New Insights Into the Northward Migration Route of Gray Whales Between Vancouver Island, British Columbia, and Southeastern Alaska

New insights into the northward migration route of gray whales between Vancouver Island, British Columbia, and southeastern Alaska

John K.B. Ford1, John W. Durban2, Graeme M. Ellis1, Jared R. Towers1, James F. Pilkington1, Lance G. Barrett-Lennard3 and Russel D. Andrews4

1. Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada V9T 6N7 2. Southwest Fisheries Science Center, National Marine Fisheries Service, National Ocean and Atmospheric Association, La Jolla, CA 3. Vancouver Aquarium, P.O. Box 3232, Vancouver, BC, Canada V6B 3X8 4. University of Alaska Fairbanks School of Fisheries and Ocean Sciences, and the Alaska SeaLife Center, P.O. Box 1329, Seward, AK 99664, USA

In Press, Marine Mammal Science, 5 March 2012

ABSTRACT

The route taken by northward migrating gray whales during spring between Vancouver Island and southeastern Alaska, a distance of about 575 km, has long been uncertain. It is generally believed that the whales closely follow the western, outer coastline of Haida Gwaii (formerly the Queen Charlotte Islands), an archipelago lying between Vancouver Island and southeastern Alaska, consistent with their pattern of migrating close to shore over the majority of their northward migratory corridor. By tracking satellite-tagged individuals and surveying whales from shore bases, we provide evidence that this is not the primary migratory corridor, but instead that most whales migrate through Hecate Strait and Dixon Entrance, broad waterways that lie to the east and north of Haida Gwaii. By using this route, northbound gray whales potentially face a wider range of industrial activities and developments than they would by migrating along the outer coast.

Key Words: Eschrichtius robustus, migratory corridor, satellite tagging, telemetry, shore survey

INTRODUCTION

Each year, the majority of the eastern North Pacific population of gray whales (Eschrichtius robustus) undertakes long seasonal migrations between summer feeding grounds in the Bering and Chukchi Seas and winter breeding grounds in Baja California. The corridor used by migrating gray whales along the mainland west coast of North America between Baja California and Vancouver Island has been well described (Scammon 1874, Rice and Wolman 1971, Darling 1984, Herzing and Mate 1984, Poole 1984, Rugh et al. 2001, Mate and Urbán-Ramirez 2003). However, the route taken by migrants between Vancouver Island and the Bering Sea was for many years unknown, primarily due to the remoteness of the region and a lack of sightings. Kellogg (1929) 2 claimed that northbound whales “follow the coast, passing Vancouver and the Queen Charlotte Islands”, despite there being virtually no empirical evidence for a coastal route at the time. In the absence of sightings of migrating gray whales off northern British Columbia and southeastern Alaska, Ichihara (1958) and Gilmore (1960) both proposed offshore routes between Washington or Vancouver Island and the Aleutian Islands. Gilmore (1960) hypothesized that northbound gray whales turn west at the northern tip of Vancouver Island and follow ocean currents to the Aleutian Islands west of Unimak Pass, and that southbound whales similarly return through offshore waters, making landfall south of Washington. Pike (1962), however, compiled observations of migrating gray whales in Washington, British Columbia and Alaska, and proposed that the migration corridor “retains close contact” with the outer coast of British Columbia and southern Alaska rather than crossing the open waters of the Gulf of Alaska, although he noted that the actual route taken by migrating whales was uncertain north of Vancouver Island.

Since Pike’s (1962) report, studies have confirmed a nearshore route for northward migrating gray whales along Vancouver Island (Pike and MacAskie 1969, Hatler and Darling 1974, Darling 1984) and the outer coast of southern Alaska (Braham 1984). However, one significant gap remains. Between Cape Scott, at the northwestern tip of Vancouver Island (ca. 50°45’N), and Cape Muzon, at the south end of Dall Island, southeastern Alaska (ca. 54°40’N), a distance of about 575 km, the path taken by northbound gray whales is very poorly known. Two different routes are possible. The first, and the one that is generally assumed to be the northward corridor, follows the outer shores of Haida Gwaii (formerly the Queen Charlotte Islands), a 300 km long archipelago located 75-130 km offshore of the mainland coast of British Columbia. This route is depicted in maps of gray whale migration corridors in Pike (1962), Braham (1984), and in data atlases produced by the US National Oceanic and Atmospheric Administration (NOAA)1. In order to use this corridor, gray whales would have to cross Queen Charlotte Sound, a >200 km stretch of open water northwest of Vancouver Island, before proceeding up the west coast of Haida Gwaii, then make a shorter 50 km crossing of Dixon Entrance to the outer coast of southeastern Alaska. The second potential route would involve whales turning northward at the northern end of Vancouver Island, then migrating up Hecate Strait, which separates Haida Gwaii from mainland British Columbia, then northwest through Dixon Entrance, between Haida Gwaii and southeastern Alaska.

Pike’s (1962) and Pike and MacAskie’s (1969) suggestion that northbound gray whales migrate up the outer coast of Haida Gwaii was based solely on sighting reports of gray whales by lightstation personnel at Langara Island, located at the northwest corner of the archipelago. They attributed the lack of other sightings of whales along this route to the absence of human habitation on Haida Gwaii’s remote west coast. Pike (1962) suggested that some northbound gray whales “become temporarily confused” in crossing

1 See http://westcoastatlas.noaa.gov/ and Strategic Assessment Branch and Northwest and Alaska Fisheries Center, 1988: West Coast of North America Strategic Assessment: Data Atlas. Marine Mammals volume. Pre-publication edition. Rockville, MD: National Oceanic and Atmospheric Administration. 58 pp. 3 the broad expanse of Queen Charlotte Sound north of Vancouver Island, which accounts for the scattered sightings of gray whales in Hecate Strait during the spring migration period. Hatler and Darling (1974) concurred with Pike’s (1962) proposed migration corridor along the west coast of Haida Gwaii, but noted that the paucity of sightings in Hecate Strait may reflect a lack of sighting effort in that area.

Migrating gray whales could potentially experience very different levels of interaction with human activities along these alternative migration routes. The west coast of Haida Gwaii is a rugged, high-energy coastline with little nearshore vessel traffic or other human presence. Hecate Strait, in contrast, is a busy waterway with considerable shipping traffic and fishing activity, and is the proposed site for several major industrial development projects.

To resolve the uncertainty in the northward migration route of gray whales off the northern British Columbia coast, we undertook studies of migrating whales during 2009- 2011 using two different approaches, satellite tracking of individuals and shore-based visual surveys. Results of these studies indicate that the Hecate Strait migration corridor is the primary one used by northbound gray whales. This finding has important implications for future management of potential impacts from existing and proposed industrial activities along this route.

MATERIALS AND METHODS

Satellite Tracking

Efforts to deploy satellite tags on northward migrating gray whales were undertaken in mid to late March over three calendar years (2009-2011) between Barkley Sound and Hesquiat Peninsula, off the central west coast of Vancouver Island (ca. 40oN, 126oW). Timing of these efforts coincided with the typical peak of the spring migration (Pike 1962, Hatler and Darling 1974, Darling 1984). Small boats (5–7 m) were used to perform visual searches for whales and to deploy “double dart” tags (Andrews et al. 2008) with satellite transmitters (SPOT5 model, Wildlife Computers, Redmond, WA; http://www.wildlifecomputers.com/). These small (49 g) tags were attached with two barbed titanium posts that penetrated up to 6.5 cm into the gray whale’s dorsal hump. Tags were deployed using a crossbow bolt fired at ranges from 10–25 m using a crossbow of 150 lb draw weight (Andrews et al. 2008); the bolt fell away on contact with the whale, leaving only the tag attached. Tags were scheduled to transmit up to 250 times during 8 h each day, timed to coincide with passes of satellites from the ARGOS satellite system (CLS America, Largo, MD; http://www.argos-system.org/). Prior to tag deployment, whales were photographed for individual identification using digital SLR cameras with 70-210 mm lenses. Received transmissions were used to calculate locations and estimated error radii, using a positioning algorithm implemented by the Argos satellite system that employs Kalman filtering of the received frequency measurements (Lopez and Malardé 2011). To make inference about movement tracks and speeds, incorporating the estimated error, we 4 fit a continuous time correlated random walk model (Johnson et al. 2008), assuming the estimated error was normally distributed about each calculated location, with each standard deviation specified by the associated error radius. Visual Surveys Gray whales were surveyed from 16 March to 10 April 2011, by shore-based observers at two lightstations on the northern British Columbia coast. As with satellite tag deployments, the survey period was designed to coincide with the peak of the northward migration based on observations along the west coast of Vancouver Island (Pike 1962, Hatler and Darling 1974, Darling 1984). One observer (JRT) was based at Langara Island lightstation (54°09’N, 133°03’W; Fig. 1) to survey gray whales migrating northward up the west coast of Haida Gwaii, and the other (JFP) was based at Bonilla Island lightstation (53°29’N, 130°38’W) to survey whales migrating in Hecate Strait. The survey period coincided with the anticipated peak of the spring migration based on timing along Vancouver Island (Pike 1962, Hatler and Darling 1974, Darling 1984). Observers at both lightstations were equipped with hand-held Fujinon™ 7x50 and tripod- mounted Oberwerk™ 25x100 binoculars. Observers surveyed from a height of 49 m above sea level (measured at higher high water) at Langara and 28 m at Bonilla, which allowed detection and identification of whales out to distances of greater than 15 km. Surveys were undertaken from approximately 0830 to 1900 each day, with effort interrupted periodically for observer breaks. Wind speed and direction and overall sighting conditions were recorded at the start and end of each survey period, as well as at 30 min intervals during survey effort. Sighting conditions, which were affected by sea state, sun glare, rain, and fog, were scored according to a scale of 1 to 6 developed by Reilly et al. (1983), with 1 being excellent and 6 being unsuitable for observation. Observers scanned for whales towards the west in arcs of approximately 80° at each survey location. For each sighting, the time, horizontal angle and number of binocular reticle divisions from the horizon were recorded. Sightings of all cetacean species were noted, which included humpback whales, fin whales, and killer whales at each lightstation, as well as sperm whales at Langara. Raw observation data from each lightstation were filtered to include only “on- effort” gray whale sightings in good to excellent sighting conditions (sighting conditions 1 to 3), categories that Reilly et al. (1983) found to cause no significant weather-related interference with shore-based surveys of gray whales. Counts of sightings and individuals were summarized by day at each lightstation. In order to take into account differences in effort between the two lightstations, hours of effort during these good to excellent sighting conditions were summarized by day as well. Distances to each sighting were calculated by counting the number of binocular reticle divisions from the horizon to the animal(s) as they passed an imaginary line perpendicular to the sighting platform, then entering these reticle values into the MS Excel geometric functions RetDist and RetDis7x50 for the Oberwerk and Fujinon binoculars, respectively (functions provided by the National Marine Mammal Laboratory, NOAA, Seattle, WA; see http://www.afsc.noaa.gov/nmml/software/excelgeo.php). The distance to each sighting from shore was then pooled into six distance intervals, 0-2 km, 2-4 km, 4-6 km, 6-8 km, 8-10 km, and > 10 km. 5

RESULTS Satellite tracking Satellite tags were deployed on a total of six gray whales, one in 2009, two in 2010, and three in 2011. One tag failed to transmit, likely because it was attached too low on the animal’s side to provide a good signal to the satellites. Five tags provided a total of 442 locations calculated by the Argos satellite system over periods of 8-16 days following deployment (Table 1). We tracked these five gray whales for a total of 60 days and 6107 km, reaching latitudes as high as 59°07’N along the northeastern coast of the Gulf of Alaska, south of Yakutat. The whales generally travelled in a consistently northwards direction following tagging, at mean estimated speeds of between 4.7 and 5.9 km/h, but one whale (#2) displayed significantly lower net displacement (average speed of 1.1 km/h). This animal remained off the west coast of Vancouver Island, where it was possibly feeding, for 10 d following tag deployment, before beginning northbound travel at a relatively fast speed of 6.3 km/h (Table 1). Tracks of tagged gray whales through British Columbia and southeastern Alaska waters are shown in Figure 1. Following tagging, all individuals stayed close to the shore as they continued to migrate north up the coast of Vancouver Island. Upon reaching the northern tip of Vancouver Island, each of the five whales turned toward the north or northeast and proceeded across Queen Charlotte Sound then north up Hecate Strait. Four of the five favored the eastern half of the Strait, while one (#4) remained near the center of the Strait. As the whales approached the north end of Hecate Strait, their trajectories converged somewhat as they rounded Rose Spit off the northeastern corner of Haida Gwaii and crossed Dixon Entrance to southeastern Alaska. Although one tag stopped transmitting in Dixon Entrance (#2), three of the other four whales rounded the southern end of Dall Island then continued north, closely following the coastline. One whale (#3) travelled up the east side of Dall Island but it is unknown whether it continued through Tlevak Narrows at the north end of the island or reversed course and rounded the south end. Photographs of the tagged whales were compared to a photo-identification catalog of the ‘Pacific Coast Feeding Aggregation’ (PCFA) of gray whales maintained by Cascadia Research Collective, Olympia, WA (Calambokidis et al. 2002, 2010). Three of the five tagged whales were found to match to animals in the PCFA catalog (whale #1 = CRC307, #2 = CRC178, and #3 = CRC135)1.

1 Personal communication from John Calambokidis, Cascadia Research Collective, 218 1/2 W 4th Ave., Olympia, WA 98501 USA, November 2011. 6

Table 1. Gray whale movements based on received satellite tag transmissions. Summary statistics include the number of days during which tag transmissions were received (duration), the number of locations calculated by the Argos satellite system from tag transmissions, the average (median) of the error radius estimated for the Argos locations, the average (median) speed estimated by fitting a correlated random walk model to the Argos locations and their error, the highest latitude and the total distance traveled from locations estimated using the model predictions.

Tag Deployment Duration Number of Average Average Highest Total Date (days) Locations error speed Latitude distance (km) (km) (km/h) (oN)

1 26-Mar-09 13 104 1.3 4.9 58.14 1,354 2 24-Mar-10 16 68 4.2 1.1 54.97 893 3 24-Mar-10 8 53 2.8 5.8 56.56 1,141 4 20-Mar-11 11 91 1.4 4.7 56.91 1,216 5 22-Mar-11 12 126 1.8 5.9 59.11 1,503

Visual surveys The shore-based surveys during March and April resulted in 121.5 h of effort in good to excellent sighting conditions (mean visibility conditions 2.5) at Bonilla Island, and 110.5 h of effort (mean visibility conditions 2.6) at Langara Island. The daily counts of gray whales at each survey location and the number of on-effort hours (in conditions of 3 or better) per day over the survey period are illustrated in Figure 2. Gray whales were seen at Bonilla on 13 of 22 days during which there was sighting effort in good to excellent conditions. A total of 111 gray whale sightings were made, representing a total of 296 individuals. Mean sighting rate for days that gray whales were observed was 3.48 whales/effort hour (SE = 0.74). Sighting rates peaked during 31 March, 1 and 2 April at mean rates of 7.0, 9.0, and 6.0 whales/effort hour, respectively. The distribution of gray whales relative to distance from shore at Bonilla is shown in Figure 3. Sightings averaged 6.7 km (SE = 0.40) from shore, with 62% of total sightings and individuals taking place within 6 km of shore. Twenty-two percent of whales passed more than 10 km from Bonilla. Average group size of whales at Bonilla was 2.7 individuals (SE = 0.13, range 1-6). Group sizes did not differ significantly among the six distance intervals shown in Figure 3 (one-way ANOVA, F5, 105 = 0.38, P = 7

0.86). All whales sighted were swimming towards the north, except for 3 sightings where they were headed northwest.

Figure 1. Positions of five northbound satellite-tagged gray whales, from Vancouver Island to southeastern Alaska, and locations of shore-based survey sites at Bonilla and Langara Islands. Also shown is the previously assumed migratory corridor (hatched lines) as depicted in NOAA’s West Coast of North America Living Marine Resources Data Atlas (http://westcoastatlas.noaa.gov/).

Gray whales were seen at Langara on only two days, 18 and 20 March, out of 19 days with sighting effort in good to excellent conditions (Fig. 2). These two sightings were of 1 and 9 individuals, respectively, and both sightings were at distances of greater than 10 km from shore. Animals in both sightings were swimming towards the north.

Figure 2. Daily counts of gray whales (bars) and hours of observation effort in good to excellent sighting conditions (lines with black squares) at (A) Bonilla Island and (B) Langara Island, 16 March to 10 April, 2011.

Figure 3. Distribution of gray whale sightings (open bars) and total individuals (shaded bars) relative to distance from shore at Bonilla Island.

DISCUSSION Having closely followed the coastline for over 3,000 km after leaving breeding lagoons in Baja California, gray whales on their spring migration are faced with the first significant stretch of open ocean when they reach the northwestern tip of Vancouver Island. In contrast to the long-held belief that the whales continue on their northwest trajectory, make the >200 km crossing to Haida Gwaii and continue up the outer coast (Kellogg 1929, Pike 1962, Braham 1984), our results from satellite-tagged whales and shore-based surveys together provide clear evidence that the majority of whales use Hecate Strait and Dixon Entrance as their migratory corridor between Vancouver Island and southeastern Alaska. All five gray whales satellite-tagged along the west coast of Vancouver Island turned to the north off the northwestern tip of the island, migrated across Queen Charlotte Sound, up Hecate Strait to the east of Haida Gwaii, then exited Dixon Entrance towards the northwest before resuming their migration up the outer coast of southeastern Alaska. Of the total 306 northbound gray whales sighted during concurrent shore-based surveys at Bonilla Island in Hecate Strait and at Langara Island on the west coast of Haida Gwaii, 97% were seen in Hecate Strait. The migratory corridor in Hecate Strait, as suggested by the five satellite-tagged whales, appears to be quite broad, perhaps 25-75 km wide, and is not closely associated with either its western or eastern shoreline. Four of the five tagged whales travelled up 10 the eastern half of the Strait, and the tracks of all five whales converged as they rounded the northeastern corner of Haida Gwaii and transited Dixon Entrance. The occasionally high sighting rates at Bonilla Island also suggest that the main corridor is in the eastern half of Hecate Strait. Rates of up to 9 whales/h were documented during 31 March to 2 April, 2011, which are comparable to rates typically seen from land during spring migration at Yaquina Head, Oregon, where the majority of whales pass within 5 km of shore (Herzing and Mate 1984). At Bonilla, most whales were within 10 km of the island but a substantial portion (22%) was beyond that distance. It is likely that some animals passed at ranges too far to the west for detection from Bonilla Island. An extensive shallow area, Dogfish Bank, dominates the western half of northern Hecate Strait, with average depths of 20 m or less that extend 20-35 km off the east coast of Haida Gwaii. Aerial and vessel surveys to determine marine mammal occurrence in the area of a proposed offshore wind energy development on this bank documented relatively few gray whales during March and April 2007-08 (LGL et al. 2009). A visual survey from a 28 m high shore-based outlook on the northeast coast of Haida Gwaii (ca. 53°37’N, 131°56’W) observed only 15 migrating gray whales during 104 h of sighting effort in March and April, 2007-08 (LGL et al. 2009). It appears that most gray whales use the deeper waters of eastern Hecate Strait during their northward migration rather than the shallower, western side of the Strait. The fact that a few migrating gray whales were observed during our survey at Langara Island suggests that the outer coast of Haida Gwaii is a migratory corridor for at least a portion of the northbound population. Pike (1962) compiled whale observations by lightstation personnel and mariners during 1957 to 1960 but there were very few records of northbound gray whales during the spring migration at Langara Island. Pike (1962), who believed that the main migration route was up the west coast of Haida Gwaii, suggested that Langara Island lightstation is “poorly located for observing gray whales, which may pass some distance offshore in commencing their crossing of Dixon Entrance”. While this may be true for casual observation without visual aids, it is unlikely to be the case for dedicated observers using high-powered binoculars, as in our survey. However, Pike and MacAskie (1969) noted that lightstation personnel at Langara reported sightings of “66 [gray whales] during the last week of March, 150 in April and 4 in June” of 1963. It is difficult to explain this anomalously high count in 1963. The current light keeper at Langara Island is a keen observer who has reported whale sightings to the British Columbia Cetacean Sightings Network (http://wildwhales.org) since 1999, yet he has sighted very few gray whales during the spring migration period. It is unknown whether the report of many gray whales at Langara in spring 1963 is an indication that the west coast of Haida Gwaii is a significant migration corridor in some years, or if the unusual report is spurious. It is interesting that three of the five tagged whales are previously-identified members of the Pacific Coast Feeding Aggregation (PCFA) (Calambokidis et al. 2002, 2010), also referred to “summer residents” (Darling 1984) or the “southern feeding group” (Frasier et al. 2011). The PCFA consists of several hundred gray whales that return in multiple years to particular summer feeding locations scattered along the west coast from northern California to southeastern Alaska, rather than spending the summers 11 on the primary feeding grounds in the Bering and Chukchi seas. Although this subpopulation is thought to migrate to the breeding lagoons in Baja California, it differs from the overall population in mitochondrial DNA haplotype frequencies suggesting that there is maternally-directed site fidelity to these southern feeding locations (Frasier et al. 2011). All three tagged PCFA whales have been identified during summer along the west coast of Vancouver Island, and two animals in particular (#2 and #3) have been identified there multiple times in most years over the past decade1. Our results suggest that at least some PCFA whales migrate northward along with the larger population in spring, then move back to southern feeding locations in summer. The approximately 575 km long migration route from Vancouver Island through Hecate Strait and Dixon Entrance to Dall Island in southeastern Alaska, is by far the longest segment of the northward migration corridor between Baja California and the Bering Sea that does not closely follow the coastline. From southeastern Alaska to Bristol Bay, northbound gray whales swim close to the coast except in a few locations where they cross open water, such as Kenai Peninsula to Kodiak Island, Alaska (Braham 1984). These open water crossings in Alaska are about 200 km or less. The Hecate Strait migration route is roughly the same distance as the alternative route following the west coast of Haida Gwaii. Gray whales migrating in the Hecate Strait – Dixon Entrance corridor could be more susceptible to impacts from existing and proposed industrial activities than would be the case if they migrated along the outer coast of Haida Gwaii. For example, a major offshore wind farm development has been proposed over a 550 km2 area of Dogfish Bank in northwestern Hecate Strait (Naikun Wind Energy Group, http://www.naikun.ca; Esteban and Leary 2011), adjacent to or partly overlapping the migration corridor. Underwater noise emitted during construction and operation of offshore wind farms has the potential to result in disturbance effects on marine mammals (Madsen et al. 2006). The Queen Charlotte Basin, which underlies Hecate Strait, Dixon Entrance and Queen Charlotte Sound, is believed to contain potentially significant petroleum reserves, and may be the focus of future oil and gas exploration and extraction (Hall et al. 2004, MacConnachie et al. 2007). Hecate Strait and Dixon Entrance contain active shipping lanes (Williams and O’Hara 2010, PNCIMA 2011) that overlap substantially with the gray whale migration corridor. Gray whales are known to be vulnerable to ship strikes, although available evidence from strandings suggests this is a relatively uncommon source of mortality (Douglas et al. 2008). This may be due at least in part to the nearshore location of most of their northbound migration corridor, where there is minimal overlap with large ships, which are the type of vessels most likely to cause severe and lethal injuries to whales (Laist et al. 2001). For more than 500 km of their transit from northern Vancouver Island through Hecate Strait to western Dixon Entrance, the route of migrating gray whales coincides with that of significant marine traffic, including large deep-sea ships.

1 Personal communication from John Calambokidis, Cascadia Research Collective, 218 1/2 W 4th Ave., Olympia, WA 98501 USA, November 2011. 12

The northward migration of gray whales is bimodal, with pregnant females, mature males, and immature whales of both sexes (Phase A) passing 1-2 months earlier than females with calves (Phase B) (Rice and Wolman 1971, Herzing and Mate 1984, Poole 1984). Off California and Oregon, Phase A whales generally migrate within 5-8 km of shore but may swim from headland to headland, crossing rather than entering bights and indentations in the coastline (Herzing and Mate 1984, Poole 1984). Females with calves, however, migrate within a few hundred meters of shore, likely to avoid predation by killer whales (Poole 1984). Our observations coincide with Phase A of the northward migration, and the route taken by females with calves north of Vancouver Island remains to be determined.

ACKNOWLEDGMENTS We thank V. Deecke and B. Gisborne for their assistance with the satellite- tagging component of this study, and C. McMillan for her assistance with shore-based observations. R. Abernethy, L. Nichol and E. Stredulinsky helped with graphics, survey design, and data analysis. B. Duggan, G. Evans and A. Morrissey of the Canadian Coast Guard assisted with logistics for the lightstation surveys, and light keepers G. Schweers and S. Westhaver were most hospitable and helpful to the survey crew. We thank J. Calambokidis and colleagues at Cascadia Research Collective for matching photo- identifications of the tagged gray whales to the PCFA catalog they maintain. Funding was provided by Canada’s Department of Fisheries and Oceans (DFO) Species at Risk program. Field studies were conducted under DFO Scientific Licenses MML 2006-027 and 2010-001.

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