Pike Country Weathermen

Pressure-Sensing Fish Can fish sense changes in atmospheric pressure? A recent study showed that movement of blacktip sharks was triggered by a drop in barometric pressure associated with Hurricane Gabrielle in 2001. Researchers with the Mote Marine Laboratory in Sarasota, Florida, report that the juvenile sharks responded to the approach of the storm by moving to deeper water, returning to shallow water after the storm’s passage. That study prompted the research being carried out by marine biology Ph.D. student Lauren Smith at the University of Aberdeen in Scotland. She’s studying pressure-sensing abilities of sharks in the wild, as well as through the use of an altitude chamber, which can mimic changes caused by weather fronts. Prior research by her supervisor, Dr. Peter Fraser, shows that sharks sense pressure using hair cells in their vestibular (balance) system. To learn more about how atmospheric pressure affects fish, Smith recommends the book Trout, Salmon, and the Evening Rise: The Barometric Breakthrough by Andrew Betts (publ. Salar Pursuits). “It provides a summary of research into pressure detection in fish,” she says. “In general terms fish with swim bladders, like pike, are able to detect pressure changes at a threshold of 0.05 millibars, while fish without swim bladders, such as sharks, have a higher but still sensitive threshold of 0.5 millibars. Physiologically speaking, there’s no reason why fish cannot detect barometric pressure changes.” (The millibar is a metric unit of atmospheric pressure; standard atmospheric pressure is about 1,013 mb at sea level). Smith explains how pressure changes in the atmosphere relate to water pressure and fish. “Say for example the air pressure rises from 1,009 to 1,010 millibars. The water pressure—the hydrostatic pressure—changes accordingly and acts as a transducer, relaying this information to the fish by having a direct effect on the swim bladder. If the air pressure remains the same, fish will be neutrally buoyant in the water column and thus able to maintain a constant depth. Increases in air pressure can cause the swim bladder to compress, so the volume of air in the fish is less, the water displaced by the fish is also less, and the fish begins to sink. “This may explain why fish with open swim bladders, like salmon and trout, come to the surface to gulp more air during increasing barometric pressure—they need to increase the volume of air in the swim bladder to become neutrally buoyant in the water column. The pike has a closed swim bladder and changes its volume of air internally.” Can dropping pressure stimulate pike to feed more actively? “Lower pressure has the opposite effect of rising air pressure, in that swim bladder volume will increase and cause the fish to rise in the water column,” Smith explains. “One hypothesis is that falling pressure causes smaller fish to become active, attracting predators such as the pike. Perhaps pike respond to an interaction of barometric pressure change, both directly on its own swim bladder and indirectly through prey response.”

“If I get a few hits on a crankbait and I know pike are in the area, I often switch to a jig-and-plastic combo,” he says. One of my favorites is a 3/8- to 1/2-ounce Northland Jungle Jig paired with a Berkley PowerBait 7-inch Ribbontail Worm. I cut the weedguard off the jig when fishing weedless areas. Another good setup is an Esox Cobra Head with a 71⁄2-inch Old BaySide Monster Mino Curltail from Lindy. I add a stinger treble by tying it with Tyger Wire to the bend on the jig’s hook.”

In lakes with the traditional weed pattern, Straw finds that sunny, high-pressure conditions make for a tough bite, pushing inactive pike tighter into vegetation. “On a good day with clouds and wind, active fish are roaming weededges, and lures like spinnerbaits and swimbaits excel,” he says. “If you’re fishing a weedy bay, don’t forget to make a some casts into the open water behind you. The bigger fish are moving, searching, feeding, and those casts often catch fish prowling open water.

“When a cold front moves in and conditions get tough, you have to think about changing your presentation to access fish that moved tighter into the vegetation,” Straw explains. “That’s when I switch to a jig-and-softbait combo, like a 5/8- to 1-ounce J-mac Musky Jig, but any quality weedless jig can be a good pike jig. Swim it and let if fall into pockets. The heavier jig also allows you to punch through thick weeds and pounce it on the fish.”

In late summer into fall, Kalkofen fishes the deeper edges of weedlines when conditions are right, but during cold fronts he goes shallower. “Instead of fishing the 12- to 18-foot depths along mainlake weedlines, I fish farther up into the weeds. The inside weededge in 5- to 8-foot depths can be good for big fish,” he says. “I like to use a spinnerbait, something with a big #7 Colorado blade that I can fish slowly, almost like I’m walking the bait under the surface. Let it drop into holes in the vegetation and work it through open lanes in the vegetation.”

“Glidebaits and jerkbaits might be the best options for these conditions,” Kalkofen says, “even though you typically wouldn’t consider Reef Hawgs, Suicks, and Husky Jerks in weeds. But with a 71⁄2-foot heavy flippin’ stick and 50- to 80-pound braid, you can rip them off when they hang up, which often triggers strikes. Rubber-skirted, bass-style jigs and plastics can be tremendous when swum over and through vegetation.”

Like Pyzer, Straw observes the same wind-driven patterns for pike on Shield lakes. “On a nicer day, you’ll find smallmouths on reefs topping out at 3 to 8 feet. Then add some rain and wind and the toothy monsters move in. There’s something about 2- to 3-foot waves billowing over shoals and reefs that causes smallmouths to vacate and pike to move in. The 15- to 20-foot depths near the reefs that were good yesterday aren’t so good today. Something about the waves is attracting active pike.

“It could be that shallow baitfish are disoriented and exposed because they’re not able to hold in secure positions among the rocks, and the big animals aren’t tossed around. I like to work suspending jerkbaits like a Rapala X-Rap under these conditions, getting it just deep enough under the effects of the wave troughs. Slash it, pause it, it’s deadly.”

It’s no fun making the trek across the lake to reach spots in conditions like this, but once you’re there, the fishing is fun. But if conditions get too dangerous, this is no time to be out. You can catch pike just about anytime if you work hard enough, but certain times are better. How does it look? Partly pikey? Mostly pikey? 100-percent chance?