it would very much depend on the situation , location , physical condition and ability, weather and state of mind all come into play.
you could consider a building a cual or weir system to direct the fish ( if any) into a pool, when "enough' lower the water level by removing a small part of the weir but at the same time using branches (stakes or woven) to keep the fish from escaping.
I always had a 20' lengths of 8lb and 3lb( sutures) line an some hooks with me in a kit and some old timers carried a small cast nets with them. You cannot rely on just one method of sustenance gathering you have to make it a full time job setting snares and deadfall traps as well as trying your hand at fishing. The idea however is to maintain or lessen the effects malnutrition. preparing a signal to rescuers etc. are all important. You are far better to invest in caching high fat/energy food supplies ie: Click ( spam)
seems that if you are heading deep into the bush a .22 rifle akin to the Henry would be a good investment and shotgun ( pump) or a 303/3006 rifle with open sights. big game should opportunity arise would be the best bet, but cover your bases.