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ManitouDan |
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Posts: 566 | had to delete . person involved didn't want involved . Cave run is getting fished pretty hard recently with temps in 83-86 range . If you want details you can PM me but I won't name any names , just describe what happened Edited by ManitouDan 9/2/2011 2:14 PM | ||
| sworrall |
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Posts: 32882 Location: Rhinelander, Wisconsin | I'm not aware of any Muskie studies you can quote, but all biologists I have spoken to tell me that over 80 degrees it should be water release and as short a fight as is possible. Anyone have a study to quote? Please stay out of this unless you have a study or other information source that would assist in providing information either way. | ||
| FAT-SKI |
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Posts: 1360 Location: Lake "y" cause lake"x" got over fished | I agree with you sworrall. all water releases if possible and back in the water as fast as possible. this is not fact.... I heard last year from a guide I went out with, if the water temp is 83-86 degrees and you fight a fish for too long, they will develop lactic acid in their swim balder and will not be able to swim correctly for quite some time. the guide told me that this usually results in death, which is why he takes 2-3 weeks off every year from guiding to not effect the fish to much. He told me that the other problem with the warm water, is the deeper you go to find them, the more likely they are to get lactic acid build up and die. He told me when the water is super hot if you can't stay off the water then take every extra precaution that you can think of... | ||
| tcbetka |
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Location: Green Bay, WI | Although I haven't reviewed the literature on this exclusively, I think Sean Landsman's paper was about the only one to even talk much about variables involved with C&R mortality. There have been relatively few studies on the subject in the first plan--all the more reason that Sean's work was/is so valuable. I don't if he's been around here in a while, so I'll have to dig his paper out and read it again. It's been a while since I did, so i don't want to misquote him. But I can tell you that I have discussed this very topic with several working fisheries biologists (two of whom practice in Wisconsin), and both were quite concerned about mortality when water temperature was higher. Having said that however, I do not recall any definite number cited by any of them in that regards. As I said--I am not at all aware of any such published value, with the possible exception of something in Sean's recent paper. I'll try to review that tonight or tomorrow, and re-post afterwards. TB | ||
| tcbetka |
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Location: Green Bay, WI | Well, I went back and re-read the excellent study presented by Sean Landsman (et al), as published in the Journal of Fisheries Research, last year. If anyone is interested in the study, I can post the full reference--or you can simply search for it online. (Disclaimer: Lengthy, science-laden response forthcoming.) While Sean's study did not correlate mortality-vs-temperature, the authors did show that the fish displayed a significant stress effect due to increasing water temperatures (80-81 degrees Fahrenheit, max water temperature). It's important to first note that they did not see any mortality in their study, but the most "harsh" treatment they showed the fish involved hook removal attempts using long nose pliers to a maximum of two minutes, at which time they discontinued that effort in favor of bolt cutters. At most, their air-exposure "admiration" time was confined to 90 seconds during this study They were able to confirm that, during the warmer water temperatures, angled muskellunge displayed higher concentrations of glucose, lactate and potassium ions in the blood--all thought to be directly indicative of stress in the fish. Certainly warmer water temps may explain some (or all) of this effect, as the metabolic rate of the fish does indeed increase...and therefore glucose (fuel for metabolism) and lactate (a by-product of metabolism) may also increase accordingly. Along that same line, the increased potassium levels observed could actually be explained in this manner as well. The intracellular potassium concentration in humans, for example, is much higher than that seen in the extracellular space (blood, in this case). And because the normal glucose active transport pump that moves sugar into the cell depends upon transportation of sodium and potassium ions down their concentration gradients (i.e.; sodium into the cell, and potassium out of the cell and into the blood), it might well explain why the level of blood potassium ions increased in these fish. However that does not necessarily explain why Beggs (et al) found in his 1980s study that some fish actually further increased their serum potassium levels, well after the stress of capture and handling had apparently resolved. And the fish that died appeared to be unable to cope with these significant increases in potassium levels, which makes one wonder whether or not this increase caused their demise (for example, through cardiotoxicity and eventual cardiac arrhythmia and arrest)...or was their death caused by some other factor (like metabolic failure), and the potassium level in the blood simply continued to increase accordingly? But it should be pointed out that the heart is quite intolerant of an elevated level of potassium, and in fact this is one method of euthanizing animals; or in the execution of humans, for that matter. Therefore although Sean's study does not provide conclusive proof that elevated water temperature causes an increased mortality level (because no fish died), it does suggest that the *mechanism* for increased mortality with increasing water temperature is very real. Simply put, the right conditions exist, and the fish may simply not be able to tolerate the added stress of these metabolic changes. Couple that with variability between fish (one healthier than the next), and it makes it even more difficult to predict an actual ONE absolute value of water temperature where angling efforts should cease. One thing Sean and I talked about while he was planning his lab analysis prior to collecting specimens, was trying to measure cardiac enzymes typically seen in death of heart cell muscles. However this would be very difficult to do in a study such as this, as heart damage sufficient to cause death of heart muscles cells and the release of these intrac-cellular chemicals takes time. For example in humans who've suffered a heart attack, it may take 12-24 hours before such levels are elevated to a degree sufficient to allow positive identification of such damage. This is simply not practicable when studying muskies, and thus we're unlikely to ever know the exact cause of post-angling mortality in these animals. Suffice it to say that anglers should give very strong consideration to any and all factors causing increased angling stress, any time they intend to release their catch. Increased water temperatures mean increased metabolic rates at the very same time that dissolved oxygen levels are decreasing, due to the temperature-dependent solubility properties of oxygen in water. So if nothing else, the fact that a fish has higher plasma potassium levels in warmer water may simply mean that they don't have the reserve to tolerate as much stress as they would tolerate at cooler water temps. But fish 'A' might have an entirely different tolerance than fish 'B,' so about all we can do is hypothesize and make generalizations in this sense. But it seems logical anyways... Therefore all we as anglers can do, to be prudent, is assume that warmer water is much harder on the fish (well-proven, by the way), so we should re-double our efforts to minimize stress in these instances. Things like minimal time spent fighting the fish (shorter casts; heavier tackle; less "fight" time), shorter time spent unhooking the fish (use of barbless hooks; bolt cutters instead of pliers) and less air exposure (in-water unhooking; no air exposure time spent in "admiration" of the catch) can pay much larger dividends when water temperatures increase during warmer months. TB Edited by tcbetka 3/20/2012 8:00 AM | ||
| muskellunged |
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 Location: Illinois | Always a good read: Handling Techniques and Survival of the Released Muskellunge Rod Ramsell http://www.thenextbite.com/node/11334?page=2 | ||
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