2018–2022 Southern Resident killer whale presence in the Salish Sea: continued shifts in habitat usage

Newswise — Monika Wieland Shields, Head of Orca Behavior Institute, has studied orcas in the Salish Sea, a Pacific Ocean marginal sea in British Columbia, Canada, and Washington, USA, since 2000. Recently, she published an article in PeerJ Life & Environment, a peer-reviewed Open Access journal, offering vital insights into the evolving habitat usage of endangered Southern Resident killer whales (Orcinus orca). Her work illuminates historical patterns and the present status of the Salish Sea's orca population. We interviewed Monika to learn more about her research and her deep enthusiasm for these magnificent creatures.

Can you tell us a bit about yourself?

I am Monika Wieland Shields, co-founder and head of the non-profit Orca Behavior Institute (OBI) located on San Juan Island, Washington, USA. Our focus is on non-intrusive research into the behavior and acoustics of two killer whale populations in the Salish Sea: the endangered Southern Resident killer whales, who feed on fish, and the thriving Bigg's killer whales, who prey on mammals. I have dedicated more than two decades to studying, capturing images of, documenting, and advocating for these magnificent creatures. In 2019, I published "Endangered Orcas: The Story of the Southern Residents."

Can you briefly explain the research you published in PeerJ?

At OBI, I engage in a significant endeavor of monitoring the evolving habitat patterns of Southern Resident killer whales. Since their classification as an endangered species in 2005, their utilization of the Salish Sea has undergone substantial modifications, closely linked to changes in their favored prey. This investigation offers an up-to-date account of the daily presence of these whales from 2018 to 2022, underscoring the ongoing occurrence of these transformative shifts.

What did you discover and where?

This study concentrates on the Salish Sea, encompassing the inland waters of Washington State and British Columbia. It reveals a remarkable reversal in the historical habitat utilization patterns of Southern Resident killer whales in this region. Previously, their highest abundance was observed from May to September, but now their occurrence has shifted to the fall and winter months, while their presence during spring and summer has experienced a significant decline.

What was significant about your findings?

Preserving habitats plays a vital role in the recovery of endangered species, and for it to be effective, protective zones need to align with the current spatial and temporal usage of the target species' habitat, rather than relying solely on historical patterns. In both Canada and the US, regional and seasonal protection measures have been implemented to aid in the recovery of Southern Resident killer whales. However, it is crucial that these measures are regularly updated to account for the shifting habitat usage by these whales. This study addresses this data gap by illustrating the utilization of the Salish Sea by these endangered orcas over the past five years and highlighting the deviations from previous trends. By doing so, it provides valuable insights for ensuring that protection measures align with the current needs of the Southern Residents.

Read the full article 2018–2022 Southern Resident killer whale presence in the Salish Sea: continued shifts in habitat usage published in PeerJ Life & Environment.