The threat of toxic contaminants to Southern Resident killer whales: monitoring POPs and PAHs in scat samples
Presentation Abstract
The Southern Resident killer whale population (SRKW; Orcinus orca) feed primarily on Chinook salmon, which is currently their primary source of exposure to toxics. We measured lipophilic persistent organic pollutants (POPs: PBDEs, PCBs, and DDTs) in SRKW scat (fecal) samples to quantify variations in toxicant levels by pod, sex, and reproductive class, as well as prey availability. We also measured polycyclic aromatic hydrocarbons (PAHs), which do not generally bioaccumulate and would reflect recent exposure to oil, engine (combustion) exhaust, among other potential exposure sources. Samples were collected using detection dogs that use scent to locate fresh SRKW scat on the water’s surface. We collected 267 samples during four 5-month study periods between 2010 and 2013. POP levels in scat had expected trends, such as increasing with age and decreasing by number of calves (for adult females). POPs were also highest when the whales primary prey source was at low seasonal abundance, presumably due to metabolizing endogenous lipid stores. By contrast, overall measures of PAHs were low (ppb, wet weight), as expected. However, PAHs indicative of motor exhaust versus oil exposure were relatively high prior to implementation of guidelines aimed at increasing vessel distances to the whales. Results point to the value of monitoring POPs by age, sex and reproductive class and in relation to changes in prey abundance to help identify what reproductive classes are most at risk to high toxic loads, what season the liability is greatest, and whether prey recovery and clean up efforts are working. The PAH exposure data will be available as baseline in SRKW feces in relation to environmental events over time, such as the circumstance of an oil spill in the Salish Sea. Addressing toxics and other vulnerabilities is important for SRKW recovery.
Session Title
Contaminants in Marine Mammals of the Salish Sea and Their Food Web
Conference Track
SSE3: Fate, Transport, and Toxicity of Chemicals
Conference Name
Salish Sea Ecosystem Conference (2018 : Seattle, Wash.)
Document Type
Event
SSEC Identifier
SSE3-610
Start Date
4-4-2018 2:15 PM
End Date
4-4-2018 2:30 PM
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--Effect of chemicals on--Salish Sea (B.C. and Wash.); Persistent pollutants--Bioaccumulation--Salish Sea (B.C. and Wash.); Polycyclic aromatic hydrocarbons--Environmental aspects--Salish Sea (B.C. and 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
The threat of toxic contaminants to Southern Resident killer whales: monitoring POPs and PAHs in scat samples
The Southern Resident killer whale population (SRKW; Orcinus orca) feed primarily on Chinook salmon, which is currently their primary source of exposure to toxics. We measured lipophilic persistent organic pollutants (POPs: PBDEs, PCBs, and DDTs) in SRKW scat (fecal) samples to quantify variations in toxicant levels by pod, sex, and reproductive class, as well as prey availability. We also measured polycyclic aromatic hydrocarbons (PAHs), which do not generally bioaccumulate and would reflect recent exposure to oil, engine (combustion) exhaust, among other potential exposure sources. Samples were collected using detection dogs that use scent to locate fresh SRKW scat on the water’s surface. We collected 267 samples during four 5-month study periods between 2010 and 2013. POP levels in scat had expected trends, such as increasing with age and decreasing by number of calves (for adult females). POPs were also highest when the whales primary prey source was at low seasonal abundance, presumably due to metabolizing endogenous lipid stores. By contrast, overall measures of PAHs were low (ppb, wet weight), as expected. However, PAHs indicative of motor exhaust versus oil exposure were relatively high prior to implementation of guidelines aimed at increasing vessel distances to the whales. Results point to the value of monitoring POPs by age, sex and reproductive class and in relation to changes in prey abundance to help identify what reproductive classes are most at risk to high toxic loads, what season the liability is greatest, and whether prey recovery and clean up efforts are working. The PAH exposure data will be available as baseline in SRKW feces in relation to environmental events over time, such as the circumstance of an oil spill in the Salish Sea. Addressing toxics and other vulnerabilities is important for SRKW recovery.
