Lori T. Quakenbush

Arctic marine mammal population status, sea ice habitat loss, and conservation recommendations for the 21st century

Abstract Arctic marine mammals (AMMs) are icons of climate change, largely because of their close association with sea ice. However, neither a circumpolar assessment of AMM status nor a standardized metric of sea ice habitat change is available. We summarized available data on abundance and trend for each AMM species and recognized subpopulation. We also examined species diversity, the extent of human use, and temporal trends in sea ice habitat for 12 regions of the Arctic by calculating the dates of spring sea ice retreat and fall sea ice advance from satellite data (1979–2013). Estimates of AMM abundance varied greatly in quality, and few studies were long enough for trend analysis. Of the AMM subpopulations, 78% (61 of 78) are legally harvested for subsistence purposes. Changes in sea ice phenology have been profound. In all regions except the Bering Sea, the duration of the summer (i.e., reduced ice) period increased by 5–10 weeks and by >20 weeks in the Barents Sea between 1979 and 2013. In light of generally poor data, the importance of human use, and forecasted environmental changes in the 21st century, we recommend the following for effective AMM conservation: maintain and improve comanagement by local, federal, and international partners; recognize spatial and temporal variability in AMM subpopulation response to climate change; implement monitoring programs with clear goals; mitigate cumulative impacts of increased human activity; and recognize the limits of current protected species legislation.

POPULATION DECLINES OF KING AND COMMON EIDERS OF THE BEAUFORT SEA

Abstract King (Somateria spectabilis) and Common Eiders (S. mollissima v-nigra) wintering off western North America migrate past Point Barrow, Alaska and across the Beaufort Sea to nest in northern Alaska and northwestern Canada. Migration counts were conducted by various researchers at Point Barrow during 1953, 1970, 1976, 1987, 1994, and 1996. We examined population trends by standardizing the analysis of the migration counts in all years. Based on this standardized procedure, the King Eider population appeared to remain stable between 1953 and 1976 but declined by 56% (or 3.9% year−1) from approximately 802,556 birds in 1976 to about 350,835 in 1996. The Common Eider population declined by 53% (or 3.6% year−1) from approximately 156,081 birds in 1976 to about 72,606 in 1996. Reasons for the declines are unknown.

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.

Diet of beluga whales, Delphinapterus leucas, in Alaska from stomach contents, March-November

At least fi ve stocks of beluga whales, Delphinapterus leucas, are found in Alaska waters: Beaufort Sea, eastern Chukchi Sea, eastern Bering Sea, Bristol Bay, and Cook Inlet. The two northernmost stocks (Beaufort Sea and eastern Chukchi Sea) are highly migratory; the two southernmost stocks (Bristol Bay and Cook Inlet) are nonmigratory. Little is known about the seasonal movements and distribution of the eastern Bering Sea stock. Beluga populations in Alaska are thought to be stable or increasing, except for the Cook Inlet stock which is listed as endangered under the Endangered Species Act. We analyzed stomach contents from beluga whales collected between the months of March and November taken in subsistence harvests, from belugas found dead, and from belugas collected for research. We describe prey species and their percent frequency of occurrence (% FO) as well as potential biases from the seasonality of prey relative to the timing of sampling, and differential feeding and digestion. Diet was highly variable among stocks. The predominant fi sh species of the Beaufort Sea stock was Arctic cod, Boreogadus saida (21% FO), although shrimp (60% FO) and smoothskin octopus, Benthoctopus leioderma (42% FO) were found more frequently. Although the eastern Chukchi Sea stock ate more saffron cod, Eleginus gracilis (7% FO) than Arctic cod (3% FO), shrimp (73% FO) and echiurids (27% FO) were more prevalent than fi sh. The eastern Bering Sea stock had the most diverse diet, and dominant fi sh species included saffron cod (95% FO), rainbow smelt, Osmerus mordax (62% FO), several species of sculpin (Family Cottidae) and fl atfi sh (Family Pleuronectidae), both at 48% FO, and Arctic cod at 43%. Dominant invertebrates included shrimp (86% FO), with polychaetes, isopods, bivalves, amphipods, and echiurids ranging from 29 to 38% FO. Pacifi c salmon, Onchorhyncus spp., predominated over cod in Bristol Bay (81% FO) and Cook Inlet (67% FO) beluga stocks, and invertebrates appeared to be less prevalent prey. In Bristol Bay, smelt were also eaten more often (43% FO) than cod (3% FO), while in Cook Inlet cod were eaten more often (39% FO) than smelt (11% FO). Invertebrates were common in the diet of all Alaska beluga stocks and shrimp (mostly from the family Crangonidae) were the most prevalent. Introduction At least fi ve stocks of beluga whales, Delphinapterus leucas, occur in the waters of Alaska (Fig. 1). These stocks were tentatively identifi ed by their summer distributions (Frost and Lowry, 1990; Richard et al., 2001), and were later confi rmed genetically (O’Corry-Crowe et al., 1997, 2002, 2010). The distribution of beluga whales in Alaska is discontinuous from Yakutat Bay1, 2 to Cook Inlet to Bristol Bay. The entire area from Bristol Bay northward and eastward to Canada is used by belugas; the Bering and Chukchi seas are used year-round and the Beaufort Sea is used in summer (Frost and Lowry, 1990). 1There is a small group of <20 belugas that appear to be resident in Yakutat Bay, a deepwater fi ord (Laidre et al., 2000; Allen and Angliss, 2011) 2O’Corry-Crowe, G., W. Lucey, C. Bonin, E. Henniger, and R. Hobbs. 2006. The ecology, status and stock identify of beluga whales, Delphinapterus leucas, in Yakutat Bay, Alaska. Rep. to U.S. Mar. Mamm. Comm., NMFS-YSB-YTT, 22 p. Beluga whales in Alaska appear to follow one of two life history strategies: migratory and nonmigratory. Migratory stocks use shallow nearshore and deepwater offshore habitats (Hazard, 1988; Frost and Lowry, 1990), and include the eastern Chukchi Sea stock (population size ~4,000 (Allen and Angliss, 2011)) and the Beaufort Sea or Mackenzie stock (population size ~39,000 (Harwood et al., 1996; Allen and Angliss, 2011)). Nonmigratory stocks use shallow, estuarine habitats year-round and include the Bristol Bay and Cook Inlet stocks. The Bristol Bay population is increasing (Lowry et al., 2008) and is estimated to be ~3,000 (Allen and Angliss, 2011). Local sightings and satellite telemetry confi rm that belugas occur in Bristol Bay in all months of the year (Harrison and Hall, 1978; Frost and Lowry, 1990; Lensink3; Quakenbush and Citta4; Quaken bush5). The population in Cook Inlet is estimated to be 312 whales and appears to be decreasing at 1.6% per year (Hobbs et al., 2015). The population declined dramatically between 1994 and 1998 (Hobbs et al., 2000) and the stock was determined to be depleted under the Marine Mammal Protection Act in 2000 (NOAA, 2000); the original cause of the decline is believed to be overharvest. Between 1999 and 2006 the harvest was restricted to fi ve 3Lensink, C. J. 1961. Status report: beluga studies. Alaska Dep. Fish Game, Juneau. Unpubl. rep., 38 p. 4Quakenbush, L., and J. Citta. 2006. Fall movements of beluga whales captured in the Nushagak River in September 2006. Unpubl. rep. to Alaska Beluga Whale Committee, P.O. Box 69, Barrow Alaska 99723, 9 p. 5Quakenbush, L., Alaska Dep. Fish Game, 1300 College Road, Fairbanks. Unpubl. data.

Prevalence of algal toxins in Alaskan marine mammals foraging in a changing arctic and subarctic environment

Current climate trends resulting in rapid declines in sea ice and increasing water temperatures are likely to expand the northern geographic range and duration of favorable conditions for harmful algal blooms (HABs), making algal toxins a growing concern in Alaskan marine food webs. Two of the most common HAB toxins along the west coast of North America are the neurotoxins domoic acid (DA) and saxitoxin (STX). Over the last 20 years, DA toxicosis has caused significant illness and mortality in marine mammals along the west coast of the USA, but has not been reported to impact marine mammals foraging in Alaskan waters. Saxitoxin, the most potent of the paralytic shellfish poisoning toxins, has been well-documented in shellfish in the Aleutians and Gulf of Alaska for decades and associated with human illnesses and deaths due to consumption of toxic clams. There is little information regarding exposure of Alaskan marine mammals. Here, the spatial patterns and prevalence of DA and STX exposure in Alaskan marine mammals are documented in order to assess health risks to northern populations including those species that are important to the nutritional, cultural, and economic well-being of Alaskan coastal communities. In this study, 905 marine mammals from 13 species were sampled including; humpback whales, bowhead whales, beluga whales, harbor porpoises, northern fur seals, Steller sea lions, harbor seals, ringed seals, bearded seals, spotted seals, ribbon seals, Pacific walruses, and northern sea otters. Domoic acid was detected in all 13 species examined and had the greatest prevalence in bowhead whales (68%) and harbor seals (67%). Saxitoxin was detected in 10 of the 13 species, with the highest prevalence in humpback whales (50%) and bowhead whales (32%). Pacific walruses contained the highest concentrations of both STX and DA, with DA concentrations similar to those detected in California sea lions exhibiting clinical signs of DA toxicosis (seizures) off the coast of Central California, USA. Forty-six individual marine mammals contained detectable concentrations of both toxins emphasizing the potential for combined exposure risks. Additionally, fetuses from a beluga whale, a harbor porpoise and a Steller sea lion contained detectable concentrations of DA documenting maternal toxin transfer in these species. These results provide evidence that HAB toxins are present throughout Alaska waters at levels high enough to be detected in marine mammals and have the potential to impact marine mammal health in the Arctic marine environment.

Marine Fishes, Birds and Mammals as Sentinels of Ecosystem Variability and Reorganization in the Pacific Arctic Region

Extreme reductions in sea ice extent and thickness in the Pacific Arctic Region (PAR) have become a hallmark of climate change over the past decade, but their impact on the marine ecosystem is poorly understood. As top predators, marine fishes, birds and mammals (collectively, upper trophic level species, or UTL) must adapt via biological responses to physical forcing and thereby become sentinels to ecosystem variability and reorganization. Although there have been no coordinated long-term studies of UTL species in the PAR, we provide a compilation of information for each taxa as an ecological foundation from which future investigations can benefit. Subsequently, we suggest a novel UTL-focused research framework focused on measurable responses of UTL species to environmental variability as one way to ascertain shifts in the PAR marine ecosystem. In the PAR, indigenous people rely on UTL species for subsistence and cultural foundation. As such, marine fishes, birds and mammals represent a fundamental link to local communities while simultaneously providing a nexus for science, policy, education and outreach for people living within and outside the PAR.

SEASONAL HEMATOLOGY AND SERUM CHEMISTRY OF WILD BELUGA WHALES (DELPHINAPTERUS LEUCAS) IN BRISTOL BAY, ALASKA, USA

We collected blood from 18 beluga whales (Delphinapterus leucas), live-captured in Bristol Bay, Alaska, USA, in May and September 2008, to establish baseline hematologic and serum chemistry values and to determine whether there were significant differences in hematologic values by sex, season, size/age, or time during the capture period. Whole blood was collected within an average of 19 min (range=11–30 min) after the net was set for capture, and for eight animals, blood collection was repeated in a later season after between 80–100 min; all blood was processed within 12 hr. Mean hematocrit, chloride, creatinine, total protein, albumin, and alkaline phosphatase were significantly lower in May than they were in September, whereas mean corpuscular hemoglobin concentration, monocytes, phosphorous, magnesium, blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, γ-glutamyltranspeptidase, and creatinine kinase were significantly higher. Mean total protein, white blood cell count, neutrophils, and lymphocytes were significantly higher early in the capture period than they were later. No significant differences in blood analyte values were noted between males and females. Using overall body length as a proxy for age, larger (older) belugas had lower white blood cell, lymphocyte, and eosinophil counts as well as lower sodium, potassium, and calcium levels but higher creatinine levels than smaller belugas. These data provide values for hematology and serum chemistry for comparisons with other wild belugas.

Baseline hearing abilities and variability in wild beluga whales (Delphinapterus leucas)

While hearing is the primary sensory modality for odontocetes, there are few data addressing variation within a natural population. This work describes the hearing ranges (4–150 kHz) and sensitivities of seven apparently healthy, wild beluga whales (Delphinapterus leucas) during a population health assessment project that captured and released belugas in Bristol Bay, Alaska. The baseline hearing abilities and subsequent variations were addressed. Hearing was measured using auditory evoked potentials (AEPs). All audiograms showed a typical cetacean U-shape; substantial variation (>30 dB) was found between most and least sensitive thresholds. All animals heard well, up to at least 128 kHz. Two heard up to 150 kHz. Lowest auditory thresholds (35–45 dB) were identified in the range 45–80 kHz. Greatest differences in hearing abilities occurred at both the high end of the auditory range and at frequencies of maximum sensitivity. In general, wild beluga hearing was quite sensitive. Hearing abilities were similar to those of belugas measured in zoological settings, reinforcing the comparative importance of both settings. The relative degree of variability across the wild belugas suggests that audiograms from multiple individuals are needed to properly describe the maximum sensitivity and population variance for odontocetes. Hearing measures were easily incorporated into field-based settings. This detailed examination of hearing abilities in wild Bristol Bay belugas provides a basis for a better understanding of the potential impact of anthropogenic noise on a noise-sensitive species. Such information may help design noise-limiting mitigation measures that could be applied to areas heavily influenced and inhabited by endangered belugas.

Potential population-level effects of increased haulout-related mortality of Pacific walrus calves

Availability of summer sea ice has been decreasing in the Chukchi Sea during recent decades, and increasing numbers of Pacific walruses have begun using coastal haulouts in late summer during years when sea ice retreats beyond the continental shelf. Calves and yearlings are particularly susceptible to being crushed during disturbance events that cause the herd to panic and stampede at these large haulouts, but the potential population-level effects of this mortality are unknown. We used recent harvest data, along with previous assumptions about demographic parameters for this population, to estimate female population size and structure in 2009 and project these numbers forward using a range of assumptions about future harvests and haulout-related mortality that might result from increased use of coastal haulouts during late summer. We found that if demographic parameters were held constant, the levels of harvest that occurred during 1990–2008 would have allowed the population to grow during that period. Our projections indicate, however, that an increase in haulout-related mortality affecting only calves has a greater effect on the population than an equivalent increase in harvest-related mortality distributed among all age classes. Therefore, disturbance-related mortality of calves at coastal haulouts may have relatively important population consequences.

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