The Stability Zone "Shangri-La for Kings" by Matt Straw

 There is another dimension, between time and space, between the swells and the lake’s floor. It’s the middle ground between emptiness and bait. It’s a place called…the Stability Zone.

An average August day on Lake Superior. We trolled in flat-calm conditions through surface temperatures of 64°F into a huge bay. Behind walls of rock hundreds of feet high, we didn’t notice the wind came up.

After deciding to head home, we picked up lines and rounded the point outside the bay to find 10-foot waves and surface readings of 40°F.

Instability is common on the Great Lakes. Wind, waves, and upwellings can instantly cause temperature fluctuations of 20°F or more near the surface and near the shorelines. Salmon sense the instability, and they can avoid it. Because, sandwiched between the turmoil of changing conditions in the Great Lakes there exists a kind of Shangri-La for kings—a stability zone, where change is never drastic.

It can be found with a simple temperature probe. And it’s worth finding. Within it, kings slash through pods of baitfish 24/7, 365 days per year.

The King’s Shangri-La

“The stability zone is always there,” says Captain Mark Chmura, owner of Pier Pressure Charters. “I find it with my down temp gauge. It begins where the reading of  49°F levels out. As you move away from the shore, that 49°F reading might not appear until you get out into depths of 50 feet or greater. Sometimes it’s right at the surface. It will keep dropping deeper. In some cases, you find it deep and it keeps rising as you move out. The key is finding an area where it levels off. It doesn’t matter how deep it is. If you go 500 yards, then another quarter mile, and keep finding that 49°F mark at the same depth, you’re in the stability zone.”

The closer you get to the middle of any of the Great Lakes, Chmura says, the more stable the water becomes.

“After a storm and an upwelling, the surface inshore often reads 42°F to 50°F,” he said. “As you head toward mid-lake, surface temperatures often begin to warm up, but the 49°F cline will eventually drop. I check temperatures every mile until that cline levels off and runs parallel with the surface. That’s the most stable zone of water in the lake, and that’s where I slow down and start hunting for activity.”

Big lakes are always colder on one side or the other, depending on wind and current patterns.

The cold side is always better, Chmura says, so he checks satellite maps on sites like coastwatch.msu.edu to see which side is which. “The cold side is always better than the hot side, because you don’t have to fish as deep. The deeper you go, the less control you have.”

Chmura should know. He was literally the first angler on earth to figure out that salmon can be caught deeper than 700 feet, and actually worked with Big Jon Downriggers to customize a unit that could fish that deep.

“Satellite maps tell you what’s happening up top, but the stability zone is a massive, buffered ‘cube’ of water that extends from somewhere below the surface down to that 49°F temperature cline,” Chmura said. “Once you’re in that zone, you often find steelhead feeding in the top 20 to 35 feet and salmon feeding somewhere from 50 to 80 feet down into temperatures of 47°F or so.”

The stability zone may move laterally, but it resists change. Even after the most violent weather, Chmura can find it. “It gradually moves up higher as the water warms in spring,” he said. “It stabilizes in summer, then slowly descends through fall. The stability zone is always down a little deeper in winter than in summer.”

Chmura calls 49°F water “home.”

That singular temperature is like a buoy, or moving signpost, telling him which way to go next.

“It’s a critical indicator,” he said. “The depth of that temperature tells me whether to go inshore or further out. When I find 49°F water close to the surface and close to shore, I know salmon will be in the harbors and on the beaches, even in June and July. Those shallow fish are impermanent. They come and go. When I can’t find 49°F water any shallower than 65 feet or so, I keep heading out.

The stability zone starts where that 49°F temperature band levels off and remains equidistant from the surface, and that’s the place to start hunting for baitfish with sonar.”

If Chmura had to choose between sonar and his Fish Hawk down-temp gauge, he’ll take the Fish Hawk.

“Hands down,” he said. “Temperature directs me to more salmon than sonar or side imaging. Not that those things aren’t important. Sonar saves time, but down temp saves the day. I run my Fish Hawk probe down on the center downrigger, which generally is the one set deepest. I’m constantly noting what that 49°F temperature cline is doing and correlating it with the depths that produce strikes. That tells me everything I need to know to catch kings 365 days a year. Down temp is a far better indicator for determining depths where you want to deploy rigs than a graph. Find the 49°F mark, stagger lines around it accordingly, and you’ll be on kings faster than you will by targeting marks on a sonar screen.”

Trolling Shangri-La

Fishing with Mark in early July a couple of years ago, we found his magic 49°F signpost pretty close to shore.

He made an immediate about-face. Pretty soon we were back in the shadow of the dunes, putting #5 Luhr Jensen J-Plugs 150 feet back with boards in 15 feet of water. The fleet of other charters and private boats was so far away, all we could see was an occasional flash of their distant windshields as we boated one king after another.

In Lake Michigan’s uber-clear waters, I could actually stand on the foredeck and watch kings disperse away from the boat.

We could predict with a fair amount of accuracy which line was going to trip next. To be able to do that inshore, a few miles from a major harbor, with no other boats in sight, in July? Priceless. But that’s not the stability zone. That’s a shadow pattern that often occurs on the cold side of the lake.

“Sudden storms with 6- to 8-foot waves crashing in flip the lake over,” Chmura said. “Ice water is churned up from the deeps. When it gets pushed toward shore, it sends a few groups of salmon toward the harbor mouths,” Chmura said. Then what, I asked, are we doing several miles down the shoreline? “The coldest water will be right where the wind cracks directly into shore for a day or so,” he said. “That cold mass of water can be 42°F on top, pushing fish right up on the beach—like right now.

“In shallow like this, I usually send out zones of baits,” he added. “In the ‘close zone,’ close to the boat, I use downriggers to deploy spoons 45 feet back on one side of the boat, 60 feet back on the other. On the center rigger, I might put one 100 feet back. The cannonballs are 7 or 8 feet down if I want those spoons scuffing bottom. Lures colliding with the bottom will provoke violent strikes. In the ‘away zone,’ I run boards with J-Plugs 100 feet back to shoreward and 150 feet back to lakeward.”

The next day we were back out to sea, looking for the stability zone. When Chmura finds it and marks significant volumes of bait, he starts dropping lures. He always brackets the 49°F mark with spoons—one below it and two above. “A pretty standard setup for me in recent years,” he said, “is to deploy three downriggers to cover that deep zone. Above that, I spread out four wire-line rigs with Dipsy Divers. And above that, I send out a copper line and a lead core line with boards on each side of the boat. Typically, those outside lines at the top of my spread are 50 to 60 feet down to start out. That’s 14 to 15 colors of 27-pound lead core line. I run 40 feet of 20-pound fluorocarbon off the end of those rigs. And if that magic 49°F mark is only 60 feet down, I bracket that depth with two lead core lines, running one rig with 15 colors and the other with 10 to 12 colors.”

Up above “the zone,” steelhead often stay in the top 20 feet. “If you want steelhead, you typically have to go outside the box that holds kings. I run Rapala Original Floaters, small dodgers with Howie Flies, or spoons up high with in-line weights or two colors of lead core for steelhead. Those setups are deployed with boards, Dipsy Divers, or both.”

Shadow Patterns

Bug slicks, abrupt changes in surface temperature, feeding birds, thermal walls, “invisible structure,” and all the other indicators salmon fishermen depend on are subordinate, in Chmura’s mind, to that magic 49°F temperature cline. “I look for all those things, sure,” he admits. “But if I can find 49°F water with the down-temp probe under those events and indicators, I feel assured kings will be in the area.”

Chmura anticipates upwellings that bring that 49°F mark closer to shore because they create those opportunities to fish inshore entirely away from the crowd.

“I love finding fish in places where nobody else is looking for them,” he said. “When the Coast Guard issues small-craft warnings and the weather service is calling for winds out of the north, an upwelling could be about to happen. I’ll be ready for what I call a shadow pattern.”

North winds generally mean cold fronts or, at least, cooler air temperatures. A lesser upwelling, Chmura says, can be caused by light north winds.

“If the wind stays out of the north for days, alewives and smelt will remain up on the beaches. Kings know that bait will be there. If I come out of the harbor, drop my probe 20 feet and find 49°F to 52°F water, I know kings will be inshore and will probably stay there as long as the wind remains out of the north. I’ve used this shadow pattern to win several summer tournaments."

“The best example I can think of,” he continued, “took place on the first of August a few years ago. We ran #5 J-Plugs clean—no attractors—150 feet behind the boards at 4 mph. It was so hot out it felt like we were fishing tarpon in Florida. Kings were balling schools of alewives into big, dark shadows. We could see the baitfish streaking through the sides of the swells and going airborne in a panic. We fished no deeper than 10 feet that day and put 12 fish in the box that weighed 160 pounds by 11 a.m. As soon as the wind switched to the south, those kings were gone.”

When conditions flip-flop, baitfish retreat and pile up along the fringes of the stability zone, conditioning themselves to the change in temperature. The edge of the stability zone acts like a plow, pushing them along in the changing wind conditions. Bait gets concentrated and another hot bite ensues out near “the zone.”

“The entire water column is more stable out there,” Chmura said. “But when air temperatures fluctuate wildly, change can run rampant along the surface, even above the stability zone. You’ll notice that the upper fringe of the stability zone resists change. It won’t flip, like that water closer to shore. Which is why you can always find some salmon there, 12 months of the year.”

Entered into evidence: One man and the vastness of the Great Lakes. One man with a boat and a down-temp gauge on a quest for salmon that took him deep…into the Stability Zone.

- by Matt Straw