Norways ice-associated whales in a changing Arctic

Key results from the ICE-whales research programme include the first population abundance survey results for all three endemic cetaceans in the Norwegian Arctic, which is a significant feat in terms of logistics and analytical effort given the highly mobile nature and quite rare status of these ice-affiliated animals. The white whale population in Svalbard is the smallest Arctic population of this species, numbering only 549 (95 % CI 436 ? 723) individuals. Additionally, we have surveyed the vast marginal ice zone across much of the Norwegian territory in the northern Barents Sea, which produced estimates of approximately 300 bowhead whales and 800 narwhals. Tracking studies undertaken in the programme have documented that white whales have an extremely coastal distribution and that these animals dive to very shallow depths to feed in the Svalbard (mostly in front of tidewater glaciers), compared to elsewhere in the species range. Adult males tend to spend much of the summer in west coast fjords, which are subject to con considerable ship traffic, although they return in the fall to areas in the east of the archipelago, where females and young tend to be remain most of the time. White whales on the west coast have in recent times started to forage in the fjords where Atlantic water masses now dominate, suggesting some accommodation to newly available prey. The Endangered bowhead whales in the Spitsbergen population were successfully tagged from helicopters (which has never been done before). Their tracks show that they remain year-round in areas with high ice concentrations, mostly along the margins of the continental shelf, occupying a vast region between East Greenland and Fran Josef Land in Russia. They come south in summer and return north in winter, in contrast to other bowhead populations which do the reverse. We have also succeeding in tracking fin whales (and blue whales and sperm whales) parallel to the ice-associated whales. For fin whales we have identified a hirtherto unknown breeding site off Morocco and discovered that these whales feed along their migratory path ? both directions. Blue whales and fin whales spend many months in the Arctic, extending from late spring until October and November, respectively. The ICE-whales programme has compiled all recorded observations of cetaceans in the Svalbard Region, recovering data from the marine research institute, field reports from the governors office etc and placed them in a proper database (which has been shared with Artsdatabanken). We have used the data to create habitat models for all cetacean species and explored temporal changes in distribution. Some species are expanding northward, while some of the endemic arctic species are not responding to the quite dramatic changes that have taken place. Analyses of sound records from our passive acoustic monitoring array have make it possible to explore the acoustic environment in the Fram Stait. We have found that this region is a breeding site for the highly endangered Spitsbergen bowhead population and that the Spitsbergen population sings extremely complex songs that shift through time. We have also documented that extensive seismic blasting is heard for many months of the year in this area, overlapping with the summer distribution of bowheads and narwhal, both of which are in the region nearly year-round. However, this region must be described as being quite pristine in that boat traffic is very rare and natural sounds (ice, waves etc) dominate the soundscape much of the time. Tissues collected during tagging operations have allowed us to document contaminant levels and their potential impacts. White whales in the region have very high levels of some toxins, though bans of some compounds are having positive results. But even species that fed at low trophic levels and have low toxic loads such as fin whales and blue whales are impacted in terms of negative effects on the functioning of their hormone receptor systems. Genetics studies undertaken in ICE-whales have shown that the Svalbard population of white whales is a unique entity as is the Spitsbergen bowhead whale population, confirming that they should be managed as populations separate from other adjacent populations. Additionally, explorations of white whale relatedness showed that the social structure is mildly connected through male relatives. Mitogenomic studies are narwhal showed that abundance of this species in the past has followed expansions and contraction is sea ice, with sea ice decreases resulting in population declines. Although plasticity is challenging to prejudge, the consequences of climate change are expected to be severe for all of the ice-affiliated Arctic whales.

The results of this research programme have provided the first abundance estimates for each of the three ice-dependent cetaceans in the Norwegian Arctic, in addition to providing a much deeper understanding of their habitat needs throughout the year. ICE-whales data have already been used nationally for management plans identifying vulnerable and valuable areas (SVOs) within the Barents Sea, northern Norwegian Sea and Svalbard Coastal Waters. Additionally, the published results have permitted updating of the National Red List, which will be released in 2021. The programme's research outputs have made a vital contribution to updating the State of Arctic Marine Biodiversity (SAMBR) for CAFF (Conservation of Arctic Flora and Fauna), which will be released in 2021. ICE-whales data is being used for Svalbard regional planning, currently being undertaken by the Environmental Directorate. This research programme has been extremely important and highly relevant to nature management in Norway.

Arctic sea ice has declined significantly in the past decade and an ice-free arctic summer is predicted to occur before the end of this century. This unique habitat has become home to 3 cetacean species (bowhead whales, narwhals & white whales) that have evolved in association with arctic sea ice or joined it over the 5+ M yrs of its existence. The ice has been a spatially extensive, virtually disease-free habitat for its' mammalian residents that has provided shelter from inclement weather & open-water predators, as well as many additional potential human impact sources. It has also provided a seasonally food-rich environment with little competitive stress. Loss of this habitat for extended periods each year is predicted to have transformative impacts on ice-associated species as well as the broader arctic marine ecosystem. In this research programme a multidisciplinary, highly international research team will explore the physical & biological factors that are most likely to have impacts on the ice whales of the Norwegian High Arctic. This will involve compiling underutilized, available data as well as collecting new distribution, abundance & habitat use data for these 3 nationally Red Listed species, as well as exploring time trends in diet, contaminant levels & health status of species for which there are regional data. An extended acoustic array will provide new infrastructure for future monitoring of cetaceans. Novel ocean data collected using animal-borne sensors will be analysed in the context of whale habitat-assessment; these cost-effectively collected ocean data will also be made available to the broader marine community for other uses. The future prospects for the ice-associated whales will be modelled in a broad context with specific attention to regional ice models, changes occurring in the food web & the shifting community structure of the Northern Barents Sea cetacean community. The data produced by this programme is vital to manage these stocks well.