Marine mammals

What is happening and why does it matter?

• Changes underway are affecting marine mammal abundance, growth rates, body condition and reproduction, impacting the resilience of marine mammal populations with concomitant effects on the people who rely on them for subsistence, economic, and cultural purposes.
• Most populations with known status are increasing or stable, but populations of beluga in the Atlantic Arctic (White Sea) and Baffin Bay-Davis Strait, polar bear in the southern Beaufort Sea, and hooded seal in the Greenland Sea are declining.
• Predictions are difficult to make for some ice-associated whale species because the nature of their affiliation with sea ice is not clearly understood. For example, bowhead whales are doing well, both at the population and at individual level, in the increased open-water conditions of the Arctic Archipelago, Hudson Complex, Baffin Bay-Davis Strait, Beaufort and Chukchi Sea of the Pacific Arctic, Arctic Marine Areas. However, this could reflect recovery from historical harvest levels masking effects of environmental change.

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.

Bowhead whale. Photo: Amy Brower, Alaska Fisheries Science Center, NOAA Fisheries Service Polar bear. Photo: Kit M. Kovacs, Christian Lydersen, NPI

What should you know about the monitoring data?

• In general, trends for wide-ranging species with little population structure (e.g., ringed seals, bearded seals, and ribbon seals) are least understood, while distinct populations or stocks that occur in well-defined geographic areas have documented trend information (e.g., narwhal and some polar bear populations).
• Interpretation of current population dynamics and trends has to take into account historical overharvest, which can mask the potential effects of climate change.
• It is difficult to evaluate species response to climate warming across the Arctic due to high regional variability as well as differences in the level of understanding of the status of different marine mammal species, populations and stocks. To help solve this problem, detailed monitoring plans such as those for the ringed seal and polar bears have been created, but these plans have not been fully implemented across the Arctic.
• Traditional and local knowledge provides a long-term and detailed wealth of information and understanding of the wildlife and resources upon which they depend.

In the Belcher Islands, Johnassie Ippak (left) and Lucassie Ippak (second from left) of Sanikiluaq, Nunavut, and graduate student Carie Hoover (right) of the University of British Columbia assist Fisheries and Oceans Canada research scientist Dr. Steven Ferguson (second from right) on a research project exploring the effects of climate change on Arctic marine mammals. The research involves, in part, attaching satellite transmitters to ringed seal to track and study their movements. Photo: DFO, 2008 Spotted seal. Photo: Jay Verhoef, Alaska Fisheries Science Center, NOAA Fisheries Service

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).

Walrus on ice. Photo: USFWS Walrus hauled out on Round Island, Alaska. Photo: USFWS

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.

Tagging seals. Photo: Josh London, Alaska Fisheries Science Center, NOAA Fisheries Service Beluga. Photo: Vicki Beaver, Alaska Fisheries Science Center, NOAA FisheriesService

Advice for monitoring: 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.

Tagging narwhal. Photo: Carsten Egevang/ARC-PIC.com Hooded seal. Photo: Aqqa Rosing Asvid/VisitGreenland.com