Harbor Seal: A Guide to the Coastal Pinniped

The harbor seal (Phoca vitulina) is a widely distributed coastal pinniped found throughout the Northern Hemisphere's temperate and subarctic waters. This species profile provides students, researchers, life-science professionals, and informed general readers with a practical identification card, an overview of harbor seal biology and behavior, and current conservation context. The guide also explains how to distinguish harbor seals from other seal species and from sea lions, addresses the related spotted seal, and summarizes recent research on harbor seal cognition, sensory biology, disease, and human interactions.

At a Glance

Species Description and Identification

Harbor seals are true seals belonging to the family Phocidae. They have a rounded head, a relatively short snout, and no external ear flaps. The coat color varies widely among individuals, ranging from light gray to dark brown or silver, with a characteristic pattern of spots, rings, and blotches that is unique to each animal. Adult harbor seals typically reach 1.5 to 1.9 meters in length and weigh between 55 and 170 kilograms, with males generally larger than females.

The most reliable way to distinguish a harbor seal from a sea lion is the presence of external ear pinnae. Sea lions have small but visible ear flaps, while harbor seals have only a small opening behind each eye. Sea lions also use their large foreflippers to propel themselves on land and can rotate their hindflippers forward to walk. Harbor seals cannot rotate their hindflippers and move on land by undulating their bodies in a caterpillar-like motion.

The spotted seal (Phoca largha) is the closest relative of the harbor seal and overlaps with it in parts of the North Pacific. Spotted seals have a lighter background coat with more distinct dark spots, and they are strongly associated with pack ice for pupping and molting. Harbor seals in the same region pup on land or tidal flats instead of on ice. Genetic research has confirmed that harbor seals and spotted seals are distinct species, and the two subspecies of harbor seal in North America, P. v. richardii in the Pacific and P. v. vitulina in the Atlantic, show the greatest genetic differentiation between them [8].

Geographic Range and Population Structure

Harbor seals are found in coastal waters across the Northern Hemisphere, including the North Atlantic, the North Pacific, and adjacent seas. In North America, the Pacific subspecies P. v. richardii ranges from northern British Columbia through California, while the Atlantic subspecies P. v. vitulina occurs from the northeastern United States through eastern Canada and Greenland.

Population genomics research using genotyping-by-sequencing of 146 harbor seals from British Columbia, Oregon, California, Quebec, and Newfoundland and Labrador identified 12,742 genetic variants and confirmed elevated genetic diversity in the eastern Pacific relative to the western Atlantic [8]. The study found divergence between British Columbia and Oregon-California populations and between Quebec and Newfoundland-Labrador populations. An isolation-by-distance signature was observed in which Oregon seals contained some of the British Columbia genetic signature, while California seals did not [8]. The authors noted that additional sampling is needed in the central and north coast of British Columbia to determine whether a discrete separation of populations exists within that region [8].

Earlier genetic studies using minisatellite loci and DNA fingerprinting methods documented the structure and amount of genetic variation within the subspecies complex of Phoca vitulina [22][23]. These foundational studies established that harbor seal populations maintain measurable genetic structure across their range, a finding that has informed subsequent management approaches.

Sensory Biology and Foraging Adaptations

Harbor seals possess a remarkable sensory system centered on their whiskers, or vibrissae. These specialized hairs are undulated in shape, a morphology that suppresses vortex-induced vibrations and enables seals to track hydrodynamic trails left by prey in the water [12][14]. Comparative flow experiments have demonstrated that phocid seal whiskers, including those of harbor and gray seals, suppress vortex-induced vibrations and provide superior signal-to-noise ratios compared to sea lion whiskers [12].

Research on vibrissal sensitivity in a trained harbor seal measured the smallest detectable velocity of directly coupled sinusoidal stimuli across frequencies from 10 to 1000 Hz [7]. The seal showed best sensitivity of 0.09 millimeters per second at 80 Hz, with velocity thresholds following a characteristic U-shaped curve with decreasing sensitivity below 20 Hz and above 250 Hz [7]. The thresholds measured were about 100 times more sensitive than previous in-air measures of vibrissal sensitivity for this species, and the results were similar to those reported for detection of waterborne vibrations but with an extended range of frequency sensitivity [7].

Recent work on the functional role of whisking in seal whisker sensing has shown that undulated harbor seal whiskers exhibit threefold lower vortex-induced vibrations and over fiftyfold higher signal-to-noise ratio than California sea lion whiskers [14]. A bionic seal muzzle with 30 natural whiskers per side, capable of whisking at variable angles and frequencies, was developed to study this system. The results indicate that undulatory morphology and active whisker protraction are essential for seals to achieve sufficiently high signal-to-noise ratios to track prey trails [14].

These sensory adaptations support harbor seals' foraging efficiency in dark or turbid waters where visual cues are limited. The whisker system has also inspired engineered flow sensors, with a fully printed MEMS flow sensor using replicated whisker geometries from harbor seals, gray seals, and sea lions demonstrating high strain sensitivity and stable performance over 3000 cycles [12].

Cognition and Learning

Harbor seals demonstrate notable cognitive flexibility, particularly in spatial learning tasks. In a study of spatial reversal learning, harbor seals quickly learned a classic spatial reversal task and showed progressive improvement over reversals, with one seal reaching one-trial performance [10]. When reversals within a session were marked by an external cue, the experimental animal achieved errorless performance in up to three consecutive reversals [10]. The authors concluded that harbor seals master spatial reversal learning experiments with ease, and the underlying behavioral flexibility can help optimize behaviors in fluctuating or changing environments [10].

In contrast, visual reversal learning in harbor seals showed significant individual differences in performance [9]. One individual solved 37 reversals with progressive improvement, reaching a minimum of 6 errors in reversal 33, while two seals mastered only two reversals and one animal failed to complete a single reversal [9]. The authors noted that harbor seal performance in visual reversal learning was inferior to results obtained in other vertebrates in comparable tasks, and they raised questions about whether the modality addressed in the experiment influences reversal learning performance [9].

Harbor seals also demonstrate the ability to use geometrical relationships between landmarks for navigation. A trained harbor seal learned to find its goal in the middle of numerous vertically and horizontally oriented two-landmark arrays and, when confronted with unfamiliar arrays, directly and consistently followed a middle rule with high precision [5]. This ability to localize goals based on geometrical information would allow seals to home in on places even from unknown positions relative to goal-defining features [5].

Research on respiratory production learning in harbor seals has demonstrated a remarkable level of respiratory control. A harbor seal learned to produce uninterrupted vocalizations spanning more than two orders of magnitude in duration, from 79 milliseconds to 9.23 seconds, exceeding its pre-experimental vocalization range of 0.202 to 2.621 seconds [4]. This capacity for respiratory production learning arises at a young age and is hardly reported in the non-human animal literature [4].

Diet and Trophic Ecology

Harbor seals are generalist predators that consume a wide variety of fish and invertebrates. In the southern North Sea, a multi-method study examined resource partitioning among harbor seals, gray seals, and harbor porpoises using stomach content analysis, metabarcoding, and carbon, nitrogen, and sulfur stable isotope analysis [13]. Gastrointestinal data from stranded harbor seals (n = 223), gray seals (n = 87), and harbor porpoises (n = 218), alongside 283 scat samples from wild seals collected between 2014 and 2021, were analyzed [13].

Harbor seals and gray seals showed high prey similarity with a Jaccard index of 0.71, while porpoises exhibited lower similarity with both seal species [13]. Interactions with prey guilds were strongest for demersal roundfish, flatfish, gobies, and sandeels. Bayesian isotope mixing models revealed consistent trophic differences among the three top predators, with seals occupying higher trophic positions than porpoises and showing minimal dietary change over time [13]. Isotopic niche metrics indicated increasing overlap between porpoises and gray seals, while harbor seals showed a contraction in niche area [13].

In the Northwest Atlantic, analysis of 148 harbor and 178 gray seal stomach samples from bycatch events between 2004 and 2018 showed that the majority of bycaught seals were young-of-the-year that consume a wide breadth of prey across three trophic groups [21]. Prey size estimates from fish otoliths and squid beaks showed that gray seals consumed larger prey than harbor seals, and prey sizes from both seals showed limited overlap with prey sizes caught by commercial gillnet fishermen [21]. Important prey for harbor seals that did not overlap with gray seals included Acadian redfish, Atlantic herring, longfin squid, and shortfin squid [21].

Haul-Out Behavior and Habitat Use

Harbor seals are semi-aquatic and must haul out on land or ice to rest, give birth, nurse their young, and molt. They typically select haul-out sites that are protected from terrestrial predators and human disturbance, including rocky shores, sandbars, mudflats, and glacial ice in some regions. Haul-out sites are often used consistently over time, and seals may travel considerable distances between foraging areas and haul-out locations.

The ability of harbor seals to return to specific haul-out sites and foraging areas is supported by their landmark-based navigation abilities [5]. Research on spatial cognition suggests that harbor seals can use geometrical relationships between landmarks to localize specific places, which would be adaptive in an environment where the information content can vary over time [5].

Mortality and Disease

A retrospective study of harbor seal mortality along the British Columbia coast from 2012 to 2020 reviewed medical records for 1,279 predominantly perinatal live-stranded harbor seals recovered by the Vancouver Aquarium Marine Mammal Rescue Centre [3]. Approximately 20.0% of these animals (256 individuals) died while at the rehabilitation center. Infectious disease was the most common cause of death, accounting for 60.5% of mortality across all age classes, followed by nonanthropogenic trauma (7.1%), metabolic illness (5.4%), nutritional deficiency (5.0%), parasitic illness (5.0%), congenital disorders (2.5%), and human-associated trauma (0.4%) [3].

Pups were the most common age class among mortalities at 87.4% and predominantly died of an infectious process (62.5%) [3]. Phocid herpesvirus-1 infection was identified in 18.9% of the mortalities, with the highest prevalence occurring in 2019 at 30.8% [3]. Fungal disease was detected in six seals, including three cases of pulmonary mycosis due to Cryptococcus gattii and three cases consistent with mucormycosis [3]. Six cases of mortality were attributed to congenital disorders, two of which involved axial skeletal malformities not currently described in the literature [3].

Congenital diseases in harbor seals from the Salish Sea were analyzed in a separate study of postmortem data [6]. Cleft palate, cleft lips, or both (n = 8) and cardiac defects (n = 5) were the most common congenital abnormalities, followed by cases with multiple defects (n = 4) [6]. No temporal trends or spatial clusters of cases were seen from 2003 to 2019, and cases could not be linked to specific causes such as environmental contamination or maternal malnutrition [6]. The study suggested that a yearly prevalence of 2.9% plus or minus 2.2 is the endemic level of congenital disease in this stable harbor seal population [6].

A case report documented the first detection of Usutu virus in harbor seals, describing fatal infections in three seals from a rescue center on the North Sea coast in Germany [15]. The most prevalent findings in clinically affected animals were neurological signs and non-suppurative encephalitis, and all animals were found dead or euthanized within 30 hours after the onset of clinical signs [15]. Blood samples from another 37 young harbor seals from the same rescue center revealed two further asymptomatic Usutu virus RNA and antibody-positive animals [15]. The sequences belonged to Usutu virus lineages Europe 2 and Africa 3, which are known to circulate in birds in Germany [15].

Human Interactions and Conservation

Harbor seal populations in many regions have recovered from historical exploitation. In New England, gray and harbor seals were targeted in legal bounty hunts between 1880 and 1962 due to perceived competition with commercial fisheries [19]. Following their extirpation, legislative protections allowed seals to recolonize historical grounds, and this conservation success has re-emerged as a source of conflict, with calls to cull populations and the spread of misinformation [19]. The authors of a community science approach study noted that even as gray seals have the highest fisheries bycatch levels of any marine mammal in the United States, resources to address these management challenges are minimal [19].

In the Northwest Atlantic, harbor and gray seal populations are recovering from early to mid-20th century exploitation, increasing their biological interactions and bycatch in northeastern US commercial fisheries [21]. The majority of bycaught seals are young-of-the-year, and prey sizes from both seals showed limited overlap with prey sizes caught by commercial gillnet fishermen [21].

Anthropogenic stress on Pacific harbor seals has been studied using behavioral observations and fecal corticosterone analyses [20]. The study examined how human disturbance affects stress physiology and behavior in harbor seals, providing a basis for managing human activities near haul-out sites.

In the Southern California current large marine ecosystem, a decrease in Pacific harbor seal counts has been documented [17]. The causes of this decline are not fully established, and continued monitoring is needed to understand population trends in this region.

Harbor seals in Latin America are addressed in a chapter on the Pacific harbor seal (Phoca vitulina richardii) in the volume Ecology and Conservation of Pinnipeds in Latin America [18]. The chapter covers the species' distribution, ecology, and conservation status in the southern portion of its range.

Interactions with Marine Renewable Energy

The overlap between harbor seal habitat and locations for tidal turbines has raised concerns about collision risk. A study using data from tagged harbor seals collected before construction and after operation of the SeaGen tidal turbine in Northern Ireland quantified the risks of an operational turbine to harbor seals [11]. The study found 68% spatial avoidance by harbor seals within 200 meters of the turbine, with a 95% confidence interval of 37% to 83% [11]. When accounting for variation in seal occupancy over depth and tidal flows, there was an overall reduction in collision risk from 1.29 to 0.125 seals per tidal cycle, a 90.3% reduction compared to risk calculated under assumptions of uniform habitat use [11]. This demonstrates the need to incorporate environmental conditions to properly assess strike risk [11].

Welfare Considerations in Rehabilitation Settings

The assessment of animal welfare in rehabilitation settings is a critical aspect of effective care. A study of anticipatory behavior in fourteen rehabilitating harbor seal pups (Phoca vitulina richardii) investigated the effects of enrichment type on welfare [16]. The study provided pups with daily sessions of either structural or cognitive enrichment and recorded their behavioral responses during scheduled feeding sessions [16]. While enrichment interaction did not directly modulate anticipatory behavior, a trend suggested that exposure to cognitive enrichment reduced anticipatory behavior duration compared to structural enrichment [16]. These findings align with previous research in zoo settings where cognitive enrichment has been linked to improved welfare through reduced anticipatory behavior [16].

For wildlife rehabilitators, this research suggests that cognitive enrichment may offer welfare benefits for harbor seal pups in care. Practical applications include providing puzzle feeders, novel objects that require manipulation, and training sessions that engage the seals in problem-solving. Records of anticipatory behavior frequency and duration before scheduled feeds can serve as a non-invasive welfare indicator.

Practical Assessment Steps for Field Observation

For researchers, students, and wildlife professionals conducting field observations of harbor seals, the following assessment steps provide a structured approach to data collection and species identification.

First, confirm species identification before recording behavioral data. Note the absence of external ear pinnae, the short foreflippers with claws, and the inability to rotate hindflippers forward. Compare these features with sea lions, which have visible ear flaps and can walk on land. In the North Pacific, distinguish harbor seals from spotted seals by checking for association with pack ice and the distinctness of the spot pattern.

Second, record the haul-out site characteristics, including substrate type, proximity to human activity, and number of animals present. Note the time of day and tidal state, as these factors influence haul-out behavior.

Third, document behavioral states using a standardized ethogram. Common states include resting, alert, moving, interacting, and nursing. For rehabilitation settings, record anticipatory behavior before scheduled feeding sessions as a welfare indicator [16].

Fourth, photograph individual animals for identification purposes. The unique spot patterns on harbor seals allow for photo-identification studies of individual movements and site fidelity.

Fifth, report any observations of sick, injured, or dead seals to the appropriate stranding network or wildlife agency. Do not approach or handle seals, as they can bite and may carry zoonotic diseases.

Records and Measurements

Wildlife professionals and researchers should maintain standardized records for harbor seal observations and rehabilitation cases. Essential data fields include date, time, location with coordinates, weather conditions, tidal state, group size, age class, sex if determinable, body condition score, and any visible marks, tags, or injuries.

For rehabilitation facilities, medical records should document admission date, stranding location, presenting condition, body weight, length, girth, diagnostic test results, treatment administered, daily feedings, behavioral observations, and outcome. The British Columbia mortality study reviewed medical records for 1,279 seals over an eight-year period, demonstrating the value of consistent record-keeping for understanding population-level health trends [3].

For population monitoring, standardized count protocols should specify survey timing, duration, and methodology to ensure comparability across years. The Southern California current large marine ecosystem study documenting decreased harbor seal counts relied on consistent monitoring effort to detect population trends [17].

Common Failure Patterns in Observation and Management

Several common errors occur in harbor seal observation, research, and management. Misidentification is the most frequent error, particularly confusion between harbor seals and sea lions or between harbor seals and spotted seals in overlapping ranges. Observers should confirm the presence or absence of ear pinnae and the ability to rotate hindflippers before recording species.

Disturbance of haul-out sites is a common management failure. Approaching seals too closely causes them to flush into the water, which can lead to injury, separation of mothers from pups, and increased stress. Fecal corticosterone analyses have been used to document anthropogenic stress in harbor seals [20]. Managers should establish and enforce buffer zones around haul-out sites, particularly during pupping and molting seasons.

In rehabilitation settings, failure to recognize the high mortality risk for perinatal pups can lead to unrealistic expectations. The British Columbia study found that 20.0% of admitted seals died while at the rehabilitation center, with infectious disease as the most common cause of death [3]. Facilities should have clear protocols for triage, euthanasia decisions, and biosecurity to prevent disease transmission among animals.

Incomplete understanding of population structure can lead to inappropriate management decisions. Genetic research has demonstrated fine-scale population structure in harbor seals, with divergence between British Columbia and Oregon-California populations [8]. Management units should reflect this genetic structure instead of treating all harbor seals as a single homogeneous population.

Limitations of Current Knowledge

Several important knowledge gaps remain in harbor seal biology and conservation. The causes of the decrease in Pacific harbor seal counts in the Southern California current large marine ecosystem are not fully established [17]. Additional research is needed to determine whether this decline reflects changes in prey availability, disease, human disturbance, or other factors.

The drivers of congenital disease in harbor seals remain unknown. The Salish Sea study found no temporal trends or spatial clusters of congenital abnormalities and could not link cases to specific causes such as environmental contamination or maternal malnutrition [6]. Continued monitoring of birth defects and overall harbor seal population status could help identify emerging teratogens [6].

The functional significance of individual variation in cognitive abilities is not well understood. Visual reversal learning studies found significant individual differences in performance among harbor seals, with some individuals solving many reversals and others failing to complete a single one [9]. The ecological and evolutionary implications of this variation remain unclear.

The extent of Usutu virus infection in harbor seal populations is unknown. The first detection of Usutu virus in harbor seals involved three fatal cases and two asymptomatic infections at a single rescue center in Germany [15]. Surveillance in other regions and populations is needed to assess the geographic and taxonomic scope of this emerging pathogen.

Professional Escalation Criteria

Wildlife professionals, researchers, and members of the public should escalate harbor seal observations to appropriate authorities under specific circumstances. Any sick, injured, or dead harbor seal should be reported to the local stranding network or wildlife agency. Do not attempt to capture, handle, or feed the animal, as this can cause further injury and may be illegal under marine mammal protection laws.

Signs that warrant immediate professional attention include visible wounds, entanglements in fishing gear, labored breathing, abnormal posture, discharge from the eyes or nose, and pups that are alone for extended periods. In rehabilitation settings, any seal showing neurological signs such as seizures, head tilt, or circling should be evaluated for infectious causes, including Usutu virus where it is known to occur [15].

Researchers planning to tag or sample harbor seals should consult with institutional animal care committees and obtain all necessary permits. Population declines, unusual mortality events, or changes in haul-out site use should be reported to management agencies to trigger appropriate investigation.

Frequently Asked Questions

What is the difference between a harbor seal and a sea lion?

Harbor seals are true seals with no external ear pinnae, short clawed foreflippers, and hindflippers that cannot rotate forward. Sea lions have visible external ear flaps, long hairless foreflippers, and hindflippers that can rotate forward to support walking on land. Sea lions are generally larger than harbor seals and are more agile on land.

How can I tell a harbor seal from a spotted seal?

Harbor seals have a varied coat pattern of spots, blotches, and rings on a gray, tan, or silver background. Spotted seals have a lighter background coat with more distinct dark spots. Spotted seals are strongly associated with pack ice for pupping and molting, while harbor seals pup on land or tidal flats. The two species overlap in parts of the North Pacific.

What do harbor seals eat?

Harbor seals are generalist predators that consume a wide variety of fish and invertebrates. In the North Sea, their prey includes demersal roundfish, flatfish, gobies, and sandeels [13]. In the Northwest Atlantic, important prey includes silver hake, red hake, white hake, Atlantic cod, Acadian redfish, Atlantic herring, and squid [21].

How long can a harbor seal hold its breath?

Harbor seals are capable of diving for extended periods, though specific dive durations vary with age, condition, and activity. Research on respiratory control in harbor seals has demonstrated their ability to produce uninterrupted vocalizations lasting up to 9.23 seconds, which reflects their extensive respiratory control [4]. For diving, harbor seals typically make shorter dives of several minutes, with longer dives possible.

Are harbor seals endangered?

Harbor seals are not listed as endangered under the US Endangered Species Act. Many populations have recovered from historical exploitation and are stable or increasing. However, some regional populations have shown declines, including a decrease in Pacific harbor seal counts in the Southern California current large marine ecosystem [17]. Harbor seals remain protected under the Marine Mammal Protection Act in the United States.

Do harbor seals migrate?

Harbor seals do not undertake long-distance migrations like some other pinnipeds. They show strong natal philopatry, meaning they tend to return to their birth sites, which can result in fine-scale genetic structure and isolation by distance [8]. Individual seals may travel considerable distances between foraging areas and haul-out sites but generally remain within a regional home range.

What diseases affect harbor seals?

Infectious disease is the most common cause of mortality in harbor seals undergoing rehabilitation, accounting for 60.5% of deaths in a British Columbia study [3]. Phocid herpesvirus-1 infection was identified in 18.9% of mortalities in that study [3]. Usutu virus has been documented as a cause of fatal neurological disease in harbor seals in Germany [15]. Congenital diseases, including cleft palate and cardiac defects, occur at an endemic level in some populations [6].

How do harbor seals find their prey?

Harbor seals use their highly sensitive whiskers, or vibrissae, to detect hydrodynamic trails left by prey in the water [12][14]. The undulated morphology of harbor seal whiskers suppresses vortex-induced vibrations and provides superior signal-to-noise ratios compared to sea lion whiskers [12][14]. Active whisking, or protraction of the whiskers, is essential for seals to achieve sufficiently high signal-to-noise ratios to track prey trails [14].

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References and Further Reading

• NCBI Literature Resources. National Center for Biotechnology Information.
• PubMed. National Library of Medicine.
• CAUSES AND TRENDS OF HARBOR SEAL (PHOCA VITULINA) MORTALITY ALONG THE BRITISH COLUMBIA COAST, CANADA, 2012-2020.. Journal of wildlife diseases, 2023.
• A harbor seal (Phoca vitulina) shows extensive respiratory control in sound production.. BMC ecology and evolution, 2025.
• A harbour seal (Phoca vitulina) can learn geometrical relationships between landmarks.. The Journal of experimental biology, 2022.
• Congenital Diseases in Harbor Seals (Phoca vitulina richardsii) from the Salish Sea.. Journal of wildlife diseases, 2021.
• Vibrissal sensitivity in a harbor seal (Phoca vitulina).. The Journal of experimental biology, 2015.
• Population genomics of harbour seal Phoca vitulina from northern British Columbia through California and comparison to the Atlantic subspecies.. Molecular ecology, 2024.
• Serial visual reversal learning in harbor seals (Phoca vitulina).. Animal cognition, 2022.
• Well-developed spatial reversal learning abilities in harbor seals (Phoca vitulina).. Animal cognition, 2022.
• Empirical measures of harbor seal behavior and avoidance of an operational tidal turbine.. 2018.
• Seal whisker-inspired fully printed MEMS flow sensor via micron-scale soft material additive manufacturing.. 2026.
• Rising competition among North Sea mammalian top predators: a multi-method perspective on trophic ecology.. 2026.
• Soft bionic actuation explains the functional role of whisking in seal whisker sensing.. 2026.
• First Detection of Usutu Virus in Harbor Seals (&lt,i&gt,Phoca vitulina&lt,/i&gt,).. 2026.
• Anticipatory Behavior and Enrichment: Insights into Assessing and Managing Harbor Seal (&lt,i&gt,Phoca vitulina richardii&lt,/i&gt,) Pup Welfare in a Wildlife Rehabilitation Setting.. 2025.
• Decrease in Pacific harbor seal counts in the Southern California current large marine ecosystem. Biodiversity and Conservation, 2025.
• Pacific Harbor Seal (Phoca vitulina richardii, Gray 1864). Ecology and Conservation of Pinnipeds in Latin America, 2021.
• A Community Science Approach to Conservation Challenges Posed by Rebounding Marine Mammal Populations: Seal-Fishery Interactions in New England. Frontiers in Conservation Science, 2021.
• Anthropogenic stress on the Pacific harbor seal ( Phoca vitulina ) based on behavior and fecal corticosterone analyses. 2017.
• What bycatch tells us about the diet of harbor and gray seals and overlap with commercial fishermen. Frontiers in Conservation Science, 2024.
• Structure and amount of genetic variation at minisatellite loci within the subspecies complex of Phoca vitulina (the harbour seal). Heredity, 1997.
• Genetic variation in phoca vitulina (The harbour seal) revealed by DNA fingerprinting and RAPDs. Heredity, 1995.

This article is educational and does not replace institutional policy, professional advice, or applicable safety and regulatory requirements.