The North Norwegian Humpback Whale Catalogue (NNHWC) was founded in 2010 by marine ecologist Fredrik Broms. The aim was to learn more about the Eastern North Atlantic humpback whale population and to examine the patterns of movement of whales from these waters in greater detail.
Whereas the ecology and migratory destinations in the Western North Atlantic have been fairly well documented, the movements of humpbacks in the Eastern North Atlantic are less well known. Pioneering studies conducted in the late 1990’s have shown that humpbacks feeding in Norwegian waters in the summer migrate to the West Indies which is utilized as a breeding and calving ground in the winter. In the spring, the humpbacks migrate northwards again and occupy the high-latitude feeding ground in the Barents Sea during the summer and autumn before once again returning to the breeding ground in the West Indies in the winter.
During recent years, large numbers of humpback whales have been observed feeding on herring off the coast of mainland Northern Norway for an extended period of the winter (ca November-February), suggesting a recent change in the migratory behavior and timing of humpbacks with significant consequences for the ecosystem of the region. This unprecedented arrival of humpbacks close to the coast offer a unique opportunity to study “Norwegian” humpbacks more closely and during the past two winters, the project has developed a strong citizen science approach to involve the public in the study of large whales in Norwegian waters and currently the NNHWC has more than 120 different photo contributors.
In 2014, the catalogue passed the milestone of 500 different individuals being identified from the area and during the winter season 2014-15, the database reached 650 individual humpback whales and the NNHWC is now one of the larger catalogues of humpback whales in the North Atlantic.
Currently, ca 10% of the individuals in the NNHWC has been matched to areas outside Norway and whales from the study area have been re-sighted in as many as 9 different countries. The NNHWC work in close co-operation with other researchers around the North Atlantic and matching of flukes from the North Norwegian feeding stopover area to the North Atlantic Humpback Whale (NAHWC) in the US is currently in process.
Why do we wish to identify individual humpback whales?
Whales are difficult animals to study. They are widespread across large expanses of ocean and spend most of their time underwater. In order to develop effective conservation strategies for whales, it is of crucial importance to be able to identify important areas for the whales as well as monitoring changes in their distribution and habitat-use over time. To be able to answer such questions, knowing the identity of individual whales and being able to distinguish individuals in a group is of critical importance.
One way to learn more about whales and their migrations is to attach satellite tags or radio transmitters to the skin of the animals but this is both difficult and expensive. Studying whales with animal-borne instrumentation can therefore often only be used to study a limited number of animals under a relatively short time period. Fortunately, we can learn a lot about whales by using a simpler method; photo-identification.
When humpbacks dive, they usually lift their tail flukes, showing the underside of the tail. Each fluke has a unique pattern of black and white pigmentation and scars and not two whales in the world look exactly the same. In the 1970’s, researchers discovered that there was enough variation in the natural markings of humpback whale tail flukes to distinguish between individuals. After this discovery, fluke photographs began to be collected from all over the world.
Once individual humpbacks have been photographed and identified, they can be added to a photo identification catalogue. As photos of new individuals, and resightings of already known individuals, are added, it is possible to combine the sightings so that they tell us a story of where and when the whales spend their time.
Photo-identification is a powerful tool that can be used to study migration destinations, habitat preferences and small-scale movements within an area. It can also be used to study social bonds, age and sexual maturity, site-fidelity (tendency to return to the same area) and is a widely-used technique to estimate the number of whales in a population.