Experts from a variety of backgrounds are working together to develop recovery strategies that comply with Canada’s Species at Risk Act. A recovery strategy is designed to prevent a species from becoming extinct. It lists the main threats to be addressed and sets out measures, goals and objectives to counter the decline of species and promote their recovery. You can learn more on the Government of Canada website.
The North Atlantic right whale was listed under the Species at Risk Act in 2005. An expert team headed by Fisheries and Oceans Canada developed this recovery strategy, in light of current knowledge and inspired from the right whale recovery plan (WWF/DFO, 2000). The recovery of the North Atlantic right whale will require international collaboration and cooperation.
What follows is a summary prepared by Whales On Line. The original Recovery Strategy outlaws this summary.
North Atlantic right whales are typical of long-lived species, maturing late and producing fewer but larger young. Long intergenerational time intervals and low annual reproductive rates make the species vulnerable to increased mortality. Furthermore, the low genetic diversity observed in this species undermines its reproductive success.
The North Atlantic right whale was decimated and pushed to the brink of extinction by commercial whaling, which began in North America with the arrival of the Basques in the 16th century and ended in the 1930s. Although this species no longer suffers from hunting pressure, it faces other threats such as:
Due to the lack of precise data on historic abundance, it is not possible to set a long-term target. However, in light of current knowledge of the status and trends of the population, it is possible to establish interim targets. The interim recovery objective is thus to achieve “an upward trend in abundance over three generations”, or a minimum period of approximately 60 years.
The seven recovery objectives to achieve this target are:
Mortality caused by ship strikes is considered the number one threat to the survival of North Atlantic right whales. Between 1991 and 2007, collisions were responsible for half of all mortalities in this species. Why do these collisions threaten right whales in particular? Firstly, they are very slow swimmers, so the speed at which they can change their course is limited. Further, the species frequents heavy maritime traffic regions such as the East Coasts of Canada and the United States. Measures have nonetheless been adopted in Canadian and US waters, for example the rerouting of shipping lanes in the Bay of Fundy, which has reduced the risk of collision by 90% in this area.
It is still unknown how right whales detect ships and other obstacles. There is strong evidence that their hearing range encompasses the frequencies produced by ships, unless high-frequency sounds such as those produced by powerful propellers lie outside of the whales’ audible frequency range. And the fact that the sounds emitted by most ships travel toward the stern and the sides – the area ahead of the bow certainly being the quietest – might explain why North Atlantic right whales do not always manage to avoid approaching vessels. It is also argued that, owing to its longevity, the right whale has not had the chance to adopt a new behaviour in the presence of ships, given that maritime traffic is a relatively new element of its habitat and that vessels have increased in speed over the past few decades. Lastly, other factors that interfere, mask or modify sounds travelling in the oceans might also play a role: sound refraction at the water’s surface, echoes off rocky seabeds and other sounds emitted in the water./p>
Between early June and late November, North Atlantic right whales frequent a number of sectors where fixed fishing gear is installed. Over 75% of North Atlantic right whales, young individuals especially, show injuries or scars caused by fishing gear. Buoy ropes, gillnet panels, floating longlines and ghost nets are most often involved, but right whales have also been reported to run afoul of longlines, cod traps and herring weirs. They usually get caught by the mouth, fins or tail. Some of these entanglements can result in the animal’s death. Whales can survive however with lines wrapped around their bodies, occasionally dragging nets, lines, buoys or traps for months or even years on end. The weakening caused by infected injuries as well as the loss of efficiency for swimming, diving, hunting and other behaviours are difficult to measure. Efforts to disentangle whales in Canada and the United States have allowed several trapped individuals to be freed, but such interventions are arduous, often unsuccessful and do not guarantee that the animal will survive.
The North Atlantic right whale feeds almost exclusively on copepods, a planktonic animal the size of a grain of rice. Since these animals are found at the base of the food chain, the right whale has less of a tendency to accumulate large concentrations of contaminants compared to whales that prey on fish, which are higher on the food chain. Conversely, the areas frequented by this species (Gulf of St. Lawrence and East Coasts of Canada and the United States) happen to be areas heavily exposed to pollution. Concentrations of organochlorine hydrocarbons in the Bay of Fundy are relatively high and heavy metal levels (lead, mercury, cadmium) are significant. Organochlorine composites, in particular toxaphene, DDT and PCBs, have been found in the fat of North Atlantic right whales, though not in concentrations considered to be of concern. The effects of chemical contamination, nutrient enrichment of water, sedimentation, and other forms of habitat degradation are difficult to document and assess. Nevertheless, recent studies on the levels of contaminants in the Bay of Fundy clearly indicate that there is cause for concern.
North Atlantic right whales depend on sounds to communicate with one another and noise of human origin can hinder this communication. Chronic exposure to noise can also cause temporary or permanent auditory problems. In Canada, in the habitat parcels most frequented by right whales, the most worrying sources of noise currently include commercial vessels and whale-watching boats, oil and gas prospecting, military testing, use of acoustic harassment devices installed on fishing gear to keep other marine mammals away, offshore construction, and sonar devices used for commercial, scientific and military purposes.
The presence of watercraft in right whale habitat, regardless of their size or function, raises a number of concerns. In addition to noise pollution and the risk of collisions, these boats can modify right whale behaviour, for example by disturbing social interactions or nursing, or even driving them away from nutrient-rich waters.
Inadequate food resources can lead to (i) a reduction in animals’ growth rates, prolonging the time required to reach sexual maturity, and/or (ii) a deficiency in the fat reserves needed by females for gestation or nursing, potentially resulting in increased calf mortality. At the present time, it is not known whether these changes are taking place. Researchers monitor different indicators such as the thickness of the blubber layer, the shape of the back and fluctuations in the number of young observed from year to year.
There is no easy solution to the issue of ship strikes. Even if captains have no intention of injuring or killing right whales, accidents nevertheless can and do occur. Proposed solutions include conducting in-depth analysis of the relationship between North Atlantic right whales and maritime traffic, reducing potential overlap, and building on collaboration and voluntary measures with captains and seamen to minimize collisions.
This objective implies both a reduction of the seriousness of incidental catches and measures to prevent them in the first place. It is obvious that fishermen have a front-line role to play in that they have a vested interesting in preventing whales from getting ensnared in their fishing nets, as such incidents damage their material and compromise the profitability of their operations.
Given the small size of the North Atlantic right whale population, risks related to human activities should be assessed with caution. Each individual’s heath can be important for the survival of the population. This strategy comprises two major elements. First, it consists of using all available information as well as common sense to act in a preventive manner to reduce potential disturbance to right whales. Second, it entails studying and better understanding potential sources of disturbance and developing means of reducing them further.
Knowledge of the health of the population and its range in Canadian waters is insufficient. The North Atlantic right whale population requires monitoring, as do the nature and magnitude of the key threats to the species.
Research on North Atlantic right whales did not truly begin in earnest until the early and mid-1980s. Despite the knowledge gained over the years on the biology, behaviour and status of the species, many aspects are still poorly understood. To advance our knowledge on right whales, certain monitoring and research projects must be pursued and others must be initiated. Researchers must coordinate their efforts and cooperate as much as possible in light of the magnitude and scope of information needed. Canadian organizations and researchers should work in close collaboration with their counterparts in the United States and, if necessary, Greenland, Iceland and other North Atlantic countries whose waters are frequented by right whales.
The protection and recovery of the North Atlantic right whale is a responsibility shared with regulatory organizations, user groups and communities within the species’ Canadian range. Foreign governments and international organizations are also interested in protecting the species or have responsibilities in this regard. Information exchange between the various stakeholders as well as their conservation efforts, which often take the form of recovery action plans, should be coordinated and formalized as needed.
Education and awareness efforts are important tools for promoting recovery efforts amongst stakeholders and the general public.
Experts from various backgrounds had previously teamed up to develop a recovery strategy in compliance with the Species at Risk Act, with the aim of better understanding threats to the beluga and proposing strategies to bring its population up to a threshold where its survival will no longer be threatened by natural or human-induced disturbances.
Download the complete strategy, published in 2012.
What follows is a summary of the strategy prepared by Whales On Line.
Historic whaling aside, the life strategy (life expectancy, late maturation and low annual rate of reproduction) and low genetic diversity of the beluga are limiting factors to the recovery of the St. Lawrence population. If a major die-off were to occur, the population’s return to its current level would be very long in comparison to other species having a shorter generation time, and the low genetic diversity could render the animals’ immune system less effective, making them more prone to pathogenic agents and chemicals. Natural factors such as emigration and predation can also lead to the loss of some individuals.
The recovery of the St. Lawrence beluga population is achievable. In the long term, the goal is to reach a population of 7,070 individuals, which corresponds to 70% of the original population. To reach this population size, the recovery objectives are as follow:
Pursuant to examination of beluga carcasses found on the shores of the St. Lawrence since 1982, significant concentrations of PCBs, DDT, Mirex, mercury and lead have been measured, as have signs of exposure to PAHs. These products are well known for their toxic effects on animal life and their impact on the reproductive and immune systems. Even after their use is banned or their emissions are curbed, many contaminants persist in the environment for decades. Nevertheless, reductions have been observed for some contaminants such as DDT and PCBs. Other compounds have entered the scene in a big way, including polybrominated diphenyl ethers (PBDE), which are flame-retardant compounds. PBDE concentrations in the tissues of belugas rose exponentially in the 1990s.
Given their feeding habitats and their position in the food chain, belugas accumulate large concentrations of contaminants. They feed on small and medium-sized fish as well as invertebrates living near the sediment. Belugas thus ingest contaminant “concentrates” and become a reservoir for these persistent chemicals. Despite recent reductions of toxic spills, the contaminant levels measured in belugas are not falling as rapidly as those in the environment. Adults continue to accumulate contaminants through their diets, while calves receive extremely high doses throughout gestation and nursing. This transfer of contaminants hampers the beluga decontamination process.
Furthermore, high rates of disease (infections and cancers) are observed in examined carcasses. Also, cancer rates observed in St. Lawrence belugas are much higher than in Arctic belugas, which are far less contaminated, or any other species of wild mammal. Moreover, the frequency of these diseases suggests that the St. Lawrence belugas’ immune systems may be being undermined by exposure to toxins. Lastly, carcass analysis leads to believe that contamination may affect the beluga’s reproductive system, which could diminish the production of offspring and thereby hinder this population’s recovery.
To survive and reproduce, any animal requires a little peace and quiet to perform its vital activities! If disturbance is recurrent and affects many individuals, the very survival of the population may be jeopardized. Significant maritime traffic in the zone frequented by St. Lawrence belugas is a potential source of disturbance. This traffic includes thousands of ships going up and down the St. Lawrence and Saguenay Rivers: ferries, fishing vessels, recreational boats of all types and whale-watching boats. The number of whale-watching excursions – including plane and helicopter tours – has surged since the early 1980s.
Boat traffic may interfere with the beluga’s daily activities such as hunting, movement and social behaviour, as well as the bonds between mothers and their calves. The presence of these vessels also increases the risk of collision. Belugas may also be affected by noise generated by commercial shipping, whale-watching, recreational boating and aerial tours. Recent studies have demonstrated that at certain locations and at certain times, maritime traffic noise is so intense that St. Lawrence belugas may sustain damage to their ears. This whale has a well developed sense of hearing and echolocation system, both of which are essential for finding food, navigating and communicating.
Belugas spend a great deal of time near the coasts. During the summer months, they are extremely faithful to certain sites in the St. Lawrence Estuary as well as in the Saguenay. These habits expose belugas to coastal human activities such as dams, construction of marinas and wharves, dredging as well as other projects associated with the growing tourism industry. To date, no case of site abandonment has ever been satisfactorily documented. Nevertheless, the absence of belugas in the Manicouagan Banks region might possibly be explained by changes in habitat following construction of hydroelectric power plants on the Manicouagan and Outardes Rivers in the 1960s. It is impossible to verify this hypothesis, however, since no data are available on the characteristics of this habitat prior to construction of the dams. On the other hand, some believe that the current absence of belugas here can be better explained by historic overhunting of the species in the region. A similar theory has been formulated to explain the absence of belugas in Tadoussac Bay, a site formerly patronized by belugas and which has been considerably altered in the wake of the substantial development of the tourism industry. Dredging work, normally performed to increase the depth and width of shipping lanes and which accompanies marina construction projects, can resuspend contaminants contained in the sediment. Every year, dredging is carried out near the Rivière-du-Loup wharf, near a site frequented by belugas, and throughout the St. Lawrence. The scale of these dredging operations will probably not decrease, judging by the size of the ships entering and leaving the St. Lawrence. Seismic exploration and oil and gas development generate high noise levels as well as a number of effects on the ecosystem as a whole. These activities are prohibited in the St. Lawrence Estuary, but permitted in the Gulf of St. Lawrence, which belugas are likely to frequent in the winter. Lastly, the introduction of exotic species by way of the ballast water from freighters represents an issue of global proportions that can alter the species composition of an ecosystem.
The repercussions that fishing might have on belugas are not well understood. The collapse of commercial fish stocks might shift efforts to other fish species, thereby putting greater pressure on the beluga’s prey. Likewise, the recent increase in the numbers of gray and harp seals will perhaps result in a reduction in the availability of prey. Fiercer competition for prey is also feared if climate change extends the season tolerable to seabirds and other animals poorly suited for the ice conditions of the St. Lawrence. However, without reliable data on the diets of belugas and other marine mammals, it is difficult to quantify the degree of competition for food resources.
In the Gulf of St. Lawrence, fishermen regularly report incidental catches involving harbour porpoises and, more rarely, other cetacean species. Bycatch in fishing gear is more uncommon in the beluga’s summer range. Since the beluga carcass recovery program was implemented in 1982, fewer than five cases of entanglement of belugas in fishing gear have been reported in the St. Lawrence Estuary. If belugas seldom get caught in fishing gear, it is probably attributable to the minor importance of the fishing industry in the beluga’s summer range, the limited use of gillnets as well as the species’ exceptional echolocation abilities. The risks of entanglement can be far more significant for animals that venture outside their usual sector, however, where fishing is more prevalent.
The St. Lawrence Estuary is used by a number of boat types that have the potential to enter into collisions with belugas; encounters can be fatal, cause injury and affect the survival of individuals. Belugas are probably more vulnerable to tour and recreational watercraft than to merchant vessels, the former having highly variable speeds and directions. The curiosity shown by belugas toward these watercraft further aggravates their vulnerability. Several belugas of the Estuary show injuries and scars in all likelihood attributable to a ship strike. Thanks to photo-identification, these marks are used today to differentiate belugas.
Few significant spills have occurred in the St. Lawrence to date. The Estuary being a semi-enclosed habitat, the consequences of a spill may be more detrimental than compared to the sea. Potential problems include the release of gases through evaporating surface oil which can damage certain fragile organs, as well as possible ingestion of a portion of the oil through contaminated prey. These problems are believed to be even more acute in winter, since oil tends to accumulate near the ice, where belugas spend a great deal of their time. This threat is thus considered to be potentially very dangerous for the St. Lawrence beluga population.
The main potential source of epidemics is viruses. In particular, the morbillivirus is believed to have caused the deaths of hundreds or even thousands of seals and cetaceans in the world. Although the St. Lawrence seals examined through 1999 had antibodies against the morbillivirus (a sign of exposure to the virus), no antibodies were found in the belugas studied. Two possible explanations exist for this absence: either belugas have never been exposed to the morbillivirus or they are resistant to it. In the first scenario, the population of St. Lawrence belugas would be highly vulnerable to an epidemic if it were to come into contact with these viruses. If they are not resistant, a morbillivirus epidemic in the St. Lawrence beluga population could be fatal given the small size of the population. Also, given the possibility that belugas’ immune systems are being affected by exposure to a number of contaminants, their vulnerability to such diseases might be exacerbated. Other pathogens such as the bacteria Brucella and the protozoan Toxoplasma gondii can also cause infectious diseases in belugas.
In the summer of 2008, a red tide extending 600 km2 struck the St. Lawrence Estuary and is believed to have caused the deaths of ten belugas. The proliferation of the toxic alga Alexandrium tamarense caused the death of several cetaceans, dozens of seals and thousands of birds, invertebrates and fish. Ingested through prey, the alga produces a neurotoxin that paralyzes the animals, resulting in asphyxiation. Eutrophication, climate change and the ensuing alteration of rainfall patterns may result in increased algal blooms, making this phenomenon a more significant threat to the St. Lawrence beluga.
Due to their threatened status, St. Lawrence belugas have been the subject of a number of scientific studies. Placement of recorders, photo-identification, performance of biopsies, and monitoring of herds on the water or from the coast; such research, though indispensable for acquiring knowledge of belugas, also has the potential to disturb them. Research work with the potential to disturb marine mammals requires a permit from Fisheries and Oceans Canada at all times and from Parks Canada when the study is conducted within the Saguenay-St. Lawrence Marine Park.
Hunting is considered to be the primary factor responsible for the decline of the St. Lawrence beluga, with thousands of individuals having been harvested at the end of the 19th century. Hunting is now prohibited and poaching is no longer considered to be a problem.
The recovery strategy work team recognizes that in order to facilitate the recovery of the beluga population, it is essential to further restrict quantities of harmful substances in the St. Lawrence and Great Lakes ecosystem from effluents and the atmosphere; to continue research efforts to better understand the impact of these contaminants as well as their evolution in the tissues of belugas and their prey; to take measures to minimize the recirculation of contaminants already present in the system (notably in sediment) and the introduction of new contaminants; and to pursue the clean-up of contaminated terrestrial and aquatic sites in the St. Lawrence and Great Lakes watershed.
LThe recovery strategy presents strategies that aim to reduce disturbance and favour a viable cohabitation between belugas and humans. To succeed in this challenge, a better understanding of the impacts that disturbance and noise pollution have is essential, as are adopting, reviewing and applying protection measures to sites heavily used by belugas. The importance of not disturbing belugas should be publicized and measures should be taken to ensure that belugas do not become targets for whale-watching cruises.
Spawning and nursery areas as well as the migratory routes for the beluga’s prey should be protected, research on beluga diets should be pursued, and new fisheries that might have an impact on belugas or their prey should be averted.
Measures to mitigate the effects of the multiple threats hindering the recovery of the St. Lawrence beluga population include developing and implementing adequate protection measures for coastal projects; maintaining the Quebec Marine Mammal Emergency Response Network; monitoring fishing gear incidents; maintaining and improving the carcass recovery program, with a particular focus on the causes of mortality; and elaborating emergency response plans for spills, algal blooms and epizootics.
It will be essential (i) to pursue research efforts to further knowledge of those zones heavily used by belugas (according to the seasons) as well as the threats to these habitats, and (ii) to implement protection measures using various legal tools (marine protected areas, zoning plan, etc.).
It is critical that the St. Lawrence beluga be monitored in order to detect any improvements or deteriorations in the status of the population. This implies conducting population censuses no less than every three years and studying beluga carcasses retrieved, which to date have been the main source of information on beluga biology (diseases, contaminant concentrations, age at time of death, etc.). The structure and size of the population must also be studied in order to detect trends, understand mortality patterns and identify recruitment problems. Data collected from live animals should help shed light on the relationships between contaminants and various health indicators.
Latest update: August 2019
After this species was classified as “endangered”, an expert team worked to develop a recovery strategy for the blue whale of the Northwest Atlantic. This program was published in November 2009. In this document, the team identifies the threats faced by this population and makes recommendations to foster its recovery. In the United States, experts published a recovery plan in 1998.
What follows is a summary prepared by Whales Online.
Some 200,000 blue whales once inhabited the world’s oceans. But the tremendous size of these animals spelled their demise; blue whales were prized by whalers who extracted from them enormous quantities of oil and meat.
In addition to hunting and natural mortality, nine threats to the species were identified. Threats were divided into three categories depending on the risk for the population. Even activities affecting a small number of individuals can have a crucial impact on the future of this small population.
Recovery of the Northwest Atlantic population of blue whales was deemed by the recovery team to be achievable. However, the blue whale’s range is vast and its recovery will therefore require efforts on an international scale. In order to meet the objective of a population of 1,000 mature individuals in Canadian waters, a number of measures are necessary, each of which is described in the recovery strategy. These measures are:
Blue whale hunting in the early 20th century greatly reduced the population of this titan in the North Atlantic. About 1,500 blue whales were hunted in Eastern Canadian waters between 1898 and 1951, including 80 to 100 by a whaling station established in Sept-Îles, Quebec, between 1911 and 1915. In total, 11,000 blue whales are believed to have been harvested in the North Atlantic between the end of the 19th century and 1960. Few blue whales were hunted in Eastern Canada after 1951; in fact, the International Whaling Commission (IWC) has prohibited the harvest of this species in the North Atlantic since 1955.
Blue whales occasionally get trapped in ice in winter and die. Between 1869 and 1992, no fewer than 41 blue whales found themselves imprisoned by ice along the west coast of Newfoundland. In 77% of the cases, the incidents were fatal for the animals. The St. Lawrence blue whale photo-identification program shows that some blue whales of this population bear scars on their backs evidently caused by ice. Some individuals linger in the Gulf of St. Lawrence in winter to take advantage of the shoals of plankton that accumulate at the edge of the ice. Shifting with the winds and the currents, these ice sheets can form deadly traps.
The only known predator of the blue whale is the killer whale, a cetacean that sometimes preys on other marine mammals. Few St. Lawrence blue whales bear the “rake” marks usually left by a killer whale attack and no such attack has ever been reported in this region. Predation is therefore probably not a very significant cause of mortality for blue whales in the Northwest Atlantic.
Seeing their environment, finding prey, communicating with other members of their species… blue whales use very low-frequency sounds for a number of their essential activities. However, increasing ambient noise compromises the transmission of these acoustic signals. In the pre-industrial era oceans, the call of a blue whale could be heard over distances of 100 to 1000 nautical miles, whereas today, communication might be reduced to just 10 to 100 nautical miles. The chances of communicating with their peers and the ability to perceive their environment are thus reduced; essential activities like feeding, social interactions, caring for young, etc. can be interrupted; and critical habitats can be avoided in the short or long term.
The St. Lawrence Estuary and the Gulf of St. Lawrence are highly important routes for shipping and, as such, represent a noisy aquatic environment. The sounds emitted by blue whales in the sector seem to lie in a broader range of frequencies than that observed in other regions of the Northwest Atlantic. Researchers have hypothesized that these differences may be caused by the high ambient noise levels in the St. Lawrence, which might be forcing blue whales to modify the frequency of their signals in order to increase their chances of detection by other blue whales. Further, seismic exploration and oil and gas extraction on the Canadian East Coast, notably east of Newfoundland and on the Scotian Shelf, are activities that can impact cetacean behaviour (e.g. modification of migratory routes, swimming speed, dive profiles, feeding).
The increased presence of krill-consuming pelagic fish species (capelin, herring) might limit the availability of this food resource for blue whales. In recent decades, the distribution and abundance of these fish have considerably changed in the St. Lawrence Estuary and the Gulf of St. Lawrence following declines of their predators, the Atlantic cod and redfish, both of which have been overfished. Commercial krill fishing in the Gulf of St. Lawrence for the nutraceutical industry might also reduce the availability of this food resource for the blue whale. This fishery has been prohibited in Eastern Canada since 1998, however. Lastly, climate change might trigger modifications in the ocean climate, which could also have an influence on krill abundance.
Considerable concentrations of PCBs and pesticides have been measured in blue whales in the St. Lawrence. Pesticide and PCB levels were analyzed from fat samples taken from 38 males and 27 females in the Gulf between 1992 and 1999. These analyses brought to light significant differences between males and females, the latter presenting lower concentrations due to mothers transferring contaminants to their calves during gestation and nursing. Concentrations of persistent contaminants measured in the fat of blue whales were approximately half of those measured in belugas in the St. Lawrence Estuary, which might be attributable to the fact that blue whales frequent the region more intermittently and feed at a lower level of the food chain (preying on krill) than do toothed whales. Contaminant concentrations in young are often similar to those of their mothers, which raises concern about the toxicological impacts of exposure to contaminants in the first stages of the whales’ lives, periods during which the animals are most vulnerable. Is there a correlation between the low number of calves observed in the St. Lawrence and contamination? Investigation continues.
In 2003, nearly 12,000 ships passed through the St. Lawrence Estuary between Sept-Îles and Les Escoumins. The routes taken by these vessels run through areas heavily used by blue whales. At least 5% of the blue whales frequenting the St. Lawrence bear deep wounds and/or scars attributable to a contact with the propeller or hull of a ship. Despite limited evidence of mortalities caused by ship strikes, the relatively high number of blue whales showing scars potentially related to such collisions indicates that this threat is real and possibly significant, all the more so in that given the low number of blue whales in the Northwest Atlantic, the loss of a few individuals per year may represent a significant obstacle to this population’s recovery.
An important marine mammal-watching industry exists in the St. Lawrence Estuary and the Gulf of St. Lawrence. A study conducted in the Estuary on the fin whale, a relative of the blue whale, revealed that if a large number of boats are present, they will shorten their dive times and possibly the time dedicated to hunting prey. Doing so may reduce the quantity of food that the whales capture, compromise their ability to build reserves, and possibly lower their chances of survival or reproductive success. A project launched in 2002 attempts to assess blue whale reactions to the presence of boats.
In addition to sometimes masking the sounds produced by blue whales and affecting their behaviour, loud or prolonged noise may also trigger temporary or permanent changes in hearing thresholds, production of stress hormones, and physical damage such as internal injuries that can lead to death. The highest noise levels are usually registered during seismic exploration or the use of low-frequency active sonar systems.
Throughout the world, hundreds of thousands of cetaceans get caught and die every year in fishing gear. In the St. Lawrence, at least three blue whales were lost to gillnets since 1979 and nearly 10% of blue whales show scars attributable to fishing gear. Further, no fewer than five cases of entangled but free-swimming animals have been reported since 1990.
In the North Atlantic, occurrences of mass marine mammal mortality caused by disease seem to have been increasing since the latter half of the 20th century, and can have serious consequences on a population with low numbers like that of the Northwest Atlantic blue whale. This increase in disease is believed to be attributable, amongst other things, to a fluctuating climate and to anthropogenic habitat degradation and pollution. However, this threat is still poorly documented.
Cetacean poisoning from toxic algae seems to be increasingly frequent in all the world’s oceans. In August 2008, nearly a dozen belugas and harbour porpoises died in the St. Lawrence Estuary following a red tide episode caused by the alga Alexandrium tamarense. The magnitude that this natural phenomenon reached is probably due to the particularly abundant precipitations registered in the summer of 2008 that led to higher temperatures and lower salinity of the surface waters. Therefore, global warming and the ensuing alteration of rainfall patterns may result in an increase in algal blooms, making this phenomenon a more significant threat to the blue whale.
The impacts of a toxic spill on blue whales are highly variable and difficult to evaluate. Although most cetaceans avoid oil slicks on the water surface, they may accidentally enter into contact with them. Even if the skin of cetaceans is an effective barrier, toxic vapours may damage sensitive tissues such as the membranes of the eyes, mouth and lungs. Moreover, marine mammals can ingest spilled products, either directly or through contaminated prey, which may trigger any of various toxic and physiological effects.
Measures recommended and deemed urgent for Objective 1
Measures recommended and deemed urgent for Objective 2
Measures recommended and deemed urgent for Objective 3
Since this population was designated “endangered”, an expert team headed by Fisheries and Oceans has been working to develop a recovery strategy. Published in May 2010, this program presents the potentially limiting factors for the population’s recovery, threats to the population and recommendations to aid its recovery.
What follows is a summary prepared by Whales Online.
The small size of the population (163 individuals), its low genetic diversity, its isolation from other populations, its dependence on the Gully (a submarine canyon located at the edge of the Scotian Shelf, 200 km from the coast) and its low reproduction rate are all factors likely to hinder the recovery of this population.
The northern bottlenose whale was once abundant in the waters of the North Atlantic. As was the case for many species, commercial whaling decimated several populations of this species. Although hunting of the northern bottlenose whale ended in the early 1970s, this small resident population of the Scotian Shelf faces other threats.
Given the possibility that this population might remain relatively small due to natural limiting factors, this recovery strategy aims to mitigate threats in order to maintain the population at current levels and prevent any further decline. Four objectives were established to achieve this goal:
Whaling in the 20th century considerably reduced the size of the North Atlantic populations of the northern bottlenose whale, including that of the Scotian Shelf. However, as the historic size of this population is not known, it is impossible to determine whether or not it has recovered from past harvests. The International Whaling Commission (IWC) designated the northern bottlenose whales as “protected” in 1977 and set a zero catch quota.
Oil and gas exploration is expanding on the Scotian Shelf. A number of commercially exploitable sources have been discovered near the Gully; the nearest oil platform is located in shallow waters approximately 35 km away. Seismic surveys are being conducted to detect potential oil and gas sources; these surveys employ powerful detonations at regular intervals. Drilling and other extraction-related operations also contribute to increasing ambient noise levels. Spills, waste material and increased shipping traffic are other threats faced by the bottlenose whale. Currently, the Gully is not being explored or developed, as it has benefited from a high level of protection since it was designated a Marine Protected Area (MPA) in 2004. However, other proximate submarine canyons that are occasionally used by the northern bottlenose whale do not enjoy any protection.
Several photo-ID’d bottlenose whales bear the marks of encounters with fishing gear, and other individuals have been observed entangled in nets. Shallow zones near the Gully have been heavily dredged in the past for exploiting bottom-dwelling fish such as halibut. This type of fishing has greatly diminished in recent years due to the collapse of groundfish stocks, but might expand in the future, depending on the status of targeted species as well as other factors. Also, tuna (longline) and swordfish (harpoon or longline) fishing continues in the Gully sector, except in deep zones where all fishing is prohibited and which represent a sizable part of the habitat of the Scotian Shelf population of the northern bottlenose whale.
It is not yet clear how noise pollution affects bottlenose whales, but effects may include habituation, disturbance to behaviour, temporary or permanent auditory impairment, acoustic masking and even injury, stranding and death. Possible sources of noise pollution include oil and gas prospecting and extraction activities, including the use of sonar blamed for fatal bottlenose whale strandings elsewhere in the world, scientific research work that uses sound, maritime and low altitude air traffic, and construction. Further, due to their diving habits in very deep water, bottlenose whales might be more vulnerable to underwater noise; sound concentrates and travels farther in deeper water layers.
Floating debris represents an important source of pollution in the Gully. Such debris – including plastic bags, fishing nets, packaging bands, etc. – might represent a threat for the bottlenose whales that reside there.
Contamination is another type of pollution that might affect northern bottlenose whales. Oil drilling development might increase contamination of the Gully as a result of drill cuttings around oil rigs, extracted water, accidental hydrocarbon spills and a rise in shipping traffic. However, nothing clearly indicates that any harmful pollution in the whales’ habitat has occurred in recent years.
Recent studies suggest that the bottlenose whales of the Scotian Shelf present higher DDT levels than in the past (though the reason for this is undetermined), and that these levels are higher than those found in the Davis Strait population. However, overall, contaminant levels in the Scotian Shelf population are comparable to those found in other cetaceans of the high sea and are not believed to be significant enough to trigger health issues.
Access to quality food resources seems to be a determining element in the northern bottlenose whale’s distribution on the Scotian Shelf. The Gully and adjacent canyons are believed to harbour an impressive quantity of prey that cause northern bottlenose whales to congregate at this location. However, any disturbance to food sources within this habitat might lead them to abandon the area, which could have a phenomenal impact on the population, as few other places seem to offer comparable feeding potential. Moreover, any future commercial fishing of squid, the bottlenose whale’s main prey, would represent a new threat for these whales.
A number of whales die every year from collisions with ships off the coast of Nova Scotia, but no such incident involving northern bottlenose whales has ever been reported. However, as these animals live far offshore, it is unlikely that the remains of any bottlenose whales fatally wounded in collisions with ships would be discovered; this is therefore a potential threat that cannot be dismissed. Whales with scars that may have been caused by such collisions have been observed.
There are considerable gaps in the knowledge of northern bottlenose whales, whether with respect to the species’ habitat, reproduction, feeding, exchanges with other populations, or mortalities. In light of these knowledge gaps, it is imperative that studies on the species’ prey, reproduction and movements be undertaken; that photo-identification of northern bottlenose whales in the Gully and the Haldimand and Shortland Canyons be pursued; that acoustic monitoring methods be developed; and that a database of beached individuals (including the results of subsequent autopsies) be compiled.
By pursuing photo-identification so as to be able to determine population trends with an accuracy of +/– 5%; by systematically monitoring any visible presence of northern bottlenose whales in their known habitat; and by studying their distribution in zones adjacent to this habitat.
Through education of concerned stakeholder groups and the general public. Identify opportunities for stewardship and convey them to relevant audiences.
The Gully (or Sable Island Gully) represents a unique and complex habitat in the Northwest Atlantic. This submarine canyon is home to a large variety of species, from corals to whales, including the endangered population of northern bottlenose whales. To protect this exceptional habitat, Fisheries and Oceans Canada (DFO) designated it a Marine Protected Area (MPA) in May 2004. The creation of an MPA at this location aims to protect this unique ecosystem while permitting a sustainable use of its resources. This designation takes place six years after having developed the Sable Gully Conservation Strategy in 1997.
In 1994 the DFO declared the Gully a whale sanctuary in an effort to diminish ship strikes and potential noise disturbance for the whales of this sector. The DFO thereby recommends that navigation in the Gully be avoided. It this is not possible, the DFO recommends slowing down, designating an observer and manoeuvring the vessel so as to avoid all marine mammal activities. Lastly, the DFO requests that all observations or collisions be reported through the local communication or traffic service. A number of companies that navigate in this region have agreed to avoid the Gully.
Lastly, other decisions have been taken in the private sector to boost protection of the Gully. For instance, in 1990 the oil company Lasmo declared a sector encompassing the Gully a “tanker exclusion zone” so that the maritime traffic associated with its operations would not interfere with whales. At the time, Lasmo was beginning to extract oil 110 km west of the Gully.
Several research projects are being undertaken to determine whether the critical habitat should extend to the Shortland and Haldimand Canyons, based on northern bottlenose whale movement.
