm and Myers, 2003).
Moreover, Fisheries and Oceans Canada (DFO) research surveys seem to show a major expansion in the geographical distribution of capelin throughout the Gulf of St. Lawrence in the 1990s (DFO, 2001). There was a concomitant increase in the observations of cetacean species such as humpback whales (Megaptera novaeangliae) in the northern Gulf of St. Lawrence (R. Sears, MICS, unpublished data). With their larger prey spectrum, these opportunist predators target both macrozooplankton and pelagic fish species (Mitchell, 1975; Borobia, et al., 1995). All these findings point to a deep change in the trophic structure of the St. Lawrence ecosystem, which may have affected or could eventually modify the distribution and abundance of blue whales. For example, the Mingan Islands in the Gulf of St. Lawrence, used to be a very active area for blue whales during the 1980s, which is no longer the case (R. Sears, MICS, personal communication).
Commercial exploitation of krill in the St. Lawrence Gulf for the nutritional food industry could reduce the availability of this food resource for blue whales. However, in 1998, a moratorium on the issuance of new licences for all the unexploited forage species (including krill) was put in place by the Minister of Fisheries and Oceans and is still in force in Eastern Canada.
Finally, climate change as a result of human activities could lead to variations in the ocean climate that are likely to have an effect on primary production as well as prey distribution or abundance for marine mammals (Harwood, 2001). Long term impacts of global warming, which is occurring at a faster rate than previously expected, are difficult to forecast, but could lead to an increase in average temperature between 1.5°C and 5.5°C by 2050, in central and southern Québec (Bourque and Simonet, 2008). From 1960 to 2003, an increase in temperature between 0.4°C and 2.2°C has been observed in several regions of southern Quebec (Yagouti, et al., 2006). For the Maritimes region, seasonal temperature trends from 1948 to 2005 reveal a general increase of 0.3°C, with a peak in the summer of 0.8°C. By 2050, summer temperatures will increase by 2°C to 4°C in Atlantic Canada (reviewed in Vasseur and Catto, 2008). Similar changes are expected in other ecosystems frequented by blue whales, such as in the Pacific, where the increase in surface water temperatures has led to a drop in zooplankton abundance since the 1970s (Roemmich and McGowan, 1995). Climate change could have an impact on blue whale food resources by affecting 1) the production of the krill included in blue whale diet, including Thysanoessa raschi and 2) the krill aggregation processes within feeding areas. For example, climate change could reduce the habitat of T. raschi, which is associated with the cold intermediate layer (Simard, et al., 1986), with unknown impacts on the medium-term production of this species. The estuarine two-layer circulation pattern observed in the Estuary and Gulf of St. Lawrence, which, presumably, is responsible for the aggregations of krill, and which depends on the freshwater inputs from the St. Lawrence River and on the vertical stratification of the water column (Saucier and Chassé, 2000; Saucier, et al., 2003; Smith, et al., 2006), will also be likely affected by climate change.
For the Northwest Atlantic, Greene et al. (2003) theorized that changes in ocean climate will adversely impact the recruitment and recovery of the North Atlantic right whale by decreasing the abundance of its food resources, made of zooplankton, mainly copepods. Considering that the blue whale is, like the right whale, a selective species in terms of food choice, similar climate repercussions on food resources for blue whales in the Northwest Atlantic could impact the species’ recovery. Consequently, climate change could be affecting existing feeding grounds, but current knowledge is insufficient to predict how.
1.5.4 Medium-risk anthropogenic threats
Contaminant sources in the aquatic environment are numerous (e.g., agricultural, industrial and municipal waste, shipping, dredging, gas and oil exploitation, aquaculture) and so are their impacts on marine mammals (e.g., depression of the immune system, altering reproductive capacity, lesions and cancer) (Colborn and Smolen, 1996; Aguilar, et al., 2002).
Levels of polychlorinated biphenyls (PCBs) and other organochlorinated compounds have been found in St. Lawrence blue whales (Gauthier, et al., 1997; Koenig, et al., 1999). The levels of contamination, although lower than those measured in St. Lawrence belugas, possibly due to differences in diet and time spent in the St. Lawrence River (O'Shea and Brownell Jr, 1994; Angell, et al., 2004; Lebeuf, et al., 2007), are sufficiently high to trigger abnormal activity in certain cytochromes, which could lead to biological impacts on the whales’ health (Angell, et al., 2004).
The impact of contaminants on blue whales is difficult to track because this threat has many variables and depends on several determining factors such as age, gender, length of exposure, intensity of the exposure, season, and nutritional status (Colborn and Smolen, 1996). Blue whales can draw on their fat reserves in winter, which increases their exposure to contaminants (Colborn and Smolen, 1996). Concentrations of contaminants generally increase with age in males, while in mature females, they decrease as they age due to the transfer of contaminants to their young (O'Shea and Brownell Jr, 1994; Metcalfe, et al., 2004). Indeed, during gestation and nursing, a portion of the contaminants from the mother is transmitted to the calf. This transfer is a serious issue that can generate contaminant levels as high in the calves as in their mothers (e.g., Metcalfe, et al., 2004). Although there is no reason right now to believe contaminants have a lethal impact on baleen whales (O'Shea and Brownell Jr, 1994), there is enough evidence to suggest that some contaminants can alter the reproductive potential and health of cetaceans (Colborn and Smolen, 1996). Consequently, improving knowledge is necessary in order to better assess the genuine risk associated with contaminants for the blue whale in the Northwest Atlantic.
188.8.131.52 Collisions with vessels
In addition to disturbing marine mammals’ activities on the water’s surface, such as breathing, feeding, socializing, and nurturing, vessels can collide with them, severely injuring or killing them. Large vessels traveling at more than 14 knots (26 km/h), such as container ships and other large vessels (i.e., measuring 80 m long and more), have been found to be the principal source of severe or fatal injuries for large whales (Laist, et al., 2001). Vanderlaan and Taggart (2007) also showed that the probability of a collision being fatal for a large whale increases quickly when vessel speeds range between 8.6 and 15 knots. Jensen and Silber (2004) estimate that at least 70% of vessel collisions with large whales are fatal.
Individuals that move along inhabited coastal areas or in busy seaways, such as the St. Lawrence Estuary, are more vulnerable to collisions with vessels (Clapham, et al., 1999; Laist, et al., 2001). According to the Bureau d’audiences publiques sur l’environnement, over 12 000 vessel movements were recorded for 2003 in the Estuary between Sept-Îles and Les Escoumins, with a little more than 6 000 west from Les Escoumins and 226 at Cacouna (BAPE, 2006). So it is not surprising that deep wounds and scars, which can be attributed to collisions with the propeller or hull of large vessels, have been observed on at least 5% of the blue whales seen in the St. Lawrence (R. Sears, MICS, personal communication).
Blue whale mortalities related to collisions with vessels have been reported in various oceans (Barlow, et al., 1997; Reeves, et al., 1998; Laist, et al., 2001). Even though there have not been many cases reported in the Northwest Atlantic, the number of St. Lawrence blue whales with scars from collisions indicates that this threat is real and likely significant (Sears and Calambokidis, 2002). It is possible that whales struck and killed by fast-moving vessels sink to the bottom without being detected, leading to an underestimate of the real impact of this threat (Sears and Calambokidis, 2002).
The blue whale’s ability to detect and avoid ships is yet to be determined (Laist, et al., 2001). Adequately locating large ships acoustically can be difficult since the main sound source, the propeller, is located at the back of the ship with a long hull dampening the sound propagation forward. The least noisy area is the prow (Arveson and Vendittis, 2000), in the direction the ship is moving, where the risk of collision is the highest. Calves and juveniles are probably more vulnerable than adults, as they spend more time near the surface and have less experience avoiding ships (Laist, et al., 2001). Because of the low number of blue whales in the Northwest Atlantic, the loss of even a few individuals can represent a significant obstacle to this population’s recovery (Laist, et al., 2001). When the critical habitat and distribution of the species in the North Atlantic is better understood, it will be easier to assess the significance of this threat to the blue whale population.
184.108.40.206 Whale watching
The increase in whale-watching activities by cruise companies and recreational boaters represents a significant threat to many coastal cetaceans, including blue whales. In the Estuary and Gulf of St. Lawrence, several sites frequented by blue whales have been attracting a significant number of tourists for a number of years. For example, Parks Canada estimates, for 2005, that nearly 275 000 people participated in whale-watching activities at sea in the Saguenay–St. Lawrence Marine Park. In the St. Lawrence Estuary, up to 50 cruise ships sail the waters in search of cetaceans. On several occasions, up to thirteen boats were observed simultaneously within 20 m of blue whales (Sears and Calambokidis, 2002). Whale watchers in the Gaspésie region seek out blue whales specifically. On several occasions, whale-watching vessels were seen within 200 m of this species (Pieddesaux, et al., 2007). In addition, teams of scientists conducting research activities aimed at improving knowledge of the species must approach the blue whales within 25 m (e.g., collecting biopsies, deploying data collection equipment), which can cause stress for these animals.
Whale-watching activities can disturb cetaceans during daily activities that are essential to their survival, such as resting, feeding, avoiding predators, communicating, socializing, mating and nurturing calves. When these disturbances are repeated or sustained, they can affect the survival of individuals and the conservation of the species. Furthermore, the dependence of these animals on certain habitats leads to the concentration of whales and whale watchers in these important areas (Lien, 2001).
There has been no long-term study on the effects of whale-watching activities in the Estuary and Gulf of St. Lawrence (Lien, 2001). Among the short-term behavioural changes observed in various cetacean species, there have been alterations in swimming, diving, breathing, vocalization, feeding, resting, socializing, nursing and aerial acrobatics, as well as the short-term abandonment of habitat (Great Barrier Reef Marine Park Authority (GBRMPA), 2000 in Lien, 2001). Cetaceans could be forced to move to sub-optimal areas that are inadequate to meet their needs (International Fund for Animal Welfare (IFAW), 1997 in Lien, 2001). There is a cost associated with these changes in behaviour and habitat, which can reduce the blue whale’s capacity to store energy reserves that are critical for ensuring reproductive success and their survival during periods when food is scarcer (Richardson, et al., 1995; National Research Council, 2003).
1.5.5 Low-risk anthropogenic threats
220.127.116.11 Anthropogenic noise: physical harm
In addition to the potential for masking the sounds produced by blue whales and affecting their behaviour (section 18.104.22.168 “Anthropogenic noise: acoustic environmental degradation and changes in blue whales’ behaviour”), high amplitude or long-term anthropogenic noise could cause, in cetaceans, temporary or permanent alteration of hearing thresholds, production of stress hormones, or physical damage such as internal lesions that could cause death (Ketten, et al., 1993; Crum and Mao, 1996; Evans and England, 2001; Finneran, 2003; National Research Council, 2003; DFO, 2004). For several species, knowledge is insufficient to clearly establish the noise levels perceived at the various frequencies and if these sounds can cause physical harm (Richardson, et al., 1995; National Research Council, 2003; DFO, 2004; Southall, et al., 2007).
It is during seismic research or the use of low frequency active sonar that the highest levels of underwater noise are usually recorded (Richardson, et al., 1995). Since the ears of mammals share certain structural similarities with other vertebrates (Fay and Popper, 2000), and some noise exposure studies on different vertebrate species indicate that it is possible that exposure to the intense noise produced close to airgun arrays might also damage the ears of cetaceans if they do not avoid the noise source (McCauley, et al., 2003; Popper, et al., 2003; Cox, et al., 2006; Lawson, 2007; Southall, et al., 2007).
High-amplitude sound energy from underwater explosions, for example originating from demolition or construction blasting, and wellhead decommissioning, can also cause injury or death to cetaceans nearby. A high-amplitude impulsive noise caused by sea floor dynamiting might have caused the death of two humpback whales found in fishing gears along the coast of Newfoundland. Both individuals had significant lesions on their temporal bones, and fractures of their auditory systems (Ketten, et al., 1993).
Even in the absence of direct physical effects from exposure to loud anthropogenic noise, it is possible that behavioural reactions by cetaceans could produce adverse effects (National Research Council, 2005). Jepson et al. (2003) reported the death of approximately ten cetaceans following the occurrence of air bubbles in their vital organs, in an area where military sonar had been used in the previous hours. The noise produced by the sonar might have precipitated a rapid, abnormal resurfacing of these deep-diving species, which might have caused these lesions (Jepson, et al., 2003).
22.214.171.124 Accidental entanglements in fishing gear
The presence of certain types of fishing gear could present a threat to blue whales since the gear can kill animals by anoxia if they become entangled. Even when blue whales manage to escape fishing gear, they can be injured and tow parts of the gear (e.g., cables, buoys) over a long time. In 1987, a blue whale was observed north of Cape Cod trailing a fishing cable and buoy that appeared to be from the lobster fishery (Reeves, et al., 1998). In some cases, entangled whales could have difficulty moving and feeding, to the point that their reproductive activities and survival are compromised (Reeves, et al., 1998; Clapham, et al., 1999). Blue whales are powerful animals that rarely become entrapped in fishing nets. Despite this, three blue whales caught in gillnets have died in the St. Lawrence since 1979 (Sears and Calambokidis, 2002). It is estimated that nearly 10% of blue whales occurring in the St. Lawrence have scars caused by contacts with fishing gear (R. Sears, MICS, personal communication).
Anthropogenic noise may also hamper the efforts of certain cetacean species to detect fishing nets by disrupting their ability to orient themselves. This phenomenon was observed on the east coast of Newfoundland; where the entanglement of several humpback whales in fishing nets was associated with noise produced by construction activities, such as explosion and drilling, that modified the underwater acoustic environment (Todd, et al., 1996). It remains difficult to evaluate the real impact of noise on the capacity of blue whales to detect fishing gear as these animals tend to flee far from the point of contact with such gear (Reeves, et al., 1998; Perry, et al., 1999). The relatively noisy underwater environment of the Gulf of St. Lawrence could pose similar threats to blue whales, but no study has yet confirmed this assumption.
126.96.36.199 Epizootics and toxic algal blooms
In the North Atlantic, the number of cases of large-scale marine mammal mortality caused by disease appears to be rising since the second half of the 20th century (Harvell, et al., 1999). According to Harwood (2001), this trend is likely to continue through the 21st century. This increase in disease occurrence is likely to be caused by climate variations and human activities related to habitat degradation and pollution (Harvell, et al., 1999). A significant number of pathogenic agents can be transmitted to marine mammals by municipal wastewater, septic tanks, landfill leachates, agricultural runoff, and commercial shipping (Measures and Olson, 1999; Measures, 2002a, b; Measures, et al., 2004b). Marine mammals that may be immunocompromised or weakened by exposure to marine pollution may also be exposed to new pathogens recently introduced into the environment or to existing pathogens that attack a greater variety of hosts (Harvell, et al., 1999).
In Canada, pathogenic agents that can cause death in marine mammals are still not well documented, but the risk is nevertheless present, and could have significant impacts on a population with a low number of individuals such as the Northwest Atlantic blue whale. According to Nielsen et al. (2000), Mikaelian et al. (1999) and DFO (2007), viral epizooty risks exist, especially for beluga whales, but have not yet been evaluated in the St. Lawrence. Viruses, including morbilliviruses, are especially dangerous because they can rapidly cause epizootics. The Atlantic white-sided dolphin (Lagenorhynchus acutus), a species that visits the St. Lawrence, and the long-finned pilot whale (Globicephala melas), another less frequent visitor, are reservoirs for these viruses. It should be noted that climate change is likely to lead to increased occurrences of new marine mammal species in the St. Lawrence such as the pygmy sperm whale, Kogia breviceps (Measures, et al., 2004a), thereby increasing the risk of exposure to new diseases (DFO, 2007). In addition, according to Measures (2004), introduction of novel or exotic pathogens from wildlife rehabilitation programs can also represent significant risks to wild populations.
In addition, there could also be a rise in the number of cases of toxic algae poisoning in cetaceans in all oceans (Harvell, et al., 1999). In summer 2008, a red tide occurred over 600 km2 in the St. Lawrence Estuary and resulted in the death of several cetaceans, including a dozen belugas and harbour porpoises (Phocoena phocoena), dozens of seals and thousands of birds, invertebrates and fish (L. Measures, DFO, unpublished data; S. Lair, University of Montreal, unpublished data). This red tide was the work of Alexandrium tamarense, a microscopic alga which occurs naturally in the Estuary and Gulf of St. Lawrence. These algae produce a neurotoxine, saxotoxine, which induces temporary neurological problems that can cause death. Whales ingest this toxin through their prey, i.e. intoxication through the food web. The size of this event is probably due to the particularly abundant rainfall during summer 2008, which resulted in higher temperatures and lower salinity of surface waters (M. Starr, DFO, unpublished data). Climate change and the resulting alteration in the rainfall regime could be responsible for an increase in algal blooms, thus rendering this a significant threat for blue whales.
Few blue whale carcasses have been found on accessible shores, and the carcasses found were usually in an advanced stage of decomposition, making it impossible to identify any diseases (Measures, 2003). However, carcasses can be examined for ship collision evidence, such as broken bones and signs of hematoma, or to detect the presence of certain parasites (Measures, 1992, 1993). More than 40 blue whale carcasses have been reported on the Canadian east coast since 1951. All documented cases were immature whales and in most, the cause of death was not determined (Measures, 2003). Parasitic infections, such as Crassicauda boopis, a 2‑m nematode that attacks the kidneys, can cause health problems and could explain the death of certain large rorquals, but their prevalence in blue whales remains unknown (Measures, 2003).
Epizootics, algal blooms or any other event resulting in mass mortalities could indeed be problematic for the blue whale because of the small size of this population.
188.8.131.52 Toxic spills
The consequences of a toxic spill for blue whales are variable and difficult to evaluate. Although most cetaceans avoid oil slicks on the water’s surface, they can accidentally come in contact with toxic products (e.g., Harvey and Dahlheim, 1994; Matkin, et al., 1994; Smultea and Wursig, 1995). The contamination risks associated with direct contact are low for marine mammals because their skin is an effective barrier (Geraci, 1990). Oil spills can nonetheless represent a risk for marine mammals because the toxic fumes can harm sensitive tissue, such as eye, mouth, and lung membranes (Geraci and Aubin, 1990). In addition, marine mammals can ingest the spilled product either directly or by eating contaminated prey, which can lead to various toxic and physiological effects (Geraci and Aubin, 1990). Cases of gastro-intestinal and pulmonary intoxication have been reported (Geraci, 1990). Finally, the whalebones of baleen whales, like those of blue whales, can temporarily be obstructed by spilled products, which can lead to feeding problems and lead to ingestion of petroleum products.
The maritime transportation of petroleum and other toxic products, such as chlorine, bauxite, and sulfite, is significant in the Atlantic, especially in the St. Lawrence Estuary, which has distinctive oceanographic conditions such as frequent occurrence of fog and strong tidal currents. Shipping traffic is therefore considered a potential source for an environmental disaster likely to impact blue whales (Savaria, et al., 2003). The exploitation of oil and gas along the Northwest Atlantic coasts and in the Gulf of St. Lawrence also represents an additional risk for pollution. Toxic spills are therefore a potential threat that cannot be ignored.
1.6 Actions already completed or under way
1.6.1 Blue whale protection
184.108.40.206 International legal protection
This species has been protected from whaling worldwide by the International Whaling Commission (IWC) since 1966. The blue whale is listed in the “protected” category, since stocks estimates are under 40% of the required numbers to sustain a maximum long-lasting yield. This species is also designated as “endangered” by the World Conservation Union (IUCN). The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) has listed the blue whale in its Appendix 1, which contains “species threatened with extinction and for which international trade is prohibited”. In the United-States, blue whale is designated “endangered” under the Endangered Species Act and the Marine Mammal Protection Act.
220.127.116.11 Canadian legal protection
In Canada, the blue whale was legally listed and protected as an “endangered” species under SARA in January 2005. Listing under this Act prohibits the killing, harming, harassing, capturing or taking of individuals of a listed species. The Act also prohibits damaging or destroying the species’ residence or any other component of its critical habitat. It includes provisions to protect critical habitat and requires the creation of a recovery strategy and action plan for each listed species.
Since 1993, the blue whale has been protected under the Marine Mammal Regulations of the Fisheries Act, according to which it is prohibited to disturb a marine mammal. A public consultation began in 2005 to amend the Marine Mammal Regulations in order to elaborate on the concept of marine mammal disturbance to make it more understandable to the public and to provide a reference point as to when a disturbance is deemed to take place. These amendments (e.g. ability to licence whale watching industry, obligation to declare any physical contact with cetaceans and to avoid approaching to less than 100 m from any cetacean) are aimed at protecting the normal life processes of marine mammals.
Food resources of the blue whale have been protected from fishing since 1998, when a moratorium on the issuing of new permits for the harvest of any unexploited forage species (including krill) was ordered by the Minister of Fisheries and Oceans Canada. This moratorium is still in effect.
Individuals found within protected heritage areas, managed by Parks Canada, the Saguenay–St. Lawrence Marine Park and the waters of the Forillon National Park, are protected under the Canada National Parks Act, the Saguenay–St. Lawrence Marine Park Act and their regulations. Note also that the Quebec government has added this species to the list of species likely to be designated as “threatened” or “vulnerable” (provincial rank S4 and global rank G3G4).
1.6.2 Habitat protection measures, awareness raising and other measures
18.104.22.168 The Saguenay–St. Lawrence Marine Park (SSLMP)
The SSLMP, with a surface area of 1245 km2, was created in 1998 to increase, for the benefit of the present and future generations, the level of protection of the ecosystems of a representative portion of the Saguenay River and the St. Lawrence Estuary for conservation purposes, while encouraging its use for educational, recreational and scientific purposes (Saguenay–St. Lawrence Marine Park Act, s. 4). Several management measures were set up and are under way in this territory to contribute to the recovery of blue whale.
- Whale watching activities within the Park are managed through the application of the Regulations on marine activities in the Saguenay–St.Lawrence Marine Park by the park’s resource conservation service. Under these regulations, the eligibility of permit applications made by marine tour businesses, research scientists and organizers of special activities are assessed. The Regulations determine mandatory approach distances (100 m from cetaceans in the case of commercial boats with marine tour license, 200 m from cetaceans for boats without license, and 400 m in the case of endangered species), the number and speed of boats, the duration of watching activities, the height of flight for aircrafts, and an obligation to report any accident resulting in wounds to or death of a marine mammal.
- An emergency environmental plan.
- A zoning plan, which is under development.
- Awareness raising activities: communication plan for species at risk, action and education strategy in terms of species at risk, awareness raising tour aimed at boaters.
22.214.171.124 Marine protected areas
Marine Protected Areas (MPA) were created or are currently under study, pursuant to the Canada Oceans Act (which came into effect in 1997), in order to raise the level of protection of marine species and their habitat.
- The Gully MPA was created on the Scotian Shelf in May 2004. This area, located about 200 km off the coast of Nova-Scotia, includes a deep underwater canyon which shelters several species of marine mammals, including the blue whale.
- Two MPA projects are under development in the St. Lawrence:
- The St. Lawrence Estuary MPA aimed primarily at the protection of marine mammals, is under development at the edge of the SSLMP, in an area in the Estuary where marine mammals concentrate and are under significant anthropogenic pressure. This project, covering approximately 6000 km2, should increase protection and ensure the long-term conservation of the blue whale and part of its habitat and food resources. For this purpose, a data acquisition study on whale-watching at sea and boating activities has been under way since 2005 in the proposed MPA in order to characterize these activities and their use of the territory (Michaud, et al., 2007). This study also aims at analyzing the distribution of observations by species, including the blue whale, in order to determine their relative importance. This information will help the management of whale-watching activities in the future St. Lawrence Estuary MPA.
- The Manicouagan MPA, covering 543 km2, aims to protect the overall biodiversity of the coastal zone up to a depth of 300 m in the St. Lawrence River and thus partially covers a territory which is occasionally frequented by the blue whale.
126.96.36.199 Awareness-raising activities
Projects aimed at informing the public and at decreasing the risk of disturbance and collision with ships have been financed under various programs.
- Increasing kayakers’ awareness of proper navigation behaviours around species of marine mammals at risk – Priority Intervention Zone (PIZ) Committee on the North Shore of the Estuary.
- Development of whale watching from the shore to protect marine mammals at risk - PIZ Committee on the North Shore of the Estuary
- Project aimed, over several years, at encouraging employees and industry leaders to rethink their whale-watching activities with, among other things, an information pack to provide a better service to their clients with regards to content – Réseau d’observation des mammifères marins (ROMM).
- A teaching kit for raising awareness on species of marine mammals at risk was distributed in schools – ROMM and Corporation PARC Bas-Saint-Laurent.
- Information panels on good marine wildlife observation practices were put up in the marinas around upper Gaspésie – ROMM
- An excellent reference and information website (http://www.whales-online.net/indexe.html) dedicated to education on the conservation of St. Lawrence whales and of their natural habitat. Weekly publication between June and October of bulletin called Portraits of whales containing updates on projects under way and on actions undertaken to protect the whales – Group for research and education on marine mammals (GREMM).
- An awareness raising initiative on the blue whales – Forillon National Park.
- Awareness campaign of hunters and fishers to obtain their observation data on marine mammals and training of disentanglement techniques – Quebec-Labrador Foundation.
188.8.131.52 Emergency response for marine mammals in difficulty
Since 2004, the GREMM in collaboration with various partners, such as DFO and Parks Canada, implemented the Quebec Marine Mammal Emergency Response Network. This network’s goal is to increase response capabilities when animals become entangled with fishing gear and to reduce mortalities of cetaceans caused by anthropogenic activities in the Estuary and Gulf of St. Lawrence. With DFO support, a similar program was established in Newfoundland and Labrador a few decades ago to allow fishers, partners and the public to report any case of marine mammal entanglement, injury or death, and for dispatching a team to help marine mammals in difficulty. Other research groups such as the Grand Manan Whale & Seabird Research Station from New Brunswick and the Marine Animal Response Society from Nova Scotia work for the conservation of marine mammals in the Maritime provinces.
184.108.40.206 Guidelines for best practices for watching marine mammals in Quebec
GuidelinesFootnote 5 for best practices for watching marine mammals in Quebec, which follow the code of ethics for the observation at sea of marine mammals, were developed by DFO. The objective of these guidelines is to minimize the risks of disturbance when encountering marine mammals. Although these best practices were developed first for the general public, they are also adapted to commercial activities. It should be noted that they have no force of law and do not override any laws and regulations in place.
220.127.116.11 Statement of Canadian practice with respect to the mitigation of seismic sound in the marine environment
DFO has developed a statement of Canadian practice with respect to the mitigation of seismic noise in the marine environment in collaboration with various partners, in order to formalize and standardize mitigation measures in Canada for conducting seismic surveys in marine environments. This statement represents a set of basic standards that can be applied by existing regulatory agencies to reduce the possible effects of seismic surveys on marine wildlife.
A number of research projects on the Northwest Atlantic blue whale population are carried out in Canada, many in the Estuary and the Gulf of St. Lawrence. Here is a non-comprehensive list of some of these programs.
- The Mingan Island Cetacean Study (MICS) focuses its efforts on the blue whale: photo-identification, collecting biopsies to determine gender and concentrations of contaminants, studying movements and distribution via observations in the field and the use of a mobile acoustic recording system by way of VHF beacons. In 2007 and 2008, MICS with the collaboration of DFO led a study of temporal variations relating spatial distribution and abundance of blue whales in the maritime Estuary and northern Gulf of St. Lawrence to food availability. This project attempted to verify whether blue whale is affected by competing smaller pelagic fish, which have been growing in numbers with the declining number of predators like Atlantic cod and redfish. The MICS, along with the ROMM, also carries out since 2007, a photo-identification project of all large rorquals around the Gaspe Peninsula.
- The GREMM has been studying whale-watching activities since 1994 for the SSLMP by placing observers on board cruise ships (Michaud, et al., 2007). The objectives of this study are: 1) to characterize the activities; 2) to assess marine mammal distribution; and 3) to measure the impacts of the management measures in place in this area. The study area covered by this project was increased in 2005 in order to include the future St. Lawrence Estuary MPA. Since 2006, the whale-watching activities from the Gaspé Peninsula are also part of a similar study carried out by ROMM (Pieddesaux, et al., 2007).
- The GREMM is also participating in the blue whale photo-identification project and the systematic numbering of large whales.
- The research group Mériscope at Portneuf-sur-mer works on the photo-identification of blue whales and on the bioacoustic programs. It records whale vocalizations and ambient noise produced by shipping traffic using mobile hydrophones. The researchers simultaneously observe the surface behaviour of blue whales in an attempt to link certain behaviours to the type of noise they produce. In addition, a project lead in cooperation with Cornell University deployed several continuous recording buoys between 2003 and 2006 in order to record vocalizations and ambient noise. In collaboration with the Mériscope team, the University of California at Los Angeles has been studying large whale feeding strategies. The whales are observed and filmed underwater in order to collect data on their behaviour, swimming speed, the volume of water ingested, the amount of food consumed and the energy spent to catch their prey.
- Since 2002, DFO has been conducting a project based on passive acoustic techniques. Autonomous hydrophones continuously record sound ranging from 5 to 1000 Hz such as whale vocalizations or ambient noise related to shipping traffic. The project goal is to study the distribution of whales in the area covered and attempt to assess their exposure to the existing noise in their environment. In 2003, a project to determine whether food abundance and whale-watching activities represent factors that could harm the recovery of blue whales was carried out with the analysis of fatty acids and the reproductive status in skin samples collected by biopsy. DFO is also coordinating the study of beached blue whales. Baleen, skin, fat and muscle samples are taken from beached cetaceans in order to study their diet and contaminant concentrations in their tissues.
- DFO, in collaboration with GREMM, has been conducting a project since 2002 to study blue whale movements and to document diving behaviour using instruments attached on individuals. The project’s objective is to increase knowledge pertaining to blue whale movements, feeding behaviour and habitat as well as to document the impact of whale-watching activities on their feeding behaviour. Knowledge acquired on characteristics of feeding areas in the Estuary will lead to the identification of other potential feeding areas in Canadian or international waters. This project will be completed within two years.
- DFO, in cooperation with the Institut des sciences de la mer de Rimouski (ISMER) and other collaborators, are investigating the biological and physical processes that are responsible for creating the large concentrations of zooplankton and fish at the head of the Laurentian Channel. Furthermore, since 1994, DFO has been studying zooplankton in the Estuary and western part of the Gulf. This project aims at better understanding abundance, production and distribution of mesozooplankton, such as copepods, and macrozooplankton, such as krill, by various plankton net sampling techniques. Another project objective is to study the impacts that changes to the cold intermediate layer have on zooplankton community structure and abundance.
- Since 2004, DFO has worked on the identification of areas of concentration of forage species (pelagic fish, macro and mesozooplancton) in the Gulf of St. Lawrence, which could constitute critical habitat for marine mammals, and in particular for baleen whales like the blue whale. This project uses hydroacoustic data combined with data from plankton nets to better characterize the vertical and horizontal distribution of prey throughout the Gulf of St. Lawrence and describe potential whale habitat. Furthermore, since 2008, DFO has put in place in the northwest of the Gulf of St. Lawrence an ecosystem research initiative (ERI). Studies are planned to identify and validate krill aggregation areas, determine and characterize blue whale feeding areas and study physical and biological processes that influence krill aggregation and abundance. In summer 2009, with the collaboration of GREMM and MICS, DFO has initiated a study to characterize food density leading to the blue whale presence.
- In 2007, a trans-Atlantic cetacean air survey in the North Atlantic was jointly conducted by the government of Canada (DFO), United States and Europe. This project was aimed at evaluating the distribution and abundance of the various cetacean species including the blue whales, and to map their summer range.
- In the Newfoundland and Labrador region, the DFO is currently mapping the geographical distribution of blue whales. Cases of cetacean sightings, beaching and ice entrapment have been reported since 1979 to a whale study group at Memorial University or to DFO. In 2007, two autonomous acoustic recorders were deployed offshore Newfoundland areas with the goal of detecting and recording blue whale vocalizations over the fall and winter.
- The blue whale and its habitat, the Northwest Atlantic, were recently the subject of scientific publications. Here are some examples:
- Contaminants found in tissues (Metcalfe, et al., 2004);
- Vocalizations (Berchok, et al., 2006; Mouy, 2007)
- Survival of adult blue whales (Ramp, et al., 2006);
- Growth rate (Branch, et al., 2004);
- Habitat selection (Doniol-Valcroze, et al., 2007; Abgrall, 2009).
- Acoustics (vocalisations and noise) (Simard, et al., 2004; Simard and Roy, 2008; Simard, et al., 2008 );
- Krill aggregations (Cotté and Simard, 2005; Sourisseau, et al., 2006; Sourisseau, et al., 2008; Simard, 2009);
- Literature review (Lesage, et al., 2007);
- Abundance and distribution (Lawson and Gosselin, 2009).
1.7 Knowledge gaps
A workshop on research priorities for the Northwest Atlantic blue whale population was held in 2002 (Lesage and Hammill, 2003). The priorities, ranked in order, are:
- increased knowledge on seasonal distribution, abundance, stock structure and seasonal migrations of blue whales;
- knowledge acquisition of population parameters such as reproductive rates, sex ratio and age structure;
- determining and defining feeding and reproductive grounds, as well as the effects that physical and biological processes have on determining distribution, behaviour and blue whale movements;
- improving knowledge on the current threats to blue whales (e.g., studying the various levels of contaminants and different sources of noise in their habitat and their impact on blue whales).
To fill these knowledge gaps, in particular those concerning reproduction and wintering areas, partnerships with several countries bordering the Atlantic will be essential.
- Footnote 3
Displacement of water masses due to the action of currents in the three-dimensional space and in time on various scales such as the semi-diurnal or semi-monthly tide, the season, the year, and multi-year cycles.
- Footnote 4
The Allee effect is a biological phenomenon that is based on a positive relationship existing between the density of a population and its growth rate, i.e., the birth rate decreases when population density decreases. If there is a density threshold under which the growth rate of a population becomes negative, the Allee effect can lead to the disappearance of this population (Allee, W. C., A. E. Emerson, O. Park, T. Park and K. P. Schmidt. 1949. Principles of animal ecology. W.B. Saunders. Philadelphia.)
- Footnote 5
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