Dear colleagues, We are pleased to announce the release of the following publication in Endangered Species Research: Riera A, Pilkington JF, Ford JKB, Stredulinsky EH, Chapman NR (2019) Passive acoustic monitoring off Vancouver Island reveals extensive use by at-risk Resident killer whale (Orcinus orca) populations. Endang Species Res 39:221-234. The paper is Open Access and can be downloaded via the following link: http://bit.ly/esr_39_221<https://bit.ly/esr_39_221?fbclid=IwAR0xWfexQBHmKxaOmSwk-SixRrCXuw_kqBm2B4XToxM4BEWwM_MBP-zp78c> PDF copies are also available upon request to: ariera@uvic.ca<mailto:ariera@uvic.ca> ABSTRACT: Two sympatric populations of fish-eating Resident killer whales inhabit the coastal waters of British Columbia, Canada: Southern and Northern Resident killer whales. These populations are listed under Canada's Species at Risk Act (SARA) as 'endangered' and 'threatened', respectively. Relatively little is known about their habitat use outside of the sheltered waters along the east coast of Vancouver Island, especially during the winter. SARA requires the identification of critical habitat for these populations. High densities of Chinook salmon-their primary prey-are found around Swiftsure Bank, an area identified as potential critical habitat for Southern Residents. However, it is a difficult area to survey for whales using conventional small-boat approaches. Here, we used 2 yr of data collected from an autonomous acoustic recorder deployed at Swiftsure Bank from 2009-2011 to assess the year-round habitat use of this area by Resident killer whales. Overall, Resident killer whales were detected on 244 of 680 monitored days (36%). Southern Residents were heard in all months, with activity peaking during the summer. Northern Residents were also heard throughout the year, but were mostly detected in the spring and fall, which indicates the 2 populations may differ in their strategies for using this common foraging area. High levels of use by both of these populations highlights the importance of Swiftsure Bank to both, supporting the expansion of Resident killer whale critical habitat to include this site. Sincerely, Amalis Riera [MERIDIAN on blue circle containing many numbers, with an orange wave pulse to the right.] Amalis Riera Acoustic Data Analyst MERIDIAN - Marine Environmental Research Infrastructure for Data Integration and Application Network Fisheries, Ecology and Marine Conservation Lab, Department of Biology, University of Victoria p: + 1 250 472 4343 m: +1 250 208 3128 a: 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada w: https://meridian.cs.dal.ca e: ariera@uvic.ca<mailto:ariera@uvic.ca>