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Lake: Canyon Lake

Canyon Lake Consumption Advisory

Post By: BioGuy      Posted: 5/9/2012 6:12:15 AM     Points: 445    
I know most of us are catch and release fishermen, but I know some folks do enjoy eating their catch. Sadly, Canyon Lake, and many lakes in Texas, are heavily affected by heavy metal pollution. There are numerous warnings thorough the state of Texas on certain fish and lakes. Here is the TPWD advisory for Canyon Lake, taken from the TPWD website on 05/09/12:

Canyon Lake in Comal County
Chemical of Concern: Mercury

For striped bass and longnose gar, adults and children 12 and older are advised to eat no more than two 8-ounce servings per month. Children under 12 should eat no more than two 4-ounce servings per month.
Pregnant women, women who could become pregnant and mothers who are breastfeeding are advised not to eat any striped bass or longnose gar from the lake.

 Reply by: Lloyd Tackitt      Posted: 5/9/2012 6:40:39 AM     Points: 18748    
Excellent information and welcome aboard!
 Reply by: rebelsportsmanl      Posted: 6/10/2012 6:46:45 PM     Points: 955    
thanks for the info. i am a catch and eat fisherman. we have canyon on our catfish club tournament list and i see they are not on the list, but if any fish have contamination, i don't see how all do not have some.
 Reply by: Lloyd Tackitt      Posted: 6/12/2012 4:24:14 AM     Points: 18748    
Rebelsportsman: OK, you got me hooked with that question! I spent a couple of hours searching the internet for the answer and learned a lot more about mercury in fish than I ever thought to. Seems that mercury mostly gets in the water from the mercury in the air settling on the lake and the surrounding area. Mixing with suflfates "activates" the mercury. Counter-intuitively lakes surrounded by forest and/or wetlands have more mercury than lakes surrounded by farm fields. Go figure. I couldn't find a direct answer to your questions though I did find some clues. Fish that eat large fish tend to have the highest mercury levels. This appears to be a function of the age of the fish consumed as all fish have some mercury and accumulate more as they age, thus a fish that eats larger fish will consume more mercury per meal. Except in highly polluted lakes I didn't see any advisories for channel catfish although I did see several for flathead catfish. Another clue was size of the fish - larger and thus older catfish have more mercury than smaller/younger catfish. My guess from what I've read is that channel catfish probably tend to eat smaller fish than flathead catfish, stripers and gar. Also channel catfish would seem to have a more diverse eating pattern than those others who it would seem primarily eat large fish. Channel cats probably consume small fish, crayfish, insects, etc. However with age mercury does accumulate. Also the advisories that are put out seem to be on the conservative side, I guess the powers that be want to err on the side of caution where pregnant women and young children are concerned. For men, and women that do not intend to get pregnant the amount of "safe" mercury is higher. Mercury accumulations do bad things to young brain structure as it develops, but no so much to brains that are already developed. From now on I think I will consider large channel cats as potentially dangerous to children if they come from waters that are known to be contaminated - but for myself I'm not going to worry much While not definitive the size of channel cats that the scientists consider large are those that exceed 20 inches. This is just my take from the research I have done, I do not profess any specialized knowledge don't you know. In other words I am not a fish biologist nor have I ever played one on tv.
 Reply by: rebelsportsmanl      Posted: 6/13/2012 3:29:56 PM     Points: 955    
very good information. i have never liked canyon lake as a fishing spot, so any reason would probably make me happy to have a negative to fish there. i do know that mercury gets into lakes in colorado and new mexico from coal deposits in the earth. it is not always the human race that puts pollution in the water. mother nature leaks oil into the ocean every day by herself.