Marine mammals 2021

In 2017 the SAMBR synthesized data about biodiversity in Arctic marine ecosystems around the circumpolar Arctic.. SAMBR highlighted observed changes and relevant monitoring gaps. This 2021 update provides information on the status of marine mammals in the Arctic from 2015–2020: More detail can be found in the Marine Mammals 2021 Technical report. Access 2017 report here

Key Findings

• Insufficient monitoring regionally, or across taxonomic groups, makes it impossible to present a holistic assessment of status and trends of Arctic endemic mammals; trends for 66% of stocks are currently unknown.

• Direct and indirect impacts of climate warming continue to be the primary threat to marine mammals in the Arctic.

• Changes in distribution and phenology (such as timing of migration) of marine mammal stocks is making some stocks less accessible to hunters and reduced predictability of weather and sea ice conditions is making hunts more challenging.

• Monitoring efforts should enhance collaboration with communities to improve knowledge of species health and population status.

• Arctic endemic marine mammals are being exposed to greater levels of threat from both anthropogenic impacts such as shipping and for some populations in the North Atlantic Arctic harvest levels are of concern; biotic changes that increase disease risks and possibly also the toxicity of contaminants are additional threats.

• At the same time, endemic marine mammal populations are likely experiencing increased predation from open water predators and competition induced by range expansions of sub-arctic marine mammals.

Status and Trends of Marine Mammal Populations

During 2015-2020, abundance estimates have been undertaken for 14% of marine mammal stocks in the Arctic. A few regional sub-stocks have also received survey attention. Additionally, information from 37 stocks has been published based on older surveys, or survey results have been revised to improve correction factors or other aspects of data treatment. However, 14% of stocks for which there is some sort of estimate are 20 years old and an additional 16% of stocks have never been surveyed (mostly seals). Trends are unknown for 66% of marine mammal stocks overall. 

Trends are known for circa 60% of whale stocks, 50% of polar bear stocks, 30% of walrus stocks and 10% of seal stocks. Seven stocks are known to be declining, including 3 polar bear stocks), one hooded seal stock, one narwhal stock and two beluga stocks (that may already be extinct).

What is happening and why does it matter?

• Insufficient monitoring regionally, or across taxonomic groups, makes it impossible to present a holistic assessment of status and trends of Arctic endemic mammals; trends for 66% of stocks are currently unknown.

• Direct and indirect impacts of climate warming continue to be the primary threat to marine mammals in the Arctic.

• Changes in distribution and phenology (such as timing of migration) of marine mammal stocks is making some stocks less accessible to hunters and reduced predictability of weather and sea ice conditions is making hunts more challenging.

• Monitoring efforts should enhance collaboration with communities to improve knowledge of species health and population status.

• Arctic endemic marine mammals are being exposed to greater levels of threat from both anthropogenic impacts such as shipping and for some populations in the North Atlantic Arctic harvest levels are of concern; biotic changes that increase disease risks and possibly also the toxicity of contaminants are additional threats.

• At the same time, endemic marine mammal populations are likely experiencing increased predation from open water predators and competition induced by range expansions of sub-arctic marine mammals.

Why are marine mammals important?

• Marine mammals are top predators in Arctic marine ecosystems and are key to ecosystem survival
• Many Arctic marine mammal species are an important resource and hold special cultural significance in Arctic communities.

What should you know about the monitoring data?

The overall knowledge regarding population trends of marine mammal stocks in the Arctic remains largely unchanged since SAMBR, with no new circumpolar monitoring programs, nor committed national monitoring programs, having been implemented for Arctic marine mammals. However, there has been considerable effort focused on assessment of polar bear stocks throughout the Arctic. Additionally, a review of status and trends of the world’s narwhal and beluga populations has recently been undertaken and some progress has been made in defining walrus stocks in the Barents Sea region. Although formal community-wide assessments have not taken place, the Arctic seals have been divided into more likely stocks/populations, increasing the number of stocks from 83 at the time of SAMBR to 100.

What are the most important drivers?

• In a warmer Arctic, endemic marine mammal species face extreme levels of habitat change, which is expected to result in dramatic reductions in sea ice dependent species. Extirpations of some marine mammal stocks are likely.
• The effects of climate change are expected to be exacerbated by increasing oil and gas exploration and production, marine mining, commercial fisheries, tourism, pollution, noise and shipping, and in combination can profoundly impact marine mammal populations and further disrupt already complex social-ecological relationships.
• Because many stocks were reduced by past unsustainable harvest, harvest history has to be included as an important driver of observed trends. Many stocks are still recovering from past harvest (e.g., bowhead whale, walrus), while others have not been able to do so, probably due to climate change (e.g., Greenland Sea hooded seal).

Where is monitoring happening?

• Little abundance and trend information is available for the many populations that occupy the Pacific Arctic and Atlantic Arctic regions. Both areas include extensive open-ocean as compared with other regions that are comparatively more defined seas over continental shelves or within archipelagos. The Arctic Basin and adjacent Beaufort and Kara-Laptev regions have the lowest number of marine mammal populations and trend information is limited in these regions.
• Population surveys are generally conducted by resource management agencies with cooperative efforts between jurisdictions to assess shared populations.

Advice for monitoring 2017: marine mammals

• Implement existing international monitoring plans such as those for ringed seals and polar bear, with adaptive management principles to address the eleven Arctic marine mammal species.
• Expand marine mammal monitoring efforts to include parameters on health, passive acoustics, habitat changes, and telemetry tracking studies.
• Obtain more knowledge about population sizes, densities, and distributions of marine mammal populations in order to understand the relationships between sea ice loss and climate change and to manage Arctic marine mammal populations in an appropriate manner.
• Involve indigenous and local peoples in the design and implementation of monitoring programs so that scientific knowledge and TLK holders are working collaboratively.
• Pursue a multidisciplinary and multi-knowledge approach and a high degree of collaboration across borders and between researchers, local communities and Arctic governments to better understand complex spatial-temporal shifts in drivers, ecological changes and animal health.