New insights into seasonal foraging ranges and migrations of minke whales from the Salish Sea and coastal British Columbia.

In the Salish Sea and coastal waters of British Columbia, minke whales are known to establish small home ranges during the feeding season. Beyond the feeding season little is known of their movements or distribution. To determine movement patterns of minke whales in these waters we used photo-identification data that were collected opportunistically from 2005-2012. These data were from four non-overlapping areas between 48ºN and 53ºN. Despite year-round search effort, minke whales were only encountered between April and October. Most of the 44 unique minke whales identified in 405 encounters displayed fidelity to areas both within and among feeding seasons. Five of these individuals also made relatively large-scale intra-annual movements between areas on six occasions. They were documented to move up to at least 424km in a northerly direction early in the season and up to at least 398km in a southerly direction late in the season. We believe that the seasonal patterns of these movements provide new insight into the foraging ranges and migrations of individuals. Ecological markers provide further evidence that the minke whales we photographed undertake annual long distance migrations. Scars believed to be from cookiecutter shark bites were observed on 43 individuals and the majority of minke whales documented with good quality images each year had acquired new scars since the previous feeding season. Furthermore, the commensal barnacle Xenobalanus globicipitis was observed on three individuals. Since these sharks and barnacles are from warm waters, it can be inferred that they interacted with the minke whales at lower latitudes. These findings may have important implications for our understanding of minke whale populations in the Salish Sea and the management of this species in the North Pacific

Anthropogenic threats to humpback whales in the Salish Sea: insights from northeastern Vancouver Island

As humpback whale (Megaptera novaeangliae) populations recover from commercial whaling throughout the North Pacific Ocean, these whales are returning to areas where they were rarely encountered or absent for the past four decades. These areas include the coastal waters of northeastern Vancouver Island (NVI) and more recently, the Salish Sea. The return of humpback whales to coastal waters leads to increased overlap between humpback whales and human activities, including vessel traffic and fisheries. We use data from NVI, an area where humpback whale numbers have been increasing over the past ten years, as an example of the effects of this overlap. Data were collected through dedicated research effort, as well as opportunistically from whale watch vessels. Between 2003 and 2013, we documented a total of 176 humpback whales off NVI. The annual number of individual humpback whales sighted off NVI increased from seven individuals in 2003 to a maximum of 71 individuals in 2011. A minimum of eight vessel strikes and five entanglements in fishing gear were witnessed off NVI since 2006. Fishing gear involved in these entanglements included prawn, crab, and seine gear. A further nine entanglement events can be inferred based on scarring and injuries on whales’ bodies. Due to the intense levels of human activity in the Salish Sea, these anthropogenic threats are likely to negatively impact both the endangered humpback whales and the humans using these coastal waters. They may also have implications for the management of humpback whales and fisheries in the Salish Sea

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