Boy, we�re turning this into quite the discussion, aren�t we???
Cecil: let�s start with your question about mortality rates in the culture pond. I read your question last night, thought about it all night and this morning, and I still can�t answer your question. One of the problems with being a teacher is that I have to generalize to make points to students. If something �works� 80% of the time out in Mother Nature, then I teach it as a pretty darn important point, and the students then think it must be 100% true. There is just too much variability out there. Bill Cody is actually discussing the same types of things in his good list of the items that make all of this so variable, which ends up making it so darn hard to generalize. I�m sure we drive the laymen crazy!! :-)
Now, having included all of these disclaimers, Cecil: I still would expect, most of the time, to see some type of annual mortality. In wild populations, time after time, you see declines in number as fish age. At southern latitudes and faster growth rates, the mortality rate is higher and the maximum age is younger. At northern latitudes and slower growth rates with shorter growing seasons, the mortality rate will be lower and maximum age increases. See, I just taught another generality. It�s true 80% of the time, give or take, and there are certainly exceptions to the rule. In a culture pond, where fish are below the maximum biomass that can be supported by the system and your feeding regime, you could certainly be in an exception situation. I just don�t have the experience to know what to expect in your case. In wild bass populations in PA, I�d think that a 35-40% total annual mortality rate would occur, even in unfished populations. How much lower you might be, and for how long, I honestly don�t know.
Cecil � yes, I sure remembered about the growing and selling of fish. Love your web site!!
Bill � very nice job on your comments.
Shawn � I responded to your private message. Thanks for the kind words.
Cecil (on the taxidermy fish): You actually make a valid management point that state agencies have to consider. If we want to manage a water body for �trophy� fish, let�s say largemouth bass in a Texas power plant cooling reservoir, we might use something cool like an 18 inch maximum length limit. That is, anglers could keep the smaller bass to keep the population thinned, but then all 18 inch and longer bass would immediately have to be released upon capture. However, the bass would die of old age. Thus, should a state management agency really use the 18 inch maximum, or would it be better to have some type of a high, protected slot regulation. Now, I�ve NEVER worked with bass this big, so I�m just guessing. BUT, would it be better to have a 18 to 28 inch protected slot length limit?? If someone catches a bass over 28 inches, it probably is about to die. Would it be OK to let that person keep the fish and put it on the wall?? We do serve a variety of user groups, and we should consider the diversity in desires/opinions of those angler groups. That is a valid consideration, I�d say. However, with all the graphite replicas available, do we really need to kill her? Maybe she�d be the one who will survive to world record size, despite astronomical odds? How�s that for trying to ride the fence???? :-)
Dave
