A fish brakes if it tries to breathe when swimming downstream - so Uncle Stanley says

[camo]

Hi deb

Your question is an interesting one, but for a start i might say that Jack Hargreaves was for me an inspiration. Jack presenting "Out of Town" introduced me to a quiet balanced countryside. Balanced because he understood and transmitted the inter relationship of all activities and species and the need for man to respect all wildlife. His introduction to fishing as well as all country actviites relied on respect whilst balancing the wants of man with the needs of flaura and fauna.

Back to Fish: fish can but do not sit in mid stream open their mouths and gill covers and let water flow over their gills. When you watch even a species such as Barbel that live in the fastest of water they make a controlled movement to open their mouths, take in water and whilst their mouth is closed force the water over their gills and out of their covers. A fish will absorb oxygen when fresh water is in contact with their gills. They can operate this system going up or down stream or in still water. When a fish moves it is rarely at top speed, and therefore any change in its streamlining will increase the effort but it is not likely to hamper their movement. Fish species have developed shape to suit the habitat including flow they live in. A Barebl is very streamlined with a flat bottom and strong current creates down force just as a spoiler on a racing car. A Bullhead has developed a large flat head as it lives under stones and needs to wedge itself in a safe place. A bream has a vertical shape with large flanks, if a Bream turns in fats water it is hit with the full force of the current however it lives in slow water where this is not a disadvantage. However Barbel can be found in slow water and Bream sometimes in fast which suggest they have a large degree of tolerance and therefore the streamlining wont have any major negative effect (in a short swim downstream). The last point is that the Gill covers are generally about 1/2 on side and 1/2 below head so they are able to open them forcing water down instead of backwards. The point of this is that with water forced downwards their is no directly opposed current acting as a brake to water ejection.

Sorry if i have gone on a bit

Roy

[Deb London]

No camo lad, you haven't gone on a bit at all. Very interesting. Of course, Uncle Stanley may well have been talking about water forced backwards out of the gills and so if a lot of it is forced downwards, it does not matter which way the fish is swimming.

Can someone tell me why fish face upstream, for the most part?

[Meta menardi]

Originally Posted by Deb London

Can someone tell me why fish face upstream, for the most part?

Not the only reason perhaps, but it is where the food comes from.

[Deb London]

Thanks MM.

Another related question, to all. Later on in the book it suggests that a big fish on the line gives in twice as fast if you can manage to hold its head in the downstream direction. He said that the fish is drowning. Is there any truth to this (even if it's not drowning, will a fish give in faster this way round) or was this an Uncle Stanley special?

[camo]

Definetly a big reason why fish face upstream is food but also because their whole body shape has evolved to face up stream. Lets look at three more examples of body shape: the Pike has a wide mouth presenting a less streamlined shape it also has all its power near its tail this is because it uses still water (often eddy's) and bursts on its prey with powerful acceleration. An eel is long and cyndrical so it can hold itself in the weeds and use a snake like movement when crossing boggy areas. The final classic fishy shape of the Dace, Trout or Chub which is designed to move around mid water with a rounded front end and a tapered back end to its tail. If you was to reverse the shape of say a dace it would lack control and the current would force it one way or the other. It is like a an aeroplane wing that has a tapered back and a kite which uses a tail to give it stability.

Roy

[camo]

Deb

I should have added the reason they face upstream is to watch for food and their shape has been evolved to make that easy

Regards

Roy

[Deb London]

Thank you very much camo.

[AndyC]

Further to all of the above - fish face upstream in a river because they have to swim to hold station in the current. All fish are very much better at swimming forward that they are at swimming backwards or sideways

Fish are perfectly capable of breathing while swimming downstream because they are going faster than the current, if they weren't they would be drifting not swimming. If you watch a fish holding station in the current they do not always go gulp gulp to breath. Quite often they just have their jaws and gill plates ajar so that there is a constant flow over the gills. Thre is absolutely no reason why they can't do this (or indeed go gulp gulp if they need to) while swimming downstream. Fish like trout and salmon dont have watertight jaws anyway.

If a fish is held with it's head downstream in a strong current and it opens it's gills water will be forced through the gills backwards. I doubt this can be said to drown them but it must be very uncomfortable, the gill filaments are designed to have water flowing over them from front to back so the reversed flow will dissarrange the filaments and it certainly doesn't do the fish any good.

From my own experience of playing salmon it is true that if you can tow them downstream quickly they do give up surprisingly quickly. I did this many times while fishing on the very clear Dorset Frome where the fish could be watched in the water while being played. The salmon didn't drown they just seemed to be disorientated and dispirited by the whole experience.

I feel I had better point out that 95% of my salmon were released to carry on with their journeys


Andy

[Deb London]

Thanks you for your very interesting input Andy. Nice to hear that Uncle Stanley might well have known a thing or two about fishing, even if his reasoning is controversial.