Event Title

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 (<5 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 (Seattle, WA : 2018)

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

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

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

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Apr 4th, 2:15 PM Apr 4th, 2:30 PM

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 (<5 >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.