By richard adeney, Feb 12 2020 08:39PM
If you have ever sat through a fire safety lecture you will know about the fire triangle. The elements of which are; heat, fuel and oxygen. If any one of these elements are missing fire will not occur.
When thinking about why and when fish feed there is a similar triangle. The feeding triangle. The elements are; available food, which is accessible, proximity of a place to hide and an optimal water temperature. If the water temperature is too low then fish will not be active and not feed. If it is too high then they will be under metabolic stress so will not be inclined to feed. If any element is not optimal then fish may not feed with confidence if al all. This concept is particularly applicable to river trout.
The first element in the feeding triangle is the abundance of food and how accessible it is. There are times when there are lots of flies present but there does not seem to be any fish rising or showing interest in the flies. Unless the food source is easy to get fish will not expend excess energy to catch their prey. Temperature can also significantly influence feeding behaviour. This is because the fish’s metabolic rate is directly related to temperature and all types of fish have an optimal temperature range. The optimal temperature range of a trout is between 8 and 15 degrees centigrade. When the water temperature is outside its optimal range feeding activity will be reduced. Another important factor is how exposed is the fish to the potential of predation. Where a trout lies close to a safe hole it will feed with confidence but fish in the tail of a pool will often be sensitive to the slightest disturbance.
How does all this affect the way we approach fishing a river? Firstly we are the predator so fish will always treat our offerings and activities with suspicion. Secondly stealth is important. Think before you move and only move slowly. Thirdly don’t waste time fishing water which is likely to be unproductive and not hold fish. When approaching a pool think where the food is, where is the safe zone for the fish and how does the food get to the fish? Where these three things come together there the fish will be. Whether we can catch it is another matter.