Tracking North Pacific Humpback Whales To Unravel Their Basin-Wide Movements

In 2014, Oregon State University (OSU) initiated a multi-year project to study humpback whale (Megaptera novaeangliae) migrations in the North Pacific Ocean using satellite tracking technology in combination with genetic and photo-identification (photo-ID) analyses. The study is highly relevant to management, given the need for new information arising from the recent separation of humpback whales into Distinct Population Segments (DPS) for listing under the US Endangered Species Act, including four DPSs in the North Pacific (“Western North Pacific”, “Hawaii”, “Mexico”, and “Central America”) with different conservation statuses. The project’s objective was to conduct a comprehensive characterization of humpback whale movements during breeding, migration, and feeding periods by tagging animals in both a feeding area (southeastern Alaska) and a breeding area (Hawaii). In order to obtain representative results, the sampling plan called for two field efforts at each site, with Pacific Life Foundation funding the southeastern Alaska portion of the project (2014 and 2015 seasons), and the Hawaii portion being cost-shared through a combination of sources including the Makana Aloha Foundation (2015 season) and the US Department of the Navy (2018 season). This final report provides the combined results and accomplishments from these efforts. Argos-based, fully implantable tags were deployed on 37 humpback whales in Seymour Canal and Frederick Sound, southeastern Alaska, in 2014 and 2015. Tracking periods ranged from 3.3 to 78.3 d (mean = 28.2 d, sd = 16.2 d), with distances traveled ranging from 73 to 6,503 km (mean = 2,010 km, sd = 1,649 km). The tracked locations for these animals ranged over 40 degrees of latitude, from Lynn Canal and Icy Strait (59°N) in southeastern Alaska to the southern tip of Hawaii Island (19°N) in the Hawaiian Archipelago. Genetic and photo-ID analyses revealed that two of the whales tagged in 2014 were re-tagged in 2015, providing a unique opportunity to compare movements between years for the same individuals. For one of these animals the movements and their timing were similar between years, as it moved from Seymour Canal into Frederick Sound with a difference of 4 d between years. However, early failure of the tag in 2014 (after 6.2 d) prevented a longer comparison. In contrast, the movements of the second animal within southeastern Alaska were similar but the timing was very different between the two years, despite a similar tracking period (21.9 d in 2014 versus 19.1 d in 2015). In 2014 this animal spent a substantial amount of time in Seymour Canal (17 d) before moving into Stephens Passage for the remainder of its tracking period, while in 2015 the animal moved into Stephens Passage soon after tagging and only for a brief period before it moved into Frederick Sound, from where it initiated the migration toward Hawaii. Differences in timing notwithstanding, the similarities in the tracks between years for both animals provided some evidence of route fidelity, as has been recently shown for several species of migratory marine animals. Twenty of the whales tagged in southeastern Alaska began their winter migration to a low-latitude breeding area, with start dates ranging from 19 November to 6 January. Three of these whales were tracked to breeding areas, two to Hawaii and one to the Mexican mainland. Another 16 whales were headed in the direction of Hawaii and one in the direction of Mexico when their tags quit. The duration and distance spent on migration for the three animals that reached a breeding area ranged from 29 to 46 d and from 4,200 to 4,700 km, respectively. The two animals that arrived in Hawaii entered the archipelago at Hawaii Island. Forty-five tags were deployed on humpback whales off Maui, Hawaii, in 2015 and 2018. Two of these tags provided no locations. Tracking periods for the remaining 43 whales ranged from 0.1 to 147.2 d (mean = 20.8 d, sd = 29.0 d), with distances ranging from 13 to 11,302 km (mean = 1,217 km, sd = 2,348 km). The tracked locations for these animals ranged over 43 degrees of latitude, from the south coast of Maui (21°N) to the Bering Sea (64°N). While in Hawaiian waters, the majority of locations were in the Maui Nui region (the waters between the islands of Maui, Lanai, Molokai and Kahoolawe), during both in 2015 and 2018. Penguin Bank was another area heavily frequented by the tagged whales. Most tagged whales moved in a predominant northwesterly direction after tagging, with animals leaving Maui headed for Lanai, Molokai, and/or Penguin Bank. Several whales were also tracked to Oahu, and one whale was further tracked to both Kauai and Niihau. Only one whale was tracked southeast to Hawaii Island in 2015, but other tagging studies have documented eastward movements to Oahu, Penguin Bank, and Maui Nui, so it is apparent that whales may move extensively between islands, both in westerly and easterly directions. Nine of the whales tagged in Hawaii began their migration to a high-latitude feeding area, with departure dates ranging from 29 January to 11 April. Four of these whales were tracked to feeding areas, three to northern British Columbia and one to the eastern Aleutian Islands. Another four whales were headed on a northeasterly trajectory toward northern British Columbia and three more on a northerly or northwesterly trajectory toward destinations in the Aleutian Island chain when their tags quit. The three whales that were tracked to northern British Columbia arrived in the Haida Gwaii Archipelago after having spent 30-44 d and 4,300-5,000 km on migration. The animal that migrated north to the eastern Aleutians arrived at an area approximately 200 km south of Unimak Pass, 28 d and 3,775 km after departing Hawaii. These results, together with those obtained from animals tagged in southeastern Alaska that migrated to a breeding area (Hawaii or Mexico), provide evidence that the travel time and distance covered by humpback whales while on migration across the North Pacific Basin can vary widely, with overall ranges of 28-46 d and 3,775-5,000 km, respectively. A 50-km buffer zone around southeastern Alaska and Hawaii was used for purposes of characterizing whale movement speeds and residence times in the feeding and breeding areas (inside the buffer zones), as well as during migration (outside the buffer zones). Residence time was computed as the time period from tag deployment to when a whale crossed the buffer zone boundary as it departed on migration. Residence time in southeastern Alaska in late fall was estimated for 20 whales, ranging from 4.4 to 49.1 d (mean = 17.3 d), although additional information from earlier tagging studies indicated that individual humpback whales may use this feeding area for periods of up to four to five months. In contrast, residence time in Hawaii was estimated for nine whales, ranging from 3.3 to 23.2 d (mean = 14.8 d), consistent with earlier photo-ID and telemetry studies and lending support to the notion that that there is a rapid turnover of individuals in this breeding area during the winter season. In any case, overall true residence time in these areas is likely longer than the minimum values we report based on satellite telemetry, as we cannot know the time a whale had spent in an area prior to tagging. Movement speeds during the different phases of the migration (feeding, breeding, migrating) were calculated based on the portions of the tracks that occurred inside or outside the 50-km buffer zones. Whales tagged in southeastern Alaska moved at a mean speed of 1.01 km/h (median = 0.47 km/h, sd = 1.28 km/h) while in the southeastern Alaska feeding area; 5.51 km/h (median = 5.63 km/h, sd = 1.98 km/h) while migrating; and 1.49 km/h (median = 1.01 km/h, sd = 1.36 km/h) once they arrived in the Hawaii breeding area. Whales tagged in Hawaii moved at a mean speed of 1.36 km/h (median = 1.00 km/h, sd = 1.21 km/h) while in the Hawaii breeding area; 4.44 km/h (median = 4.32 km/h, sd = 2.18 km/h) while migrating; and 2.00 km/h (median = 1.53 km/h, sd = 1.53 km/h) once they arrived in the southeastern Alaska feeding area. These results showed that whales moved much slower while in the feeding and breeding areas than while migrating, and that travel speed from the feeding to the breeding areas was somewhat faster than from the breeding to the feeding areas. Biopsy samples were collected from 27 of the whales tagged in southeastern Alaska in 2014 and 2015, and from 39 of the whales tagged in Hawaii in 2015 and 2018. These 66 samples were identified by a unique multi-locus genotype of at least 14 microsatellite loci, which indicated they represented 64 unique individuals (after accounting for the two animals that were re-tagged). The 25 individuals tagged in southeastern Alaska represented 14 females and 11 males. The 39 individuals tagged in Hawaii represented four females and 35 males. The DNA profiles of the 64 individuals were compared to a reference database of 1,805 individuals sampled from 2004 to 2006 in the North Pacific by the program SPLASH, which revealed nine matches (i.e., genotype recaptures). Of these, six matches were recaptures within an area (four within southeastern Alaska and two within Hawaii) and three were recaptures between whales tagged in Hawaii and sampled previously on feeding areas in either northern British Columbia (n = 2) or southeastern Alaska (n = 1). Mitochondrial deoxyribonucleic acid (mtDNA) sequences of the 64 individuals resolved seven haplotypes for the consensus region of 500 base-pairs. All seven haplotypes had been previously described for North Pacific humpback whales by SPLASH, but only two occurred in the southeastern Alaska samples while all seven occurred in the Hawaii samples, supporting earlier results indicating a greater haplotypic diversity in the Hawaii breeding area than in the southeastern Alaska feeding area. Further, pairwise tests of differentiation between the tagging areas and the 18 SPLASH regional strata were consistent with those reported in that study, supporting our current understanding of humpback whale population structure, migratory destinations, and site fidelity in the North Pacific. Photo-IDs (fluke photographs) were obtained from 30 whales tagged in southeastern Alaska and from 24 whales tagged in Hawaii. Comparisons with the online Happywhale photo-ID database as well as with OSU’s own ID catalog revealed matches for 25 of the tagged whales (18 from southeastern Alaska and seven from Hawaii). Thirty-five percent of the tagged whales with an ID were found in Happywhale and 13 percent in OSU’s catalog. Most matches (19 of 25) were made within the same area in which the whale was tagged, with time spans between sightings of up to 14 years. Two whales tagged in southeastern Alaska in 2014 each had only one photo-ID match in a different area than the one in which they were tagged. Both had been previously photographed in Hawaii, one in 1997 (17 years apart) and in 2004 (10 years apart). The remaining four resighted tagged whales had both within- and between-area matches. Three of these latter whales were tagged in southeastern Alaska, with two of them matching sightings in Hawaii (1987 and 2019, respectively), and the third one being resighted in central California on two consecutive years (2017 and 2018). The fourth whale was tagged in Hawaii and matched sightings over six consecutive years (2013-2018) in southern British Columbia/northern Washington. An additional 26 matches were found in Happywhale from among 149 fluke photographs of untagged whales collected by OSU in Hawaii. Of these, 13 matches were made within Hawaii (with a maximum time span between sightings of 21 years); nine matches were made between Hawaii and different parts of Alaska, including southeastern Alaska, Kodiak Island, Cook Inlet, and the Shumagin Islands; four matches were made between Hawaii and Washington State and Vancouver Island, British Columbia; and one match was made between Hawaii and the Chukchi Sea, near Kolyuchin Island, northeastern Russia. Through the combined use of satellite tagging, genetics, and photo-ID, we characterized the patterns of humpback whale occupation in both a breeding and a feeding area in the North Pacific Ocean, as well as the long-distance migratory movements that these animals undertake seasonally between these areas. The results of this study revealed the complex migratory linkages between Hawaii and the high-latitude feeding areas with unprecedented detail. Genotype and photo-ID recaptures of multiple individuals between migratory destinations supported previously known strong connections between breeding and feeding areas (e.g., Hawaii and southeastern Alaska/northern British Columbia, and Hawaii and Washington/southern British Columbia). Satellite tracking also revealed the movements and migratory connections between Hawaii and feeding areas in the Aleutian Islands and the Bering Sea, while photo-ID recaptures demonstrated additional connections between Hawaii and feeding areas in the northern Gulf of Alaska (Shumagin Islands, Kodiak Island, Cook Inlet) and the Chukchi Sea. Additional years of sampling during different parts of the reproductive season and in other parts of the main Hawaiian islands (e.g., Kauai and Hawaii), as well as in the northwestern Hawaiian Islands, would provide valuable information to address outstanding questions about the humpback whale DPS using this extensive breeding area, as well as its broader connections to remote feeding areas throughout the North Pacific Basin, most of which are poorly known. Also, while the majority of whales tracked from southeastern Alaska showed a strong connection to the Hawaii breeding area, a small proportion of these animals demonstrated a connection to the Mexican mainland breeding area, indicating some mixing of the Hawaii and Mexico DPSs in the southeastern Alaska feeding area. These animals are of particular interest, as in their transit along the western coast of North America they overlap with animals from the Central America DPS, which forages off California and Oregon. Further tagging work to better understand the patterns of habitat use and the extent of the overlap between the Mexico and Central America DPSs in this region would greatly help current needs to improve how animals are assigned to DPS for management purposes in the context of relative exposure to anthropogenic activities, given their different conservation statuses

The role of resilience in mediating stressor-outcome relationships among grandparents raising their grandchildren

The incidence of custodial grandparenting has increased over the last decade, and grandparents raise their grandchildren for a variety of reasons, i.e., the death, drug use, divorce, or incarceration of the child’s birthparents. While it is commonly recognized that grandparents face added stress and much adversity that arises from caregiving, current research tends to be mixed regarding the effects of grandparents raising grandchildren. Indeed, while much research concludes that grandparent caregivers experience declines in over all health and well-being, other work suggests that grandparent caregiving may actually be a positive experience, leading to personal growth and to deeper, more satisfying relationships with a grandchild. That some studies paint a negative picture while others do not may be a consequence of varying levels of resilience among custodial grandparents. The model proposed and tested in this study centralizes resilience as an adaptive quality that grandparent caregivers possess in varying degrees, and examines resilience as a mediator of relationships between several antecedent grandchildrelated and life situation-related (life resources) variables that affect custodial grandparents in both parental and well-being related ways. Based upon data gathered from 239 custodial grandparents, it was found that resilience, as well as its parental equivalent, parental efficacy, was significant in mediating the effects of grandparent caregiving. Thus, grandparent caregivers who vary in terms of personal resilience are likely to fare better or worse in coping with thedemands of raising a grandchild

Migratory destinations and spatial structuring of humpback whales (Megaptera novaeangliae) wintering off Nicaragua

Abstract Understanding the migratory patterns of large whales is of conservation importance, especially in identifying threats to specific populations. Migration ecology, including migratory destinations, movements and site fidelity for humpback whales (Megaptera novaeangliae) remain poorly studied in parts of the range of the Central America population, considered endangered under the United States Endangered Species Act. This study aimed to investigate the migratory destinations of humpback whales sighted at two study sites in Nicaragua, which are part of the Central America population. A ten-year photographic database of humpback whales observed off Nicaragua was combined with citizen science contributions and sightings from dedicated research programs. The resulting image collection was compared with available historical photo identifications and databases using an automated image recognition algorithm. This approach yielded 36 years of photographic identification totaling 431 recaptures in Nicaragua (2006–2008 and 2016–2021) and 2539 recaptures (1986–2020) in both feeding and breeding grounds of 176 unique individuals sighted in Nicaragua. Our results showed that photo-identified whales were recaptured between October and April in breeding grounds and year-round in feeding grounds between British Columbia and California, with peak recaptures between June and October. Our study provided first-time evidence on fine-scale site affinity of individual humpback whales within Nicaraguan waters and to other breeding and feeding grounds

Bellwethers of change: population modelling of North Pacific humpback whales from 2002 through 2021 reveals shift from recovery to climate response

For the 40 years after the end of commercial whaling in 1976, humpback whale populations in the North Pacific Ocean exhibited a prolonged period of recovery. Using mark–recapture methods on the largest individual photo-identification dataset ever assembled for a cetacean, we estimated annual ocean-basin-wide abundance for the species from 2002 through 2021. Trends in annual estimates describe strong post-whaling era population recovery from 16 875 (± 5955) in 2002 to a peak abundance estimate of 33 488 (± 4455) in 2012. An apparent 20% decline from 2012 to 2021, 33 488 (± 4455) to 26 662 (± 4192), suggests the population abruptly reached carrying capacity due to loss of prey resources. This was particularly evident for humpback whales wintering in Hawai‘i, where, by 2021, estimated abundance had declined by 34% from a peak in 2013, down to abundance levels previously seen in 2006, and contrasted to an absence of decline in Mainland Mexico breeding humpbacks. The strongest marine heatwave recorded globally to date during the 2014–2016 period appeared to have altered the course of species recovery, with enduring effects. Extending this time series will allow humpback whales to serve as an indicator species for the ecosystem in the face of a changing climate

A collaborative and near-comprehensive North Pacific humpback whale photo-ID dataset

Abstract We present an ocean-basin-scale dataset that includes tail fluke photographic identification (photo-ID) and encounter data for most living individual humpback whales (Megaptera novaeangliae) in the North Pacific Ocean. The dataset was built through a broad collaboration combining 39 separate curated photo-ID catalogs, supplemented with community science data. Data from throughout the North Pacific were aggregated into 13 regions, including six breeding regions, six feeding regions, and one migratory corridor. All images were compared with minimal pre-processing using a recently developed image recognition algorithm based on machine learning through artificial intelligence; this system is capable of rapidly detecting matches between individuals with an estimated 97–99% accuracy. For the 2001–2021 study period, a total of 27,956 unique individuals were documented in 157,350 encounters. Each individual was encountered, on average, in 5.6 sampling periods (i.e., breeding and feeding seasons), with an annual average of 87% of whales encountered in more than one season. The combined dataset and image recognition tool represents a living and accessible resource for collaborative, basin-wide studies of a keystone marine mammal in a time of rapid ecological change

Acknowledgements and Photo Contributors from Bellwethers of change: population modelling of North Pacific humpback whales from 2002 through 2021 reveals shift from recovery to climate response

All photo and data contributors who provided complete names have contributed to this work are acknowledged in this supplementary fil

Geographic stratification region boundaries as displayed in Figure 1 from Bellwethers of change: population modelling of North Pacific humpback whales from 2002 through 2021 reveals shift from recovery to climate response

For the 40 years after the end of commercial whaling in 1976, humpback whale populations in the North Pacific Ocean exhibited a prolonged period of recovery. Using mark–recapture methods on the largest individual photo-identification dataset ever assembled for a cetacean, we estimated annual ocean-basin-wide abundance for the species from 2002 through 2021. Trends in annual estimates describe strong post-whaling era population recovery from 16 875 (± 5955) in 2002 to a peak abundance estimate of 33 488 (± 4455) in 2012. An apparent 20% decline from 2012 to 2021, 33 488 (± 4455) to 26 662 (± 4192), suggests the population abruptly reached carrying capacity due to loss of prey resources. This was particularly evident for humpback whales wintering in Hawaiʻi, where, by 2021, estimated abundance had declined by 34% from a peak in 2013, down to abundance levels previously seen in 2006, and contrasted to an absence of decline in Mainland Mexico breeding humpbacks. The strongest marine heatwave recorded globally to date during the 2014–2016 period appeared to have altered the course of species recovery, with enduring effects. Extending this time series will allow humpback whales to serve as an indicator species for the ecosystem in the face of a changing climate