Red fishing line

[corydoras]

Yes red does change colour at depth but I often read that it turns black. This is rubbish. Black is not a colour as such. It's a complete lack of light or colour.The red would probably change in contrast to some form of grey, which may still be quite visible against the bottom of the water you are fishing so forget the idea that red maggots miraculously disappear after 15 feet or so. It simply changes colour.

All the colours that we humans can see change with depth. Colours tend 'change' into their complimentary colours, so as the depth of the water increases a red object would tend to change to green, not black.

Oceanographers divide the ocean into three zones depending on the light that is received.

• The euphotic or sunlit zone is the layer that receives enough sunlight to support photosynthesis. Depending on the clarity of the water this zone extends to a maximum of about 180-182 metres. I doubt that any of you have been that deep on a recreational dive.
   
  Descending further would take us into the disphotic or twilight zone, which spans the region from the bottom of the euphotic zone down to about 900 metres. Less than 5% of sunlight can reach this zone. There is not enough light to support photosynthesis at this depth so there is no vegetation.
   
  Below the disphotic zone we enter the aphotic zone or midnight zone. Sunlight cannot reach this zone (so there would be no colours)
  

I think that there is a bit of anthropomorphism in this topic. Some folks are assuming that humans are gifted by excellent vision, but compared to a wood pigeon or a peregrine falcon we are visually impaired. Fish in general don't have vision systems like ours. Many fish have vision systems that appear to be motion and contrast detectors rather than vision as we think of it, others have excellent vision. Some fish have 4 colour vision systems. As we are limited to only three colours that would mean that such a fish would be able to see hues of colours that we humans cannot. Some other fish have 5 colour vision systems, so would be able to see colours that we cannot.

 

Slightly off topic but dogs are often referred to as colour blind. I guess that most of us assume that this means that a dog sees the world in monochrome, like an old black and white movie, but in reality they probably see the world like a man with red green colour blindness.

 

Here is a link to an article by Dr David Ross http://www.midcurrent.com/articles/science/ross_color.aspx

 

David Ross an emeritus professor at the Woods Hole Oceanographic Institution and an angler. He has written a book on this subject, The Fisherman’s Ocean

[chevin]

Well I have to say that I really don't understand much of what is said there. I do know that even in the crystal water we have here I can get to a depth where red becomes green while snorkeling. I certainly haven't been to anything like the depths Corydoras mentions but I have been to 34 metres and it is a very different world there. Few colours show and being as you don't know what the colour of the objects you are studying would be at the surface it is impossible to guess what it might be. The interesting thing is, and it puzzled me at the time (you don't think too clearly at those depths) was that the 'ready light' on my strobe was flashing red! It wasn't until I got to the surface that I realised that it was because it was an electrically lit light. It did not need anything from the surface - it would have still showed in pitch blackness!

[corydoras]

I certainly haven't been to anything like the depths Corydoras mentions but I have been to 34 metres and it is a very different world there.

That was meant to be tongue-in-cheek mate. Few recreation divers descend below 40m (about 130 feet) because it is too dangerous and a tank of air will not give you much bottom time at that depth. You have been down deeper than me, but I was using Desco Full Face Mask like this and breathing from a diesel compressor rather from air tanks. The demand valve in the Desco full face mask does not get held in your mouth like it does in scuba gear. This means that you can talk to the dive controller on the surface via a comms line. Normally you cannot talk to your dive partner with this system, but messages can be relayed via the surface. On slight disadvantage is that you need to have mastered the technique of clearing your ears without touching your nose to use one.

 

I'd better stop now. Getting way

Edited February 22, 2007 by corydoras

[Steve Burke]

Here is a link to an article by Dr David Ross http://www.midcurrent.com/articles/science/ross_color.aspx

 

David Ross an emeritus professor at the Woods Hole Oceanographic Institution and an angler. He has written a book on this subject, The Fisherman’s Ocean

 

If members haven't already done so I'd suggest they do have a look at the excellent article by David Ross. Anyone interested in the subject would also do well to get hold of books such as "The Scientific Angler" by Paul Johnson or "What Fish See" by Colin Kageyama.

 

Talking of books I've just ordered "The Fisherman's Ocean". Thanks for the heads up, Corydoras!

[corydoras]

If members haven't already done so I'd suggest they do have a look at the excellent article by David Ross. Anyone interested in the subject would also do well to get hold of books such as "The Scientific Angler" by Paul Johnson or "What Fish See" by Colin Kageyama.

 

Talking of books I've just ordered "The Fisherman's Ocean". Thanks for the heads up, Corydoras!

Don't mention it. I love to read about natural history in general and the way that animals sense the world about them in particular. Some bird species are gifted with spectacular vision. I used to have a bookmark about starlings, who can see well into the UV. It showed a photo of how a starling looks to us and how it looks to another starling. The pretty plain looking (to us) strarling looks like some kind of bird of paradise to another starling. If I can find it agin i will post the link, but don't hold your breathe. I have googled for it many times and cannot find it again.

[chesters1]

All the colours that we humans can see change with depth. Colours tend 'change' into their complimentary colours, so as the depth of the water increases a red object would tend to change to green, not black.

Oceanographers divide the ocean into three zones depending on the light that is received.

• The euphotic or sunlit zone is the layer that receives enough sunlight to support photosynthesis. Depending on the clarity of the water this zone extends to a maximum of about 180-182 metres. I doubt that any of you have been that deep on a recreational dive.
   
  Descending further would take us into the disphotic or twilight zone, which spans the region from the bottom of the euphotic zone down to about 900 metres. Less than 5% of sunlight can reach this zone. There is not enough light to support photosynthesis at this depth so there is no vegetation.
   
  Below the disphotic zone we enter the aphotic zone or midnight zone. Sunlight cannot reach this zone (so there would be no colours)
  

I think that there is a bit of anthropomorphism in this topic. Some folks are assuming that humans are gifted by excellent vision, but compared to a wood pigeon or a peregrine falcon we are visually impaired. Fish in general don't have vision systems like ours. Many fish have vision systems that appear to be motion and contrast detectors rather than vision as we think of it, others have excellent vision. Some fish have 4 colour vision systems. As we are limited to only three colours that would mean that such a fish would be able to see hues of colours that we humans cannot. Some other fish have 5 colour vision systems, so would be able to see colours that we cannot.

 

Slightly off topic but dogs are often referred to as colour blind. I guess that most of us assume that this means that a dog sees the world in monochrome, like an old black and white movie, but in reality they probably see the world like a man with red green colour blindness.

 

Here is a link to an article by Dr David Ross http://www.midcurrent.com/articles/science/ross_color.aspx

 

David Ross an emeritus professor at the Woods Hole Oceanographic Institution and an angler. He has written a book on this subject, The Fisherman’s Ocean

 

 

not sure dogs are colour blind as a colour will seen but not nesseserally the same one as we do , i used to be a gardener in an estate with 2 stupid boxers (the dogs not the chinamen ) when they were little i accidentally frightened them with a red watering can and they avoided this from then on .

when strimming (they went mad at this novelty) i discovered if i had the red watering can near me they didnt come near ,i had an identicle shaped one in green which they totally ignored.

 

thus dogs maybe not colour blind but colour is different to them ,it may just be shades of grey but even a very slightly different red watering can was ignored ,i had to scour the region for a watering can the correct red for it to work and found although it was a different shape to the old one it still worked!!

 

and i would presume red line wouldnt go immediatly black under the critical point but change colour due to the other colours "beneath" the red , if the colour was pure red this could be wrong but most colours are mixes of others and the red maybe prominant but not alone in the line.

 

colour is very strange we think we see in RGB (red green blue) but your tv is transmitted just using red and blue ,the colour that cannot be made on tv is brown but you wont notice that. the green colour is the Y signal this is used so B&W tellies work ,in reality they are green tellies!

Edited February 22, 2007 by chesters1

[Dick Dastardly]

Well it seems that its not only a fishs colour perception that varies from humans but between humand themselves!!

 

Admitedly Im colour blind! but as well as everything apearing blue to me when below a depth of 15' (whilst in clear enough freshwater to actually see any way!) all of the theoretical/class room stuff Ive done plus the accepted literature (divining wise) Ive read also agrees this and indeed gives the scientific reasons behind this.

 

That said though! Yes I know what chevin is saying about "blood colour" causing confussion! and once again another contradiction! The only time Ive ever seen blood under the water from a human was whilst I was diving on the Mary Rose.Conditions were extremely poor visability wise due to the amount of disturbed sand/silt only lighting avaiable was artificial (flares in this instance) another diver cut himself very badly on a broken/frayed SWR cable....and his blood looked to be....................brown!!! I give up! Seriously though not only is it the depth your at,the individuals colour perception but also the source of the light! Try looking at photos taken under UV light or Hallogen etc etc. Like I said before dont care what it looks like to me or any other angler just interesting to know how a fish sees it! Cant ask one so must jusy assume bt angling results/experience what colours are usefull.

[chesters1]

it may have been the flares changing the colour ,fish must see differently which is proved when you light up corals etc tens of yards down ,their all colours ,surely nature would have removed anything not needed millions of years ago ,if their red then something must react to it? in a completely lightless place fish are a colourless wish wash or seethrough such as blind cave fish etc pointless having any colour when it cant exist,mind you i expect they go pink on boiling

[Dick Dastardly]

Yes I would definately have thought so Chesters. Good point about "why have colour if it cant be seen".