Assessment of Resident Killer Whale Body Condition Using Aerial Photogrammetry and Possible Implications for Salmon Management
Presentation Abstract
The southern resident killer whale population is listed as endangered in both the US and Canada and its critical habitat in the trans-border area of the Salish Sea is legally recognized by both countries. Resident killer whales feed on fish, principally salmon, and a multi-year period of low Chinook salmon abundance coastwise was associated with a spike the mortality rates of both populations (Ford et al. 2010 Biol. Lett. 6:139). Attempts to determine the impact of salmon fisheries on southern residents based on fluctuations in their mortality rate in relation to salmon abundance have had limited success (Report of the Independent Science Panel on the Effects of Salmon Fisheries on Southern Resident Killer Whales 2012). Here, we use a novel approach to address this question based on assessments of killer whale body condition from aerial photogrammetry. High quality aerial images of photo-identified members of the population are obtained at regular intervals using a small unmanned hexacopter. Measurements of length, width and shape from the photos are used to estimate growth rates and detect subtle changes in body condition. An index of body condition will be developed based on these photogrammetric measurements; changes in this index in individuals, matrilineal groups and populations will be assessed relative to changes in the abundance, distribution and timing of salmon runs. Here we describe two seasons of photogrammetric field work on northern residents (>80 individuals assessed each year) and one on southern residents (all 82 population members), photogrammetric analysis methods, and plans for at least two more seasons of field work on both populations. We also describe implications of this project--and of a continuing monitoring program that may evolve from it-- for salmon fisheries management approaches that explicitly incorporate the food requirements of the two at-risk killer whales populations.
Session Title
General species and food webs
Conference Track
Species and Food Webs
Conference Name
Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)
Document Type
Event
Location
2016SSEC
Type of Presentation
Oral
Genre/Form
presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Killer whale--Monitoring--Salish Sea (B.C. and Wash.); Chinook salmon--Monitoring--Salish Sea (B.C. and Wash.)
Subjects – Names (LCNAF)
Whale Museum (Friday Harbor, Wash.)
Geographic Coverage
Salish Sea (B.C. and Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Assessment of Resident Killer Whale Body Condition Using Aerial Photogrammetry and Possible Implications for Salmon Management
2016SSEC
The southern resident killer whale population is listed as endangered in both the US and Canada and its critical habitat in the trans-border area of the Salish Sea is legally recognized by both countries. Resident killer whales feed on fish, principally salmon, and a multi-year period of low Chinook salmon abundance coastwise was associated with a spike the mortality rates of both populations (Ford et al. 2010 Biol. Lett. 6:139). Attempts to determine the impact of salmon fisheries on southern residents based on fluctuations in their mortality rate in relation to salmon abundance have had limited success (Report of the Independent Science Panel on the Effects of Salmon Fisheries on Southern Resident Killer Whales 2012). Here, we use a novel approach to address this question based on assessments of killer whale body condition from aerial photogrammetry. High quality aerial images of photo-identified members of the population are obtained at regular intervals using a small unmanned hexacopter. Measurements of length, width and shape from the photos are used to estimate growth rates and detect subtle changes in body condition. An index of body condition will be developed based on these photogrammetric measurements; changes in this index in individuals, matrilineal groups and populations will be assessed relative to changes in the abundance, distribution and timing of salmon runs. Here we describe two seasons of photogrammetric field work on northern residents (>80 individuals assessed each year) and one on southern residents (all 82 population members), photogrammetric analysis methods, and plans for at least two more seasons of field work on both populations. We also describe implications of this project--and of a continuing monitoring program that may evolve from it-- for salmon fisheries management approaches that explicitly incorporate the food requirements of the two at-risk killer whales populations.
Comments
Happy to consider another session if recommended by the program committee