Caddisflies look like tiny moths. They belong to the insect order Trichoptera (hair wings). There are over 11,000 types of caddisflies world-wide, but they all have the same insect life pattern: egg, larva, pupa, and adult. They all require water for the larval stage, and trout love them in whatever stage they are in.

"A single fish can devour hundreds of thousands of caddis during its lifetime," said Greg Policky, an aquatic biologist for the Colorado Division of Wildlife from Salida.

The adult caddis live for several days to a few weeks, emerging to complete their life cycle and lay eggs back into the water again. After dropping their eggs, the females die and lay spent on the surface. It during this brief cycle each year that trout gorge themselves, and as most anglers know, the best time to catch fish is when they are feeding.

The caddis hatch usually starts in early April near Canon City, where the Arkansas spills out onto the eastern plains. Daily changes in the weather can cause the caddis hatch to progress in fits and starts, but once it begins, it gradually moves upriver as water temperatures warm to about 54 degrees Fahrenheit. Cold water from runoff can stall the hatch, but in years where runoff is delayed, the hatch will move upstream to Leadville - usually by the end of May.

"The hatch is sometimes called the 'Mother's Day" hatch, but it might be more appropriate to think of it as the 'Tax Day' hatch because that's when it really gets going," Policky said.

Due to heavy snowpack, flows will likely be higher than normal this spring on the Arkansas River. The colder, faster water might cause the hatch to end earlier than normal.

During the peak, the air is thick with insects. The soft bugs don't bite, but the swarms can be annoying because they are everywhere, including in the ears, noses and behind the eyeglasses of anglers.

People are advised to wear bandanas, protective glasses, and earplugs or cotton in their ears to prevent the bugs from getting where you don't want them to go, which includes up your pants and down your shirt.

Some anglers like to be on the leading edge of the hatch. Others like to be on the back edge, and a few hardy souls like to be right in the middle of it where the flies are the thickest.

Throw in blue-winged olive (BWO) mayflies on cool, cloudy days; and trout go into a feeding frenzy.

Policky offers the following tips to anglers during the spring caddisfly season. As water temperature warms, fish will move out of deeper, winter pool habitat into the head of 3-5 foot deep runs. Upstream riffles produce a lot of food that trout are keying into. The best runs have boulders scattered throughout them where fish can rest outside the current and dart out where food drifts closely by. Anglers will most successful when fishing these types of habitats.

A two fly setup is recommended, imitating two insect life stages or different species, thereby covering more water. The top fly often acts as an attractor or strike indicator for the trailer fly. Fishing close to the banks or habitats where the current is not as strong will produce the best results.

For those who have never experience it, the annual caddisfly hatch is something to see - millions of caddis buzzing about, some spent on the water, some on rocks, some emerging, while others are laying eggs. Adding to the experience are flocks of swallows and other birds enjoying a feast just above the water while trout are getting filled to the gills below.

Anglers are reminded that the following regulations are in effect on the Arkansas:

• From the US 24 river overpass downstream to the lower boundary of the Hayden Ranch, fishing is by artificial flies and lures only and the bag and possession limit for trout is one fish under 12 inches in length.


• From the Stockyard Bridge (Chaffee Co Rd 102) below Salida seven-and-a-half miles downstream to the confluence with Badger Creek, fishing is by artificial flies and lures only and all rainbow trout must be returned to the water immediately upon catch.

News Source: Colorado DOW - Apr. 11, 2008