# What fish see



## spooled1 (Sep 16, 2005)

Snells window and high contrast blacks might be a tool to consider but how does that explain the enduring power of the Qantas colored lure?


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## spooled1 (Sep 16, 2005)

Beyond about 30m humans can only assume what a fishy world might look like.

I read somewhere that as the depth drops to say 100m and beyond, the UV spectrum keeps on punching through the water column. Here's where it gets interesting. Blood is both photo luminescent and UV reflective. Some fish are UV reflective while others are UV absorbent. Either way it doesn't really matter because deep water predators supposedly chase the disturbance first and then when they lock on, they target the actual meal.

I think Kayak anglers here on the East Coast are probably more likely to experience the snells window scenario because of the many shallow scenarios. Tuna and Mackeral are a good example where they can see a lure before it even hits the water. Painting jigheads in lumo colors or looking for UV reflectants when you work 60m sometimes seems to help but seems to do stuff all in depths less than 20m.


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## gonetroppo (Jan 29, 2011)

I thinks theres more to these conartists, Ive seen fish swim through a mix of slugs and hardbodys (silvers and dark colours) just to smash the blooping kangaroo on top. I think colour is the key but it seems to be a case of flavor of the day.


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## Guest (Sep 11, 2011)

Snells window would only apply when the fish is directly below the lure. This would be more relevant fishing surface lures and dry flies. If a fish is approaching side on then there would be less contrast against the light above.

One reason for the success of the Quantas colored redhead white body lure is that from behind, when the lure is vibrating, the flash of red contrasted against the white body is supposed to look like the red gills of a baitfish.


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## spider25160 (Jun 20, 2011)

Back in the seventies one of my fishing hero's, Vic McCrystal wrote of an experiment he did with a completely clear lure. After many and varied tests he did using various colours including a totally clear plastic lure his results suggested that colour had no effect on the number of fish caught. More important was movement and sound. Having said this these experiments were done in the filthy mangrove estuaries of north Queensland on species like mangrove Jack and Barramundi etc. These fish in these conditions would not be using sight to track their prey.
The most important thing when offering a lure or a fly to any fish is to "match the hatch" If the target species is feeding by sight then your lure needs to look and behave like the prey it is chasing. If on the other hand the target species is feeding by vibration then your lure must "sound" like its prey.
Colours are far less important particularly at depth. Even in the clearest water reds and yellows become black in over 10 meters without artificial light.


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## goanywhere (Feb 22, 2011)

Another thing to consider is that some fish display much more curiosity than others. Fish can be attracted by anything that moves, flashes etc.and may strike just to find out what 'that thing' is. This is particularly true of pelagics and aggressive species such as flathead etc. I have seen salmon caught on nothing more than a piece of coloured cloth trolled through the water. So I think it's a matter of all sorts of variables, including how hungry the fish is, the presence of predators etc. That explains why a lure may do nothing on one day, but absolutely smash them another.

Fishing is part science, part art and part luck, that's what makes it a sport. ;-)


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## kayakone (Dec 7, 2010)

goanywhere said:


> ...... Fish can be attracted by anything that moves, flashes etc.and may strike just to find out what 'that thing' is. This is particularly true of pelagics and aggressive species such as flathead etc. I have seen salmon caught on nothing more than a piece of coloured cloth trolled through the water. So I think it's a matter of all sorts of variables, including how hungry the fish is, the presence of predators etc. That explains why a lure may do nothing on one day, but absolutely smash them another. ............


Heard that about movement. In the South Pacific fish are caught on a piece of wool or cotton. No expensive lures there.



spider25160 said:


> Back in the seventies one of my fishing hero's, Vic McCrystal wrote of an experiment he did with a completely clear lure. After many and varied tests he did using various colours including a totally clear plastic lure his results suggested that colour had no effect on the number of fish caught. More important was movement and sound. ....... If on the other hand the target species is feeding by vibration then your lure must "sound" like its prey......


"Sound" raises a question. Some HB's have 'rattles'. But what about SP's? I use a SP brand with a slot underneath. Has anyone experimented with adding small ball bearings to a SP to make sound??


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## spider25160 (Jun 20, 2011)

> "Sound" raises a question. Some HB's have 'rattles'. But what about SP's? I use a SP brand with a slot underneath. Has anyone experimented with adding small ball bearings to a SP to make sound??


The movement of anything through the water produces vibrations. If the vibrations are at the right frequency then we humans can hear them. Fish on the other hand can hear and feel vibrations that we have no idea exist.
So when your soft plastic appears to glide soundlessly through the water it is actually producing vibrations which predatory fish can sense with their lateral line or other sensing devices. For want of a better description I call this "sound" even though you and I can't hear it.

I know that there are rattles you can add to SP's. I have never used them and I doubt I ever would however I am willing to be convinced otherwise.


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## sunshiner (Feb 22, 2006)

Firstly colour is an illusion -- it's all in the mind. Colour is an interpretation by human, and many other brains, of the frequencies of electromagnetic waves, emanating from the sun and reflected by objects, which the brain's receptors (usually the eyes) are detecting. Sound is similar, in that sound is the brain's interpretation of the frequency and strength of vibrations carried to it via the medium (commonly air or water) in which its "sound" receptors (ears) are immersed. Smell also is all in the mind.

The ability to detect variations in the frequency of reflected electromagnetic waves is very important for the survival of certain species. For example, an individual fruit-eating animal which can detect "red" fruit against a "green" background may have a significant survival advantage over another which "sees" only shades of "grey".

Presently, as far as I am aware, we have no way of knowing exactly how fish perceive the variations in reflected electromagnetic waves. I have read that there is strong evidence that fish can differentiate between the various electromagnetic wave frequencies and thus can "see" colour and am prepared to believe that may be true. This is especially as humans, who can "see" colour, evolved, along with all other land animals, from fish. Note however that many land animals (most mammals, for example, including your pet dog or cat) cannot "see" colour the way that humans perceive it. It's also highly likely that fish can perceive frequencies of reflected electromagnetic radiation which are beyond human capabilities. Perhaps, in the process of evolution, our ancestors discarded this capability because it is of limited use above water and is expensive to retain.

So it seems clear that some fish may detect not only electromagnetic wave frequencies that we can detect but may also detect frequencies which we cannot without technological help. From what I have read, fish also may be very "short sighted" possibly because there would appear to be little survival advantage in having long distance vision in a medium such as water. And of course this denser medium absorbs electromagnetic wave frequencies at higher rates than the earth's atmosphere, thus leading to a quicker loss of human-perceived colours ("red", for us, starts to disappear at a mere five metres).

Many times while fishing with lures I've pondered the colour question. In shallow, well-lit trout streams I've caught trout on many different colours of metal bladed lures and have concluded that it's the movement not the colour that brings the strike. The same applies to soft plastics fished deep or shallow; movement, however subtle, seems to be the important factor. But I admit to trying different colours from time to time, just in case. One thing I'm confident of is that if I just let my SP sit on the bottom I probably won't catch fish.

And then there's the silhouette question. Many years ago I used to teach fieldcraft in the Australian Army and I still recall the "five S and one M" aide-memoire in the "Why things are seen" lesson. This acronym alerted a soldier to the things an enemy might use to find him and kill him. The "M" stood of course for movement and one "S" stood for silhouette.

Predatory fish likely use silhouette extensively. Probably the best indicator of this is the success of using poppers or slugs, on the surface when targeting feeding tuna or mackerel. It also possibly explains the success record of one of our favourite trolling lures which runs at a depth of only one metre, and thus puts it above most predators and right within Snell's window.

Thanks for bringing up the subject Brad. I wasn't aware that the window I see when scuba diving or snorkelling had a name and now I understand better how it affects fish.


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