Zero In On Temperatures To Target Individual Species

Editor's note: This blog installment comes from Fishhound pro staffer Capt. Lou Borrelli.

In two previous articles I spoke about equipment needs and delivery methods for targeting salmon and trout. In this third segment I'll discuss where and how to catch these Great Lakes fish. Before we continue, though, there are two very important things everyone needs to know:

1. The water temperatures the fish prefer
2. How to find those temperatures in the water column

Salmon and trout typically like cold water. Here's a breakdown of the temps in Fahrenheit that each species prefers:

Atlantic salmon: 52-60 degrees
Brown trout: 54-60 degrees
Rainbow trout/steelhead 52–58 degrees
Lake trout: 42-52 degrees
Coho salmon: 52-58 degrees
Chinook salmon: 42-48 degrees

This doesn't mean fish won't move out of their preferred temp zones. However, most often you'll find the fish in their temperature ranges listed above.

As the summer progresses and the lake temperatures settle, there'll be a definitive temperature difference in the water at some depth. This is called a temperature break or thermocline. It's important that you target the fish around this area, as you'll eliminate a huge section of fishless water.  

To find where in the water column the fish are, you'll need some method to probe the water at different depths. A speed-and-temp sensor is a tool that attaches to your downrigger and gives you the speed of the lure you're using and the temperature at its depth. This is a very important piece of equipment, because it'll continuously report data as you troll. The sensor shown to the right, from Cannon, is called the IntelliTroll Speed-N-Temp System.

Let's say for example you and I are fishing on Lake Ontario, N.Y. We'll assume it's a nice, mid-summer day with bright skies and a mild west wind. The surface temperature of the lake is 74 degrees.

We'll be running four rods – two on downriggers, two with Dipsy Divers. The first task is to attach the speed and temp sensor to the 'rigger and let it down along with a lure of choice. Most often, I run a spoon on this 'rigger and stop it when it reaches approximately 48 degrees.

On the adjacent rigger, I'll run a flasher-and-fly combo (pictured below) early in the morning. I'll run the flasher-and-fly approximately 10 feet below the other 'rigger. In other words, the 'rigger with the speed-and-temp sensor might be at 48 degrees and 80 feet down, while the other rigger will be 90 feet down in colder water.

I do this for two reasons. First, if you're searching for fish, this will give you a wider range of coverage. Remember that the fish like water between 42 and 60 degrees, so you want to cover as much of that temp zone as you can until you dial in on the fish.  Second, the two lures work together in the presentation. As noted in part 2 of this series, fish often come up to see a lure and as they swim away, they see the other lure and strike. 

With the two 'riggers set in the water, it's time to deploy the Dipsy Divers. If I'm in search mode, I'll run my divers spread apart. For example: If I've found 48 degrees at 80 feet down over 150 feet of water, on Dipsy rod No. 1 I'll attach the lure (usually a flasher-and-fly) and let out approximately 240 feet of line. That will put the lure down about 80 feet.

On Dipsy rod No. 2 I'll let out approximately 320 to 360 feet of line. This will put the lure down about 100 to 115 feet. I'm trying to pull deep kings out of cold water with this Dipsy rod No. 2.

Once I find the fish, I like to move the Dipsy rods closer together to put the lures where the fish are. If I caught a Dipsy fish on rod No. 1 at 240 feet back, I may run the same rod at 240 again and bring the No. 2 rod up to 260. This method will help both lures work together, because they'll be within a few feet of each other in the water column.

When running Dipsy Divers, make sure each Dipsy is set to the correct side of the boat. Also pay close attention to the number settings.  A No. 1 setting will keep the lure closer to the boat, while a No. 3 will push the lure higher and further away from the boat. In the early morning, it may be wise to set the Dipsys on a No. 1  or 1.5. As the sun rises, you may want to spread them out to a No. 2.5 or 3.

Capt. Lou Borrelli learned to fish with his grandfather and now owns and operates Get The Net Charters out of Rochester, N.Y. Capt. Lou runs trips along the south shore of Lake Ontario from Wilson to Fair Haven, N.Y. Visit GTNFishing.com or send him an email at captainlou@gtnfishing.com.