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Post by guidduglucy on Sept 22, 2011 18:31:03 GMT
The usual way of working is for the water to come through the mouth, but while the direction is not important for the actual gas transfer in the gills, where Oxygen crosses the membrane in to the blood stream, that is not the main story The important part is that there should be constant fresh, oxygenated, water coming on to the membranes, and the best way to get this is for the water to be flowing in the one direction, new water coming on to the gills and "used" water leaving them. If the fish is moved back and forward, the water in the gills will also move back and forward, bringing used water back on to the membranes, so you are right, it is best to to keep the water flowing through them in the one direction, either by pushing them forward through the water or holding them head forward in a current. Got this from Tweed foundation Biologist. what ever they do it seems to work for the fish.
Ronald
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Post by borderer on Sept 22, 2011 21:57:56 GMT
this must be the norm for all fish then? even at sea they must always swim against the tide?? explains why runs might be late/ early depending on the flow of the sea??
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Post by guidduglucy on Sept 23, 2011 19:06:39 GMT
Could be, never given that one any thought always put it down to food supply and how far fish have to travel to find it then get back home.
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