Sally Evans

Baleen whales are key marine predators that were heavily exploited throughout the 20th century, resulting in reductions in population size for many species. Whilst population recovery is evident for some species, baseline information on ecological niches is still unknown, rendering it difficult to forecast the manner in which baleen whales will reoccupy their former ecological niches as they recover. Biogeochemical analyses of bone fragments from 20th century whaling provide invaluable information on the foraging ecology and trophic niches of whale populations in the past, and provide a baseline for assessing recovery. Here, we combined Zooarchaeology by Mass Spectrometry (ZooMS) and DNA barcoding to assign bone specimens to species from 3 former whaling sites in the western South Atlantic, and used stable isotope analysis of carbon and nitrogen to infer differences in the long-term foraging preferences of baleen whales utilising western South Atlantic feeding grounds. These data sets indicate that baleen whale species partitioned prey resources with slight overlap in isotopic niches for 3 of the 4 species, with sei whales Balaenoptera borealis likely to be foraging predominantly on different feeding grounds relative to Antarctic blue B. musculus, fin B. physalus, and humpback Megaptera novaeangliae whales. Niche sizes reveal that Antarctic blue and sei whales are specialist feeders at the population level, suggesting that they are less likely to adapt to continuing climate change relative to more generalist fin and humpback whales. Characterising historical foraging baselines such as these are essential for assessing the ecological implications of changing oceans for recovering whale populations.

Archaeological faunal remains provide key insights into human societies in the past, alongside information on previous resource utilisation and exploitation of wildlife populations. The great whales (Mysticete and sperm whales) were hunted unsustainably throughout the 16th - 20th centuries (herein defined as the modern period) leading to large population declines and variable recovery patterns among species. Humans have utilised whales as a resource through carcass scavenging for millennia; however, increasing local and regional ethnographic and archaeological evidence suggests that, prior to the modern period, hunting of the great whales was more common than previously thought; impacts of earlier hunting pressures on the population ecology of many whale species remains relatively unknown. Hunting guided by traditional ecological knowledge may have been sustainable and likely originated in societies that also incorporated opportunistic use of stranded individuals. The collation of georeferenced zooarchaeological data of the great whales between the 1st - 20th centuries CE worldwide will provide insight into the timescale and distribution of resource utilisation of the great whales and how this varied within and between societies, and may have changed over time. By comparing regions of known resource utilisation and breeding and feeding grounds of current-day whale populations, this information will subsequently be used to infer regions where whale populations were possibly lost or extirpated prior to detailed historical records. This systematic review protocol also provides a template for archaeologists, ecologists, and historians interested in using faunal remains to infer historical ecology and resource use of wild animal populations. The transparency of our data collection approach provides opportunities for reproducibility and comparability with future datasets.