I’ve always struggled with fish vision and how it fits with my imitation of prey. Like most anglers I’m probably too quick to declare fly tying “success” and my brief victory may be for all the wrong reasons.
It’s hard enough to get into a fish’s head, but to look out their eye compounds the issue a hundredfold. The only adequate simulation is to chug a fifth in a single draught, erasing 160 IQ and yielding “fish eye” vision – but doesn’t give adequate time to tie enough flies before the remedy is expelled violently.
We’re left to guess at what fish see and think.
Prevailing theory has all manner of interesting wrinkles that most fishermen should be aware of:
Development of receptors for “blue” are among the last grown in human children, and it’s suspected that more primitive eyeballs (fish) lack these receptors – and view the color differently.
Fish eyes are tuned to their prey, and the movement of a fleeing baitfish is seen better by a Striped Bass, than a smelt.
Fish vision is not binocular, they must integrate two separate images of the same scene when looking to the front. There is a gap of missing information between the two images – as fish have eyes mounted on their sides and cannot see what’s in front of their nose.
Fish eyes have evolved over many millions of years in a pristine environment, now the Man has “muddied the waters” vision is limited by turbidity, and fish diets are changing – from what they’re attuned for, to what they can see.
While it’s a struggle to resolve the scientific detail, and our laymen’s understanding of vision, this has to be one of the reasons why a #16 Royal Wulff catches fish during a Pale Olive hatch.
While the Royal Wulff doesn’t resemble a Pale Morning Dun, if it enters the right focal plane it might be missing the entire red floss center section, or the skewed visual of hackles obscure enough to make it resemble what’s hatching.
It’s food for thought certainly, and when you stop to consider some of these theories, how many well known mayflies and caddis are blue?
Flowers are color coded so that the best pollinator responds to its bloom, I’m sure similar holds for the balance of nature – it’s why we gaze in rapture at the pictures on the restaurant menu, then gaze in wonderment at the lifeless turd that arrives on our plate.
I’d describe myself as an impressionistic fly tier, I rarely use exacting imitations with knotted legs and painstaking detail, those flies work best on fishermen. I like simulation and movement rather than detail, and the precise proportions we’re taught to use are skewed by water quality and the perceptive limitations of our quarry.
It’s akin to reincarnation, everyone is someone famous in a past life, and we accredit fish with all the “smart” traits because they outwit us. If that holds water, it’s likely they’re victimized by flatulence and bad breath as well.
I’d guess that trout eat as many twigs and stems as mayflies, like humans they can’t all have perfect vision, and the older the fish gets the bigger its prey. Not because it’s “big fish big meal” – rather it can see the big meal clearly, and little stuff could be food, but often as not it’s debris.
Could be I’ve stumbled upon the reason why there’s so many discrete streams of air bubbles in the Little Stinking, and how the residents earned the “coarse fish” label. We’re so concerned about the methane released by cows – and we’ve overlooked the real culprit.