Will the Sun Set on the Southern Resident Killer Whales?

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PC Photograph: Elaine Thompson, AP

A combination of food loss, activity disruption, pollution, and vessel noise is responsible for declining southern resident killer whales (SRKW) inhabiting the Pacific marginal sea bioregion containing the Strait of George, Strait of Juan de Fuca, and Puget Sound. But little, outside of endless debate and study, has been done to protect them.

Whales in the J, K, and L pods are called southern residents because they permanently reside in a specific bioregion instead of migrating or swimming in the open ocean. These critically endangered orcas are native to the Pacific Northwest, distinct in morphology, ecology, genetics, and behavior from other offshore or transient orcas—and there are only 73 of them left.

PC Illustration: Mark Garrison

NGOs, various committees, and state agencies alike have been searching for solutions to the SRKWs dwindling numbers, yet few want to take responsibility. This prompts a nearly perpetual state of inaction, where parties lob blames back and forth between:

  • Diminished food sources result in near-starvation diets
  • Encroaching whale watching tours cause activity disruptions
  • Decades-old, banned, and cumulative pollution causes bodily dysfunction
  • Increased vessel or boat traffic noise prevents echolocation

Such hotly debated responsibilities have their supporters across industries and government with money being the greater arbiter. But regardless of the number or length of scientific studies or even which vested interest “has the floor,” we’re left with heartbreaking news videos etched in our minds.

Do you recall the mother orca who carried and grieved her dead 4-year-old child for 17 days in 2018? After nearly three weeks of intense coverage, agencies and groups still couldn’t agree upon real action or policy change to prevent such a tragedy from ever happening again. That inaction may have been the biggest tragedy of all.

What’s happened to the orca’s food source?

PC Photograph: John Durban, NOAA

King or Chinook salmon, Oncorhynchus tshawytscha, are the SRKW’s food primary source. They, too, are listed as endangered under the Endangered Species Act (ESA). Chinook salmon already have compounded threats of their own—from overfishing and pollution to dams on the Columbia River.

Dams prevent these North Pacific salmon from returning to native spawning grounds while slowing the river’s speed. No longer rushing, a slower river means warmer water where the anadromous salmon, still young smolt, strain to make the time-extended journey to the sea or because they become easier prey while moving so slowly.

Chinook salmon are also much smaller and less nutritious, which means that the effort to locate and chase a dwindling food source results in a fraction of basic dietary needs.

Could whale watching tours be to blame for dwindling orca numbers?

Not all whale watching tours are to blame, just those that don’t follow the set regulations. Rule-breaking boat captains and overly curious kayakers (canoeists and paddleboarders, too) reportedly cause undue stress to orcas that would otherwise be able to feed, travel, and socialize with unrestraint.

Encroaching recreational vessels can startle the SRKW out of pursuing food or protecting their young, particularly when the whale breaches only to find itself nearly on top of human activity. But not all boaters and paddlers fail to observe the guidelines, and some agencies have initiated even stricter guidelines than federal mandates require.

PC Photograph: Author credit

How is chemical pollution decreasing orca populations?

Orcas are apex predators that sit atop the trophic chain. It’s a complex food web, beginning with phytoplankton (seaweed), which is eaten by zooplankton (krill and jellyfish). Smaller fish eat the zooplankton and larger fish (salmon) eat the smaller fish. Finally, the SRKWs consume those larger fish, ingesting every chemical pollutant from the seaweed up to the salmon.

Through this hierarchical food web, a process called biomagnification takes effect where orcas face a heavily contaminated build-up of polychlorinated biphenyls or PCBs (found in oil paints and coolants). Deemed so dangerous, PCBs were banned in the 1970s and 1980s thanks to the work of Rachel Carson and others, but not before entering global marine ecosystems.

Diagram showing PCB biomagnification in the Puget Sound food web. PC Image: Seattle Post-Intelligencer

Over time, PCB levels in the oceans have diminished very little while pollution levels in orca food chains build, layer, and compound, bioaccumulating with every meal. The pollutants also pass from mother to baby, affecting development, behavior, immune and endocrine systems, reducing reproduction rates with each generation.

How much responsibility does noise pollution hold for decreasing orca populations?

Underwater, ambient geophonic, and marine biophonic sounds transmit topography, predator detection, and social interactions like mating. But human anthrophonic disturbances (noise pollution) such as commercial and recreational vessels can cause behavioral, physical, and physiological changes, including modifications to reproductive behaviors, sensory cognition, and growth or body conditions. Studies of acoustic noise pollution alongside SRKW pod locations have even found that small vessel traffic adversely affects foraging rates.

Vessel-caused acoustic disturbances have increased and will continue to rise (unless policies force change), while marine-made sounds have been decreasing due to drops in orca populations caused by the previously anthropogenic noise and an altered contribution of geophysical sources.

Infographic courtesy of the Vancouver Fraser Port Authority’s Enhancing Cetacean Habitat and Observation (ECHO) Program, aimed at better understanding and managing the impact of shipping activities on at-risk whales throughout the southern coast of BC.

This data, among other things, shows that we must evaluate ship density impact for SRKW populations showing that noise also varies with vessel size. These findings inform better policymaking for vessel traffic, especially in light of increased anthropogenic marine activity throughout the bioregion. For the SRKW, vessel traffic has been increasingly harmful, which is why mitigating noise pollution is now framed within the Marine Strategy Framework Directive and part of the United Nations Sustainable Development Goal 14, or Life Below Water.

What’s being done to support orcas in the Pacific Northwest bioregion?

PC Photograph: Elaine Thompson, AP

Quiet Sound collaborating with the nonprofit Washington Maritime Blue is proposing voluntary initiatives for vessel noise reduction. Through an App easily installed on their smartphones, ship captains will be alerted to the presence of orcas. They can then slow ships down to a reasonable speed, reducing vessel noise.

Such mitigative efforts not only diminish underwater noise in the most pressing and disruptive noise pollution hertz bands between 10Hz and 1kHz but, as a bonus, save at least 10% or more in fuel costs.

With vessel traffic expected to double by 2040, all current pollutive events are sure to be negatively cumulative without these reductive noise efforts.

It’s not unusual for eco-friendly business measures to result in money-saving. In fact, institutionalizing propeller boss caps to reduce cavitation, travel at slower speeds, and even regular hull maintenance increases savings. Then again, energy efficiency has always been more cost-effective whether through energy-efficient equipment or general maintenance of ships, ensuring proper function.

Are these initiatives and proposals just more fruitless debate?

Although noise pollution is just one concern for the decreasing SRKW populations, it’s also a point source of pollution that policies can effectively mitigate in the short term—other efforts such as salmon stock improvements, human encroachment, and pollution reduction could take longer. Still, effective change isn’t going to come without some effort on our part.

What can you do?

  • If you’re a boater, take time to learn the protection zone and steer clear of it.
  • If you see a boat or paddler harassing orcas, report them.
  • Petition to your legislators not once, but ten times—and get your friends to do it, too.
  • Skip the motorized boat tour, bring some binoculars, and watch from ashore.
  • Educate yourself so that you can help others understand threats to orcas and federal regulations.
  • Join a nonprofit that supports counteracting the various threats against orcas.
  • Let your photos be your voice online, sharing them with the larger community for a greater reach of audience.

Some final thoughts.

Countless species globally are under threat of extinction in the coming years due to climate change and the destruction caused by humans. It’s up to you to be part of the generation that says “no more” to the nonsensical status quo of environmental chaos when alternatives, albeit cheaper ones, exist.

 

 

Further reading:

Benecki, P., Kinyua, B. G., & Muchira, N. “Quieting the waters.” Maritime Executive. 4 June 2018. www.maritime-executive.com/features/quieting-the-waters

Cominelli, S., Devillers, R., Yurk, H., MacGillivray, A., McWhinnie, L., & Canessa, R. “Noise exposure from commercial shipping for the southern resident killer T whale population.” Marine Pollution Bulletin, (136), 177-200, 2018. www.orcanetwork.org/Main/PDF/shipnoise_exposure.pdf

Duarte C.M. et al. The Soundscapes of the Anthropocene Ocean. Science 371, eaba4658, 2021.

Gassmann, M., Kindberg, L. B., Wiggins, S. M., & Hildebrand, J. A. “Underwater noise comparison of pre- and post-retrofitted MAERSK G-class container vessels.” UCSD. October 2017. cetus.ucsd.edu/Publications/Reports/GassmannMPLTM616-2017.pdf

Holt, M. M., Noren, D. P., Veirs, V., Emmons, C. K., & Veirs, S. “Speaking up: Killer whales (orcinus orca) increase their call amplitude in response to vessel noise.” The Journal of the Acoustical Society of America, 125(1). doi:10.1121/1.3040028, 2019. asa.scitation.org/doi/full/10.1121/1.3040028?mimetype=application%2Fpdf&crawler=true&

Lusseau, D., Bain, D., Williams, R., & Smith, J. “Vessel traffic disrupts the foraging behavior of southern resident killer WHALES Orcinus orca.” Endangered Species Research, 6, 211-221. doi:10.3354/esr00154, 2009. Retrieved February 26, 2021, from www.int-res.com/articles/esr2008/6/n006p211.pdf

Merchant, N. D. “Underwater noise abatement: Economic factors and policy options. Environmental science & policy, 92, 116-123, 2019.

O’Neill, C., J. Wladichuk, Z. Li, A.S. Allen, H. Yurk, and D. Hannay. “Cumulative Noise Modelling in the Salish Sea.” Document 01369, Version 1.0. Technical report by JASCO Applied Sciences for Noise Exposure to the Marine Environment from Ships (NEMES), University of Victoria, 2017.

Patterson, A. M., Spence, J. H., & Fischer, R. W. “Evaluation of underwater noise from vessels and marine activities.” 2013 IEEE/OES Acoustics in Underwater Geosciences Symposium. doi:10.1109/rioacoustics.2013.6683985, 2013.

Seely, E., Osborne, R. W., Koski, K., & Larson, S. “Soundwatch: Eighteen years of monitoring Whale Watch Vessel Activities in the Salish Sea.” PLOS ONE12(12). 2017. doi.org/10.1371/journal.pone.0189764

Welch, Craig. “Half the World’s Orcas Could Soon Disappear—Here’s Why.” National Geographic, 3 May 2021. www.nationalgeographic.com/environment/article/orcas-killer-whales-poisoned-pcbs-pollution

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