Researcher
Stephanie Yue of the University of Guelph in Canada shares her
team’s surprising findings on fish sentience and ponders the ethical
implications.
It is not uncommon to find a variety of whole fish
displayed on ice at any average grocery store. Yet practically every other
type of meat is cut into portions and wrapped in clean packages that bear
no physical semblance to the animal from whom they came. While most people
in our Western culture would find it disturbing to see whole cows and pigs
on sale for meat, most have no problem with the sight of a large salmon
laid out in a similar manner.
A case of classical
conditioning—cued by a blue light signal, a trout swims through a
door into an adjacent chamber in order to avoid an oncoming plunging
dip net. photos: Stephanie
Yue
Our emotional distance from fish may stem from the
general feeling that they fall below the phylogenetic line where sentience
begins. This may be because our present knowledge of assessing suffering
in fish is inadequate—in part because fish do not typically display
traditional and obvious signs we are familiar with in other animals. They
are not capable of facial expression, nor can most species of fish
vocalize; given their general anatomical structure, changes in body
posture are extremely limited. Consequently, their use in scientific
experimentation, in place of birds and mammals, is seen as ethically
acceptable.
Overcoming Taboo
It’s not surprising then to see that, according to
statistics provided by the Canadian Council on Animal Care, there is a
rising trend in the use of fish in research. In Canada, there was a 463
percent increase between 1975 and 2002, resulting in over 600,000 fish
used for scientific research in 2002. Fish consumption has also risen
steadily, mostly due to increased interest in a healthy alternative to
traditional protein sources such as beef, chicken and pork. Huge numbers
of fish are used by humans on a regular basis.
However, recent anatomical, physiological,
neuropharmacological and behavioral studies suggest fish can suffer in
ways similar to "higher" vertebrate animals. Considering the large numbers
of fish we use, these findings should be enough of a reason for us to
consider their welfare as a serious matter. In addition, animal welfare
should be defined by how an animal "feels"—not just by how well it
physically copes with environmental conditions such as absence of disease,
lack of injury and good growth. Since sentient creatures have the capacity
to subjectively and consciously experience things, it makes sense to
investigate the fish’s capacity to suffer.
This is the project our fish welfare group at the
University of Guelph is currently undertaking. It is not a trivial
endeavor, for whether fish even possess the neuroanatomical structures
that generate the phenomenon of consciousness is still a subject up for
debate. The topic of consciousness has had a tumultuous history itself,
and it has been less than a couple decades since words like
"consciousness" and "sentience" have reappeared in scientific animal
literature. We are only slowly overcoming the taboo of studying conscious
thought processes and voluntary behavior.
From our studies on highly domesticated rainbow
trout, we have seen these fish show behavior that is much more flexible
and complex than was previously acknowledged. We have found that trout
have some cognitive capacity that rivals that of mammalian laboratory
animals, like rats. They not only show the ability to learn, but they also
have memory of the things they learned—so they can anticipate
events and adjust their behavior accordingly. This means some of their
behavioral repertoire is "purposeful" and lends evidence toward
"conscious" behavior.
Analyzing Fear
Not unlike a rat who will
press a lever for a food pellet, the trout in this photograph
presses a pendulum for a food reward during a recent investigation
of fear responses in rainbow trout.
Most of our experiments delve into the phenomenon of
fear. We try to tease apart which responses to negative stimuli (in our
case, an oncoming dip net) are likely to be reflexive and which are
deliberate. These experiments often require fish to be trained in tasks
ranging from simply swimming away from an area where an aversive stimulus
resides, to highly artificial and relatively sophisticated tasks such as
pressing a lever in order to obtain a reward.
We found that trout follow similar behavioral
patterns when frightened, as do other animals like mice. Mice show
avoidance, fleeing, freezing, and scanning of their environment and
general decrease in activity followed by gradual resumption of normal
behavior. Mice are deemed sentient animals with the capacity for a range
of subjective experiences. Why then should these same behavioral patterns,
when seen under similar experimental paradigms, not be employed as
evidence toward the possibility of subjective experiences in fish?
There is more evidence that fish do have some level
of consciousness than there is evidence against it, and it is logically
more likely that fish are sentient animals than they are not. What level
of consciousness they possess, however, remains to be determined. We still
have much to learn before we can properly generate guidelines specifically
tailored to the needs of different species of fish kept in captivity. Yet
we are moving in the right direction by entertaining the notion that fish
may indeed be worthy of more moral consideration than they have had in the
past.
This research project was made
possible through a grant from Animal Welfare Institute and the Center for
Alternatives to Animal Testing.
