What’s Killing Killer Whales? Pathology Reports on More Than 50 Killer Whales in the Northeast Pacific and Hawaii

Healthy Killer Whale in Ocean

A southern resident killer whale swims in the Salish Sea in 2018. An endangered species, this population of just over 70 individuals lives year-round off the coasts of Oregon, Washington and British Columbia. Credit: Joe Gaydos, UC Davis Sea Doc Society

Pathology reports on more than 50 killer whales stranded over nearly a decade in the northeast Pacific and Hawaii show that orcas face a variety of mortal threats — many stemming from human interactions.

A study analyzing the reports was published today (Dec. 2) in the journal PLOS ONE. The study findings indicate that understanding and being aware of each threat is critical for managing and conserving killer whale populations. It also presents a baseline understanding of orca health.

The study was conducted by a team of marine mammal specialists led by a veterinary pathologist with the British Columbia Ministry of Agriculture and coordinated through SeaDoc Society, a Washington-based program of the University of California, Davis’ School of Veterinary Medicine. The study received guidance and support from Canada’s Department of Fisheries and Oceans and the United States’ NOAA Fisheries, the two federal agencies that manage this species.

The whales include those from healthy populations as well as endangered species, such as the southern resident whales regularly sighted off the coasts of British Columbia, Washington and Oregon.

Stranded Orca

This 18-year-old male southern resident killer whale, J34, was stranded near Sechelt, British Columbia on December 21, 2016. Postmortem examination suggested he died from trauma consistent with vessel strike. Credit: Paul Cottrell, Fisheries and Oceans Canada

Of 52 whales stranded between 2004 and 2013, causes of death were determined for 42 percent. For example, one calf died from sepsis following a halibut hook injury. Another starved from a congenital facial deformity. Two whales died from the blunt force trauma of vessel strikes. Additional causes of death include infectious disease and nutritional deficiencies.

‘We Can Do Better’

Despite there being no singular common cause of death, the study found a common theme: Human-caused deaths occurred in every age class — from juveniles to subadults and adults.

“Nobody likes to think we’re directly harming animals,” said SeaDoc Society Director Joe Gaydos, a wildlife veterinarian with the Karen C. Drayer Wildlife Health Center in the UC Davis School of Veterinary Medicine. “But it’s important to realize that we’re not just indirectly hurting them from things like lack of salmon, vessel disturbance or legacy toxins. It’s also vessel strikes and fish hooks. That humans are directly killing killer whales across all age classes is significant; it says we can do a better job.”

Gaydos and lead author Stephen Raverty, a veterinary pathologist with the BC Ministry of Agriculture, co-developed a standardized killer whale necropsy protocol in 2004. Revised in 2014 with help from Judy St. Leger, a pathologist working for SeaWorld, this guide helped improve examinations of deceased whales.

“The results from systematic necropsies of dead killer whales in this review is unique and will establish critical baseline information to assess future mitigation efforts,” Raverty said. “This work contributes to a better understanding of the impacts that ongoing human activities and environmental events have on killer whales.”

The authors acknowledge the report is an incomplete picture of orca health and mortality. Necropsies can only be performed on whales found in an adequate state to receive them, and even then, the cause of death cannot always be determined. But the report offers one of the most comprehensive looks yet at the multitude of human and environmental threats affecting killer whales and can help inform strategies to better protect them.

Reference: “Pathology findings and correlation with body condition index in stranded killer whales (Orcinus orca) in the northeastern Pacific and Hawaii from 2004 to 2013″ by Stephen Raverty, Judy St. Leger, Dawn P. Noren, Kathy Burek Huntington, David S. Rotstein, Frances M. D. Gulland, John K. B. Ford, M. Bradley Hanson, Dyanna M. Lambourn, Jessie Huggins, Martha A. Delaney, Lisa Spaven, Teri Rowles, Lynne Barre,  Paul Cottrell, Graeme Ellis, Tracey Goldstein, Karen Terio, Debbie Duffield, Jim Rice and Joseph K. Gaydos, 2 December 2020, PLOS ONE.
DOI: 10.1371/journal.pone.0242505

Additional coauthors include scientists from a wide range of institutions including Cornell University, NOAA Fisheries, Alaska Veterinary Pathology Services, Marine Mammal Pathology Service in Maryland, UC Davis One Health Institute, Fisheries and Oceans Canada, Washington Department of Fish and Wildlife, Cascadia Research Collective, University of Illinois-Brookfield, Portland State University, and Oregon State University.

Funding was provided by NOAA Fisheries and multiple grants from the John H. Prescott Marine Mammal Rescue Assistance Grant Program. Additional support came from Fisheries and Oceans, Canada; Vancouver Aquarium Research Program; SeaDoc Society; SeaWorld; Animal Health Center of the BC Ministry of Agriculture; Washington Department of Fish and Wildlife; and numerous First Nations, Alaska Native, and Inuit communities.

6 Comments on "What’s Killing Killer Whales? Pathology Reports on More Than 50 Killer Whales in the Northeast Pacific and Hawaii"

  1. Sekar Vedaraman | December 2, 2020 at 1:24 pm | Reply

    Exactly.

    All creatures of God on Land Air and Sea (and probably in Other Environments we have not yet become aware of including those which creatures which dwell deep within the bowels of a planet or star or other places where life as we know or life as we dont know can flourish) are Curious creatures!

    Dont even think for a minute that they are any less intelligent than human or other species. They are quick learners and like all Creatures want to exist once they have been granted existence by the Gift of Life and breath of the Almighty.

    Humanity as well catostrophic events have been responsible for the extinction of many species and many are on the verge of extinction. Every Species saved and existing are a wonderful creation of the Almighty and a wonder to behold beyond compare.

    All who do the work to protect them from exctinction are doing Gods work. Every Life is precious – Human or otherwwise . Labellling them “Killer” WHALES and then Invading their environment where either Curiousity or Search for Food Kills them is very subjective Judgment.

    Science is based on Curiousity of the Human Species and the same should be encouraged. However, the same needs to practised so that it does not harm a single creatureof of the almighty and minimise the same to the extent possible. VIEWS EXPRESSED ARE PERSONAL.

    • Sekar,
      You said, “Dont even think for a minute that they are any less intelligent than human or other species.” What makes you come to such a conclusion? Have you spoken with them?

    • Your comment is well written and so true. I wish I could see a good, happy, fruitful future for this world, but I don’t and cannot.
      Best wishes
      Mary

  2. Fukushima disaster is what’s killing them. Just recently Japan decided to dump the polluted water into the ocean. Now, its everyones problem.
    Starfish are disintegrating/melting, plankton & fish are disappearing. 100% human related. We have the wrong “leaders” in charge of our REAL issues. Their “leading” got us here.
    Clyde Spencer: you’re an idiot. So ib your limitless wisdom, having a conversation (in English I bet) is how you measure intelligence? They know sonar, but since you know English and have paper money you think you are special? You know nothing. It shows. Stick to commenting on youtube hip hop videos.

  3. Hans&Franz from Germany | December 3, 2020 at 5:42 am | Reply

    Are Orca’s intelligent? Definitely they are, as we see them mastering their huge environment and social life in an excellent way. They may not do things we might think as intelligent, but they live embedded in nature and experience each -without any pollution- more than any human is just able thinking of. They lived here before us and will probably sustain, after the virus human being has killed itself.

  4. Vivienne Magalhaes | December 3, 2020 at 6:15 pm | Reply

    It is extremely depressing to see an orca in the prime of his life, only 18 yo this magnificent and so intelligent creature bleeding dead after having collided with a vessel . Something quite common nowdays. AND HORRIFIC. With the rise of the human population AROUND 8 BILLION NOW 2020 seems to me there is only space for us selfish humans in this world and the usual few domestic animals…. AND PEOPLE still INSIST IN HAVING BABIES IN A WORLD THAT IS TURNING UP SIDE DOWN and with all the uncertanties of a near future….. Lack of fresh water, food becoming more artificial and less as a proper food, lack of space, new deseases, more floods, violent and impredictable climate due to climate change, melting of the glaciers, cities under the water…..
    What have we donne to this world ? Is this the beginning of the end? We humans are the most selfish and arrogant of all species.and we have been killing and destroying all forms of life on EARTH without a care in the world. The man – made global warming is a proof of that.

    I m wondering if it is worth to live on EARTH AND NOT TO BE DEAD IN ANOTHER FORM OF LIFE the spiritual life in another dimension or in a parallel
    UNIVERSE AND NOT TO WITNESSES THESE ATROCITIES ANYMORE and the FALSE WORLD WE LIVE IN…..
    I DO AGREE THAT OUR LIDERS ARE THE WRONG ONES….. BIG CORRUPTION IN THE UK, EUROPE, USA, AUSTRALIA, CHINA, ALMOST EVERYWHERE

    WE CAN PROTECT THE MAMMALS IN THE OCEANS FOR INSTANCE, TO FORBIDE THE USE OF PROPELARS FOR GOOD AND REPLACE THE DANGEROUS PROPELARS FOR SOMETHING THAT DON T HARM THE MARINE MAMMALS WHO LIVE IN THEIR HOME, THE OCEANS…
    ALSO STOP OVER – FISHING. REMEMBER SALMON IS FOR OTHER CREATURES WHO FEED ON THEM AND HAVE MORE RIGHT TO EAT SALMON THAN US GREEDE HUMANS…..
    I DO NOT HOPE THE BEST FOR HUMAN RACE, WE HAVE TO PAY FOR WHAT WE HAVE DONNE, AND FOR STILL LIVING IN SUCH FALSE MATERIALISTIC SOCIETY AND THE NEW “ORCA” ( VERY APROPRIATE NAME) PLANT TO CAPTURE CO2 AND STORE IT UNDERGROUND MIGHT WORK MIGHT NOT, BUT WHILE THE POPULATION STILL GROWING I BELIEVE WE ARE JUST GAINING TIME FOR WHAT IS TO COME …..
    SORRY FOR MY BAD ENGLISH.

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