Steven J. Jeffries

Trends and status of harbor seals in Washington State: 1978-1999

In the first half of the 20th century, harbor seal (Phoca vitulina richardsi) numbers were severely reduced in Washington state by a state-financed population control program. Seal numbers began to recover after the cessation of bounties in 1960 and passage of the Marine Mammal Protection Act (MMPA) in 1972. From 1978 to 1999, aerial surveys were flown at midday low tides during pupping season to determine the distribution and abundance of harbor seals in Washington. We used exponential and generalized logistic models to examine population trends and size relative to maximum net productivity level (MNPL) and carrying capacity (K). Observed harbor seal abundance has increased 3-fold since 1978, and estimated abundance has increased 7 to 10-fold since 1970. Under National Marine Fisheries Service (NMFS) management, Washington harbor seals are divided into 2 stocks: coastal and inland waters. The observed population size for 1999 is very close to the predicted Kfor both stocks. The current management philosophy for marine mammals that assumes a density-dependent response in population growth with MNPL > K/2 is supported by growth of harbor seal stocks in Washington waters.

PCB-related alteration of thyroid hormones and thyroid hormone receptor gene expression in free-ranging harbor seals (Phoca vitulina)

Persistent organic pollutants are environmental contaminants that, because of their lipophilic properties and long half-lives, bioaccumulate within aquatic food webs and often reach high concentrations in marine mammals, such as harbor seals (Phoca vitulina). Exposure to these contaminants has been associated with developmental abnormalities, immunotoxicity, and reproductive impairment in marine mammals and other high-trophic-level wildlife, mediated via a disruption of endocrine processes. The highly conserved thyroid hormones (THs) represent one vulnerable endocrine end point that is critical for metabolism, growth, and development in vertebrates. We characterized the relationship between contaminants and specific TH receptor (TR ) gene expression in skin/blubber biopsy samples, as well as serum THs, from free-ranging harbor seal pups (n = 39) in British Columbia, Canada, and Washington State, USA. We observed a contaminant-related increase in blubber TR-α gene expression [total polychlorinated biphenyls (∑PCBs); r = 0.679; p < 0.001] and a concomitant decrease in circulating total thyroxine concentrations (∑PCBs; r = −0.711; p < 0.001). Consistent with results observed in carefully controlled laboratory and captive feeding studies, our findings suggest that the TH system in harbor seals is highly sensitive to disruption by environmental contaminants. Such a disruption not only may lead to adverse effects on growth and development but also could have important ramifications for lipid metabolism and energetics in marine mammals.

Harbor seals (Phoca vitulina) in British Columbia, Canada, and Washington State, USA, reveal a combination of local and global polychlorinated biphenyl, dioxin, and furan signals

The harbor seal (Phoca vitulina) can serve as a useful indicator of food web contamination by persistent organic pollutants (POPs) because of its high trophic level, wide distribution in temperate coastal waters of the Northern Hemisphere, and relative ease of capture. In 1996 through 1997, we live-captured 60 harbor seal pups from three regions, spanning remote (Queen Charlotte Strait, BC, Canada), moderately industrialized (Strait of Georgia, BC, Canada), and heavily industrialized (Puget Sound, WA, USA) marine basins straddling the Canada-United States border. Biopsy samples of blubber were taken and analyzed for congener-specific polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) by using high-resolution gas chromatography-high-resolution mass spectrometry. Harbor seals in Puget Sound were heavily contaminated with PCBs, whereas seals from the Strait of Georgia had relatively high concentrations of PCDDs and PCDFs. Pattern evaluation and principal components analysis suggested that proximity to sources influenced the mixture to which seals were exposed, with those inhabiting more remote areas being exposed to lighter PCB congeners (those with lower Henrys law constant and K(ow)) that disperse more readily through atmospheric and other processes. Total toxic equivalents to 2,3,7,8-tetrachlorodibenzo-p-dioxin for the PCBs, PCDDs, and PCDFs suggest that Puget Sound seals are at greatest risk for adverse health effects, and that PCBs represent the class of dioxinlike contaminants of greatest concern at all sites.

Evidence of Brucella infection in Parafilaroides lungworms in a Pacific harbor seal (Phoca vitulina richardsi).

Multiple isolates of Brucella sp. that differ from the recognized species within this genus have recently been isolated from viscera of 4 harbor seals (Phoca vitulina), 2 harbor porpoises (Phocoena phocoena), 1 common dolphin (Delphinus delphis), an Atlantic white-sided dolphin (Lagenorhynchus acutus), 2 striped dolphins (Stenella coeruleoalba), a hooded seal (Cystophora cristata), and a gray seal (Halichoerus grypus), 9,18 all from the Scottish coast. A similar Brucella sp. was isolated from an aborted fetus of a bottlenose dolphin (Tursiops truncatus) from the coast of Califomia. During routine capture operations, 18 of 102 Pacific harbor seals (Phoca vitulina richardsi) and 4 of 50 California sea lions (Zalophus californianus) from Puget Sound, Washington, had been reported with positive titers to Brucella sp. In this report, we describe the isolation, tissue location, and immunohistochemical and ultrastructural features of Brucella sp. infection in a pacific harbor seal. These findings suggest that transmission of brucellosis by infected lungworms is a possibility. On March 28, 1996, a 7-9-month-old 17.5-kg male Pacific harbor seal (105 cm length, snout to tail tip) was collected dead from Restoration Point on Bainbridge Island in the Puget Sound, Washington. The seal had been dead for 2-5 days, and there was slight decomposition. The carcass was transported to the Washington Department of Fish and Wildlife Marine Mammal Investigations Laboratory in Tacoma and necropsied. Blood drawn from the heart was separated by centrifugation, and serum was sent to the Washington Department of Agriculture Laboratory to screen for antibodies to Brucella sp. Values were compared with the standards outlined in the Brucellosis Eradication Uniform Methods and Rules (1992, revised 1994, USDA, APHIS). The sample was tested using B. abortus antigens provided by the National Veterinary Services Laboratory (NVSL), Ames, Iowa. Official protocols for

Detection of Pathogenic Leptospira Bacteria in Pinniped Populations via PCR and Identification of a Source of Transmission for Zoonotic Leptospirosis in the Marine Environment

ABSTRACT Leptospirosis, caused by the spirochete Leptospira, is a geographically widespread disease that affects a broad range of mammals, including marine mammals. Among pinniped populations, periodic epizootics of leptospirosis are responsible for significant die-offs. Along the west coast of North America, the most recent leptospirosis epizootic occurred in 2004, during which samples were collected from cases ranging from California to British Columbia. The primary objective of this study was to use this well-defined sample set to determine the feasibility of using PCR techniques to diagnose Leptospira infection among pinniped populations in comparison with diagnostic methodologies commonly used for marine mammals. Successful amplification was achieved from a variety of samples, including freshly collected urine, urine stored at −80°C for less than 6 months, and kidney (freshly collected, frozen, and decomposed), as well as feces- and urine-contaminated sand collected in the vicinity of a live-stranded animal. Pathological examination of tissue collected from Leptospira-infected animals revealed the presence of leptospiral antigen in the kidneys. The use of species-specific primer pairs revealed a pattern of host specificity for Leptospira interrogans in sea lions and Leptospira kirschneri in elephant seals. These studies indicate PCR is a sensitive and specific diagnostic tool for the detection of Leptospira infection in pinnipeds and reveal a potential source for epizootic, enzootic, and zoonotic spread of leptospirosis in a marine environment.

New insights into the diets of harbor seals (Phoca vitulina) in the Salish Sea revealed by analysis of fatty acid signatures

Harbor seals (Phoca fvitulina) are an abundant predator along the west coast of North America, and there is considerable interest in their diet composition, especially in regard to predation on valued fish stocks. Available informationon harbor seal diets, primarily derived from scat analysis, suggests that adult salmon (Oncorhynchus spp.), Pacific Herring (Clupea pallasii), and gadids predominate. Because diet assessments based on scat analysis may be biased, we investigated diet composition through quantitative analysis of fatty acid signatures. Blubber samples from 49 harbor seals captured in western North America from haul-outs within the area of the San Juan Islands and southern Strait of Georgia in the Salish Sea were analyzed for fatty acid composition, along with 269 fish and squid specimens representing 27 potential prey classes. Diet estimates varied spatially, demographically, and among individual harbor seals. Findings confirmed the prevalence of previously identified prey species in harbor seal diets, but other species also contributed significantly. In particular, Black (Sebastes melanops) and Yellowtail (S. flavidus) Rockfish were estimated to compose up to 50% of some individual seal diets. Specialization and high predation rates on Black and Yellowtail Rockfish by a subset of harbor seals may play a role in the population dynamics of these regional rockfish stocks that is greater than previously realized.

Persistent organic pollutants in the diet of harbor seals (Phoca vitulina) inhabiting puget sound, washington (USA), and the strait of Georgia, British Columbia (Canada): A food basket approach

Harbor seals (Phoca vitulina) inhabiting Puget Sound (WA, USA) recently were found to be seven times more contaminated with polychlorinated biphenyls (PCBs) than those inhabiting the adjacent Strait of Georgia (BC, Canada). We carried out a food basket approach to approximate realistic dietary exposures of both new (e.g., polybrominated diphenyl ethers [PBDEs]) and legacy (e.g., dichlorodiphenyltrichloroethane [DDT]) persistent organic pollutants (POPs) for these harbor seals. Food basket homogenates, each consisting of over 200 individual prey items, were constructed using documented dietary preferences for harbor seals in these basins, and analyzed for organochlorine pesticides, flame retardants, and other persistent contaminants. Concentration rankings for the major contaminant classes in the Puget Sound food basket were sigmaPCBs > sigmaPBDEs > sigmaDDT, and for the Strait of Georgia food basket were sigmaPCBs > sigmaDDT > sigmaPBDEs, highlighting the emergence of PBDEs as a significant concern in the regional environment. Consistent with observations in harbor seals, PCB concentrations in the Puget Sound food basket were seven times higher than in its Strait of Georgia counterpart. Based on our food basket results, the estimated daily intake of sigmaPCB toxic equivalents to dioxin by Puget Sound harbor seals exceeds some wildlife consumption guidelines for PCBs. Our results indicate that both legacy and new POPs present a health risk to these marine mammals.

Long Distance Movements and Disjunct Spatial Use of Harbor Seals (Phoca vitulina) in the Inland Waters of the Pacific Northwest

Background Worldwide, adult harbor seals (Phoca vitulina) typically limit their movements and activity to <50 km from their primary haul-out site. As a result, the ecological impact of harbor seals is viewed as limited to relatively small spatial scales. Harbor seals in the Pacific Northwest are believed to remain <30 km from their primary haul-out site, one of several contributing factors to the current stock designation. However, movement patterns within the region are not well understood because previous studies have used radio-telemetry, which has range limitations. Our objective was to use satellite-telemetry to determine the regional spatial scale of movements. Methodology/Principal Findings Satellite tags were deployed on 20 adult seals (n=16 males and 4 females) from two rocky reefs and a mudflat-bay during April–May 2007. Standard filtering algorithms were used to remove outliers, resulting in an average (± SD) of 693 (±377) locations per seal over 110 (±32) days. A particle filter was implemented to interpolate locations temporally and decrease erroneous locations on land. Minimum over-water distances were calculated between filtered locations and each seals capture site to show movement of seals over time relative to their capture site, and we estimated utilization distributions from kernel density analysis to reflect spatial use. Eight males moved >100 km from their capture site at least once, two of which traveled round trip to and from the Pacific coast, a total distance >400 km. Disjunct spatial use patterns observed provide new insight into general harbor seal behavior. Conclusions/Significance Long-distance movements and disjunct spatial use of adult harbor seals have not been reported for the study region and are rare worldwide in such a large proportion of tagged individuals. Thus, the ecological influence of individual seals may reach farther than previously assumed.

Haul-Out Behavior of Harbor Seals (Phoca vitulina) in Hood Canal, Washington

The goal of this study was to model haul-out behavior of harbor seals (Phoca vitulina) in the Hood Canal region of Washington State with respect to changes in physiological, environmental, and temporal covariates. Previous research has provided a solid understanding of seal haul-out behavior. Here, we expand on that work using a generalized linear mixed model (GLMM) with temporal autocorrelation and a large dataset. Our dataset included behavioral haul-out records from archival and VHF radio tag deployments on 25 individual seals representing 61,430 seal hours. A novel application for increased computational efficiency allowed us to examine this large dataset with a GLMM that appropriately accounts for temporal autocorellation. We found significant relationships with the covariates hour of day, day of year, minutes from high tide and year. Additionally, there was a significant effect of the interaction term hour of day : day of year. This interaction term demonstrated that seals are more likely to haul out during nighttime hours in August and September, but then switch to predominantly daylight haul-out patterns in October and November. We attribute this change in behavior to an effect of human disturbance levels. This study also examined a unique ecological event to determine the role of increased killer whale (Orcinus orca) predation on haul-out behavior. In 2003 and 2005 these harbor seals were exposed to unprecedented levels of killer whale predation and results show an overall increase in haul-out probability after exposure to killer whales. The outcome of this study will be integral to understanding any changes in population abundance as a result of increased killer whale predation.

Coxiella burnetii Infection of Marine Mammals in the Pacific Northwest, 1997-2010

Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii. Humans are commonly exposed via inhalation of aerosolized bacteria derived from the waste products of domesticated sheep and goats, and particularly from products generated during parturition. However, many other species can be infected with C. burnetii, and the host range and full zoonotic potential of C. burnetii is unknown. Two cases of C. burnetii infection in marine mammal placenta have been reported, but it is not known if this infection is common in marine mammals. To address this issue, placenta samples were collected from Pacific harbor seals (Phoca vitulina richardsi), harbor porpoises (Phocoena phocoena), and Steller sea lions (Eumetopias jubatus). Coxiella burnetii was detected by polymerase chain reaction (PCR) in the placentas of Pacific harbor seals (17/27), harbor porpoises (2/6), and Steller sea lions (1/2) collected in the Pacific Northwest. A serosurvey of 215 Pacific harbor seals sampled in inland and outer coastal areas of the Pacific Northwest showed that 34.0% (73/215) had antibodies against either Phase 1 or Phase 2 C. burnetii. These results suggest that C. burnetii infection is common among marine mammals in this region.