Dr. Lori Marino, President of the Whale Sanctuary Project, is the lead author of a new peer-reviewed paper on “The Harmful Effects of Captivity and Chronic Stress on the Well-Being of Orcas.”
June 24, 2019: A paper published today in the Journal of Veterinary Behavior assembles an unprecedented body of evidence to support a clear link between chronic stress and high morbidity and mortality in captive orcas. (Download the complete paper here.)
The paper demonstrates that the poor well-being and high mortality rates of orcas (killer whales) in captive facilities can be explained by known effects of chronic stress and its association with immune system dysfunction, disease and disorder in mammals.
A clear link between chronic stress and high morbidity and mortality.The paper represents a unique collaboration among marine mammal researchers, veterinarians and physicians, who have applied well-accepted scientific models of chronic stress in humans and other animals to extensive evidence for insufficient well-being of orcas living in concrete tanks.
The authors review the neuroscientific, cognitive, behavioral, ecological and physiological make-up of orcas and explicate how each of five inter-related situations inherent to living in marine theme parks and aquariums (social stress, confinement, sensory disturbance, lack of control and boredom) are related to chronic stress and disorders. Examples include:
- Social: Artificially-formed social groups and frequent transfers in and out of facilities disrupt mother-calf bonds, perpetuating a cross-generational cycle of poor maternal care and negative impacts;
- Confinement: Inadequate depth and horizontal space in tanks prevent the expression of species-specific movement and lead to behavioral anomalies and physiological de-conditioning;
- Sensory disturbance: Exposure to loud artificial sounds both above and below the water surface e.g., fireworks, audience noise, construction and filtration system noise creates anxiety and sensory interruption. Additionally, the concrete tank walls create an abnormal acoustic environment;
- Lack of control: Loss of autonomy and control over daily activities leads to the well-known stress-related psychological condition known as learned helplessness, which manifests as depression, lack of motivation, impaired learning, anorexia, and eventual immunocompromise;
- Boredom: Daily monotony and lack of appropriate challenges in such a large-brained complex animal, lead to immobility (increased logging behavior on the surface), depression, irritability and increased anxiety.
“The scientific evidence has been building over the years showing that orcas fare poorly in concrete tanks because of the mismatch between their natural adaptations and life in these facilities,” said neuroscientist Dr. Lori Marino, senior author on the paper.
The authors bring expertise in both marine mammal and human clinical science to articulate a reasonable, empirically-based account of a link between chronic stress and increased morbidity and mortality in orcas kept in concrete tanks.
They demonstrate that because of the intelligence and social complexity of orcas, life in marine theme parks and aquariums is fundamentally at odds with their nature and that a new paradigm is required in their treatment in order to better meet their complex needs.
“Intelligence – meaning cognitive complexity – can be a liability, rather than a buffer, for these animals as they attempt to cope with life in artificial barren settings,” Dr. Marino said.
The authors conclude that increased access to veterinary records would allow this model to be more directly tested for this species.