Flyfishing Entomology


Re: Hatches and Bass


From: TerryLee
Posted: : Sunday, November 10, 2005 02:39 AM on www.FlyTyingForum.com

Just what it says on the sign out front, what's a hatch and how can it help me catch more bass?

I have heard all this stuff about hatches and matching the hatch, but I really don't think I get it. I am guessing it has to do with when certain types of insects are "born", but aside from that I am lost.

Will someone please point me in the right direction?



The following description is quite generalized, so there are some exceptions, which I won’t attempt to explain here.
The term, “hatch” is used by fly fishers to describe an insect’s emergence from its aquatic environment. The aquatic insect starts life as an egg, deposited by a female adult. After a variable period of time (usually a few weeks), it exits the egg and begins actively feeding and growing.

Depending on the type of insect, this life stage is called a nymph or a larva. For example, in this life stage, mayflies, stoneflies, damselflies, dragonflies, and waterbugs are called nymphs. Whereas, caddisflies, true flies, beetles, and others are called larvae. In either case, they spend the vast majority of their life in this stage, feeding, growing, and periodically shedding their external skeleton when it is no longer able to accommodate additional growth.

The larva has an additional life stage. The larva seals itself in a cocoon-like structure for a period, transforms into a pupa, and begins developing wings. Once mature, the pupa exits the cocoon-like structure, emerges from its aquatic environment, transforms to a winged stage, and takes flight.

The nymph begins developing wings in wing pads during its later stages of development. Once mature, the nymph emerges from its aquatic environment, transforms to a winged stage, and takes flight.

This is what is referred to as a hatch, or as hatching, or as emergence. Now I’ll address the second part of your question, “how can this help me get bass?”

Most fish (bass included) depend on aquatic insects for some part of their diet. So, as with any fish, it is useful to understand when a particular life stage of a particular insect becomes a significant part of the diet for the fish you are targeting. Of course, one also needs to select an appropriate artificial, make an appropriate presentation, and impart appropriate action in order to consistently fool your target fish, particularly the larger/wiser ones.

Although it may not be necessary to have even rudimentary understanding of insect behavior in order to catch your target fish, it certainly can’t hurt, particularly at those times when they are keying on aquatic insects. This may be during the aquatic portion of insect life, during emergence, or when adults return to the water’s surface for purpose of mating or egg-laying.  Hope this helps.

To view the full thread, click Fly Tying Forums > Entomology > What's a hatch, and how will it help me get bass?

Created: 11/13/2005   Last modified: 08/25/2006    www.FlyfishingEntomology.com