Matching The Hatch as Philosophy and Methodology
"Matching the Hatch" as a philosophy and methodology in the sport of fly fishing has been around for a very long time. The phrase became popular in North America when Ernest Schweibert published his book of the same name in 1955. It was his first of many books and was written when he was 24.
The match the hatch method of fishing is reliant on intimate knowledge of how trout function, and how the environment that they live in functions. It involves the study of how trout feed, and their relationship to the various prey organisms that exist in their environment. It also entails knowledge about how these same organisms live and behave to survive. This approach to fly fishing is actually a study of biology at many levels.
The theory concludes that trout tend to be very efficient feeders and often target organisms that are inclined to be pretty small in comparison to the trout themselves. There are calories gained in each acquisition, but not in large amounts. Each trout has to be careful not to expend more energy than is gained from every morsel, lest the fish starve to death.
In most stream environments, average size trout feed primarily on aquatic insects and crustaceans, which belong to the phylum Arthropoda. Many Arthropoda are adapted to a wide variety of aquatic habitats. Crustaceans are critters whose skeletons, like insects are on the outside of their bodies. They are well designed for life on or in the bottom of rivers and lakes. They spend most of their lives crawling around where they are often seen by game fish but rarely by humans.
Insects and crustaceans differ in one very important aspect. Crustaceans such as crayfish don't have a phase where they leave the water and become air breathing as many aquatic insects do. In fact, most aquatic insects not only have an aquatic and a terrestrial stage, they also have swimming and flying stages as well. This transition from an aquatic juvenile insect to an adult flying insect is called a "hatch," but is really a metamorphosis from one stage of life to another. However, this transformation from one stage to another is probably what started the "match the hatch" philosophy of fly fishing. Aquatic stages of insects in their true environment are hard to see and study. Even more difficult to observe is how trout react to them, or feed upon them. As soon as insects get above the surface of the water, they become more visible to humans. So do the trout that are feeding on them. Mayflies are especially visible while they are emerging through surface of a river, and so are the trout that are eating them. Emerging mayflies were probably the insects that first promoted dry fly fishing. As dry fly fishing became popular the methods were adapted to other aquatic insect emergences.
Today a hatch can be defined as anything that makes a specific kind of food available in such a way that predator fish key on it. It may in fact be a hatch such as insects emerging from terrestrial sources, such as a flight of queen ants or yellow jacket wasps drinking from the surface of a river. Years ago I witnessed such activity on the Deschutes River where Wasps were collecting caddisflies that had become stuck in resins secreted by giant edge water grass. Every so often a wasp would alight on the surface of the water to drink. A couple of larger than average redband trout were preying upon them, and a large Yellow Humpy fly fooled both of them.
Some hatches are extremely hidden in the most unexpected ways, but can still influence your fishing. During fall months certain rivers in the Pacific Northwest have hatches of large nocturnal stoneflies with all the males being flighless. In order for these flies to cross a river, they must run across the surface. While doing so these heavy insects leave a tail or wake of foot falls on the meniscus. Some of these river also contain summer steelhead. The Tenkwa Stone dry fly is a pattern developed by Mike Maxwell for fishing on the Bulkley River for wild steelhead. Telkwa refers to the nearest village, which is just outside of Smithers, BC. There are other steelhead waking flies that mimic the activity of these and other large insects.
Are waking flies actually mimicking a male flightless stonefly running across the surface of the water? No one knows for sure, but it does seem probable.
Would you call a small olive crab walking on a dry sand bar at low tide a hatch? On some sand bars there are hundreds of them scuttling around out of reach of fish and out of view of small camera lenses. But when the tide rises everything changes.
Knowing that a rising tide will cover the sand bar with water which will expose the crabs to patrolling redfish and snook might prompt a smart angler to tie on a olive crab fly and get ready for the hatch.
Knowing that a rising tide will expose crabs to feeding fish is not really a hatch, but it has the same effect in creating a feeding cycle for fish that you can capitalize on.