Colour blind fish??

Member Joined: Dec 02, 2005 Posts: 92 Location: Dorset

Hi All

'I've been using amnesia for hook lines and red mainline - a guy in a tackle shop in Southsea told me that fish can't see red'.

I copied the above off another post and it got me thinking. does anyone know about colour and fish eye sight? I for one have found that red 'red gills' often are one of the best lures at catching pollock on wrecks at this time of year.

I always use colourless line and sometimes flurocarbon any thoughts on this as well certainly red line is visible to humans under water whereas clear lines are not so easy to see

Ray

Posted: Fri Jan 12, 2007 10:02 pm

Hi Ray, I don't know the answer, but how's about this then?
For humans, red is the first to drop off the distinguishable spectrum at about 750nm. We'd still pick out the shape/silhouette using the rod receptors in our eyes, making it the same as clear or black line once the light level falls. Dunno why we use them for traffic lights though, if they were all miles away the red would be the first one you couldn't make out. That said, fish don't just see, they have lateral lines and some have face sensors or barbels.
Redgills flutter, it would be interesting to try them at night to see if there is any change in catch rate between colours then. If so, there's something in the dye that changes the consistency of the rubber. When wrecking I get the impression the fish are lying low and attacking up, so they'll only see the silhouette, and not the colour, contrasting against the surface/sky anyway.
I'm spending far too much thinking time on something similar - my traces have 'invisible' fluoro bodies, some running to as low as 10lb 'invisible' fluoro snoods, then I put beads on the snood that can be 'charged' by holding them to your headlamp or a flashgun to fluoresce to make the whole damn thing visible again. Time and money to make it invisible, then every effort to reverse it.
Right: I'm gonna use some left-over Xmas tinsel, wrap it the whole length of the trace and snoods and try it in daylight with a chemical light rammed up a king rag. You can laugh, I'm already in trouble having been caught trying to waterproof one of the wife's vibrator motors and sticking it up a calamari, but we gotta keep thinking, all the time. MK

Guest

RaytheRay, interesting subject. According to a fish behaviour book I have on the shelf fishes use two types of receptor in their eyes, cone cells and rod cells, with the cone cells (the colour receptors) being used in good light and the rod cells being used in low light conditions i.e. at night, in deep water or when the water is coloured. The rod cells used in low light conditions are extremely light sensitive but only see in black and white so in theory colour should not make a difference in low light conditions. That being said it obviously does because certain colours of lure will often work better than others, even in low light conditions. I've always thought that it was to do with the way colours reflect the light rather than the actual colour itself - if you get what I mean.

MadKev's comments about fishes picking up the silhouette against the background of the light penetration of the sky certainly rings true; a few years ago in Devon I was catching Mackerel and Pollack one after another on a sunny afternoon on a completely black lure and have since done the same with black Mackerel feathers at the same venue and used to use black plugs to catch Pike when I was a kid.

Posted: Sat Jan 13, 2007 12:46 pm

Found this while surfing the web.......

Narration: Anyone who’s a diver knows that as you go deeper, the ocean becomes bluer. The water works like a filter. While we see the world with a retina sensitive to red, green and blue, if you’re living in a blue world there’s no point in having a red channel because there is no red light to see with. It turns out that many fish that live at depth are red but what they’re trying to be is dark. It’s just easier for a fish to make an invisible red pigment than black.

But this doesn’t mean fish are colour blind - far from it. Even a goldfish eye has 4 different colour channels. And while some reef fish seem to lack a red one, they have receptors for colours we can only dream about, down beyond the deep blue end of the spectrum.

JUSTIN MARSHALL: Many reef fish actually can see ultra violet. We found that perhaps half of the fish on the reef do, half of the fish on the reef don’t. Those that do have the potential for a private communication channel. They can talk to each other with ultra violet markings which the other fish can’t see.

Narration: Many of the small damsel fish on the reef seem to accentuate their existing patterns with these ultraviolet colours, probably to flash signals about their fine physical condition to their neighbours.

JUSTIN MARSHALL: It seems to be the case that many predators
don’t have UV vision, so perhaps Damsel fish are talking to each other in the ultra violet in a language that the predatory coral trout can’t see at all.

JUSTIN MARSHALL: But the coral trout has its own tricks. It’s one of many fish which can change its spots – in this case to sneak up on its prey.

Narration: Just as military camouflage experts discovered in World War II, pattern can be as important as hue…

JUSTIN MARSHALL: If you have an animal which has many diagonal patterns and very highly contrasting colours and place that in the context of a highly contrasting environment like a coral reef, again it will merge into the background. When you see a humbug, it’s a black and white striped fish, and that’s the highest contrast colours you can have. However, where they live is actually a very stripey environment. In some ways this is the same as the zebra effect on land and one of the theories for why zebras are black and white striped is because they live together in herds and it’s very difficult to tell literally when one zebra stops and the next one starts so for a predator diving into the middle of a bunch of these animals whether it’s zebras or fish it’s hard to know what end of which one to go for.

Narration: Justin is working his way through the thousand or more species on the reef, interrogating every fish by spectrophotometer. With our visual bias for the colours of fruit, this is the only way to measure the precise wavelengths reflected from spots, stripes and scales. And the fish must be scanned alive...

JUSTIN MARSHALL: Any fisherman knows that pull a fish aboard it’s brilliantly coloured, the colours fade within 10 minutes, so we have to catch the fish, keep them alive, measure their colours and then return them to the sea. One can spend as much time as you like looking at pictures in books, but until you actually come out into the field and look at what they’re doing you can’t get even more than a ten percent understanding of actually what the colours are for.”

JUSTIN MARSHALL: This is one of my favourite fish. Oxymonacanthus longirostris. It’s a file fish. Each of these little spots is the cell which makes up the colour on the side of the fish. This is the nose of a parrotfish. These rather intricate patterns could even act as individual recognition markers a bit like a fingerprint. This is the eyelid of a Long Tom and I have absolutely no idea what these colours are for.

Narration: Species by species, the language of fish colour is being decoded. And it’s giving a new insight into this city beneath the sea...

JUSTIN MARSHALL: It’s like standing in a subway station in New York, everyone shouting about different things all at the same time but instead of doing this with sound although fish do use sound they’re doing it with colour. The reason they do that is because there are so many of them together packed in close. They have to make rapid decisions about who’s about to eat whom and who should I escape from and who to mate with.

Member Joined: Dec 02, 2005 Posts: 92 Location: Dorset

Thanks Limey

Lots of information anyone else got any views on this.

It sounds like red is seen as black by fish at depth so black red gills should be the same as red ones on the deep wrecks

I wonder why red gurnards/red mullet (and the other spinney bottom living fish like scorpion fish) are red. I thought is was some sort of warning to other fish that they don't make pleasant eating.

Ray

Posted: Sun Jan 14, 2007 8:16 pm

RaytheRay wrote:

Thanks Limey

Lots of information anyone else got any views on this.

It sounds like red is seen as black by fish at depth so black red gills should be the same as red ones on the deep wrecks

I wonder why red gurnards/red mullet (and the other spinney bottom living fish like scorpion fish) are red. I thought is was some sort of warning to other fish that they don't make pleasant eating.

Ray

Wouldn't know mate...... I have never eaten any of them.. :lol: :lol: :lol:

Posted: Sun Jan 14, 2007 11:11 pm

Bet chemical tip lights give out UV as well as visible light. Everyone must have tried one of them up a bait, even out of desperation. Anyone tried it comparatively / scientifically? Can anyone make them flash? MK

Posted: Mon Jan 15, 2007 9:11 am

There is a 12 volt device that is being sold that gives off a greenish light.
Evidently you sink it in the water via a length of wire connected to a battery on the boat.
It is supposed to attract fish. At over a hundred pounds it must work.....