Fri Jun 08, 2012 4:40 pm
Hope this isn't too technical; All sea fish face the problem of osmosis which causes them to lose water from their body fluids and tissues to the stronger seawater in which they live. Bony fish (cod, mackerel etc) drink seawater, their kidneys get rid of the salt and the water is retained to replace water lost by osmosis. Rays (and sharks too) maintain relatively high levels of a substance called urea in their blood to raise the concentration of their blood to about the same as seawater to avoid osmotic problems. Urea is a waste product (as in urine and hence references to "pissy ray") and is already present in the ray flesh. It needs to be removed from the flesh quickly as it can break down to ammonia, I remember a charter skipper in Kerry trailing ray wings out the back of the boat on a rope on the trip home to "wash out the ammonia". Ammonia/urea has a fairly pungent smell and rays and sharks are famous for their acute sense of smell so it wouldn't be surprising that they would detect it. But would the smell repel them? Would it make a good shark repellant? I suspect that if you saw a large shark coming towards you in the water you might well find yourself releasing some urea into the water! It didn't help Quint in Jaws.
@myworldfishing and freedom1916, with reference to my earlier post, can I point out that I was quoting and have no problems with Dubs!
Fri Jun 08, 2012 7:01 pm
johnwest wrote:@myworldfishing and freedom1916, with reference to my earlier post, can I point out that I was quoting and have no problems with Dubs!
Thats fair enough dude, but your quote is a direct finger point to dubs fishing out ray... Also why even quote it?