John J. Citta

The Northwest Passage opens for bowhead whales

The loss of Arctic sea ice is predicted to open up the Northwest Passage, shortening shipping routes and facilitating the exchange of marine organisms between the Atlantic and the Pacific oceans. Here, we present the first observations of distribution overlap of bowhead whales (Balaena mysticetus) from the two oceans in the Northwest Passage, demonstrating this route is already connecting whales from two populations that have been assumed to be separated by sea ice. Previous satellite tracking has demonstrated that bowhead whales from West Greenland and Alaska enter the ice-infested channels of the Canadian High Arctic during summer. In August 2010, two bowhead whales from West Greenland and Alaska entered the Northwest Passage from opposite directions and spent approximately 10 days in the same area, documenting overlap between the two populations.

Perfluorinated contaminants in ringed, bearded, spotted, and ribbon seals from the Alaskan Bering and Chukchi Seas.

Perfluorinated contaminants (PFCs), such as perfluorooctane sulfonate (PFOS) and related synthetic compounds have been used as industrial and commercial surfactants and stain repellents for more than 50 years (Prevedouros et al., 2006). PFCs are thought to bioaccumulate and are believed to be extremely resistant to physical and biological degradation and to biotransformation (Giesy and Kannan, 2001). PFCs behave differently from lipophilic organochlorine compounds such as dichlorodiphenyl-trichlorethane (DDT) and polychlorinated biphenyls (PCBs) because they bind to proteins rather than lipids. PFCs are believed to negatively influence cellular function and intercellular communication as well as promote tumor growth (Berthiaume and Wallace, 2002; Hu et al., 2002). Transport mechanisms and source locations for the Arctic are unknown but PFCs have been detected in ringed seals (Phoca hispida) from Canada (Martin et al., 2004; Butt et al., 2007), Greenland (Bossi et al., 2005), and Europe (Kannan et al., 2002). PFCs have also been detected in polar bears (Ursus maritimus) in Alaska from the Chukchi and Beaufort Seas (Kannan et al., 2005; Smithwick et al., 2005a, b). Few data are available regarding levels of PFCs in the United States. Many people living in Alaskan coastal communities eat seal tissues, including muscle, some organs, and blubber. Seals are known to accumulate concentrations of persistent organochlorines (e.g., PCBs and DDTs) and may be bioaccumulating PFCs as well. Levels of PFCs have not previously been reported for seals in Alaska. The objective of this analysis was to quantify levels of PFCs in liver from four species of seals (ringed, bearded, Erignathus barbatus; spotted, P. largha; and ribbon, P. fasciata) that are consumed by humans and polar bears in Alaska. We quantified concentrations of PFCs in liver tissue of 17 ringed seals, 17 bearded seals, nine spotted seals, and eight ribbon seals using liquid chromatography and mass spectrometry. All seals were harvested by Alaska Native hunters in the Bering and Chukchi Seas during 2003–2007. PFCs examined include perfluoroheptanoate (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), perfluorooctane sulfonate (PFOS), perfluorohexanesulfonate (PFHS), perfluorobutanesulfonate (PFBS), perfluorodecanesulfonate (PFDS), and perfluorooctanesulfonomide (PFOSA). Liver samples were collected from the subsistence seal harvest near the villages depicted in Fig. 1, between 2003 and 2007, through the Alaska Department of Fish and Game’s (ADF&G) Ice Seal Biomonitoring Program. Canine teeth were collected for determining age. Teeth were sectioned and stained by Matson’s Lab, Milltown, MT, and age was determined by counting growth layer groups in the teeth (Benjaminsen, 1973; Stewart et al., 1996). Liver was collected in the field, frozen, and transported to the laboratory at ADF&G where it was subsampled under clean conditions using titanium knives on a Teflon covered surface as described by Becker

Trace Element Concentrations in Bearded Seals (Erignathus barbatus) Near Red Dog Mine Compared to Other Locations in Alaska

To determine if bearded seals (Erignathus barbatus) harvested near a zinc and lead mine (Red Dog, Alaska , USA) by subsistence hunters from Kivalina, Alaska, were as safe to eat as bearded seals from other locations in Alaska, we compared 19 trace element concentrations in liver tissue. Liver concentrations from nine bearded seals harvested near the Red Dog Mine (RDM) port site were compared with 15 bearded seals from two reference sites (Hooper Bay and Little Diomede, Alaska, USA). Concentrations did not differ by gender, but we found statistically significant trends in concentrations of cadmium, mercury, manganese, selenium, and vanadium with age. Arsenic and copper were the only elements found to be more concentrated in the liver of bearded seals harvested near RDM than in the other locations. The predominant form of arsenic in marine mammals is known to be a nontoxic organic form, not the toxic inorganic form, and copper is an essential element. Although elevated near RDM, neither element was found at concentrations that presented health risks. We found no evidence that bearded seals harvested near RDM were less safe to eat or that trace element concentrations were greater than those found in bearded seals harvested elsewhere in Alaska or Canada.

Migratory culture, population structure and stock identity in North Pacific beluga whales (Delphinapterus leucas)

The annual return of beluga whales, Delphinapterus leucas, to traditional seasonal locations across the Arctic may involve migratory culture, while the convergence of discrete summering aggregations on common wintering grounds may facilitate outbreeding. Natal philopatry and cultural inheritance, however, has been difficult to assess as earlier studies were of too short a duration, while genetic analyses of breeding patterns, especially across the beluga’s Pacific range, have been hampered by inadequate sampling and sparse information on wintering areas. Using a much expanded sample and genetic marker set comprising 1,647 whales, spanning more than two decades and encompassing all major coastal summering aggregations in the Pacific Ocean, we found evolutionary-level divergence among three geographic regions: the Gulf of Alaska, the Bering-Chukchi-Beaufort Seas, and the Sea of Okhotsk (Φst = 0.11–0.32, Rst = 0.09–0.13), and likely demographic independence of (Fst-mtDNA = 0.02–0.66), and in many cases limited gene flow (Fst-nDNA = 0.0–0.02; K = 5–6) among, summering groups within regions. Assignment tests identified few immigrants within summering aggregations, linked migrating groups to specific summering areas, and found that some migratory corridors comprise whales from multiple subpopulations (PBAYES = 0.31:0.69). Further, dispersal is male-biased and substantial numbers of closely related whales congregate together at coastal summering areas. Stable patterns of heterogeneity between areas and consistently high proportions (~20%) of close kin (including parent-offspring) sampled up to 20 years apart within areas (G = 0.2–2.9, p>0.5) is the first direct evidence of natal philopatry to migration destinations in belugas. Using recent satellite telemetry findings on belugas we found that the spatial proximity of winter ranges has a greater influence on the degree of both individual and genetic exchange than summer ranges (rwinter-Fst-mtDNA = 0.9, rsummer-Fst-nDNA = 0.1). These findings indicate widespread natal philopatry to summering aggregation and entire migratory circuits, and provide compelling evidence that migratory culture and kinship helps maintain demographically discrete beluga stocks that can overlap in time and space.

Presence and behavior of bowhead whales (Balaena mysticetus) in the Alaskan Beaufort Sea in July 2011

The Western Arctic bowhead whale (Balaena mysticetus) is highly adapted to sea ice and annually migrates through the Bering, Chukchi, and Beaufort seas. While the overall distribution and seasonal movements of bowhead whales are mostly understood, information about their distribution in the Alaskan Beaufort Sea in early to mid-summer has not been well documented. In July 2011, we conducted an exploratory flight in the Alaskan Beaufort Sea, north of Camden Bay (71°N 144°W), near the location of a single satellite-tagged bowhead whale. Eighteen bowhead whales were observed, and behavior consistent with feeding was documented. To our knowledge, this is the first documentation of behavior consistent with feeding north of Camden Bay in mid-July. Few studies have focused on bowhead whale distribution in the Alaskan Beaufort Sea in early to mid-summer, and no long-term, region-wide surveys have been conducted during summer. Bowhead whales are already exposed to anthropogenic disturbance in the Canadian Beaufort Sea in summer, the Alaskan Beaufort Sea in fall, and the Chukchi and Bering seas from fall through spring. The presence of bowhead whale aggregations in the Alaskan Beaufort Sea in summer should be considered when assessing the cumulative effects of human-related activities.