Most angling does not need sight of the quarry but it does need the proximity of the fish for the process to have any chance of success. Having, by one means or another, brought the fish close to our angling trap we then have to rely upon the co-operation of the fish to complete a successful sequence leading to hooking. Angling skill nianifests itself, thus far, in getting the fish near a bait, presenting the bait in such a manner as to allay the fish's suspicion and in providing a bait attractive enough to be taken. If any one of the elements fails then the whole process fails. In the end, hooking success depends upon the fish.
Anglers can prepare the circumstances but the circle has to be completed by the fish.
Beyond this there is skill required in playing and landing the hooked fish but this aspect is common to all waters, whether 'natural' or 'bagging'. There is an aspect of relativity here for anglers have, over many years, tampered with fish stocks in waters. Failing any other objective measure we need to look to advice from science as to what constitutes a healthy and natural environment for fish to live in. This means that, amongst other things, we need to heed advice on recommended stocking densities. The closer we can approximate to nature's levels, as measured by environmental scientists, then the more confident we can feel that we are not straying too far from this facet of angling's fundamental principles.