COLUMN: Fishing in Thermopolis successful despite the rain

The fishing was very good most places I journeyed to and the cloudy, cooler weather made for some great insect hatches on rivers and lakes around the Big Horn Basin.

The Big Horn River fished great last week. A long time friend and visitor to the Cody area and I spent a day floating on the Big Horn. We had originally planned to fish the North Fork, but that river was muddy well above Pahaska due to rain and melting snow. Because it’s a 100 mile round trip from Cody to the upper North Fork, then another hour and half to Thermopolis, we didn’t pull into the parking lot at Wedding of the Waters on the Bighorn until 11:30 a.m.

Despite the late launching of our boat, we hadn’t floated very far before the first fish of the day, a nice 21-inch rainbow, was off to the races with a wet fly my friend had drifted into the trout’s feeding zone. We didn’t land that fish because it managed to roll off the barbless hook in the process of trying to get it to go quietly into the net, but we did manage to land about 15 trout apiece before our day and float ended at the takeout at 8th Street Bridge in Thermopolis. 

The cloudy weather brought out the blue wing olives in huge numbers. The lack of sun caused the trout to lose all caution. Surprisingly, we found few trout rising to eat the adult blue wings which were literally everywhere on the float downriver.

We caught most of our trout on a Charlie Craven mayfly nymph pattern called the Juju Baetis in a size 16. When we ran out of those, we also found the trout were not bashful about taking an olive jig style nymph that also mimicked the blue wing olive nymphs that were in abundance under the surface. As most anglers who fish the Big Horn know, there seems to be an abundance of trout in the 18-22 inch range. Some of these larger trout have enough girth and power in their tails to really test light tippet and also put a lot of stress on the smaller and lighter wired hooks that our Juju Baetis flies were tied upon. If memory serves, I lost at least a half dozen of those larger trout because they would shake their heads and exercise their muscles enough to literally straighten the curve of my fly’s hooks.

 Talk about fun and amazement!

Insect action also picked up at Luce, Hogan and East Newton reservoirs last week. The waters have warmed enough for the first emergence of the Callibaetis mayfly, a larger cousin of the Baetis (blue wing olive) that prefers lakes, ponds and slower moving waters to live in rather than the swifter moving rivers and streams. Callibaetis are a cream to tannish body colored mayfly with a speckled wing. They typically become active on the water of lakes and ponds around mid-morning. 

When the hatches of spring begin, these mayflies are generally size 12 or 14. Fly fishers can use sparkle duns, compara duns, or hackled duns in these colors for dry flies. If one has a parachute Adams with a light tan or pale cream body, these also do well when the trout are sipping adults or emergers at or near the surface.

The nymphal form of the Callibaetis has a quick swimming motion in the water and can look a lot like a miniscule fish when swimming and darting about amongst the weed beds or shoreline vegetation that is wetted. Because trout feed 90% of the time underwater, it is recommended for anglers to go below the surface for better hook/catch rates. Wet flies that work well are Callibaeits nymphs that have a gray or tannish colored body with a slight soft hackle wrapped up front near the hook eye. 

These imitations work very consistently when the angler casts the flies out 20 to 40 feet, then retrieves them with a short, quick stripping action.

The takes by the trout are positive and firm when they see these speckled dun fly patterns moving in the lake. Gold-ribbed hare’s ears and pheasant tail nymphs are also great substitutes. These flies are usually in every fly fisher’s fly boxes. Again, size 12-16 are suggested when fishing in the hatch in May. As the spring months progress to summer, then fall, there will be two more emergences of the Callibaetis, but each emergence results in smaller and smaller adults and nymphs to match the hatch and the insect’s activity. It looks like I am going to be on the water a lot this coming week, too!