DOSSIER UPDATED FEBRUARY 8, 2016  – In 2015, of the 14 carcasses found, four have been confirmed as newborns and two others may also have been newborns, three were females that died while giving birth (signs of recent calving or complications during calving) and one was identified as a hermaphrodite. What do the researchers who work with this population make of it all? Check out their most recent articles on the subject.

In 2012, abnormally high mortalities of newborn belugas sounded the alarm. In 2013, scientists who work with belugas multiplied their efforts to further their analyses of data collected over the past 30 years. Their conclusion is alarming: belugas have been declining since the early 2000s. And the recent mortalities might be accentuating this trend. In December 2014, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) evaluated the population of St. Lawrence belugas as “endangered”.

An Alarming Finding

In 2012, abnormally high mortalities of newborn belugas sounded the alarm for researchers studying the St. Lawrence population. The phenomenon made headlines for several weeks as there was considerable speculation as to the possible causes and concern about the implications of this situation for the beluga’s recovery.

In 2013, scientific teams working on different aspects of this population all stepped up their efforts to update their data and conduct further analysis. Some data series cover over 30 years.

These teams had agreed to meet in the fall of 2013 to assess the situation. The conclusion reached by the end of this meeting is alarming: the analysis did not allow researchers to pinpoint the cause of the 2012 mortalities, but it did reveal a more fundamental problem: the population, which had previously been considered to be stable, had been declining since the beginning of the 2000s. This conclusion was the object of a Science Advisory Report. In December 2014, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) evaluated the population of St. Lawrence belugas as “endangered”.

To learn more: Committee on the Status of Endangered Wildlife in Canada (COSEWIC): Beluga, St. Lawrence Estuary population.

Clues to Understanding

Researchers point out that the beginning of the decline coincides with a combination of significant changes in the St. Lawrence ecosystem. Rising water temperatures, reduced ice cover in the winter and changes in the abundance and distribution of prey all represent unfavourable conditions for this already fragile population. The rapid rise of a new class of contaminants through the early 2000s and the increase in maritime traffic and disturbance in the Upper Estuary further contribute to the degradation of beluga habitat.

An Uncertain Future

The picture is thus bleak for the St. Lawrence beluga. The increase in newborn mortalities remains unexplained, but researchers are especially concerned about the impact that these deaths will have on the population’s trajectory. These “absent” newborns will surely translate into “absent” juveniles and adults in coming years, which may accelerate the decline observed over the last decade. Further, it is expected that climate change will accelerate, progressively eroding the conditions for the St. Lawrence belugas.

The enigmatic beluga was the catalyst behind a very broad mobilization to clean up and protect the St. Lawrence in the early 1980s. Decontamination, stricter regulations on industrial waste, creation of the Saguenay-St. Lawrence Marine Park, banning of hydrocarbon exploration and drilling activities in the Estuary… many initiatives have their origins in the alarm sounded by the beluga on the state of the rich yet fragile St. Lawrence. Today, the St. Lawrence and belugas face new pressures. What does the future look like for the St. Lawrence beluga? Can we save these canaries of the sea? Three St. Lawrence beluga specialists share their views.

Scientists Take the Floor

Stéphane Lair, veterinarian for the beluga necropsy program:
LairStephane“In the 1970s, scientists revealed serious problems related to chemical contaminants such as PAHs and PCBs, which led to regulatory changes. We’re beginning to see the benefits of these measures: some of these contaminants, which were present in record concentrations in belugas in the 1980s, have since declined. Cancers, which were the main cause of mortality in adults in the 1980s and 90s, have also become less frequent. No beluga born after 1971 has died from cancer. But at the same time, the population is suffering from other problems, most likely related to climate change. It’s very worrisome.”

Robert-MichaudRobert Michaud, GREMM scientific director and St. Lawrence beluga specialist:
“We have been closely monitoring the belugas of the St. Lawrence for over thirty years now. The data that enabled us to sound the alarm in the early 1980s and to understand the evolution of this population are the result of an extraordinary collaboration between a number of governmental, academic and private institutions. These data were also used to implement protection measures such as the creation of the Saguenay-St. Lawrence Marine Park. The belugas’ future is closely linked to our will and capacity to monitor and comprehend the upheavals that they are increasingly subject to. Protecting the St. Lawrence and its inhabitants requires long-term commitment.”

DSC_0106_vlesageVéronique Lesage, marine mammal scientist at the Maurice Lamontagne Institute (Fisheries and Oceans Canada), oversees the aforementioned meeting which will culminate in the publication of a Science Advisory Report:
“Even if the population of the St. Lawrence beluga was considered to be stable or slightly increasing before the 2000s, it should be noted that its growth rate was well below what is considered normal for a healthy beluga population. The population was therefore already exposed to pressures that were limiting its growth, and these pressures are still present today. The decline that began in the early 2000s coincides with significant changes in their ecosystem that have brought about unfavourable environmental conditions. We might not have direct or immediate control of these conditions, but we can take action on the stressors caused by our activities such as maritime traffic, disturbance to sensitive areas for mothers and young, contamination, habitat damage and competition with fisheries.”

Fisheries and Oceans Canada and the GREMM have given nearly a dozen interviews on this issue in the media

To Learn More: Science Advisory Report and Research Documents

Following the annual meeting of the Marine Mammal Peer Review Committee in St. Johns, Newfoundland and Labrador, from October 7 to 11, 2013, the Canadian Science Advisory Secretariat published and posted on line a Science Advisory Report and a number of research documents.

The analyses and conclusions that follow stem from discussions held during the annual meeting of the Marine Mammal Peer Review Committee in St. Johns, Newfoundland and Labrador, last October 7-11, as collected and interpreted by the Whales On Line team following interviews with some of these scientists.

Population Trends

      • A beluga carcass analysis and recovery program has been in place since 1982. The number of carcasses found annually has remained stable at about 15 a year. The number of newborns found dead varied between 0 and 3 until 2007, and was exceptionally high in 2008 (8), 2010 (8) and 2012 (16). The average age of females found dead has been falling since the 2000s and, since 2010, more females have been reported as dying from complications arising during calving.
      • Between 1988 and 2009, eight aerial photographic surveys were conducted in an effort to estimate the number of belugas. The 2009 estimate is the lowest of the series, though no trend can be confirmed as the number of censuses is too low and the variations are too great. A second series of aerial surveys – visual surveys this time – was performed between 2001 and 2009. The 2009 count is also the lowest of the lot, but once again no trend can be confirmed with this tool as the period covered is too short and its accuracy is too poor.
      • These aerial surveys do however detect a decline in the proportion of young in the population (first-year animals): this ratio went from 15.1-17.8% in the 1990s to 3.2-8.4% in the 2000s.
      • A mathematical model was developed on the basis of data collected from the aerial surveys and the carcass recovery program. The model suggests that the population was likely stable or slightly increasing up until the early 2000s, and that it has been declining ever since. The model estimates the size of the population in 2012 at 889 belugas.
      • The model also suggests that the beluga population has been experiencing a period of instability since the early 2000s, notably with a decline in the proportion of juveniles and newborns in the population and highly fluctuating newborn mortalities.
      • The conclusions of this modelling exercise concord with the observations of the annual beluga census program using photo-identification (1989-2012). This independent data set reveals the same trends as the model in terms of the evolution of the proportion of young and the production of newborns.

Searching for explanations

      • Analysis of stable isotope ratios measured in carcasses between 1988 and 2012 shows that there has been a change in the source of carbon (and thus probably in their diets) in belugas since 2003.
      • An analysis comprising 28 environmental indices monitored between 1990 and 2012 shows that the system has undergone significant changes in the past few years, with a decline in the biomass of certain fish species, below-normal ice conditions in winter and above-normal water temperatures.
      • These belugas are amongst the most heavily contaminated marine mammals in the world. Certain contaminants have been diminishing in the past decade or so (e.g. PCBs, DDT), while polybrominated compounds (PBDE) increased exponentially in the 1990s. PBDEs might have an impact on the survival of young or the ability of females to care for them.
      • Maritime traffic associated with tourism and recreational boating peaks in July-August, at the same time as the beluga’s calving season. This traffic increased between 2003 and 2012 in certain sectors, including those used by females and young.

Another look at newborn mortalities

      • In 2008, the newborn mortalities (8) were associated with a bloom of the toxic alga Alexandrium tamarense in the Estuary. Numerous other marine mammals had experienced unusual mortalities that summer and chemical and pathological examinations concluded that saxitoxin had played a role, whether alone or in conjunction with other unfavourable factors.
      • In 2010 and 2012, unknown factors reduced young belugas’ chances of survival. This period coincides with a period of even more pronounced changes in terms of reduced ice cover in winter and higher water temperatures.

Conclusions

      • The model suggests that the population of St. Lawrence belugas has been declining since the early 2000s. This decline corresponds to a period of unfavourable environmental conditions, high levels of polybrominated contaminants (PBDE), increased exposure to noise and maritime traffic and a toxic algal bloom.
      • The St. Lawrence population’s ecosystem is undergoing tremendous changes that could have an impact on the beluga as they intensify. Even if little can be done in the short term to counteract these changes in the ecosystem, we can focus our efforts on reducing the impacts of our activities, such as disturbance to sensitive areas, chemical contamination, habitat loss or competition with fisheries.

Related Dossier

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