When do fish spawn and when do they eat?

By Tom Keer

Mar 23, 2016

When I was a 14 years old, my football coach took me fishing.

When I was a 14 years old, my football coach took me fishing. When we got to the river, he pulled out a thermometer and held it in the water. "Today is going to be a great day," he said. "We are going to catch 'em up."

I thought he was nuts. Why wouldn't he at least make a few casts to see if we were going to catch a fish? The fact that Coach was also my science teacher made me think of two things: I didn't want to run post-practice wind sprints for asking a dumb question, and I didn't want to fail his class. I kept my mouth shut, but he fortunately continued.

"When the water temperature is at a specific temperature, fish burn off a lot of food and they need to eat. So when the water is between 55 and 65 degrees, the trout we're trying to catch will burn up one stomach full of food per day. When it's colder or warmer, those same trout will burn up one stomach-full of food every four days, and that means they don't need to eat. Today, they need to eat.

"But we also need to know when they spawn, because if they are focused on spawning they won't want to eat. It's just like you and your teammates get distracted when the cheerleaders run on the field."

Since then, a thermometer has been as important a tool as a rod, reel, and line itself. There are some regional variations for both spawning and feeding temperatures, but here is a chart to help you put the ball in the endzone.

Species     Temperature Range        Ideal Feeding Range
Largemouth bass                68-72                    70-80
Smallmouth bass                59-60                    65-70
Spotted bass                63-68                    70-78
Black crappie                62-68                    70-75
White crappie                60-65                    70-75
Striped bass-fresh                59-65                    60-70
White bass                45-48                    50-60
Bluegill                65-80                    70-75
Channel catfish                75-80                    65-75
Blue catfish                70-75                    65-75
Northern pike                40-52                    50-60
Rainbow trout                40-55                    55-65
Brown trout                47-52                    55-65
Brook trout                45-48                    55-65

Source: USFWA

Tom Keer
Tom Keer
Tom Keer is an award-winning writer who lives on Cape Cod, Massachusetts.  He is a columnist for the Upland Almanac, a Contributing Writer for Covey Rise magazine, a Contributing Editor for both Fly Rod and Reel and Fly Fish America, and a blogger for the Recreational Boating and Fishing Foundation’s Take Me Fishing program.  Keer writes regularly for over a dozen outdoor magazines on topics related to fishing, hunting, boating, and other outdoor pursuits.  When they are not fishing, Keer and his family hunt upland birds over their three English setters.  His first book, a Fly Fishers Guide to the New England Coast was released in January 2011.  Visit him at www.tomkeer.com or at www.thekeergroup.com.