Great Lakes Salmon And Trout

Remembering the Eye in the Sky Venerable salmon reporter John Oravec first spread the word through In-Fisherman about “eye-in-the-sky” tactics 16 years ago, soon after daily satellite maps of the Great Lakes first appeared on the Internet. “Before the captains of Lake Ontario begin to apply any seat-of-the-pants savvy for finding the stable offshore honey holes, we go to coastwatch.msu.edu for a surface-temp map with a GPS overlay,” Oravec says. “It saves time and gas. With the boat on a trailer, you can chase the best water more effectively than many a gas-guzzling charter boat can.” Satellite maps show surface temperatures and reveal where the coldest surface water was when the photo was taken (so, get up early and get on the Net before pulling out of the driveway). Coldwater masses can move or dissipate quickly. The spots representing the shortest distances between warmwater and coldwater masses are the places to circle on a satellite map. That’s where the best thermal bars and other “invisible structures” exist near the surface of the lake. The “stability-zone” angler uses satellite maps, too. But he might circle the spots where coldwater masses appear closest to shore, then go there and use down temps to determine whether salmon are inshore or in pockets along the way out. If 49°F to 52°F water can’t be found anywhere above bottom, it’s time to head well offshore, to the largest area of stable water in the lake, hunting along the way. Satellite maps tell us what’s happening on the surface, but the zone of stability primarily encompasses a buffered body of water beginning somewhere under the surface and extending through the middle of the water column, often all the way to the bottom. Temperature gauges on downriggers or self-contained, depth-probing thermometers become necessities in the search for the stability zone.

“Whenever you get 10 miles or so off the shoreline, the water is more stable. It resists flipping over and the conditions remain pretty constant. The edges of that zone flip, but not out in the middle. If the water out there describes a zone of stability, the water within 10 miles of shore describes the opposite or a zone of instability, because it’s more vulnerable to rapid surface-temperature change. In the summer, steelhead hang out above that deep, stable water that won’t be affected as much by wind-driven conditions and won’t change temperature rapidly,” he says.

“I came up with the stability-zone concept while steelheading at midlake. Three years ago, we found steelhead by using the same GPS coordinates at midlake all summer long. Day after day we noticed that the relative temperatures below us never changed, even though surface temps and bug slicks that originally attracted us to the spot were long gone. That demonstrates how stable conditions remain at the lake’s center. The center of a truly huge lake adamantly resists change. It’s like a teeter-totter, fluctuating wildly in height at each end while staying precisely the same height in the center.”

The fringe of the zone moves in and out, relative to shore. It could be 8 miles out one day and 10 the next, but the edge is relatively easy to find with a down-temp probe, and it’s where you want to set up camp—the place to be for consistent king salmon activity throughout the year (yes, that includes winter, and Chmura goes out there whenever conditions allow). Edges always produce fish, but in this case they also collect fish, almost by force. Baitfish retreating from flip-flopping conditions can pile up along the edges of the stability zone, where they get pushed along by the advance of cold water when the fickle wind shifts direction.

The key to finding and staying within the stability zone is simple: Down temp. “I’m constantly looking at my down temperature while fishing,” he says. “I would rather have my temp gauge than my graph. I use a Fish Hawk on my center downrigger, which is generally the one I run deepest. I’m constantly noting what the 49°F temperature cline is doing, and correlating it with the depths that produce strikes. That tells me everything I need to know. Down temp is a far better indicator for determining the depth of your presentation than a graph. It tells you precisely where the fish are biting. On a graph, you see all the fish, and can easily confuse the biters with the non-biters when the key temperature band is rising or falling in the water column.”

While the entire water column is more stable in the center of a big lake than it is near shore, the stability zone is primarily a sub-surface phenomenon. When air temperature fluctuates wildly and big winds persist, change can rage across the surface, even above the stability zone. The fringe of the area that changes least is found somewhere below the surface (but not far, as the near-constant presence of steelhead attests).

Finding the stability zone is one thing. No matter how good the spread or how well it’s worked, the presentation program won’t function properly without constantly monitoring down temps. Got kings? Get down (temp).