Fish feel pain, Purdue researcher says Fishermen say right gear, techniques can reduce sufferingBy Dann Denny 331-4350 |
ddenny@heraldt.comChris Mullis scans the expansive waters of Lake Monroe, his eyes shielded from a blinding sun by a pair of dark-colored shades, as he contemplates the possibility that fish feel pain.
“I never heard any of them complain to me,” he says, casting his line into the water at Paynetown beach.
Mullis, a 36-year-old Bloomington resident, has been fishing since he was big enough to hold a pole.
“I’d fish every Saturday morning with my dad and grandfather,” he said. “If it was raining, we’d just put a canopy on the pontoon boat, and away we’d go.”
But Monday afternoon, Mullis was informed that a Purdue researcher recently found that while fish don’t make noises or contort their faces when hooks are pulled from their mouths, they very likely find it painful.
“The hook might cause them a little pain, but not much,” conceded Mullis, who fishes for walleye in Lake Monroe and large-mouth bass, crappie and blue gill in Lake Lemon.
“The hook goes through a thin membrane in the bottom of the fish’s jaw, and there are very few pain sensors there.”
But Joseph Garner, an assistant professor of animal sciences at Purdue University, sees things differently. He and his colleagues developed a test that found that goldfish almost certainly do feel pain, and react to it the same way humans do.
“I don’t think there is any question that fish feel pain in the same way we do,” Garner said.
Garner and Janicke Nordgreen, a doctoral student in the Norwegian School of Veterinary Science, outfitted goldfish with tiny jackets containing foil heaters, then slowly increased the temperature.
“The heaters were designed with sensors that prevented any physical damage to a fishes’ tissue,” Garner said.
Half of the fish were injected with morphine, and the others received saline. The researchers believed that those with the morphine would be able to withstand higher temperatures before reacting in a distressed fashion — by swimming more rapidly and displaying fearful, escape-response behavior.
But both groups of fish showed those telltale behaviors at about the same temperature, leading the researchers to conclude that their responses might be a reflex rather than a cognitive reaction to pain.
“A reflexive response is similar to a person involuntarily moving a hand off a hot stove,” Garner said. “The person reacts before he actually experiences any pain.”
But minutes later, when the fish were placed back into their home tanks, Garner and his colleagues noticed that the fish who’d been given morphine were acting as they always had, “just swimming around and being fish.”
“But the fish who’d been given saline acted with defensive anti-predatory behaviors, hovering at the bottom of the tank and not moving at all,’ Garner said. “Clearly, this behavior indicated they were fearful and anxious because they’d previously experienced some degree of pain from the foil heaters.”
When they were later placed in their home tanks “they turned the pain they’d experienced earlier into fear, just like we would,” Garner said.
Nordgreen said that together with work done previously by other researchers, the fishes’ behavior in their home tanks “indicates that the fish consciously perceived the test situation as painful and switched to behaviors indicative of having been through an averse experience.”
Implications?
Despite his findings, Garner feels it’s unfair to target anglers as brutish sportsmen. But given his findings, he does think the fishing industry should use less painful methods to kill fish.
“The technology is available to kill fish in more humane ways,” he said. “If we know that fish experience pain, we have an ethical responsibility to render them unconscious before killing them.”
Garner said in some countries fish are frozen to death in ice-cold water, or have their gill arches cut.
“Cutting the gill arches is the fish equivalent of having your throat slit,” he said. “And being frozen to death is undoubtedly a very nasty experience for the fish.”
Rob Caplinger, a fisherman from Morgantown, is not surprised by Garner’s findings.
“I graduated from high school and that’s it, but it stands to reason that if you get poked with a sharp hook it’s going to hurt,” he said. “But I feel fish can tolerate more pain than we can.”
Caplinger fishes frequently, often with his 22-year-old son. He throws most of his catches back into the lake.
“I think that if the fish gets hooked in the mouth and you can get the hook out nice and easy, the fish feels very little pain,” he said. “But if it swallows the hook, that’s got to be pretty painful when you pull the hook out.”
Agreeing with that assessment is Roger Fields, a Columbus man who was fishing Monday at Lake Monroe with his 11-year-old son Andrew.
‘We caught a blue gill recently that had swallowed the hook,” he said. “When we pulled the hook out it ripped up the fish’s insides. We threw it back in, but it quickly died.”
“That kind of bothered me,” Andrew said. “It bothered my dad too.”
Mullis, the Bloomington fisherman, said many anglers are now using “circle hooks” designed to reduce or eliminate the amount of pain experienced by hooked fish.
“A circle hook allows the fish to set the hook rather than the fisherman,” he said. “You hold the tension and the fish tightens the line. It’s 99.9 percent effective in setting the hook in the corner of the mouth rather than down inside the throat.”
