Captain Mark Chmura tells the first mate to “send one downtown.” When the cannonball hits 400 feet, it’s not there yet. When this crew sends a bait “downtown,” people speaking Chinese pick it up on sonar. Chmura, the salmon-pro, angling-theorist, Renaissance man who came up with the Stability Zone, which we chronicled in our June 2007 issue, would like to announce that king salmon are biting, right now, in depths exceeding 500 feet all over the Great Lakes.
Recent findings by scientists working for the U.S. Geological Survey back this up, meaning king salmon go deeper than anyone previously believed, deeper than common lake trout, and on a regular basis. Roger Bergstedt, research fishery biologist for the U.S.G.S., says he implanted recording devices called “depth tags” in chinook salmon and released the fish into Lake Huron. “The data chip records depth, temperature, and time,” he says. “I’ve got over 30 tag returns from anglers, and these tags tell us there are more deep movements of kings than people think.
“Kings make a lot of vertical movements. They’re not hanging in there at 54°F all day. Any day. Movements to deep water are common and I’ve got to believe they’re down there on business. They’re hunting, and if you put a lure in front of them they’re probably going to take it.” Bergstedt says one of the tagged fish journeyed into the deepest water in Lake Huron, into depths exceeding 700 feet, during the night in winter. At daybreak the next morning, that salmon traveled from the bottom to the surface in a matter of minutes.
“One of the most interesting things we noticed in the preliminary analysis was that salmon were close together at night, and just after dawn they really spread out,” Bergstedt says. “Some actually went deeper at dawn, some shallower. If we plotted maximum depth by hour during late summer, they’re tightly grouped during the night at 55 to 60 feet. Once the sun came up, some fish went deeper than 400 feet. In winter, the deepest one we marked was within a meter or so of the deepest point in Lake Huron, or a little over 700 feet. In winter, the chinooks we tagged were 400 feet down at night, but they would come right up to the surface in the morning. They would be up there very briefly and head right back down to bottom. Tagged salmon were making daily vertical movements of 400 to 600 feet in a matter of minutes, sometimes once every hour or so. These were larger specimens, too. It seems smaller salmon are drawn to warmer water much of the time, but in winter they all head deep.”
Like a scattering of lost pieces from a jigsaw puzzle, these findings fit snugly into the overall picture of salmon movements in Chmura’s mind. But just because he knew they were there didn’t mean it would be easy catching them.
The Final Frontier
“This is bigger than telling people we can catch salmon 500 feet deep,” Chmura says. “The real news is that we’re on the right track with respect to understanding salmon behavior in the Great Lakes. From an angler’s point of view, this could be the biggest change in perspective in salmon trolling history.”
