spring die off according to fish @ wildlife
[B]FRANKFORT, Ky. [/B]Research indicates a condition similar to “the bends” in divers likely played a role in the deaths of hundreds of thousands of Asian carp in two western Kentucky rivers last month The die-off of invasive silver carp happened in the Cumberland River below Lake Barkley dam and Tennessee River below Kentucky Lake dam “Preliminary results show they’ve got bubbles in the gills,” said Aquatic Nuisance Species Biologist Paul Wilkes of the Kentucky Department of Fish and Wildlife Resources. “You can see it very clearly Gas bubble disease can occur in water supersaturated with dissolved gases, and biologists believe it is a contributing factor in this case Gas supersaturation is something that can happen below dams,” Wilkes said. “When a fish is breathing this water with gas supersaturation it essentially causes an air embolism in the gill, which is similar to a diver getting the bends. A gas bubble will get trapped in the gill tissue of a fish and prevent blood circulation.”
Complete article can be found on fish and wildlife web page, pick fish tab then the more tab.
Interesting But something else might have happened
[QUOTE=clc;538402][B]FRANKFORT, Ky. [/B]Research indicates a condition similar to “the bends” in divers likely played a role in the deaths of hundreds of thousands of Asian carp in two western Kentucky rivers last month The die-off of invasive silver carp happened in the Cumberland River below Lake Barkley dam and Tennessee River below Kentucky Lake dam “Preliminary results show they’ve got bubbles in the gills,” said Aquatic Nuisance Species Biologist Paul Wilkes of the Kentucky Department of Fish and Wildlife Resources. “You can see it very clearly Gas bubble disease can occur in water supersaturated with dissolved gases, and biologists believe it is a contributing factor in this case Gas supersaturation is something that can happen below dams,” Wilkes said. “When a fish is breathing this water with gas supersaturation it essentially causes an air embolism in the gill, which is similar to a diver getting the bends. A gas bubble will get trapped in the gill tissue of a fish and prevent blood circulation.”
Complete article can be found on fish and wildlife web page, pick fish tab then the more tab.[/QUOTE]
I wonder why this only effected the silver carp and not the native fish species that live in the same highly saturated water? One would think that such a physical property as highly dissolved oxygen in the water would have a effect on all the fish that were swimming and breathing that highly oxygenated water.
The key to this might be the brain lesions that were discovered in the silver carps brain tissue. I think that the article said something about bleeding in the brain tissue.
Also I wonder if the outgassing of oxygen bubbles might have occurred after death? If the fish were breathing highly oxygenated water the O2 Pressure in their blood might have been higher when they were alive and after they died the floated to the surface where they were captured. I'm speculating about the floating to the surface but it's a good speculation as if they sank they would not have been collected for study. So they must have been floating on the surface in order for them to be found and collected by the biologists. That would make more sense to me. But I'm not for sure as the article didn't say that did it? Oh Well. After they died the super amount of oxygen in the blood vessels of the gills allowed the gas bubbles to come out of the gill's capillaries. Maybe that's what happened.
Why are Catfish not affected by the high oxygen content in the water below those dams. Many other fish species are caught right below the dams all the time and yet they are not dying of this high oxygen water. Maybe the new species have not adapted to this type of water where the native fish have figured out how to adapt to this type of water quality. But that's not really making sense to me.
Id like to see the results from the tissue sample studies. There are a lot of things about disease in both human's and other animals that we just don't know much about ... yet. This might be another one of those cases.
I do however wish and hope that some day someone (anyone) can figure out how to get rid of these silver carp and other grass carp species so as to preserve our native fish species. But I fear that won't happen. We might have to just get used to chasing a new fish species if we want to continue to fish at all. Hopefully that's not going to be the case. I'd hate to have to give up fishing for bass and crappie due to the fear of getting hit in the face while driving the boat at high speed by a 30 lb. flying Silver Carp. Not to mention that these silver carp take up most all the edible biomass in the waters and leave little for our young native fish to feed on. This may only get worse if these silver carp continue to expand their numbers. Which leads me to another thing that I learned in my Wildlife Biology 400 level class. Animal populations have bio feed back mechanisms that help to control their own populations. When there are too many of one species in a single area the spread disease more easily. Maybe this is what happened. Maybe one of the fish was sick and he spread it to the other's below the day as the small area below the dam was so full of other fish that fish to fish spread of the disease was made easier? That can happen with humans when they are all confined in a small area such as a school and the flu is going around. .