IAB7: Bowhead whale conservation and future research cooperation

Date: Wednesday October 10, 2018

Location: Saivo, Lappia Hall

Time: 10:30-12:00

This session facilitates cooperation on bowhead whale research, which has been identified as a knowledge gap in the CAFF State of Arctic Marine Biodiversity Report (2017). This session explores recent developments and partnerships, including monitoring techniques and tools such as acoustics, vessel designs, tagging and aerial surveys to help identify critical areas and calving grounds and further conservation and protection of this important and iconic Arctic species.

Chairs: Gert Polet, World Wide Fund for Nature; Erik van de Linde, Ice Whale Foundation

Format: Series of presentations followed by discussion

Presentations:

  • Spitsbergen’s bowhead whales (Balaena mysticetus) – a summary of new findings: Kit Kovacs, Norwegian Polar Institute 
  • Proposed inventories of Bowhead whale distribution and behavior in the dynamic drift ice zone in the Fram Strait during the polar winter: Herman Sips, Ice Whale Foundation pdf
  • Bowhead whale acoustic occurrence and vocal behavior in Fram Strait: Karolin Thomisch, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research pdf
  • You can’t always go back: bowhead whales, over-exploitation, global warming, and orca predation: Steven Ferguson, Fisheries and Oceans Canada pdf
  • Abundance and distribution of bowhead whales during winter and summer in the Greenland Sea: Rikke Guldborg Hansen, Greenland Institute for Natural Resources pdf
  • Okhotsk Sea bowhead whales as a live model on how climate change may affect the species in the polar regions: Olga Shpak, A.N. Severtsov Institute of Ecology and Evolution pdf
  • Application of environmental DNA for monitoring abundance and diversity of bowhead whales (Balaena mysticetus): Morten Tange Olsen, Natural History Museum of Denmark

 

Abstracts:

Spitsbergen’s bowhead whales (Balaena mysticetus) – a summary of new findings

Kit M. Kovacs1, Jon Aars1, Heidi Ahonen1, Dmitry Glazov2, Mads Peter Heide-Jørgensen3, Olga Shpak2, Kathleen Stafford4, Jade Vacquie Garcia1 and Christian Lydersen1
1 Norwegian Polar Institute, Fram Centre, N-9296, Tromsø, Norway.
2 A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow
3 Greenland Institute of Natural Resources, Box 570, 3900 Nuuk, Greenland
4 Applied Physics Lab., University of Washington, Seattle, Washington 98115, USA

The Spitsbergen bowhead whale population was the first cetacean population in the world to be driven to the brink of extinction by commercial whaling. Despite many decades of protection from harvesting, this population remains Critically Endangered. However, Passive Acoustic Monitoring (PAM) in the northwestern Fram Strait has revealed significant amounts of vocal activity by bowheads on a year-round basis. Singing by the bowheads in this area is most intense during periods of heavy ice-cover in the winter months, when breeding likely takes place. The song diversity recorded at this PAM site (with more than 184 different songs recorded in a 3-year period) is unique among wild mammals, being “bird-like” in its complexity. A combined ship-based and aerial survey in the Marginal Ice Zone (MIZ) north of Svalbard, conducted in August 2015, estimated that 343 (CI 136-862) bowhead whales were present in the 52,000 km2 study area. All whales were observed from the air, well within the MIZ; none were seen during the ship transects. The results of the PAM efforts and the survey led to a trilateral tagging effort (Norway-Russia-Greenland) that took place in 2017, during which 16 satellite transmitters were deployed on bowhead whales in the Spitsbergen population. The whales were tagged in a small area in the middle of the Fram Strait, but spread throughout the whole distributional range of this stock over the following year (from East Greenland through to Franz Josef Land). These studies in combination reveal that the status of the Spitsbergen stock of bowhead whales is much better than previously thought. However, this extremely ice-affiliated population faces many challenges in the coming decades associated with a warming Arctic, and warrants directed conservation action.

Proposed inventories of Bowhead whale distribution and behavior in the dynamic drift ice zone in the Fram Strait during the polar winter

Herman Sips, Ice Whale Foundation; Fleur Visser, Royal Netherlands Institute for Sea Research

The Ice Whale Project is a private initiative aimed at scientific research on and public promotion of the Bowhead Whale Balaena mysticetus, in connection to its rapidly changing Arctic sea-ice environment. The Ice Whale Foundation's goals are: a) To assess the presumed breeding population, mating grounds and mating behavior of the Ice Whale in the Fram Strait and the species' vulnerability to sea-ice reduction and increased shipping and exploration. b) To turn the distinctive, but to the larger public unknown Bowhead Whale into the 'Icon of the Arctic' and simultaneously raise awareness to conserve the sea-ice ecosystem. Supported by several Dutch knowledge institutes, we are preparing a series of scientific polar winter expeditions, for which a dedicated compact and robust research vessel is now being designed. The first Arctic winter expedition is scheduled for the polar winter 2020-2021. The principal goal of the winter expeditions is to assess the assumed mating grounds and mating behavior of the Bowhead Whale along the East Greenland shelf and to understand the species' ecological as well as behavioral dependency on Arctic sea-ice and its vulnerability to changes in sea ice conditions and human activities. The first objective is to validate the presence of an active breeding population in the Fram Strait, and if so, to define how big this population is and how far this breeding area extends over latitudes from north to south. The research initiative builds largely on recent publications of Kathleen Stafford, Kit Kovacs, Heidi Ahonen and others who describe recordings of complex Bowhead whale songs at unexpected high latitudes in dense sea-ice, indicating mating areas. To assess the distribution, gatherings and mating behavior of Bowhead whales deep into the drift ice zone, each winter expedition will consist of a series of passive drift tracks in silent mode from different starting positions, applying passive acoustical triangulation techniques and UAV-based IR-observation and eDNA-sampling. We intend to carefully tune the Ice Whale project with the research programs of relevant international institutes such as the Norwegian Polar Institute, the Greenland Institute of Natural Resources, the Alfred Wegener Institute and the Danish Arctic Research Centre, among others. We welcome the critical discussion of our project with experienced scientists from these and other organizations.

Bowhead whale acoustic occurrence and vocal behavior in Fram Strait

Karolin Thomisch1, Olaf Boebel1, Svenja Neumann1, Stefanie Spiesecke1, Ilse Van Opzeeland1,2
1 Ocean Acoustics Lab, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, 27570 Bremerhaven, Germany
2 Helmholtz-Institute for Functional Marine Biodiversity at the University of Oldenburg [HIFMB], 26129 Oldenburg, Germany

Passive acoustic monitoring enables data collection on marine mammals over large temporal and spatial scales and in remote areas such as the Arctic Ocean. Passive acoustic data are collected at different recording sites in eastern and central Fram Strait since 2012, contributing to the Arctic Observatory FRAM (FRontiers in Arctic Marine Monitoring). Here, data recorded at 78°50 N, 0°E from July to November 2012 were analyzed for the daily acoustic presence of marine mammals. Bowhead whales (Balaena mysticetus) were acoustically present during 12 days in October and during 16 days in November, but acoustically absent from July to September. Downsweep song (three types) was present both in October and November, while upsweep song (one type) was only present in October. Besides bowhead whales, blue whales (Balaenoptera musculus), fin whales (B. physalus), narwhals (Monodon monoceros), sperm whales (Physeter macrocephalus) and harp seals (Pagophilus groenlandicus) were recorded. Acoustic species interactions regarding the overlap of species-specific sounds in time and frequency range were explored. In this context, temporal and spectral overlap of biophonic (blue and fin whale vocalizations) and anthrophonic (airgun) signals were detected in the low-frequency (<100 Hz) spectrum. Our results emphasize the importance of Fram Strait as marine mammal habitat, possibly providing (summer) feeding opportunities for blue and fin whales and an overwintering ground for bowhead whales and narwhals. Understanding the spatio-temporal patterns in the distribution and acoustic behavior of marine mammals considerably benefits the development of effective conservation and management strategies for critical habitats in the Arctic Ocean.

 

You can’t always go back: bowhead whales, over-exploitation, global warming, and orca predation

Steven Ferguson, Fisheries and Oceans Canada

Bowhead whale (Balaena mysticetus) distribution has waxed and waned with geological changes in circumpolar sea ice extent, and Inuit hunting for subsistence occurred at low levels for millennia. However, all three recognized bowhead populations declined to very low numbers following over 500 years of commercial harvesting from European and American whalers that ended ca 1915. The Bering-Chukchi-Beaufort population has returned to historic numbers and the Svalbard-Barents Sea population has recently shown some population increase, whereas the Eastern Canada-West Greenland (ECWG) population growth appears stalled mid-way towards its original pristine numbers. The ECWG population has a small co-managed subsistence harvest in Canada and Greenland that is not responsible for this stalled growth. To understand why this population has not shown the same exponential growth observed elsewhere, we explore three possible explanations: (1) carrying capacity has changed due to environmental effects of global warming; (2) killer whale (Orcinus orca) predation is greatest in this region; and (3) the ecosystem has been severely altered due to over-harvesting and cannot return to the original system equilibrium. First, we used a model to estimate pre-exploitation abundance to approximate carrying capacity, developed reference points and management zones, and found that the population is likely to be within the healthy (N50 to N70) zone. However, the population does not seem to have grown at the expected exponential rate or be approaching pristine carrying capacity. Large uncertainty about demographic variables argues for the need for research to monitor this population in the context of climate change. Second, bowhead whales have evolved successful tactics to minimize predation from killer whales, including seeking refuge in shallow inlets and fjords with summer sea ice. Traditional ecological knowledge and sighting records from the ECWG bowhead range have suggested that killer whale predation occurs frequently on bowhead whales – largely on vulnerable calves. Approximately 10% of ECWG bowhead whales display rake marks from killer whale attacks, a rate higher than found for other bowhead whale populations and higher than typical of baleen whale populations generally. Third, the marine environment may have undergone a transformation due to novel species combinations and relative abundances that have not occurred previously. Key changes in ecosystem functioning due to human overharvesting may have inadvertently degraded the original native or 'wild' ecosystem making it very difficult to return to its previous state. Although conclusions are elusive, history reminds us that over-exploitation can have large-scale, unintended, and sometimes irreversible consequences.

 

Abundance and distribution of bowhead whales during winter and summer in the Greenland Sea

Rikke Guldborg Hansen* and Mads Peter Heide-Jørgensen*
*Greenland Institute of Natural Resources, Post box 570, 3900 Nuuk, Greenland

We investigate the abundance and spatial distribution of bowhead whales’ (Balaena mysticetus) use of the Northeast Water polynya in winter (NEW) and summer (NEW and south to Scoresby Sound covering the shelf break). To determine the abundance of marine mammals in the polynya, visual aerial surveys involving double observer platforms were conducted in April 2017 and August/September 2017. Bowhead whale abundance will be estimated using strip-census estimation of abundance corrected for perception- and availability bias and presented for the first time at the CAFF conference.

 

Okhotsk Sea bowhead whales as a live model on how climate change may affect the species in the polar regions

Olga Shpak, A.N. Severtsov Institute of Ecology and Evolution

Okhotsk Sea population of bowhead whales in summer occupies coastal waters of the western Okhotsk Sea (so called Shantar region, latitudes 53˚-54˚N. Ice period in this region may last up to 250 days, but during several months, when the area is completely ice-free, killer whales present a serious threat to bowheads. Killer whale predation seem to be growing in recent years, probably due to orcas having polished their hunting techniques, and is affecting bowhead whale behavior and distribution. At present, bowhead mortality due to killer whale predation is likely at the level when it can be compared to the speed of bowhead reproduction. Most important, killer whales hunt not only calves but also independent juveniles of ca. 2-5 years of age. The external look of Okhotsk Sea bowheads is quite different from the whales from northern populations due to intensive molt (probably, seasonal and stimulated by warm temperatures and low salinity), high ectoparasitic infestation and scarring of unknown etiology (but probably not only of traumatic nature). In summer, juvenile whales are pushed by killer whales close to shore and into the shallow warm bottoms of the bays. Close proximity to shore, tens of meters, where whales hide from killer whales, increases entanglement risks (there are confirmed cases of entanglement in salmon fishery nets and a trap). Quickly developing tourist industry has already recognized the benefits of such distribution: videos from tourist sites with apparent whale harassment are available. Current (as per 2016) abundance estimate for the Shantar summer aggregation, which is thought to constitute the major part, if not the entire population, is 218 (CV=0.22). This number means, the Okhotsk population is likely the smallest isolated population of the bowhead whale. There are no signs of recovery, and if declining trend is confirmed, the population will be assigned a CR category under IUCN Red List. Environmental conditions, in which resides the bowhead population in the Okhotsk Sea, resemble (except for the amount of light) what is expected to be happening in the summer ice-free Arctic in few decades.

 

Application of environmental DNA for monitoring abundance and diversity of bowhead whales (Balaena mysticetus)

Natasja Lykke Corfixen1#, Louise Mørch1#, Mads Peter Heide-Jørgensen2, Morten Tange Olsen1*
1Natural History Museum of Denmark, University of Copenhagen
2Greenland Institute of Natural Resources
#Equal contribution
*Presenter

One of the major obstacles in assessing the effects of climate change on Arctic ecosystem is the logistical and methodological challenges associated with data collection in remote, harsh environments. Thus information on the status and pressures affecting e.g. Arctic marine mammals is often restricted to certain species and/or geographical regions. Here we tested the applicability of environmental DNA (eDNA) as a simple, non-invasive and cost-effective tool for monitoring the distribution, abundance and diversity of bowhead whales in Disko Bay, Western Greenland. First, we extracted DNA from 150 water samples collected during May 2017 and 2018 from the “footprints” of diving whales or along random transects. Next, using novel bowhead whale qPCR probes we obtained an eDNA-based relative estimate of bowhead whale distribution and abundance, nicely correlating with the visually observed occurrence of whales. Moreover, we show that haplotypes obtained from footprints of individual whales match the haplotypes obtained from skin biopsies. Thus, by sequencing all water samples with presence of bowhead DNA we were able to reconstruct the mtDNA haplotype distribution and frequencies estimated through more than a decade of biopsy sampling and genetic profiling of bowhead whales in Western Greenland. As such, our study demonstrates the large potential for routine eDNA monitoring and population genetic inference of not just bowhead whales, but also other Arctic marine fauna.