In the waters of the St. Lawrence float innumerable microscopic algae invisible to the naked eye. Coming in all shapes and sizes, diatoms and dinoflagellates are essential to the food chain of the ocean as well as the Estuary and the Gulf of St. Lawrence. However, some of them contain a biological toxin that severely affects the nervous system of organisms that consume them.
Sometimes they take advantage of the smörgåsbord and multiply quickly and uncontrollably. This is called a bloom, which leads to a proliferation of these algae. These algal beds then form red tides, which can have dire consequences for wildlife.
Massacre in the St. Lawrence
In 2008, the St. Lawrence Estuary experienced an exceptional red tide. Thousands of fish, 591 birds, 85 seals, 10 belugas and 1 fin whale succumb to the paralyzing neurotoxin of the alga Alexandrium tamarense.
This alga, a single-cell dinoflagellate, is naturally present in the St. Lawrence ecosystem. However, in 2008, conditions are ripe for proliferation of A. tamarense: abundant rainfall, increased water temperature, pronounced stratification and eutrophication. Capitalizing on this timing, the algae begin to proliferate and reach densities so high that they make the water red!
Contaminating the food chain
The link between microscopic algae and the death of a whale is not obvious. If whales do not eat seaweed, why do they suffer the effects of toxic algal blooms? Toxins from red tides do not affect whales directly. However, they are found in their prey or in their prey’s prey. As whales are carnivores sitting at the top of the food chain, they accumulate toxins by ingesting a large amount of contaminated prey. This phenomenon is known as bioaccumulation.
How can they be prevented?
Red tides occur naturally. However, it has been observed that they are increasingly frequent. Indeed, human activities can increase the frequency, intensity and geographic extent of toxic algal blooms such as A. tamarense.
Currently, there is not much that can be done when an outbreak occurs. However, actions can be taken to prevent them. By limiting the use of fertilizers that end up in the St. Lawrence with runoff, we prevent additional nitrogen and phosphorus from entering the water, nutrients that are essential for phytoplankton growth.
Last update: July 2019
How can microscopic algae kill a 45-tonne whale? (Whales Online, 2015)
What was learned from the exceptional red tide of August 2008? (Whales Online, 2017)
10 Years Later: The Red Tide Phenomenon (in French, Whales Online, 2018)
Climate change represents a real and measured phenomenon. Average air and water temperatures have changed in many regions, important ocean currents have been altered, the Arctic and Antarctic are melting at alarming rates and the acidification of waters is sometimes making them unsuitable for life. Although the consequences of climate change on the marine environment are undeniable, the repercussions on whales are still unknown. However, scientists expect that climate change will impact the giants indirectly: by modifying their habitat and affecting their food resources. A few of the ways climate change is affecting whales are described below.
Physical and chemical properties of the water
The ocean captures about a third of atmospheric CO2, one of the main greenhouse gases that contribute to global warming. With an overabundance of CO2 to absorb, the water becomes acidic and certain chemical reactions become unbalanced. These changes can be harmful to organisms that have to synthesize calcium carbonate shells or skeletons such as phytoplankton and zooplankton, mollusks, crustaceans and gastropods. Ocean acidification has the potential to impact the entire food chain. Many whales depend on these organisms for their food, including blue whales, which feed exclusively on krill. Species in the Gulf of St. Lawrence are particularly vulnerable, as these waters are acidifying faster than average.
Temperature and salinity
Climate change is causing a shift in the temperature and salinity of the water, which can have direct physiological effects. For example, this can lead to thermoregulatory problems in species that are more geographically restricted, mainly toothed whales.
Modifications in water temperature can also affect the growth and survival of fish, and thus the availability of food for whales. Changes in salinity can alter the distribution of prey, and in turn competition between species. Water temperature can also influence the distribution and abundance of pathogens (e.g. viruses and bacteria) and predators. Additionally, higher water temperatures might favour toxic algal blooms, which contaminate the prey of marine mammals and can lead to mortality.
Lack of oxygen
Water with a low concentration of oxygen is called hypoxic, a phenomenon that is partially related to climate change. Indeed, higher water temperatures diminish the solubility of oxygen. Hypoxia does not affect whales directly, as they breathe on the surface. Their prey, on the other hand, need oxygenated water to breathe through their gills. In the St. Lawrence, researchers have observed an area of hypoxia in the deep waters between Tadoussac and Sainte-Anne-des-Monts, with the lowest concentrations off Rimouski and Matane. Oxygen levels in the deep waters of the St. Lawrence have been declining for at least a decade.
There are several types of marine currents: some are local while others traverse entire oceans. Currents will most certainly be affected by climate change as they are defined by water temperature, salinity and wind.
Marine currents are at the basis of the entire food network: they allow mixing of water layers and thus a recirculation of nutrients conducive to the growth of microscopic algae. They can also help create areas rich in animal plankton and fish such as upwellings and polynyas (ice-free polar areas), habitats that are often critical for cetaceans. A change in the trajectory of the current can therefore disrupt an entire ecosystem.
Upwellings are particularly important at the head of the Laurentian Channel near Tadoussac, since they carry krill, an important prey for the whales of the St. Lawrence Estuary. This oceanographic phenomenon is enabled in particular by an exchange between the waters of the Great Lakes and those of the Gulf: the fresher waters of the Great Lakes float on top of the more saline waters of the Estuary and are then evacuated by the Gaspé Current. This constant “loss” of water helps sustain an upstream current from the Gulf to the Estuary for deeper waters, which then resurface at the head of the Laurentian Channel. However, a reduction in freshwater inflow caused by increased evaporation and reduced precipitation on account of climate change would diminish this pumping force.
Ice represents a productive feeding ground: algal blooms under the ice attract zooplankton, which in turn attract fish. Less ice cover would imply a decrease in winter food resources for zooplankton such as krill, the main food resource for certain species, including the blue whale. Belugas and narwhals benefit from the higher fish concentrations to feed at the edge of the ice. In winter, ice also allows belugas to seek shelter from storms.
In the Arctic, melting pack ice is opening up new shipping routes. Similarly, reduced winter cover in the St. Lawrence could lead to increased maritime traffic. Melting ice could therefore increase the risk of collisions as well as noise pollution.
Rising sea levels
In addition to melting ice, the sea level is also rising due to the fact that water expands as it warms. The average annual increase is estimated at 3.2 mm, but some areas are much more affected than others. As a result, certain marine mammals that give birth and care for their young in shallow water may experience habitat loss.
Occasionally positive changes… for now
Declining ice cover might allow some cetacean populations to remain in their feeding areas for a longer portion of the year and even explore new feeding grounds that they did not previously have access to.
However, the positive effects for this population are probably temporary. Several other factors are also at play, including acidification and ocean temperatures. With a reduction in ice cover and changes in migration periods, whales may soon have to compete for the same territory and the same food resources during certain periods of the year. And killer whales take advantage of these ice-free paths to hunt whales.
Adapting to the pace of change
Marine protected areas are often established by targeting critical feeding areas for species at risk. However, these habitats could change rapidly. Should marine protected areas be a mobile, adaptable concept that takes into account the potential effects of climate change?
The International Whaling Commission is facing strong pressure by some of its member countries to lift the moratorium on commercial harvesting. This request is based on arguments related to the size of several whale populations. However, in light of the drastic changes facing our ecosystems, is it still wise to advocate resuming large-scale commercial whaling?
By combining scientific research with flexible management and protection tools, perhaps we can overcome a monumental challenge: predicting the unpredictable and making decisions today that will contribute to the whales’ recovery tomorrow.
Whaling leaves few people indifferent. From environmentalists who go as far as to risk their lives to demonstrate their opposition, to aboriginal peoples who see a means of reviving their heritage, to nations where consuming whale meat is completely natural, there is a whole host of cultural, social, economic and political arguments. What is the debate really all about?
Commercial whaling was probably first practised in the 9th century in the North Sea and in the 12th century in the Bay of Biscay. As the right whale populations in Europe were in decline, whalers headed to North America in the 16th century. Over time, a genuine industry took shape along the North American coasts, with thousands of right whales, rorquals, sperm whales, gray whales and several other species being harvested every year. Whaling intensity increased with the advent of explosive harpoons and powerful boats. Between 1904 and 1985, over 2 million whales were harvested in Antarctic waters alone. This hunting drove several species to the brink of extinction. In 1946, in the wake of obvious overhunting of whale populations, the International Whaling Commission (IWC) was created. Its mandate is to oversee the conservation of populations in order to ensure the sustainable development of the whaling industry. In 1982, a moratorium on whaling was declared by IWC member countries. Although this moratorium was initially scheduled to last from 1986 to 1990, it has yet to be lifted. But according to the 1946 convention, any member can oppose a resolution like the one that led to the moratorium and thus issue commercial quotas; this is what Norway did in 1982. Before resuming commercial whaling per se, the country undertook a scientific whaling program. Then, in 1993, commercial whaling was resumed, with annual targets of between 500 and 800 minke whales in Norwegian territorial waters. The meat is sold on the local market.
Norway has been attempting since 2002 to resume exports of whale products (particularly blubber, which is not consumed by Norwegians) despite the Convention on International Trade of Endangered Species (CITES). But their products are rejected by Japan (the chief potential importer) due to their levels of contaminants, particularly PCBs. In February 2012, Norway reinstated the whale harvest quotas, authorizing its whalers to harpoon nearly 1000 minke whales, i.e. about 45% more than the quota awarded in 2009, despite the their persistent difficulties in reaching the allowable number of takes.
Iceland ,which had withdrawn from the IWC in 1991, rejoined the Commission in 2002 and announced that it would resume commercial harvesting of minke and fin whales in 2006. The capture of some 100 fin whales, a threatened species whose meat is exported mainly to Japan, sparked a wave of protests in nearly a dozen countries. In 2011-2012, no fin whales were harvested due to the collapse of its sole market, Japan, which had been hit by a tsunami and a nuclear disaster. According to the Icelandic government, the whaling practised by the country is entirely legal, compliant with international obligations, and based on rigorous scientific data.
While the harvesting of great cetaceans has fallen over the past twenty years, the consumption of small cetaceans has been on the rise since the 1970s. Most of these species are not as rigorously monitored as great cetaceans and don’t benefit from as much attention or information for their conservation. In some countries, these takes, whether from dedicated hunting or bycatch, compensate for a lack of food or protein resources. They even generate economic benefits in certain countries from market sales. The rising number of harvests may become extremely worrying for species that are already at risk. The IWC has emphasized the importance of protecting such species and has even created a fund for this purpose.
Some member countries of the IWC have long abandoned whaling and fiercely oppose any resumption of commercial whaling. The main arguments of these countries are practical in nature: several whale populations, rendered vulnerable by hunting in the past, are simply unable to sustain commercial harvesting. In their view, it would be impossible to regulate and monitor these harvests and the ensuing trade. This position is shared by a number of environmental groups. Some object to whaling on moral grounds as well: whales are “special” creatures and hunting is cruel. Equally problematic are the various threats faced by whales such as pollution, climate change and fisheries. Can we adequately predict their effects on whale populations and manage harvests accordingly?
Pro-whaling countries consider that the IWC, in accepting countries that oppose whaling on moral or ethical grounds, is straying from its original mandate, i.e. the sound management of whaling practices. They consider that whales can be hunted in the same way as any other wild animal. They have strong cultural, social, economic and political attachments to whaling. The whale harvesting (commercial and subsistence) practised today mainly provides food for human consumption. According to pro-whaling countries and groups, harvesting is well regulated and is carried out using methods that minimize animal suffering.
At the IWC’s 2010 Annual Meeting, negotiations were held to possibly lift the moratorium and limit commercial whaling quotas. On the third day of the meeting, negotiations were suspended. The countries at odds mutually accuse one another for the deadlock in discussions. The years to come will be crucial for the future of whaling.
Intensive whaling has provided us with invaluable information on cetaceans. But it has also driven several species to the brink of extinction. Japan continues to harvest whales in the name of science. Indeed, the 1946 convention of the International Whaling Commission (IWC) stipulates that each member country may issue scientific whaling permits. Can this approach still be justified today? Does scientific whaling really serve science or is it just a smokescreen for commercial interests?
At the present time, Japan is the only country to have undertaken scientific whaling programs as soon as the moratorium came into force in 1986. The oldest of such programs is JARPA, conducted in Antarctica, where more than 400 minke whales were harvested annually between 1987 and 2004. Amongst other objectives, this program aimed to estimate certain biological parameters of this species (for example its natural mortality rate) and to study its role in the Antarctic ecosystem. The successor to this program, JARPA II, undertaken in 2005, calls for the harvest of nearly 900 minke whales, 50 fin whales and 50 humpback whales. Under JARPN, a second program launched in 1994, around 100 or so minke whales are taken annually in the North Pacific. This program aims to better understand the feeding ecology of minke whales. In 2000, the Japanese added the Bryde’s whale (50) and the sperm whale (10) to the program, and in 2002, the sei whale (100). Proponents of these harvests maintain that they have enhanced knowledge and provided useful information for managing stocks of minke whales and other targeted species. The products of harvested whales are sold on the local market, as stipulated in the International Convention for the Regulation of Whaling. However, these products don’t market well and often the meat is sold at low prices or distributed at no cost in establishments such as school cafeterias and retirement homes. Moreover, recent genetic analysis seems to have proven the existence of an illegal whale meat trade between Japan and certain countries that are parties to CITES without restriction, including the United States and South Korea. Some researchers propose an independent, transparent and reliable monitoring system to enforce international treaties pertaining to the wildlife trade.
In July 2012, after a 25-year hiatus, South Korea announced its intention to resume whaling for scientific purposes. Strongly condemned by anti-whaling countries and the public from around the world, the South Korean government ultimately scrapped plans for this hunt and opted instead to study cetaceans without killing them. The scientific whaling programs pursued by Japan are also strongly criticized. For several years now, during their Annual Meeting, IWC members adopt (often by a narrow majority) a resolution to encourage Japan to abandon its whaling activities. In 2002, Phil Clapham and his colleagues, all members of the International Whaling Commission’s (IWC) Scientific Committee, published an article in the journal BioScience. They emphasize that Japan’s program does not include hypotheses to be tested or other performance indicators, that the data collected are not necessary for managing whale populations and that such data do not undergo an independent review process, that more useful information could be gathered without killing the animals, and that the program sacrifices more whales than what the IWC would advocate for quotas in the absence of a moratorium. They also argue that scientific hunting is merely a pretext for maintaining a demand for whale products and encouraging the resumption of commercial whaling.
If scientific whaling continues, should the IWC require that this activity be subject to rigorous scientific evaluation criteria? And, if indeed it is only a cover-up for commercial activities, should the IWC lift the moratorium and “officially” regulate these harvests? A resolution to this thorny debate should be reached in the course of the IWC’s forthcoming meetings.
In addition to commercial and scientific whaling, some countries practise what is known as “subsistence” whaling. According to the International Whaling Commission (IWC), subsistence hunting is practised by aboriginal peoples who share strong community, family, social and cultural ties to a traditional dependency on the harvesting of whales and the products derived therefrom. Also, the purpose of the hunt must be for consumption by aboriginal peoples only, and shall aim to satisfy the latter’s nutritional and cultural needs.
This definition is not universally accepted, however. Many question the subjective definition of “aboriginal”, amongst other things. If the definition is “inhabiting or existing in a land from the earliest times…” (Oxford), then wouldn’t the Norwegians, Icelanders and Faroese be considered aboriginal and couldn’t they also practise subsistence whaling? The definition of the term “subsistence” is also questioned. If the term means “to meet the essential needs” of an indigenous community, how is it that the products of subsistence whaling in Greenland (approved by the IWC) can be found on the local market? What is the difference between this hunt and the one practised by Norway, for example? And doesn’t trade allow to satisfy essential needs? Also, does preventing aboriginals from selling the products of their resources not limit their avenues for developing their economies? These are just a few of the arguments put forward by those who question the concept of subsistence whaling.
Whatever the case, a number of countries practise subsistence hunting with permits and quotas granted by the IWC. Greenland (Denmark) has an annual quota of 9 fin whales, 2 bowhead whales, 10 humpback whales and approximately 200 minke whales, not counting takes of smaller cetaceans: narwhals, belugas, pilot whales and harbour porpoises. Native peoples of Chukotka (Russian Federation) share with the Eskimos of Alaska (United States) a quota of 336 bowhead whales and 744 gray whales for the 2013-2018 period. They also hunt belugas and narwhals. In addition to the subsistence whaling catch limits that they share with Chukotka Natives, the Eskimos harvest just over 200 belugas a year. The Makah, an indigenous people of Washington State (United States) obtained an annual quota for subsistence harvesting of gray whales in 1999. But an appeal by environmental groups was upheld by the federal courts, preventing the Makah from taking advantage of this permit. The National Oceanic and Atmospheric Administration (NOAA) is still reviewing the matter. The Caribbean islands of St. Vincent and the Grenadines harvest several dozen short-finned pilot whales and a number of dolphins. Additionally, they have a harvest quota of 24 humpback whales.
Other IWC non-members practise whaling according to their own rules. Canada, which withdrew from the IWC in 1982, regulates the hunting of hundreds of belugas and narwhals by the Inuit for subsistence. Further, about one bowhead whale is harvested every two years (except in Baffin Bay where one take is permitted every 13 years). In the Faroe Islands, 1,000 pilot whales and a few dozen dolphins are hunted annually on average. Indonesia and the Philippines also harvest whales, but statistics for these countries are not readily available. They are believed to hunt sperm whales, Bryde’s whales, killer whales and other small cetaceans.
In the St. Lawrence
The St. Lawrence’s reputation as an exceptional location for whales is nothing new. Already in the 16th century, the Basques were crossing the ocean to hunt whales in the Gulf and Estuary. Belugas were also the target of local hunting, and the Norwegians established whaling stations for large rorquals at the beginning of the 20th century. Today, these fascinating animals are observed in their natural environment!
Basques in the Americas
Between 1510 and 1730, the Basques navigated the St. Lawrence from spring to fall, drawn by the large pods of whales. They sought the bowhead whale, now confined to the Arctic, and the North Atlantic right whale, which is now rare in the St. Lawrence. The Basques had developed a dangerous but effective technique to kill and haul to shore whales whose thick layer of blubber was rendered into oil and transferred to barrels. Traces of their activities can be found in the Strait of Belle Isle, notably in Red Bay, where they reached industrial levels. In the Estuary, they were present at Île aux Basques (opposite Trois-Pistoles), Anse du Chafaud aux Basques (near Baie-Sainte-Catherine), and Anse à la Cave (near Cap de Bon-Désir). Findings have been made at these sites of Basque-made stone kilns and red roof tiles used to cover the shelters of these summer visitors.
Local populations took advantage of this abundant and gregarious species. At Pointe-Lebel, belugas were dragged into shallow water with motor boats before being killed with a rifle. At Les Escoumins, whales were harpooned and killed from sailing canoes. Beginning in the 18th century, at Île aux Coudres and Rivière-Ouelle, they were capture in weirs made of saplings laid out in a B-shaped configuration with an opening in the centre. The belugas entered at high tide and remained captured at low tide, sometimes in herds numbering up to 500. This technique was also used both at Pointe aux Alouettes and Moulin Baude in Tadoussac. In the 1930s, the beluga was the target of an extermination program (bombing, bounties, rewards) by the Quebec government, as it was believed to be harming the fisheries. The program ended when the first studies on the St. Lawrence beluga showed that the species did not feed on species of commercial interest. Commercial harvesting of belugas continued through the mid-1950s, and sport hunting, until 1979.
To view the Pierre Perreault and Michel Brault film Pour la suite du Monde (sometimes screened in English under the titles Of Whales, the Moon and Men or For the Ones to Come), which traces the history of beluga hunting, visit the National Film Board of Canada website.
© National film board
Norwegian station in Sept-Îles
At the turn of the 20th century, Sept-Îles was still a small village. In 1905, a whaling station under Norwegian control contributed to its development and prosperity. The facility employed some forty men from the region and about 20 Scandinavians. They hunted blue and fin whales, harvesting some 70 to 85 a year. The animals were pursued in whaling boats and captured using explosive harpoons fitted with a device that enabled air to be forced into the animals’ lungs so that they would float. They were then hauled back to the whaling station, vestiges of which can still be seen today. The station was abandoned in 1914, at the dawn of the First World War. [Special thanks to Steve Dubreuil, archeologist at the Musée régional de la Côte-Nord in Sept-Îles].
Collisions between ships and cetaceans are rather frequent despite the former being relatively loud and the latter having an excellent sense of hearing. Cetaceans are nevertheless capable of reacting to danger quickly, but in certain situations are less alert, for example when they are sleeping or resting at the surface, feeding, nursing their young or reproducing. If taken by surprise by a ship, they don’t always have the time to react or move out of the way, particularly in the case of the slower species. Although collisions are a recognized cause of cetacean mortality in the world, data on the subject remain scarce. It is therefore difficult to evaluate the importance and the repercussions of ship strikes on cetacean populations. Clearly, for certain populations such as that of the North Atlantic right whale, the threat is real. It is not easy to develop appropriate mitigation measures, however.
Injuries that speak for themselves
A collision between a ship and a cetacean can injure or kill the animal, depending on the angle and the force of the impact. A ship’s propellers can gash and cut into the animal’s flesh and blubber and sever off pieces of its tail. Other types of injuries require closer examination to identify a collision with a ship. The impact can result in fractures and ecchymosis (bruises) that are not always apparent. Given the force necessary to break the large bones of cetaceans, it is unlikely that fractures to the skull, jaw and vertebrae could be caused by anything but a strike by a vessel. The ribs and the bones of the pectoral fins, more fragile than the larger bones, may be broken by stranded animals writhing on shore and are not necessarily attributable to the impact of a boat. Some cetaceans, generally the more streamlined species like rorquals, occasionally get caught by the stem of a ship. They are then transported a certain distance until the crew takes notice of the situation or the ship slows down, generally upon arrival to port. For example, a fin whale struck by a cruise ship off the coast of Cape Cod, Massachusetts in 1995 was transported on the bow of the ship all the way to Bermuda, over 1,000 km away.
An incomplete but worrying picture
These incidents are poorly documented, as crews are not always aware of the collision or fail to report them to the responsible authorities. Further, the carcasses may sink or never resurface, especially if the impact severed the animal. Navigators are encouraged to report such collisions. Doing so enables authorities to search for and come to the aid of a wounded cetacean or to locate a floating carcass representing a navigation hazard. In the longer term, it will help pinpoint the places where these strikes are most frequent and to take measures accordingly.
According to a study conducted on collisions between motorized vessels and great cetaceans (baleen whales and sperm whales) in various regions of the world, fatal cetacean collisions date back to the end of the 1800s, when ships first began to attain speeds in the range of 13 to 15 knots (24 to 28 km/h). Collisions were uncommon back then, but became more frequent between 1950 and 1970 as boats increased both in number and in speed. The authors of the study cited collisions with 11 different whale species. Although impacts with fin whales are the most common, those with southern right whales, North Atlantic right whales, gray whales, humpback whales and sperm whales are rather frequent in certain regions. It seems that most fatal or serious injuries are caused by ships exceeding 80 m in length and travelling at speeds of at least 14 knots (approximately 25 km/h). But vessels of all sizes and types can strike whales and inflict more or less serious injuries.
In the St. Lawrence, data on collisions between cetaceans and ships are scarce. Of 18 collision incidents reported in the region of the Saguenay-St. Lawrence Marine Park between 1992 and 2005, there was at least one mortality, and between 1983 and 2004, 6% of beluga mortalities were attributable to ship strikes. However, since the Marine Activities in the Saguenay-St. Lawrence Marine Park Regulations took effect in 2002, a maximum of three collisions per year have been reported. A MICS analysis of the St. Lawrence blue whale photo-ID bank has revealed that at least 5% of individuals bear marks of collision with a ship.
Collisions between ships and cetaceans can be of particular concern for small populations. They currently threaten the survival of the North Atlantic right whale. Notably, 38% of mortalities in this species are attributable to boat collisions. Since this population numbers less than 500 individuals, collisions are the main obstacle to its recovery. Ship strikes probably have a negligible effect on cetacean species that are abundant such as the humpback whale and the fin whale, but may be a source of concern for certain populations for which collision frequency is high. For example, in the Mediterranean, where shipping traffic is intense, 26% of fin whale mortalities between 1986 and 1998 were attributable to a ship strike. Since this population is small and does not reproduce with other populations of the Atlantic, this statistic is a matter of concern.
Du côté des États-Unis, certaines voies navigables ont été reconfigurées sur la côte Est. Parallèlement, un système de survols aériens permettant de repérer les baleines noires et de communiquer leurs positions aux navigateurs a été mis en place. Mais cette technologie ne permettrait de repérer qu’une baleine noire sur quatre; qui plus est, elle est limitée par la météo et est risquée pour les observateurs. Un système d’écoute a donc été développé par Christopher Clark de Cornell University et financé par les compagnies gazières ; il signale la présence des cétacés aux navires gaziers qui doivent ralentir et les éviter.
In the United States, some shipping lanes on the East Coast have been reconfigured. In parallel, aerial flyovers are performed to spot North Atlantic right whales and communicate their positions. But this technology is believed to detect only one right whale in four; further, it is limited by meteorological conditions and can be hazardous for observers. A listening system was thus developed by Christopher Clark of Cornell University and financed by gas companies; the system signals the presence of cetaceans to gas tankers who can then slow down to avoid them.
Maritime traffic is not about to plateau or taper off, quite the contrary. Will this development take place to the detriment of whales? The measures tested today to urgently address the decline of the North Atlantic right whale might serve as a model to limit the consequences on other populations of large marine mammals.
Fishery yields are both an economic and humanitarian concern, especially since human population growth has given rise to food supply issues. This is why marine mammals that prey on fish are sometimes perceived as competitors to be controlled in order to increase our share of the pie. Fishermen worry about the potential impacts of seals and whales on target fish species, while whaling countries use this argument to underscore the necessity for their harvesting activities. But what role do marine mammals truly play in the reduction of fish stocks? And does controlling their populations really allow for an increase in fishing yields?
Are marine mammals at fault?
Let’s take a look at the case of the collapse of cod stocks in the Gulf of St. Lawrence. Although the government and fishermen disagree on the primary cause of this situation, they do agree that the abundance of seals in the Gulf of St. Lawrence may undermine the recovery of cod stocks. Undebatable scientific truth or scapegoat syndrome? Would reducing harp and gray seal populations really help us reverse the cod situation and see this fish thrive once again? The question is still open to debate, as demonstrated by the Fisheries Resource Council of Canada (FRCC) September 2011 report entitled “Towards Recovered and Sustainable Groundfish Fisheries in Eastern Canada”, which advocates the culling of 140,000 gray seals over a 5-year span, in order to verify their impact on the recovery of cod in the southern Gulf. Science? Or politics?
In the case of the Atlantic salmon, it has also been pondered whether or not seals were to blame for its decline. Studies show that salmon are seldom consumed by seals. For example, of the 700 stomachs of gray seals harvested at Anticosti Island, a high density sector for Atlantic salmon, only one contained salmon. Likewise, examination of 9,000 stomachs of harp seals over the past 30 years has revealed the presence of but one salmon. The mystery of the salmon decline is a complex one, but seals do not seem to play an important role.
History recap: the case of St. Lawrence belugas
In the 1920s, St. Lawrence belugas were blamed for the scarcity of cod and salmon. The government distributed rifles and cartridges and offered bonuses to fishermen to kill as many belugas as possible. After eight years of this scheme, Dr. Vladykov undertook a study on beluga diets. His work proved that belugas feed essentially on species of no commercial value such as sand lance, capelin, nereid worms, and various molluscs and crustaceans.
Fewer marine mammals, more fish?
Whatever the case, if we wanted to guarantee a more substantial share of fish stocks, wouldn’t controlling marine mammal populations be an effective method? The argument in favour of this method appears to be quite straightforward: simply reduce the size of a predator population to increase the population of a species (Species 1), and thereby boost the catch. However, if we add to this reasoning another fish species (Species 2) that is both a prey of the predator and a predator of Species 1, the equation becomes more complex. Indeed, a reduction in the predator’s numbers will favour the population of Species 1, but by the same token will also favour that of Species 2. An increase in the population of Species 2 might then translate into an even greater predation pressure on Species 1! It is quite difficult to predict whether the population of the desired fish species (Species 1) will increase or decrease in response to a decline of either of these predators. And this model is still oversimplified compared to what really occurs in the natural environment: often times there are not two but thousands of “paths” between the predator targeted and the prey sought by the fishing industry. To make such a model more realistic, the notion of time must be accounted for: as certain “paths” are longer than others, the desired effect might be achieved in the short term, only later to be followed by the opposite effect.
of the Institut des sciences de la mer à Rimouski (ISMER) examined the impact of great cetaceans on the tropical ecosystems in northwestern Africa and the Caribbean in response to the controversial Japanese theory, i.e. that baleen whales are the main culprits in the global collapse of fish stocks, and whaling is an effective method to counter this decline. Certain countries of coastal regions support this model and speak out in favour of whaling for their economic security, which often depends on fisheries. The results of the study, published in the journal Science, demonstrate that even a complete elimination of baleen whales would not lead to any significant increase in economically important fish stocks in these regions. Not only is the impact of whales on these fish practically non-existent, but it is also one hundred times less than that of fishing.
Despite the uncertainty that prevails, considerable pressure remains to shift the blame to marine mammals. Are they held accountable because they are more visible than other predators? Might it be because they are already considered pests by fishermen due to the problem of incidental catches in their fishing gear?
Less fish… fewer marine mammals?
What if we asked the question the other way around? And we asked what effects fisheries can have on marine mammals? Are there cases in which Man has entered into competition with them and depleted their food resources? What would happen if the moratorium were lifted on forage species, in other words those at the bottom of the food chain? And if a fishing industry targeting krill – a small crustacean that a multitude of predators rely on – were to take off, what would be the effects on bird, marine mammal and fish populations?
Humans, unlike natural predators, have access to powerful technologies and an abundance of alternative resources. Fisheries can have a significant impact on predator populations as well as on the entire ecosystem. Better managing what we harvest from nature and curbing excessive exploitation of the marine environment seem to be the best solutions to consider, as much to ensure fishery yields as to protect marine ecosystems.
The St. Lawrence is not entirely pristine. Many contaminants have ended up and are still present in these waters. Fortunately, water quality has improved since the 1980s and 90s. Despite these improvements, chemicals dumped into the water, including those that are currently banned, may persist for decades in marine mammals. There are also replacement products for those that have been outlawed.
At the top of the food chain
Day in and day out, cetaceans consume enormous volumes of fish and invertebrates. Each of these prey contains a tiny amount of contaminants that will be transferred to the whale. Over time, this can result in high levels of toxicity. Bioaccumulation of contaminants is particularly acute in whales since they are at the top of the food chain.
If adult whales are contaminated by their food, their calves are affected by these toxic compounds even before they are born: a gestating mother that has accumulated contaminants transmits them to her baby during pregnancy.
Since St. Lawrence belugas do not migrate, they are particularly vulnerable to contaminant exposure. They cannot take a “break” from the highly industrialized waters of the St. Lawrence by leaving to spend a few months a year in the ocean.
This prolonged exposure may explain why the endangered St. Lawrence beluga population is not recovering. Compared to their Arctic cousins, the tissues of St. Lawrence belugas are four times as contaminated.
These contaminants have a detrimental effect on their health, especially their immune and reproductive systems. Beluga carcasses analyzed in recent years have shown that individuals with high levels of contaminants are often plagued with infections and cancer.
These analyses reveal high concentrations of particularly toxic contaminants including:
- PCBs (polychlorinated biphenyls are used as insulating fluids)
- DDT (dichlorodiphenyltrichloroethane is an insecticide)
- Mirex (this chlorinated organic compound has been marketed as a flame retardant and a pesticide)
- PAHs (polycyclic aromatic hydrocarbons are products derived from combustion and are mainly associated with aluminum smelters)
Disturbance by whale-watching
Around the globe, the whale-watching craze continues to grow. According to the most recent statistics, 13 million people took to the seas in search of whales in 2008. They spent nearly US$2 million in 119 countries and territories. People often talk about ecotourism, as it represents an incomparable occasion to make these legendary animals ambassadors of marine environmental stewardship. Yet, there is concern about the impact that boats might be having on cetaceans.
EIn response to these concerns, codes of ethics, guides of conduct and regulations have been put into place virtually everywhere that whale-watching excursions are offered. Even the International Whaling Commission (IWC) adopted general principles to regulate whale-watching practices worldwide in 1997. All of these guidelines are based on the experience of captains and marine scientists with whales, and, sometimes, scientific studies that document disturbance to cetaceans. But the design of these studies presents many challenges, the results are often difficult to interpret and the response varies with the species, time of year, activity in which the animal is engaged, etc. This is why the IWC recommends that regulations and codes of conduct be flexible, so that they might be adapted as new information becomes available. We must still ask ourselves if short-lived behavioural changes can have a an impact on whales in the long term.
Is whale-watching really a conservation issue? Jon Lien, a Newfoundland-based researcher that has spent his life with whales, drafted a document on the topic in 2000, at the request of Fisheries and Oceans Canada. He sounds the alarm: cetaceans’ characteristics make them vulnerable to disturbance. Indeed, many whale populations are still fragile, their environment is undergoing significant and rapid changes, and the animals depend on critical habitats where they congregate, which in turn leads to a concentration of whale-watching activities. The disturbance then becomes repetitive, and the effects can be cumulative, which can result in repercussions on their health and thus their chances of survival and reproduction. It is thus critical to exercise caution and do one’s utmost to respect the whales and avoid disturbing their essential activities. The future of these fascinating animals is at stake, as is that of the riverside communities who live today by the rhythm of the whales.
What disturbs whales?
Science in a nutshell
Here’s how Jon Lien summarizes the results of all studies conducted on boat-induced disturbance to whales: the essential activities of whales may be interrupted if there is a large number of boats, if the boats approach too closely, if the boats are travelling too fast or too noisily or if the animals are being chased. Some studies did not demonstrate any reaction, but emphasize that whale behaviour is also dictated by other factors such as social and geographic conditions, their physiological state and their past experience.
Vox Pop: what the seamen think
Even if researchers agree almost unanimously that disturbance by boats can have a serious impact on whales, it is not easy to determine precisely which behaviours should be avoided. Captains and naturalists working in the whale-watching industry in the Saguenay-St. Lawrence Marine Park share their opinions: What constitutes disturbance:
- Fast, repetitive movement on the observation sites.
- Numerous changes of direction.
- Numerous loud boats (more than five).
- Changes in engine speed (rpm).
- Boats that encircle a whale.
- Chasing (advancing rapidly and repetitively toward a whale moving away).
- A boat that cuts off a whale.
- Competition amongst boats vying for a good observation. We then forget that the whale is not there for us, creating the potential for abusive and disruptive behaviour.
For blue whales: any rapid approach, even at a considerable distance.
Quiet or noisy, small or large, any recreational watercraft can disturb whales. Once a boat finds itself near a whale, it has the potential to interfere with any of the animal’s essential activities such as feeding, communication, socialization, rest and reproduction. It is thus considered a potential source of disturbance. Recurrent disturbance can have a negative impact on whales’ chances of survival and breeding success.
The essential activities of cetaceans may be interrupted if there is a large number of boats, if the boats approach too closely, if the boats are travelling too fast or too noisily or if the animals are being chased.
To avoid disturbing whales, it is forbidden to approach within 100 metres of any marine mammal, anywhere in Canada. In the Saguenay-St. Lawrence Marine Park, one must maintain a minimum distance of 200 metres for most cetaceans. However, if you encounter a threatened or endangered species such as a beluga or a blue whale, be sure to stay at least 400 metres away from the animal(s). To familiarize yourself with the law governing navigation in the presence of marine mammals, consult the Marine Activities Regulations.
What if I encounter a beluga?
The presence of a watercraft within beluga habitat may distract the animals’ attention, reducing the amount of time they dedicate to their usual activities such as foraging and caring for their young.
If you cross paths with belugas, change course to navigate around them while maintaining a distance of at least 400 m. Maintain a constant speed of between 5 and 10 knots (9-18.5 km/h) when distancing yourself. This speed limit must be respected until you are at least a half a nautical mile from the animal(s), i.e. 926 metres.
And if I see a blue whale?
The largest animal in the world, the blue whale is also an endangered species. These whales come to feed in the waters of the St. Lawrence where they hunt day and night for several weeks straight. To feed, blue whales execute long dives to gather their prey before engulfing them. The presence of a watercraft can disrupt their diving and reduce their feeding and resting times.
If you cross paths with a blue whale, change course to navigate around it and maintain a distance of at least 400 m. Also, stay alert, as other blue whales may surface near your boat.
Kayaks and paddle boards
It’s hard to believe that a kayak quietly gliding through the water can disturb belugas and other whales of the St. Lawrence. Yet noise is not the only source of disturbance to whales.
A kayak becomes an unexpected obstacle and can be stressful to cetaceans. The distrustful animals will examine the craft and deviate from their usual activities such as foraging, socializing, caring for their young, etc. If whales only encountered one or two kayak groups a day, the impact would be minimal, but over 40,000 kayakers visit the Marine Park area annually.
If the presence of a watercraft, even one as quiet as a kayak, alters a whale’s behaviour, it is considered to be a disturbance. Recurrent disturbances can have a negative impact on whales’ chances of survival and breeding success.
In the Saguenay-St. Lawrence Marine Park, one must maintain a minimum distance of 200 metres for most cetaceans. However, if you encounter a threatened or endangered species such as a beluga or a blue whale, be sure to stay at least 400 metres away from the animal(s). To familiarize yourself with the law governing navigation in the presence of marine mammals, consult the Marine Activities Regulations.
What should I do if the belugas approach my kayak?
Belugas occasionally approach kayaks on their own. To protect them from themselves and minimize the impact of your craft on the animals, it is better to continue your journey and avoid interacting with them.
If you do encounter belugas, stick together and continue paddling until you are at least 400 metres away. As it is not always easy to estimate distance on the water, it is recommended to move away until the animals are out of sight.
Baie Sainte-Marguerite in the Saguenay Fjord is a popular habitat for herds of belugas and their offspring. To help protect the endangered St. Lawrence beluga, no boats – regardless of whether or not they are motorized – are permitted to enter the bay during the summer months.
Like belugas, seals will also on occasion investigate a watercraft. They occasionally approach kayaks and, in rare circumstances, may even attempt to climb aboard! If you see seals approaching, the best attitude to adopt for your safety and that of the animals is not to encourage these encounters and to calmly continue on your way.
Every year, over 5,000 merchant ships are recorded passing through the St. Lawrence Estuary. Whales may exhibit one of several reactions to these vessels: the most common is to avoid the ship, either by fleeing across the water surface or by diving.
This avoidance has a negative impact on the daily activities of cetaceans, as they spend less time eating, resting and socializing. Such disturbance can occur even at great distances: fin whales detect ships and modify their behaviour, even if the vessel is half a nautical mile (926 metres) away! In the long term, disturbance by marine traffic can result in the loss of whale habitat.
The two main causes of shipping-related disturbance to whales are noise pollution and collisions.
Oil and other hydrocarbons are a prized resource. With the looming depletion of global reserves, the rise of prices and international conflicts, it is becoming increasingly profitable to explore the ocean floors in search of new deposits.
But oil and gas exploration is no small matter. The seismic surveys involved consist of pummelling the seabed with powerful sound waves. A boat tows an array of compressed air guns. The result is detonations every 10 seconds, 24 hours a day for weeks, even months. These low-frequency and high-intensity sounds are used to survey the geological composition of the seabed and pinpoint areas where hydrocarbons are most likely to be found in exploitable quantities.
These sounds are not confined to the path between the air gun array, the seabed and the boat. They travel hundreds of kilometres, covering territories spanning tens of thousands of square kilometres. According to Chris Clark, director of Cornell University’s (US) Bioacoustics Research Program, seismic exploration is the worst form of noise pollution after acoustic military exercises.
This form of acoustic pollution can have serious impacts on wildlife, especially marine mammals, which depend entirely on sound for every aspect of their lives: communication, finding prey, detecting predators, and navigation. The sounds associated with oil and gas exploration result in behavioural changes that can affect cetaceans’ survival or reproductive success, and can even result in losses of auditory sensitivity, injury or death. These effects are better documented in cetaceans, but studies have shown similar effects in fish and other marine animals.
Gas and oil exploration of course open the door to hydrocarbon production, which presents further risks for the marine environment. A single drop of oil can contaminate up to 25 litres of water. The first thing that comes to mind is accidents that can lead to the explosion of a well or the rupture of a pipeline. In many cases, existing response technologies are inadequate to contain and recover spills, leading to serious or even catastrophic ecological damage to the marine environment, like the explosion of the BP Deepwater Horizon drilling platform in April 2010, which resulted in over four million barrels of crude oil being spilt into the Gulf of Mexico. Even in the absence of a spectacular disaster, leaks are commonplace. For example, every year 110 million litres of oil leak from wells, pipelines and other infrastructures of the American oil industry. That’s three times as much as the Exxon Valdez oil spill.
Day-to-day operations also present other hazards. Drilling mud comes to rest on the ocean floors and, even if treated, represents a genuine toxic soup of heavy metals and hydrocarbons. Contaminants also find their way into the ecosystem surrounding oil platforms via air pollution. For example, excess gas is flared off by measure of security, producing hydrocarbon emissions. Additionally, as the platforms are lit at all times, they also present a risk to migratory birds. And, lastly, even the decommissioning of platforms after the source has dried up, presents serious environmental problems. In general, the rules and procedures to follow are insufficient to effectively mitigate environmental risks, with the initiative largely lying with the company.
Conflicts of use
The problems associated with hydrocarbon exploration and production are all the more acute in that these activities conflict with other uses of the sea. From a social perspective, can we justify favouring one activity based on a non-renewable resource when it presents risks for other well established activities like fishing and tourism? These risks are difficult to assess, especially if we attempt to capture the long-term cumulative effects. Further, they often exacerbate other stresses already being sustained by fragile ecosystems depended upon by the economy and way of life of coastal human populations.
What, then, should the future of hydrocarbon development look like? Should we not exercise greater caution, especially in marine environments? Are there more fragile and more “precious” places where this type of activity should even be outlawed? Can’t we strive to achieve higher energy efficiency and develop alternative sources to meet our energy needs? These questions represent genuine challenges for our society, and we need not look any farther for an example than the Gulf and Estuary in our own backyard, which are certainly deserving of the designations “fragile” and “precious”.
Who hasn’t already heard of whales that die after getting caught in fishing gear? But did you know that in certain cases, this problem is so serious as to endanger entire populations? Here are a few examples of this type of incident around the world, a vast problem with no one-size-fits-all solution.
The vaquita, a species of porpoise endemic to the Gulf of California, numbers no more than a few hundred individuals. However, 30 or 40 vaquitas are estimated to perish every year in the gillnets and shrimp trawlers of Mexican fishermen. Even if the vaquita’s fate is alarming, imposing drastic solutions to the fishing-related mortality issue is difficult. Indeed, it would be unthinkable for Mexico to forbid fishermen struggling to provide for themselves and their families from fishing, which is the only social and economic motor in this desert region. Three countries are involved in porpoise conservation: Mexico, the United States and Canada. The conservation measures implemented; the sanctuary zone off limits to fishing with its financial compensations deemed by fishermen to be insufficient; attempts to employ new fishing methods; permitting; and illegal practices: for the time being, nothing seems to ensure the vaquita’s future. Its survival is tied to that of local communities and to the economic diversification of their region. A vision and new, creative actions common to all stakeholders must be structured around this twofold challenge.
Great whales also at risk
Generally speaking, small coastal cetaceans like the vaquita are more sensitive to incidental catches, either because they are drawn to captured fish or because they don’t recognize the danger that fishing gear represents. Even the great whales are not safe from incidental catches, as evidenced by the North Atlantic right whale. This species was nearly driven to extinction by whaling at the end of the 1800s. Today, far from having rebounded following several decades of protection, the right whale is endangered. A mere 409 were counted in 2018, and bycatch in fishing gear represents the second most important cause of mortality. It is estimated that more than 80% of all North Atlantic right whale is entangled at least once in their life time. Despite numerous measures put into place (modifications to fishing gear, educational material for fishermen, etc.) in an attempt to reduce the risks of collisions and incidental catches, mortalities continue to this day. In addition to being dangerous if not deadly for whales, these entanglements are costly for fishermen, who must replace lost or damaged ropes and traps.
In the St. Lawrence
The magnitude of this problem in the St. Lawrence is not well known. Off the coasts of Newfoundland, when cod fishing was at its peak, humpback whale bycatch was a major issue. The situation led Jon Lien to assemble a team of specialists that, in collaboration with fishermen, has been freeing trapped whales since 1978. The real impact of bycatch on other species inhabiting the St. Lawrence is poorly understood, but every year, minke, humpback and even blue whales are reported entangled in nets or ropes.
The story of Tryphon
In June 2009, the best known sperm whale of the St. Lawrence, Tryphon, was spotted trapped in crab trap ropes off the coast of Sept-Îles. Despite the fact that some of the ropes had been removed and the close monitoring of the response teams, his carcass – still wrapped up in the ropes – was found floating in the Estuary a few days later.
The story of Capitaine Crochet
Capitaine Crochet is that well known fin whale in the Tadoussac region that had gotten herself ensnared in fishing gear in the spring of 2013. This female had returned every spring since 1994 and had even escorted a few calves over the years. The incident had mobilized numerous experts to attempt to free her, stirred up strong emotions amongst those who had known her for years and created a bit of a media buzz. Despite all these efforts, the animal could not be freed; she left the Marine Park one week later and has never been seen since. It is assumed that she died given the seriousness of her entanglement.
Of course, ideally we could prevent bycatch. But that’s easier said than done… For example, in the Gulf of Maine, every year harbour porpoises die by the thousands in fishing gear, and to date none of the solutions tested has led to a significant reduction in these mortalities. To keep the porpoises away, sorts of “acoustic scarecrows” are placed on the nets. The results of this technique are inconclusive, as it seems to work in some cases and remains ineffective in others. The same can be said for fishing zones and seasons established with the objective of minimizing conflicts between fishing activities and harbour porpoises. The problem is all the more worrying in that we have here one of the best contexts to tackle the problem: American law is strict in terms of protecting marine mammals, and teams comprising scientists, fishermen and other concerned stakeholders have been working for a number of years to reduce incidental catches. It must therefore be concluded that the problem is a complex one, and hope that the creativity and perseverance demonstrated in the case of porpoises in the Gulf of Maine will also serve as an example for addressing bycatch issues elsewhere in the world.
What’s the danger for the whales?
Despite what Jacques Cousteau used to say, the oceans are far from being the “world of silence”. The wind, shifting tectonic plates and the calls of the whales compose a complex soundtrack. But over the past 50 years, human activities have completely transformed this soundtrack. Some go so far as to call it noise pollution, and biologists are concerned about its effects on marine mammals. Why? On one hand, the oceans have become awfully loud, and noise levels continue to escalate. On the other hand, marine mammals depend on sound for navigation, feeding, reproduction and socialization. Along with hunting, habitat loss and chemical contamination, noise is now recognized as one of the biggest threats to marine mammal survival.
Shipping, the mining and oil industries, military activities, acoustic thermometry, and fisheries all contribute to the relentless increase of sound levels in the oceans. Furthermore, all these sounds might travel up to 70% farther by 2050 with the rising ocean acidity caused by greenhouse gases.
With globalization, the merchant fleet has surged and is anticipated to double again by 2025. All these ships (oil tankers, tugboats, freighters, icebreakers, etc.) fill the farthest reaches of the oceans with a constant roar in a frequency band in the 500 Hz range. Drilling activities are also a significant source of low-frequency noise. For example, oil exploration requires the use of a compressed air gun array towed behind a boat, which produces tens of thousands of explosions. In fact, from exploration to production all the way through to the dismantling of facilities at the end of a site’s service life, every stage of hydrocarbon extraction beneath the ocean floor adds to noise levels.
The US military and NATO also contribute to rising sound volumes in the oceans. In order to detect today’s ultra quiet submarines, they have developed low-frequency active sonar systems (LFA). These systems don’t just listen, they also produce powerful sound beams (230 dB at the source) that fan out in all directions for hundreds of kilometres.
Low-frequency sounds travel great distances, and this characteristic makes them an interesting research tool. Since the speed of sound is a function of temperature, the mean water temperature can be calculated by measuring the time it takes a sound to travel a known distance. As part of the ATOC program (Acoustic Thermometry of Ocean Climate), American researchers placed in the Pacific two transmitters (one in California and the other in the Hawaiian Archipelago) and about a dozen receptors in order to study climate change. For ten years, these transmitters produced sounds of 195 dB at regular intervals. The same group of scientists is contemplating placing such transmitters in all the world’s oceans.
Fisheries have also contributed to noise pollution in their attempts to address the problem of marine mammal bycatch in fishing gear. Fishermen install sorts of “acoustic scarecrows” in order keep whales and pinnipeds at bay. The effect of these sounds is relatively localized compared to that of the noise sources discussed above. Nevertheless, these sound beacons aim to produce an effect on marine mammals and might have significant impacts on the use of critical habitats by coastal species such as the harbour porpoise. Lastly, the construction of offshore infrastructure such as ports, oil and gas platforms, tidal and wind power projects, etc. also help ratchet up the decibel level in the oceans.
…a hazard for whales?
The effects of noise pollution depend on the distance from the noise source, among other factors. If the sound is powerful and the animals are in close proximity, it could lead to permanent damage to the ears, internal injuries or even death. Less acute sounds can also result in temporary deafness, as demonstrated by studies conducted on seals, dolphins and belugas in captivity. Previous studies on whale strandings during military exercises have even demonstrated that the animals showed internal injuries, notably in the internal ears and cervical areas. The United Nations, the US-based National Oceanic Atmospheric Administration (NOAA), and the International Whaling Commission (IWC) have suggested that there could be a link between the use of military active sonar and cetacean strandings.
A study published in February 2012 and conducted on the feces of North Atlantic right whales in the Bay of Fundy demonstrated that the greater noise pollution is, the higher the so-called stress hormone will be. It was in the context of the events of September 11, 2001 that researchers were able to establish this correlation. Indeed, on this day, traffic diminished considerably and the volume of acoustic emissions emitted under the water surface fell by half. No seasonal or occasional drop in hormone levels such as the one measured in 2001 had ever been observed in whales in previous studies.
Further, if exposed to multiple sources of stress, whales might also suffer from diving-related decompression accidents. Indeed, this type of intense sound may have a direct impact on nitrogen bubble formation or on the behaviour of whales, which might alter their dive profiles (time and depth), exposing themselves to excessive tissue saturation and significant gas bubble formation. These results – obtained from a seminar bringing together some twenty international experts in diving-related physiology in both humans and marine mammals – are published on the Internet site Proceedings of the Royal Society B.
In addition to the physiological effects, anthropogenic sounds can impact cetaceans’ behaviour. Studies have shown that relatively acute sounds can cause whales to deviate from their trajectory or reduce their time spent feeding. Chronic exposure might even force marine mammal populations to abandon habitats. Some species of cetaceans stop vocalizing for several hours or even several days when they are exposed to low-frequency sounds. Moreover, even thousands of kilometres away from any noise source, whales might suffer from increased background noise in the oceans, which is likely to mask certain important sounds. This effect may make the difference between detecting a prey or not, escaping a predator or not, locating other pod members or not. This form of pollution is all the more alarming in that the frequency bands used by whales coincide precisely with those that have increased the most in the oceans. In certain maritime zones, the distance at which blue whales communicate is even believed to have shrunk by 90% due to increased noise.
Unfortunately, there is a paucity of data available to evaluate the real problems presented by noise pollution. Published studies are particularly oriented toward short-term effects, and raise many questions. What do these reactions really mean for animal biology? When no reactions are apparent, are the animals truly out of danger? What about the rest of the ecosystem? Might whales be suffering from noise pollution through the latter’s impact on their food sources? Biologists don’t yet have the answers to these complex questions. In the fall of 2011, the International Quiet Ocean Experiment was launched. Undertaken over a 10-year period, this program aims to acquire scientific knowledge on marine noise pollution and its impacts on organisms, and to coordinate research on an international scale. The objective is to fill knowledge gaps in this still poorly understood field and to envision measures to mitigate the impact of harmful noise pollution.
Regulating noise pollution… a formidable challenge
Although the issue has been known since the 1970s, initiatives to mitigate it are relatively recent. Reports published in 2008 by the European Science Foundation and the National Marine Fisheries Service (NMFS) all advocated the establishment of standards to address noise pollution. After years of legal battles, a coalition of environmental groups headed by the Natural Resources Defense Council (NRDC) announced in 2008 that it had reached an agreement with the American Navy. The Navy, recognizing the impact of its sonars on cetaceans, undertakes to finance research, prepare impact assessments and make information on its sonars publicly available.
Certainly, long-term monitoring of the impact of noise pollution on ocean life in general and marine mammals in particular is essential. International cooperation shall also be promoted in order to identify solutions to recognized problems and practical means of implementing noise reduction standards. These are major challenges when one considers the wide array of activities that contribute to ocean noise pollution. In fact, this form of pollution is but one aspect of a broader problem (and one of the concerns of the United Nations environmental program): our growing use of the oceans.
And in the St. Lawrence?
Maritime traffic combined with the local topography creates some of the noisiest environments in North America, such as the mouth of the Saguenay Fjord. Construction of offshore infrastructures or gas exploration raises serious concern for the integrity of the St. Lawrence, notably with regard to noise pollution. Chronic stress has physiological effects, particularly on the immune system. Daniel Martineau, veterinarian at the Université de Montréal’s faculty of veterinary medicine, has been monitoring pathologies in St. Lawrence belugas since 1982. He points out that stress can act in synergy with contaminants and lead to even more acute effects to weaken the immune system, especially in young animals. What if this constant noise that we impose on belugas compromised their chances of facing all the threats to this fragile population?
Every day, whales ingest enormous quantities of fish and invertebrates. The fin whale, for example, takes in up to 2,000 kg of small fish a day! But what happens if whales’ prey become increasingly difficult to find?
Up until a few years ago, North Atlantic right whales would enter the Bay of Fundy every summer to feed on tiny crustaceans called copepods. However, the latter have disappeared. As a result, the whales have deserted the bay and are venturing farther afield to explore for food.
They can now be found in the Gulf of St. Lawrence. Although the quantity of copepods present in St. Lawrence waters has also declined, it remains sufficient to meet the right whales’ energy requirements.
In the Pacific, grey whales are also struggling to eat their fill. This shortage has catastrophic effects on migration: if they do not get enough energy before they leave by devouring deep-water amphipods, grey whales may not reach their destination. In 2019, there was an unusually high number of grey whale mortalities due to malnutrition.
Threats to prey
Whales’ prey – whether fish or invertebrates – face a number of threats including the collapse of fisheries due to overfishing, habitat disturbance and degradation, declining food resources and the effects of climate change such as rising water temperatures and falling oxygen levels, which is known as hypoxia.
Three species of “forage” fish that make for popular snacks for St. Lawrence whales are the following:
- Atlantic herring (Clupea harengus harengus) is one of the most abundant fishes in the world! There are two populations of this small species in the St. Lawrence: fall spawners and spring spawners. The fall spawner stock remains at a moderate level. However, spring spawner numbers have been falling since 1997 and have remained at a low level since then.
- Capelin (Mallotus villosus) stocks in the St. Lawrence collapsed in the 1990s. Of the 6 million tonnes of capelin estimated at the time, just one tonne remains. As their numbers plummet, there has also been a decrease in the size of capelin. Fortunately, in recent years capelin have been beginning to return to normal size.
- In 2012, a significant mortality event for American sand lance (Ammodytes americanus) was observed in the St. Lawrence. Hundreds of these eels perished as a result of warming surface waters. Without sand lance, seabirds and whales lose one of their prey. This small coldwater fish is not targeted commercially in the St. Lawrence and its biology is poorly understood.