Originally from Canada, a country blessed with good fishing, Cory Suski likes to drop a line himself now and then.
Which only adds to the University of Illinois professor's interest in fisheries management and conservation, particularly recreational fisheries, whether large mouth bass in East Central Illinois or bonefish in the Bahamas.
"Ultimately, what I'm concerned with is conserving that resource so that our grandkids can go out and catch fish," Suski, a natural resources and environmental sciences professor, said recently.
Suski has previously looked at issues like temperature change and changing oxygen levels in relation to the health of fisheries.
Now, he and colleagues are looking at how catching and releasing sport fish may affect their chances of survival once back in the water.
The idea isn't to eliminate catch-and-release fishing, just the opposite. The UI researchers, in effect, are looking for baseline standards that will maximize the chances of a fish, and its progeny, living to fight, be landed and get photographed another day.
"The longer you fight the fish, the longer you keep it out of the water, the greater the physiological disturbance," Suski said.
That's one major conclusion of a study looking at bonefish and recapped in the journal Comparative Biochemistry and Physiology.
Bonefish are a good model because, not considered very good eating, they're almost exclusively caught for sport and released, as well as being part of an economically valuable tourism industry, Suski said.
"They're very fun to catch," he said.
The researchers found that the longer it takes to land the fish and get them back into the water, the longer it takes for them to begin swimming normally again. Like a runner at the end of a race, their bodies are taxed.
The concern is that the situation may expose the fish to increased risk of being caught again – this time by a predator – and eaten.
The researchers also tested calcium, glucose and lactate levels in the blood of the fish at various intervals to determine when they returned to normal. All three help indicate the extent to which a body remains stressed after exertion and the amount of energy it expended.
Our bodies produce lactic acid when we run, for example, more the harder we run. (That cramp you get in your leg when you overdo it is believed to be related to lactic acid buildup.)
"We're looking at a few different systems," Suski said. "When you put those all together, it tells you a sort of well-rounded story of how the animal's responding."
To put the fish through their paces, the researchers caught them in a net and placed them in a large swimming tank, then allowed them to rest.
When the fish had cooled down, so to speak, they were then chased around the tank with a hand to simulate being caught.
In some cases, the researchers chased the fish for a minute, in others four minutes. They also chased the fish for a minute and four minutes with and without exposing them to air.
Suski said they found that a minute's chase with no air exposure did little to disturb the fish, while a minute with air exposure created a slight disturbance. But at four minutes, with and without air exposure, it could take the fish two to four hours to recover.
The physiological response probably is similar in other fish, Suski said, although factors such as water temperature could have an influence. Fish, which are cold-blooded, may respond faster in warmer water.
The UI researchers are looking at whether size matters, that is whether big or small fish tend to recover faster or slower, in that case focusing on large mouth bass in Illinois.
Suski said the message at this point is to minimize the time it takes to catch and release a fish if you want to maximize its chances of survival.
http://www.news-gazette.com/news/local/2007/10/29/prof_fishes_for_clues_concerning_best