A new essay published in Issues in Science and Technology argues that current animal welfare science and policy frameworks overlook a fundamental aspect of the lives of fish and other aquatic "water-breathing" species — and calls for a shift in how governments, researchers, and industry assess humane treatment in aquaculture, research, commercial fisheries, and in the wild.
The essay — authored by Jennifer Jacquet, a professor in the Department of Environmental Science and Policy at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science, and Daniel Pauly, professor of fisheries and zoology at the University of British Columbia — contends that longstanding animal-welfare models were built around mammals and birds and fail to account for the central biological reality of aquatic life: access to oxygen[JJ1] .
Jacquet and Pauly maintain that the influential "five freedoms" framework guiding global welfare standards was conceived by and for air-breathing animals and therefore omits a critical dimension for fish and other aquatic organisms — the ability to breathe safely in water. They point out that air exposure, crowding, warming waters, and declining dissolved oxygen levels can cause severe physiological stress and pain in these species, particularly in industrial fishing and aquaculture settings.
"Water-breathers without water to irrigate their gills are suffocating," the authors write, noting that experiments and field studies demonstrate that even brief periods of air exposure can be associated with acute distress and elevated mortality in fish. The essay highlights emerging research showing behavioral and neurophysiological indicators of intense pain during air asphyxiation — the most common method of fish slaughter worldwide — and warns that some proposed alternatives may produce even greater suffering if not carefully evaluated.
The authors also draw attention to climate and industry-driven risks, including marine heatwaves, declining ocean oxygen levels, and high-density aquaculture operations where fish cannot escape low-oxygen environments. Recent studies, they note, have linked such conditions to increased mass-mortality events in farmed salmon.
Despite the scale of global aquaculture — which now produces tens of millions of metric tons of animals each year across more than 400 species —basic welfare research is missing for over half of farmed aquatic species. Jacquet and Pauly also noted the shift in modern welfare science and its recent expansion beyond productivity and survival metrics to consider both suffering and the potential for positive welfare experiences.
To address this systemic blind spot, the authors call for:
• Updating welfare frameworks to explicitly include "freedom from asphyxiation" alongside freedom from hunger and thirst
• Prioritizing dissolved-oxygen availability in research, aquaculture design, and regulatory guidance
• Reducing or eliminating unnecessary air exposure in research, recreational, and commercial handling
• Supporting humane stunning methods prior to slaughter
• Expanding species-specific welfare research across aquaculture and fisheries
They suggest that greater public and scientific recognition of aquatic species' vulnerability — similar to shifts in thinking that reshaped international attitudes toward whales — could spur meaningful reform across policy and practice.
"Breathing air relatively easily should not keep us from learning to care," the authors conclude, urging policymakers, scientists, and producers to confront longstanding terrestrial bias in welfare standards and to center oxygen access as a primary dimension of aquatic animal wellbeing.
The full essay, "Water Breathing Is a Blind Spot in Animal Welfare Science," was published on January 12, 2026 in the Winter 2026 issue of Issues in Science and Technology.
The authors are Jennifer Jacquet from the University of Miami Rosenstiel School and Daniel Pauly from the Institute for the Oceans and Fisheries at the University of British Columbia, principal investigator of the Sea Around Us initiative.
