Strategies For Trout and Salmon in Maine Lakes

Reprinted from Fly Fishing Quarterly

Maine Salmon FishingThe decision to carry our canoe from the logging road to the stream at the head of the frozen lake turned out to be a good one. It was only a mile or so over fairly flat terrain, and we covered the distance in a little over an hour. Because of this effort, we were rewarded with a hundred yard piece of open water in front of an inlet stream that provided some of the best fly fishing action in recent memory. The funny thing is, we had almost given up on this spot because trips in several previous years had been almost totally unproductive.

The only difference this time was, since we didn’t wait for the ice to clear on the lake, we arrived at the inlet stream about two weeks earlier. But this slight shift in timing had a significant impact on our success, because it brought us to the area at a time when trout were gathered to feed on spawning smelts. Eventually, through trial and error, we learned that there is about a ten day window, just before the ice goes out on the lake when fish congregate at this spot in significant numbers. Hit it right and it can be fly fishing heaven. If you arrive after the bait fish have dispersed, however, it can be barren as a ski slope on the 4th of July.

This illustrates the dramatic effect that a single environmental factor can have on the distribution of fish in a lake. In this case, a readily available food source was the reason trout were concentrated near the smelt spawning stream. During other times of year, water temperature, dissolved oxygen levels and proximity to spawning sites can be equally important.

To be successful on large lakes, fly fishermen must find some means of transforming their vast expanses of open water into something that can be read like a stream. Knowing the biological cues that influence the distribution of trout, is a big step in the right direction. The ability to use this information to pinpoint localized areas where significant numbers of fish are concentrated, however, is what distinguishes a recent stream-side transplant from the true big water aficionado.


Maine Landlocked SalmonAnglers should never lose sight of the fact that fish are cold-blooded animals whose body temperature is controlled by their external environment. Unlike the constant body temperatures maintained by humans and other warm-blooded animals, the body temperature of fish is essentially equal to the temperature of the water they are living in. In northern latitudes or at high elevations, this can result in a 35o-40o F seasonal shift. Such drastic changes in body temperature have a profound influence on a fish’s metabolism and represent an important tool that can be used to help develop a successful fly fishing strategy.

Each group of fish has a rather narrow range of temperatures around which it is most comfortable. But for convenience, the groups are often simply classified as either warm-water or cold-water species. The optimum water temperature for most cold-water species is between 50o-65o F; and as water temperatures move away from this range, their metabolism drops off proportionately. In water below 40 F or over 70 F, most trout move around very little, feed only sporadically and do not fight very well when hooked.

Research indicates that temperature changes as slight as 1/10 F can be detected by many fish. And, that they will actively migrate to regions of a lake that are most comfortable. Obviously, you’ll find more action by fishing waters that are near the optimum temperature for the species you are interested in. Of course, temperature isn’t the only factor influencing the distribution of fish in a lake. But, when it comes to zeroing in on a particular location or depth to begin fishing, most experienced anglers find it to be a fairly good place to start.


Rangeley BoatsThe typical temperature profile of a lake at ice-out shows that a rather narrow band of near freezing water at the surface is supported by a much larger volume of 39 F water that extends to the bottom. This configuration occurs because water reaches its maximum density at 39 F, and gets trapped below the colder, lighter layer of recently melted ice water above.

As might be expected, these cold, near uniform water temperatures tend to keep fish more sluggish and scattered then they will be during the peak of the angling season. Still, for early season anglers determined to beat the odds, there are several locations that usually produce fairly consistent results.

I like to cast or troll bait fish patterns along the edges of shallow shoals and shelves because these are the areas which receive the maximum benefit from the spring sun’s first warming rays. On calm days during the first week or so after ice-out, I routinely record water temperatures more than 5 degrees higher here than in the deep water areas of the lake. Considering the sensitivity to water temperature that most fish display, it’s easy to see why they are attracted to these areas. The challenge for anglers lies in identifying these warm-water oases.

Three items that go a long way toward helping you do this are: depth maps, a thermometer and a bottom sounder. Used in conjunction with each other, they will frequently allow you to locate potentially productive areas in new lakes in less than an hour. And, you don’t need to spend a lot of money on fancy electronics to get the job done.

Good depth maps can usually be obtained from state fish and game departments or local tackle shops. A perfectly adequate bottom sounder can be made by attaching a two ounce sinker to a white string that has been marked off in three foot increments. The type of thermometer you use is a matter of budget and convenience. Since I do a lot of exploring, I invested in a Cline Finder made by Catalina Technologies, which can provide a near-instant temperature reading from any depth. A simple $10 stream thermometer on a string can do nearly the same thing; you just have to wait 30 seconds or so for the information.

Good early season action can also be found at the mouths of many inlet streams. Here, food being washed into the lake or bait fish congregating for spawning often combine with favorable water temperatures to attract trout to the area. Proper timing is often a key to success. Thus, it may be necessary to visit an area repeatedly before determining the optimum time to fish it.


Within a week or so after ice-out, the surface waters of most lakes reach 39 F. At this point, the entire water column is the same density and free to circulate from top to bottom. Driven by wind and wave action, this “spring turnover” replenishes the oxygen supply in the deep water regions of the lake and delivers important nutrients from the bottom sediments.

Although this event is critical to the well-being of all aquatic organisms living in the lake, most fish tend to remain lethargic and scattered because the water temperature is still uniform and extremely cold. Thus, I generally continue to concentrate my efforts around shallow shoals and the mouths of inlet streams until surface waters begin to approach 50 F.


Maine Lake TroutFollowing spring turnover, only surface waters are able to reap the benefits from additional inputs of heat, because as they become warmer, they get lighter, and float upon the cold, denser water below. In effect, this insulates the bulk of the lake from the sun’s warming rays and draws fish to this thin layer of warm water at the surface.

The amount of time trout remain on top depends largely upon how long it takes for surface waters to warm beyond their optimum temperature range. Because latitude and elevation are key determining factors, anglers in northern areas generally have a much longer window of opportunity than their southern counterparts.

For me, the problem is that most of the lakes in my particular area of Maine tend to get good at the same time. So, if I only fished locally, I’d have an abundance of choices for the couple of weeks surrounding Memorial Day weekend and fairly slim pickings the rest of the season. Mobility is one of the most overlooked elements that contributes to success in surface fishing on big lakes. So, whether you live in the Rockies and move from the desert floor to the high country, or along the east coast and follow the season north, the bottom line, is that in order to catch fish on top, you must be willing to travel to where the conditions are right.


Ultimately, unless you go to extremes of elevation or latitude, most deep lakes eventually become stratified into three zones of water which differ greatly in temperature and density.

The warm, lightest layer found at the surface is referred to as the epilimnion and generally increases in size and temperature as the summer progresses.

Next comes a narrow, abruptly colder band of water referred to as the thermocline. It can best be visualized as a transitionary zone between the warm, oxygen-rich epilimnion above, and the cold, oxygen-poor hypolimnion below. In Maine, the thermocline on most lakes is 20 – 30 feet down. Most cold-water fish spend the summer months here because it fulfills their basic requirements of temperature, food and oxygen.

Occasionally, during an evening hatch or period of inclement weather, fish will abandon the comfort of the thermocline to take advantage of a locally abundant food source near the surface. Typically, these migrations are brief, and an angler interested in surface-fishing has to be fortunate to hit it just right.

The extremely deep, cold layer of water below the thermocline is referred to as the hypolimnion and is beyond the reach of anglers employing traditional surface-fishing methods.


Maine Autumn ColorsThe final episode of the seasonal cycle for lake anglers begins when cooler air temperatures in the early fall drop the water temperature of the epilimnion back to a level which is suitable for salmoniods. At that point, trout and salmon are free to leave their summer lies along the thermocline and can be reached by surface-fishing anglers.

The best fall fishing, however, usually occurs later in the season when the lake reaches 39 F. At that point, waters are again free to circulate oxygen from top to bottom; and frequently, fish whose metabolism has been somewhat reduced during the summer, are spurred into a period of heavy feeding in preparation for spawning and the long winter ahead. Streamer flies trolled around points and islands or cast in the vicinity of inlet and outlet streams often produce the best results at this time of year.

Learning to catch trout in large lakes is not an easy task. At first glance, their flat, seemingly featureless surface looks barren and foreboding compared to the more intimate surroundings of a trout stream. And, fish can be very elusive to those not attuned to the influence that water temperature and other factors have on their distribution. As a result, anglers often abandon these places before ever really giving them an honest try.

For those who stick with it, however, the rewards of fishing large lakes can be tremendous. Fish tend to be large because bait fish form the cornerstone of most food webs. And, you never have to worry about being crowded out of your favorite pool. Best of all, once you invest some time identifying where fish are located during a certain season, you will find that they re-appear in the same places year after year.