Three theories more (3rd and last part)

Minimum effort theory

Scientific basis: high-average-low
My own experience: well verified-occasionally-hardly ever
General reliability rating (from 0 to 10): 3

Description

Julián Narro, biologist and a great fly fisherman, encouraged me to include this theory. He says that, although there are no studies about this, its argumentation is promising, interesting and worth considering. So I heed his advice and disclaim any responsibility.
The minimum effort theory has also appeared recently and describes a peculiar behavior that trout develop after inhabiting catch and release stretches of streams for several years. Apparently these trout become less selective and even fight much less when hooked. The theory reveals behavior acquired through being caught and released many times in their lives (in some American studies, up to 20 times a year). It's almost as if they develop an awareness of the fact that they are going to be released. “What the hell. If they're going to let me go, why knock myself out?” (an anthropomorphically unhinging comment).

General selectivity theory

Scientific basis: high-average-low
My own experience: well verified-occasionally-hardly ever
General reliability rating (from 0 to 10): 9

Description

This theory completely rejects the idea that the trout's so admired and feared selectivity is proof of its intelligence. It tries to show that, in any case, it's the opposite. The trout's selectivity can be defined as genetically acquired behavior that makes its life a little easier.
The trout's tiny brain is mostly concerned about covering its basic needs: obtaining food, protection and oxygen. When there's an abundant hatch of a given species of insect, the trout focuses its attention on only that insect, ignoring all others. This theory defines selectivity as a trance-hypnotic or numb state more than a manifestation of intelligence or wiliness. This behavior makes the energy and time spent on feeding much more productive and profitable while the hatch lasts.

Acceptance theory

Scientific basis: high-average-low
My own experience: well verified-occasionally-hardly ever
General reliability rating (from 0 to 10): 9

Description

This theory was developed by the great Gary LaFontaine. It explains the three-phase process of a trout taking a dry fly. He divides it into:

  • recognition phase
  • confirmation phase
  • acceptance phase
The first phase occurs when the fly is still at a distance and the trout only fixes on what LaFontaine calls the main trait of the fly. In the confirmation phase, the fish is very near the fly and it happens when the trout can confirm the identity of that insect, perceiving some secondary trait. In the acceptance phase, with the fly almost stuck to the fish's snout, it examines its behavior. Only if it behaves naturally does it end up getting eaten. Some interesting ideas about this fascinating theory:
  • What differentiates a primary from a secondary trait is the distance at which the fish can perceive it.
  • The recognition phase is instantaneous.
  • The confirmation phase is slower.
  • It's in the acceptance phase when presentation becomes important.
If the trout breaks the surface rejecting the fly, the cause of this rejection lies in the acceptance phase.

Carlos