MORTALITY RISES WITH WATER TEMP?

BLACK KNIGHT · 07-28-00, 04:58 PM

Found on FAOL regarding cold water fish, ie; trout:

"The CSU study found that a quickly played and carefully released fish stands a 94% chance of survival. However, once the water temperature exceeds 65 degrees F, that percentage drops to less than 60%."

Anybody care to elaborate? Are we killing far more than we know about in the summer?

Chris England · 07-28-00, 05:02 PM

Probably are in the mountain streams, but remember that the Hootch, being a tailrace, leaves the dam somewhere in the upper 40's, and warms to the mid 60's about 20 miles down.

(I haven't taken any temp readings below Jones, in quite a while, anyone care to provide those numbers?)

-- tight lines

[This message has been edited by Chris England (edited 07-28-2000).]

beowulff · 07-28-00, 05:05 PM

As the temp in H20 rises, the amount of dissolved oxygen (all other things staying steady) decreases. If you overstress a fish to the point where it is, in a humna sense, hyperventilating, then it's struggling to breathe. If the water it breathes has lower O2 levels, it can't recover as quickly and would, logically, be more likely to pass into the great beyond (or whereever it is that trout go when they die - they used to go to my stomach, until I learned the error of my ways)... Kind of like being chased across the top of Long's Peak in Colorado...you struggle to breathe, the chase keeps up, you struggle more until you can struggle no more. You give up, and you're tossed back out into an avalance to fight while you're tuckered out. I wonder if trout literally drown this way? Is it possible for a fish to drown? Have to ask Mr. Limpet I guess. Were is Don Knotts when you need him? He's been downhill ever since Three's Company....

fly on the wall · 07-28-00, 05:15 PM

Jones Bridge has been a pretty steady 58 degrees the last few weeks.

BLACK KNIGHT · 07-28-00, 05:32 PM

Not everybody can fish the hooch, guys! I'm talking in generalities, here. Burrell's Ford was 64 degrees on 7/21. Lower Eastatoe was 72. How about the other small streams?

The Professor · 07-29-00, 12:01 AM

It's just for that reason that the "fish-for-pay" places along the Soque shut down during the summer.

------------------
Neal Gilchrist
hnealg@bellsouth.net

gerald · 07-29-00, 01:37 PM

Beowulff has the correct explanation for the increased mortality at higher temps.Remember,
with the lower O2 tensions,fighting fish will build up lactic acid in their tissues sooner and at higher concentrations-----this can really stress them making recovery more difficult.Still,I would not over play fish.I have seen hybrids and stripes fight themselves to death.I dont think it is any secret that this time of of year trout are going to seek deep pools and the lies below broken water(as rapids)and especially head waters which are often cooler.It has been some 35 years since I fished Estatoe but it use to be very dependable in summer much higher up--near NC--you have a much greater rate of fall up there.

BLACK KNIGHT · 07-31-00, 09:33 AM

You are correct, I am assuming, Gerald, because the river stays comfortable enough to support a wild population in the upper portions of the E.

What's the answer- is it even ethical to fish for trout in marginal temp waters if you plan to release?

JOHNKIES · 07-31-00, 09:49 AM

Just for fun one time I backed a fisheries biologist into a corner and got them to 'fess-up that from the fish's point of view the best time for a closed trout season in Georgia would be May 31st to October 1st. Tough time for the fish unless, as others have pointed out, they're in a tailwater.

Wouldn't it be fun to watch the political fall-out from that notion?

---JCK---

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07-28-00, 04:58 PM	#1
BLACK KNIGHT Hall of Fame Member Join Date: Nov 1999 Location: Greenville, SC, USA Posts: 3,328	Found on FAOL regarding cold water fish, ie; trout: "The CSU study found that a quickly played and carefully released fish stands a 94% chance of survival. However, once the water temperature exceeds 65 degrees F, that percentage drops to less than 60%." Anybody care to elaborate? Are we killing far more than we know about in the summer?

07-28-00, 05:02 PM	#2
Chris England Native Join Date: Oct 1998 Location: Cumming, GA Posts: 922	Probably are in the mountain streams, but remember that the Hootch, being a tailrace, leaves the dam somewhere in the upper 40's, and warms to the mid 60's about 20 miles down. (I haven't taken any temp readings below Jones, in quite a while, anyone care to provide those numbers?) -- tight lines [This message has been edited by Chris England (edited 07-28-2000).]

07-28-00, 05:05 PM	#3
beowulff Native Join Date: Jul 2000 Location: Adairsville, GA, USA Posts: 112	As the temp in H20 rises, the amount of dissolved oxygen (all other things staying steady) decreases. If you overstress a fish to the point where it is, in a humna sense, hyperventilating, then it's struggling to breathe. If the water it breathes has lower O2 levels, it can't recover as quickly and would, logically, be more likely to pass into the great beyond (or whereever it is that trout go when they die - they used to go to my stomach, until I learned the error of my ways)... Kind of like being chased across the top of Long's Peak in Colorado...you struggle to breathe, the chase keeps up, you struggle more until you can struggle no more. You give up, and you're tossed back out into an avalance to fight while you're tuckered out. I wonder if trout literally drown this way? Is it possible for a fish to drown? Have to ask Mr. Limpet I guess. Were is Don Knotts when you need him? He's been downhill ever since Three's Company....

07-28-00, 05:15 PM	#4
fly on the wall Native Join Date: Jun 2000 Location: lawrenceville, ga Posts: 1,175	Jones Bridge has been a pretty steady 58 degrees the last few weeks.

07-28-00, 05:32 PM	#5
BLACK KNIGHT Hall of Fame Member Join Date: Nov 1999 Location: Greenville, SC, USA Posts: 3,328	Not everybody can fish the hooch, guys! I'm talking in generalities, here. Burrell's Ford was 64 degrees on 7/21. Lower Eastatoe was 72. How about the other small streams?

07-29-00, 12:01 AM	#6
The Professor Native Join Date: Oct 1998 Location: Lawrenceville Posts: 320	It's just for that reason that the "fish-for-pay" places along the Soque shut down during the summer. ------------------ Neal Gilchrist hnealg@bellsouth.net

07-29-00, 01:37 PM	#7
gerald Native Join Date: Jul 1999 Posts: 408	Beowulff has the correct explanation for the increased mortality at higher temps.Remember, with the lower O2 tensions,fighting fish will build up lactic acid in their tissues sooner and at higher concentrations-----this can really stress them making recovery more difficult.Still,I would not over play fish.I have seen hybrids and stripes fight themselves to death.I dont think it is any secret that this time of of year trout are going to seek deep pools and the lies below broken water(as rapids)and especially head waters which are often cooler.It has been some 35 years since I fished Estatoe but it use to be very dependable in summer much higher up--near NC--you have a much greater rate of fall up there.

07-31-00, 09:33 AM	#8
BLACK KNIGHT Hall of Fame Member Join Date: Nov 1999 Location: Greenville, SC, USA Posts: 3,328	You are correct, I am assuming, Gerald, because the river stays comfortable enough to support a wild population in the upper portions of the E. What's the answer- is it even ethical to fish for trout in marginal temp waters if you plan to release?

07-31-00, 09:49 AM	#9
JOHNKIES Hall of Fame Member Join Date: Nov 1998 Location: Laurel Park, NC USA Posts: 3,771	Just for fun one time I backed a fisheries biologist into a corner and got them to 'fess-up that from the fish's point of view the best time for a closed trout season in Georgia would be May 31st to October 1st. Tough time for the fish unless, as others have pointed out, they're in a tailwater. Wouldn't it be fun to watch the political fall-out from that notion? ---JCK--- ------------------