Brett Roper

One question all anglers are eternally seeking to answer is what makes a fish take a fly, lure or bait.

It is this question that defines fishing and what makes this activity different from hunting. In hunting, if you are in an area with lots of animals, spend time scouting and at the range, you will likely be successful. In contrast, sometimes you can be angling in a location with feeding fish all around you and still not get one to take your bait.

There are times of the year when fishing is better. Warming temperatures in the spring, cooling temperatures in the fall, the onset of spawning and the presence of a concentrated food source all trigger fish to feed at a higher rate. The exact times of these events depends on the species, where you’re fishing and the year.

A good example of this the Logan River. While the first week of July is typically a great time to be on the river pursuing cutthroat trout, this year’s high stream flows are keeping these fish tucked along the stream edges and making it difficult for anglers to wade. These environmental conditions mean the best time to fish this year will be in late July. So while it pays to plan when to go fishing, it is also important to factor in annual differences such as weather and water levels.

The warmer the water, the faster food is assimilated. Most fish are also sight feeders. Putting these two things together suggest that during the heat of the summer, it is beneficial to be on the water early in the morning when fish are hungry and the low light level means they are more prone to confuse an artificial fly or lure with the prey they are seeking. This is not always true. In rivers with cold water temperatures, fish often don’t become active until the middle of the afternoon, so it won’t cost you to sleep in.

A great time to pursue fish is around the time they spawn. In this region that means targeting walleye in April; bass and crappie during May and June; and brown trout throughout October and November. As fish disperse to a broader set of habitats following spawning, they become less aggressive and are more difficult to find.

In thinking about this article, I spent time looking for research explaining when and why anglers are likely to have greater success. To my surprise, I couldn’t find any articles on this subject. This doesn’t mean weather, barometric pressure, cloudiness or rain don’t affect angler success, but that this understanding has rarely been subjugated to the scientific method.

This lack of research does not apply to commercial fisheries. Competition among commercial anglers leads to the rapid adoption of new equipment that has been demonstrated to improve success. The increasing efficiency of commercial fleets leads to over-harvest and is why these fisheries are strictly regulated.

In contrast, recreational anglers are often slow to adopt new technologies. Many people still don’t have rods rigged with fluorocarbon or braided lines, even though there are situations when these lines provide a much better chance of catching fish. While I love the old lures I inherited from my grandfather, the ones manufactured today are much more effective at eliciting a strikes from fish.

Catching fish is about presenting the right lure in the right place and in the right way. Even though a fish’s brain is often smaller than a BB gun, it can take a lot of knowledge to convince one to take a lure. Most of the time, if you have something approximately the same size, color and silhouette of what fish are feeding on, you will be successful. This is easier to say than to do. One way to make sure they are feeding on what you think they are is to use a stomach pump for gastric lavage. Many times I have been fooled and find fish feeding on something other than what I was expecting.

Understanding how to get a fish to bite can be improved by reading books, viewing videos and watching television. None of this matters, however, if you don’t get out and test this knowledge on as many lakes and rivers as possible.

Brett Roper is a fisheries biologist for the Forest Service who has been lucky enough to make a career out of thinking about and spending time outdoors. He can be contacted at

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