My introduction to California’s Hexagenia hatch was unconventional. In 1983, at the ripe old age of 13, I started tying flies commercially. I wasn’t tying thousands of flies every month, but I was earning some good money for a kid that age. My dad worked as a route driver for a meat-products company, and he would deliver orders all the way up Highway 299 and to the Mount Shasta, McCloud, and Dunsmuir areas. A lot of these stores sold pretty much everything, including flies, and over time, they began to order from me, with Dad making the deliveries.
One of the stores in Fall River was a little mom-and-pop grocery store (now gone) at the edge of town. The owner asked Dad if I could tie a special fly for them. The next night, he returned home with my new orders, the money from the flies that he had delivered, and that sample fly. That was the first time I held a huge, size 6 Hexagenia pattern in my hand. Dad just laughed and said, “Good luck.”
I got so that I could tie around twenty of them an hour. I sold them for $1.75 each, which was a lot of money back then. The orders poured in, especially from folks around Fall River Mills. And that’s how I learned the Hexagenia mayfly is literally a big deal on a number of Northern California waters.
The Hex
The Hexagenia limbata, or simply the “Hex,” is a mayfly in the family of Ephemeridae. They make U-shaped burrows in the mud of a lake, pond, creek, or river. These flies are approximately an inch and a quarter to two inches long, and when sitting on the surface of the water, they can reach at least one inch in height. Their colors range from a brilliant yellow-chartreuse to a golden yellow-brown. On the water, they look like sailboats, as all mayflies do, but these look like big America’s Cup sailboats. They are impressive.
In Northern California, Hexagenias are found in many fisheries. The most notable are the Fall River, the Thermalito Afterbay, Lake Almanor, Butt Valley Reservoir, and Lake Davis. In every body of water where they are found, the fish will aggressively feed on them.
The Fall River
The Fall River, in essence a wide and deep spring creek, is one of Northern California’s blue-ribbon trout waters. It is an amazing fishery nestled in the beautiful Fall River Valley. The main headwaters of the Fall River are Thousand Springs and Rainbow Springs, and it is fed by small streams such as Bear Creek in the north, also gaining water from Spring Creek and the Tule River. The river then heads south toward the town of Fall River Mills, where it flows into Fall River Lake, a large holding pool for transferring water via a pipe through Haney Mountain to the Pit River Number 1 Powerhouse.
The valley has an agricultural economy that ranges from organic rice farms to cattle ranches, and the river mostly flows through private property with limited public access. You pretty much have to fish it from a boat. Many fly fishers hire guides for the Fall River just to get access to a boat, and many guides offer special rates just for Hex evenings. However, if you have the right kind of properly equipped boat, you can fish the Fall River Hex hatch on your own.
There are three public boat launches or access areas. (See “If You Go...” for how to reach them.) The first access, located on Island Road, is owned and operated by California Trout. The CalTrout website specifies that boats launching from their property must use electric motors and that boats must be put in the water by hand — no trailers can be driven into the water. Launches are limited to boats that can be carried to the river.
The second public boat launch is located at Big Lake. This launch is called the Rat Farm access and is gravel in moderate physical shape. It will allow smaller trailered boats to be launched.
The third launch is the PG&E Tule River access. This launch area also is limited to boats that can be carried. Boulders are placed around the site to stop trailers from entering the water.
The prime Hexagenia stretch is usually from the confluence of the Fall River and the Tule River downstream to the town of Fall River Mills. This means the fly fisher needs to travel approximately five river miles from the CalTrout access, approximately five river miles from the Rat Farm access, and one to two miles from the PG&E Tule River access.
I asked two Fall River guides, Matt Mitchell and Andrew Harris, for their takes on prime time Hexagenia fishing on Fall River, as well as on equipment and rigging. The Hex hatch usually starts in early June and runs into August, peaking between June 20 and July 20. It starts usually around 8:30 p.m. and lasts well past dark, but the California Department of Fish and Wildlife regulations state that you must stop fishing one hour past sunset on the Fall River. Anglers fishing the hatch will be returning to their launch points in the dark and need to be mindful that many other boaters will be on the river. Driving boats at night must be done with caution.
Because the Hex hatch can attract large fish, the fly rod of choice is a medium-fast 9-foot 6-weight with a reel that has a smooth drag and is loaded with a weight-forward floating line. An appropriate leader is 9 feet long, tapered to a 3X (8-pound) tippet. Tie on a Hex dry fly, and you are all set for the hatch. Make sure you have fly floatant handy. Andrew’s favorite fly is Nealley’s Adult Hex. Prior to the hatch, trout can be caught subsurface with Hex nymph imitations like my Lance’s Hex Nymph, and sometimes even an olive Woolly Bugger.
On the Fall River, both Matt and Andrew stressed that boats should be anchored in the river with the anglers fishing into the sun. That way, in low light, after the sun has set, the Hexagenia duns are going to stand out.
On lakes, I position myself in the same manner while casting dry flies during the Hex hatch. This tactic will provide more hookups. It helps to see your dry fly.
I asked both of the guides about boat etiquette for the Fall River. Andrew stressed that boaters must have stern and bow lights turned on while traveling on the river during low light and nighttime conditions. There have been many close calls on the water due to the fact that boaters could not see other boats.
Thermalito Afterbay
The Thermalito Afterbay is located in the Oroville Wildlife Area just west of the city of Oroville. Highway 99 borders the west side of the lake, and Highway 162 crosses the lake on a 300-yard bridge. The water in the Thermalito Afterbay is part of the flood-control, hydroelectric power, and irrigation network located downstream from Lake Oroville. The afterbay has become a hot spot for bass, surplus steelhead (planted fish from the Feather River Hatchery), panfish, and carp. On this lake of many fish species, everything eats the Hex.
The construction of the afterbay started in 1965 and was completed in 1968. It is a vast water-storage impoundment with an approximate size of 4,300 acres and a maximum capacity of around 50,000 acre-feet. The reservoir is designed to pump water back up to Lake Oroville and to warm the cold water from the lake that irrigates the rice and grain fields to the west of the reservoir. The afterbay is fairly shallow and varies from mere inches to 20 feet deep.
A rock-crest dam encompasses much of the shoreline, which on the southeast side is flood plain. The consistent rise and fall of the water gives this area a tidal quality that the fish seem to like. Big carp love this area. They act like big drum or even bonefish on the flats there. This is also the area where other species prepare redds for the spring spawn.
There are three public boat ramps on the afterbay: the Wilbur Road boat ramp, the Larkin Road Boat Ramp, and the Monument Hill boat ramp. (Again, see “If You Go…”) You can launch all varieties of boats from these cement launches. Make sure you follow all of the California Department of Boating and Waterways regulations while on the lake.
The impoundment has a healthy Hexagenia hatch that starts in late May and runs into early July, with the peak in early to mid-June. The top-water bass and panfish action is excellent with Hexagenia adult dry flies or small yellow poppers. The steelhead usually are found in the northeast corner of the lake, in the canal that brings water down from the Oroville Forebay.
The last time I fished the afterbay, I launched my boat at the Larkin Road boat ramp. There is a big island directly south of the launch, approximately 300 yards away. The area between the launch and the island is ideal habitat for the Hexagenia, having a mud bottom that produces massive hatches of bugs. I usually start fishing around 7 p.m. with a 9-foot 6-weight rod, casting a weight-forward hover line with a 9-foot 3X leader and with one of my Lance’s Hex Nymphs tied on. The bass and panfish engulf Hex nymphs, so make sure the hooks are barbless and you have a pair of forceps to reach down into the fish’s throat. Around 8:30 p.m., I switch to a small yellow panfish popper. I like the yellow-and-black combination. I fish the little size 10 popper on the same rod and leader.
Lake Almanor and Butt Valley Reservoir
Lake Almanor and Butt Valley Reservoir are located just six miles apart as the crow flies. They also share the same water when hydroelectric generators are running at the Butt Valley Powerhouse. The dams of these manmade lakes are located where giant mountain meadows once were. Construction of Almanor’s Canyon Dam began in 1916. Canyon Dam collected the water from the Hamilton Branch and the North Fork of the Feather River. At Butt Valley Reservoir, Butt Creek was dammed to form the impoundment. The meadows’ soil became the mud lake bottom and a haven for Hexagenia nymphs.
Butt Valley’s elevation is 4,150 feet and Lake Almanor’s elevation is 4,505 feet. Pacific Gas and Electric moves water from Lake Almanor via a 15-foot-diameter pipe that runs through the mountain and down to the Butt Valley Powerhouse, generating large amounts of hydropower for the region. The elevation change also means that the Hexagenia hatch starts earlier on Butt Valley than on Lake Almanor. The hatch at Butt Valley usually begins in late May and runs into late July. The hatch at Lake Almanor starts in early June and runs into early August. There are approximately 7 to 10 days difference in hatch start times.
Adjacent to the lakes are large National Forest and PG&E properties that are open to public access. The east shore of Butt Valley is wide open to fly fishers, and a dirt road runs along it. Access on the west side is limited to gated fire roads. Lake Almanor has less public land.
The west shore is National Forest and PG&E land, with approximately 11 miles of shoreline available for public access. However, there is private property in the communities of Westshore, Almanor, and Prattville.
The west shore of the lake has the majority of the Hexagenia habitat. Fishing this side of the lake can be done from float tubes, pontoon boats, prams, and other watercraft. I even see folks in houseboats casting f lies for the hatch. The best choice, in my opinion, is a float tube or pontoon boat. These allow you to move around on the lake and through the other boats. They also allow you to fish different tactics, from sinking lines with nymphs early in the evening to dry flies as the bugs emerge. Anglers using floating watercraft on Lake Almanor and Butt Valley Reservoir must have a personal flotation device (PDF), a light, and a whistle. The Plumas County Sheriff’s Department strictly enforces the rules.
As on other waters, a 9-foot 6-weight rod is a good choice. I usually carry three rods on Lake Almanor and Butt Valley Reservoir. Two are lined with full sinking lines for nymph fishing — a Type III line and an intermediate line. This allows me to fish the entire water column. To keep nymphs at the same depth as my sinking lines, I use short leaders that are just 3X tippet material approximately 6 feet long. The third rod has a standard weight-forward floating line and 9-foot leader with a 3X tippet. The fish at Lake Almanor and Butt Valley aren’t leader shy. My favorite flies there are my Lance’s Hex Nymph, size 6, and Lincoln’s Stillborn, a dry fly, also size 6.
Lake Davis
Lake Davis is an impoundment that was completed in 1966, when the Grizzly Valley Dam was finished, creating an impoundment of Grizzly Creek, a tributary of the North Fork of the Feather River. The lake basin was another large mountain meadow, and the lake is another prime habitat for Hexagenia mayflies.
According to Jon Baiocchi*, a guide very familiar with Lake Davis, the Hexagenia hatch starts in the middle of June and runs throughout the summer, with the peak time from the end of June into the middle of July. There is also a small Hexagenia emergence in the first weeks of October. The best access area for the Hex hatch at Lake Davis on the west shore of the lake is the Camp 5 boat ramp area. On the east shore, it’s Fairview Point, the Lighting Tree boat ramp, and right in front of the Grizzly Campground.
Lake Davis trout are known to especially target the emerging or adult Hexagenia. Jon recommends that fly fishers focus their efforts on the last 45 minutes of the day. Top flies for Lake Davis are Milt’s Hexagenia Cripple, size 6, and Lincoln’s Stillborn, also in size 6. Jon likes a 10-foot 5-weight or 6-weight fly rod with a soft tip, lined with a standard weight-forward floating fly line and a 9foot tapered leader with a 3X or 4X tippet. Boating safety at Lake Davis is the same as all the other lakes. Please follow the California Department of Boating and Waterways guidelines, and always carry a personal floatation device, a light, and a whistle.
The Hexagenia hatch in Northern California is one of the most exciting events of the angling year, and the places where this large mayfly lives are spectacular venues. The Hex brings friends, family, and fishing buddies together. It always leaves a smile on your face. If you haven’t fished it yet, you’re missing one of the state’s signal angling experiences.
*As we were preparing this issue for press, we learned, sadly, that Jon Baiocchi, 56, passed away on April 22nd while guiding on the Feather River. More next issue. —Ed.
Nealley’s Adult Hex
Hook: TMC 2312, size 6
Thread: Yellow Danville 6/0 Flymaster
Rib: Tobacco brown Danville 6/0 Flymaster
Body: Yellow Cherub DK Yarn
Tail and back: Moose body hair
Wing: Yellow Nature’s Spirit select cow elk hair
Legs: Yellow round medium rubber legs
Lance’s Hex Nymph
Hook: TMC 9395, size 6
Weight: .025-inch nontoxic wire, 20 wraps
Eyes: Black extra-small bead chain
Thread: Yellow Danville 6/0 Flymaster
Tail: Olive dyed pheasant tail
Rib: Medium gold wire
Gills: Light gray saddle hackle filoplume
Body: Hexagenia Wapsi Antron Sparkle Dubbing
Wing case: Natural hen turkey wing quill
Thorax: Hexagenia Wapsi Antron Sparkle Dubbing
Legs: Natural hen pheasant neck fibers
Lincoln’s Stillborn Hex
Hook: TMC 5262, size 6
Thread: Yellow Danville 6/0 Flymaster
Tail and body: Gray ostrich plumes
Rib: Medium gold wire
Thorax: Glimmer olive Jay Fair’s Short Shuck
Wing case and head: Pearl yellow Loco Foam, cut to shape
Milt’s Hexagenia Cripple (Paranymph)
Hook: TMC 2312, size 6
Thread: Yellow Danville 6/0 Flymaster
Tail: Olive dyed pheasant tail
Body: Yellow rabbit Hareline Dubbing
Rib: Medium gold wire
Gills: Light gray saddle hackle filoplume
Thorax: Yellow rabbit Hareline Dubbing
Rib: Medium yellow wire
Wing case: Yellow 2-millimeter foam
Wing: Yellow Nature’s Spirit select cow elk hair
Hackle: Yellow neck hackle
If You Go…
The Fall River, the Thermalito Afterbay, Lake Almanor and Butt Valley Reservoir, and Lake Davis all are situated near multiple resources for dining, groceries, and lodging or camping. Here’s how to get to each of these Hex hatch destinations.
The Fall River
The California Trout boat launch is located on Island Road, which you can reach by taking McArthur Road west out of McArthur. The Circle 7 Ranch, also located off of Island Road, offers fly fishers boat rentals if you are staying at the ranch as a guest.
The Rat Farm and PG&E Tule River accesses are accessible from the town of McArthur. From Highway 299, turn north on Main Street in McArthur and continue north. Main Street will turn into a dirt road. This road is called Rat Ranch Road by the locals. The road follows a canal on the east side of the road. Follow the dirt road until you come to an intersection that has one road turning east and going over the bridge on the canal. That spur will lead you to the Rat Farm access.
If you continue straight at the intersection, you will still follow the canal. The canal turns west and heads toward the Tule River, and so does the road. Follow it until it ends. This is the PG&E Tule River access.
Thermalito Afterbay
The Wilbur Road boat ramp is located right off Wilbur Road and also can be accessed from Highway 162 between Wilbur Road and Highway 99. The Larkin Road boat ramp is located off of Larkin Road on the south side of the afterbay, and the Monument Hill boat ramp located on the east side of the Highway 162 bridge that crosses the lake. You can launch all varieties of boats from these cement launches.
Lake Almanor and Butt Valley Reservoir
Lake Almanor is located just south of the small mountain community of Chester. On the west side of the lake is Highway 89, while to the north is the town of Chester and Highway 36. The east and south of the lake are bounded by Highway 147 and Plumas County Road A13. Butt Valley Reservoir is located off of Highway 89 to the west of Lake Almanor.
There are two campgrounds at the Butt Valley Reservoir’s edge: Ponderosa and Cold Springs Campgrounds. A cement boat ramp is located just north of the Cold Springs Campground, named for a legendary sheriff’s deputy and retired California Highway Patrol officer — the Ray Adams Boat Launch.
Three large campgrounds are situated just west of the small community of Almanor. They are Legacy, South Almanor, and North Almanor Campgrounds, and are operated by the U.S. Forest Service. Legacy Campground is built for RVs and has large, paved pull-throughs that have power and water. Legacy Campground is a first-come, first-served campground that takes no reservations. South Almanor Campground has flush toilets and older paved sites. It takes reservations and has some first-come, first-served sites, as well. The same goes for North Almanor Campground, which also has a cement double-lane boat ramp where launching any type of boat is free. The only other campground is located on the south side of the lake on the west shore: Rocky Point Campground is a PG&E campground that has sites right on the water. These sites are reservable and fill quickly.
Lake Davis
Lake Davis sits just north of the small town of Portola, through which Highway 70 runs. To get to the lake, turn north off Highway 70 onto Lake Davis Road. Once at the lake, you can drive all around the lake to various access areas. Lake Davis has multiple campgrounds, boat launches, and public restrooms, and facilities there are usually top notch, well cared for, and safe.
— Lance Gray
