Hatches on the new Grand River are changing each year, possibly in response to continued improvement in water quality and to increased predation pressure from the large population of trout now in the river. Mayfly hatches have become more important in the upper river than they were a few years ago, though they are still less common above Fergus than in the middle and lower river, with the possible exception of Tricos. One mayfly--the Great Olive Spinner (Hexagenia)--has decreased markedly in importance in the last four years. Filtering caddis larvae continue to dominate the middle and upper river, where plankton-rich water from the dam provides a ready food source to be trapped in their silken sieves.
Trout season on the Grand runs from the last Saturday in April to September 30. In the early season, the water is often cold and high, and short-line fishing with a weighted nymph rig is usually the most productive method until warmer water and the first good hatches move fish to the surface. Use an indicator of strike putty or yarn (remember that an indicator dry fly cannot be used because of the one-fly rule on the special regs water) and fish a short line to dead-drift the nymph through pockets, riffles, and runs. Don't ignore shallow water--many fish over 20 inches are taken from water less than knee deep. Short-line nymphing is a popular technique, and the trout are wary, so strike at the slightest movement of the indicator. Popular nymph patterns imitate larvae of the three most common caddis larvae, as well as Hendrickson and other mayfly nymphs. Another effective early-season pattern is an imitation of a Sowbug (Isopod), as these crustaceans are common throughout the river.
The best dry-fly fishing on the Grand River happens from late May to early July, with another burst of surface activity in late August and into September. The river has good hatches of both mayflies and caddisflies, and these occur at different times and in different areas along the river, so it pays to research the river a bit. My book, "Fly Fishing the Grand River," covers the hatches in much more detail, but here I'll highlight some of the top hatches on the Grand River calendar.
First among the season's hatches are the Hendricksons (Ephemerella subvaria and Ephemerella rotunda), which come off in the cold water of early spring. These are the most prolific mayflies in the Grand, and the emergence begins about May 18 most years, running for between two and three weeks. Hendricksons are most common in the lower river, but decent hatches are found as far up as Fergus. Early on in the hatch, trout may key on nymphs if the water is cold or high. This can result in a spectacle to frustrate the dry fly angler--a river covered with millions of duns, with no rising fish in sight. Try a Bead-head Pheasant Tail while you hope for warmer weather.
As the hatch progresses and the weather warms, there will be lots of rising fish sharking down duns in the afternoon or sipping spinners in the fading light of evening. When fish move to duns on the surface, I favor a Haystack pattern, but one tied with a wing of natural dun CDC rather than the traditional, Adirondack-style deer-hair wing. First-time visitors accustomed to Catskill or Michigan rivers are often taken aback by the olive-tan color and smaller size of the Hendrickson duns found on the Grand. They often dash back to the vise or into the fly shop to stock their fly boxes with more accurate imitations. Regulars on the Grand look forward to fierce attacks of mosquitoes, because they know this pest always coincides with the best Hendrickson spinner fishing. It's the fisherman's yin and yang. My favorite Hendrickson spinner pattern is the Half Round Spinner, which sits low on the water but is still visible in the near darkness.
After the Hendricksons, the menu expands as multiple hatches overlap through June and into July. The lower river--below Elora--supports a good population of Brown Drakes (Ephemera simulans) that emerge for a short time around June 12. The spinner fall of these big flies produces some of the best trophy fishing of the season to anglers who are on the right water at the right time. Dark Grey Fox (Stenonema vicarium), the Large Red Fox (Stenonema tripunctatum), several types of Cahills (Stenonema ithaca, Stenacron interpunctatum), the Lead Wing Coachman (Isonychia), and small Olives (Baetis) emerge through this period as well, so a well-stocked fly box is an essential resource.
In August you'll see hatches of Tricos (Tricorythodes) and other small mayflies early in the morning. The best fishing during these hatches is usually upstream of Fergus, in the long flats below the bridge at the Garafraxa 2nd Line Road. Typically, a bright, hot morning in mid-August will provide good fishing from 6 to 8 A.M., after which breakfast is more productive than further fishing.
The Grand boasts immense populations of caddisflies. Three genera provide much of the food base of the river and are responsible for the rapid growth rate of the trout. These genera--I call them the "Kraft Dinner" of the trout--are the Spotted Sedges (Hydropsyche), Speckled Sedges (Cheumatopsyche), and the Little Black Caddis (Chimarra). Larvae of all three are caseless, and grow so rapidly by filtering food from the river water that the adults of a single species may emerge in early June, and their offspring grow to adulthood by late July. In some cases, three generations of the same caddis species may hatch in one fishing season. Later generations require smaller imitations, as the size of adults may decline from 10 mg (#12 hook) in the first generation, to 2 mg (#18 hook) by the last generation of the year.
Early in the season, imitations of these larvae are a favorite fly of local anglers, and whenever nothing is hatching, a Spotted Sedge nymph is the "go to" fly. Once emergence begins, effective surface imitations of Spotted and Speckled Sedges include common flies such as the Try-it or Elk-hair Caddis. I prefer the Try-it over the Elk-hair Caddis because it has no hackle and a lower profile on the water. If the naturals are fluttering, I switch to an olive-bodied Adams. The Little Black Caddis is smaller, with a black wing and dark olive body, and imitations are best tied no larger than a #16.
In June and July, look for caddis hatches early in the morning and again in the evening, especially in the river above Elora.
In August and September, a cold, rainy day is ideal weather for a hatch that may last the whole afternoon while the river is almost deserted by other anglers. Foul weather in the late season also brings a good emergence of the Lead Wing Coachman (Isonychia). This fly is a filtering mayfly that, like the common caddisflies, has a second generation in late summer from adults that emerged and laid eggs in June. Look for this hatch in on rainy afternoons in the river below Elora. Click here for a Grand River hatch chart.
Ian Martin is co-author of Fly Fishing the Grand River.
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