Do fish feel pain?

News and commentary about environmental issues.
May 29 2009 12:50 PM

Frying Nemo

Do fish feel pain?

Illustration by Charlie Powell. Click image to expand.

Here we go again. There is a new study out that contends fish feel pain. A professor at Purdue and his Norwegian graduate student attached small foil heaters to goldfish. Half of the goldfish were injected with morphine, half with saline, and then the researchers turned on the attached micro-toasters. After the heat was gone, the fish without painkillers "acted with defensive behaviors, indicating wariness, or fear and anxiety." They had also developed a lovely brown crust. These results echo a 2003 study by researchers from the University of Edinburgh who shot bee venom into the lips of trout. The bee-stung fish rubbed their lips in the gravel of their tank and generally seemed pissed off.

Whenever one of these studies about fish pain appears, animal lovers start glaring at me and my fellow fishermen. If fish can experience pain, then angling must be a cruel sport, right up there with deer hunting, bear baiting, and eating hot dogs. Why can't we just leave fish alone and do something else?

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The online reaction to the goldfish pain study was both typical and funny—especially in the United Kingdom, where they seem to take animal news more personally. The assembled mob at the Daily Mail got very rowdy. In one corner, you have comments like this: "Every time I see an angler, I say a little prayer that he will get his fishing hook lodged in his body, and then perhaps he will give some thought to the barbaric 'sport' he is pursuing." In the other corner, comments like this: "I'm a trout fisherman and I can tell you all with 100% accuracy that the trout I catch feel absolutely no pain after I've smacked them over the head with a cosh." The pro-angling side rattled off some good jokes about whether or not carrots feel pain when they are peeled. They also directed a surprising amount of vitriol toward lentils and those who eat them.

Obviously, anglers are on the defensive. They've seen what has happened to hunters, who watched their public image go from grandpa-in-the-duck-blind to toothless-gun-nuts-on-four-wheelers. Shooting a deer has become a half-murder. Anglers also know that PETA has them in their sights. The animal-rights group has a "Fishing Hurts" campaign, armed with papers demonstrating that "fish are more intelligent than they appear" and with a video from the late Linda McCartney. "Have you ever seen a fish gasping for breath when you take it out of the water?" she asks. "They're saying 'Thanks a lot for killing me. It feels great.' " The whole strategy is rather charming in its blatancy. For the kids, PETA wants to rebrand fish as "sea kittens." You can create your own sea kitten here. I named mine "Blair."

In my free time, I like to catch what you might call "stream kittens." My childhood house in Pennsylvania had a limestone-spring-fed stream behind it, and as a teenager, I spent evenings on the water casting dry flies. (I still fish whenever I can.) This was the early 1990s, and I was indoctrinated in the catch-and-release ethic that was growing at the time. (The idea of catch-and-release has been promoted by the conservation group Trout Unlimited since the 1950s, yet there are still many parts of the country where fishermen think it's ridiculous. When I started fishing, most guys I met on the banks liked to catch their daily limit of trout and eat them.) To release a fish properly, you wet your hands before handling it (so as not to take off the protective slime), gently remove the barbless hook from its mouth, and then swish it back and forth in the water until it gets its bearings (though fish usually just flit away at the earliest opportunity). Like many anglers, I had the experience of catching the same fish twice, even three times. I wasn't hurting them; it was as though we were wrestling.

Research studies back up the fishermen's intuition that catch-and-release works. Generally, if you don't deep-hook a fish, exhaust them on the line, hold them out of the water too long, or bash them on the head, they have a good chance of living to fight another day. But do they feel pain? I'll admit that they don't seem happy thrashing about in the water, and some fish make an unpleasant croaking sound when you're trying to get the hook out. Seeing them gasping for air, it's hard not to feel like a jerk sometimes.

The 2003 Edinburgh study confirmed that trout have polymodal nociceptors around their face and head—i.e., they have the ability to detect painful stimuli with their nervous system. But, according to some definitions of pain, the detection of painful stimuli is not enough. The animal must have the ability to understand it is in pain to really feel pain. Putting a hook in the mouth of a trout stimulates it to race around the water, to not go where the line wants to force it. But this doesn't mean that the fish is thinking "Shit. Shit. Shit. This sucks. This sucks. Ow. Ow. Ow." What seems like a desperate escape might be a reflexive reaction, similar to your leg moving when the doctor taps your knee.