# Do fish ever die due to a forest fire?

**URL:** <https://boards.straightdope.com/t/do-fish-ever-die-due-to-a-forest-fire/754350>\
**Category:** Factual Questions\
**Created:** [May 8, 2016, 11:45pm UTC](https://boards.straightdope.com/t/do-fish-ever-die-due-to-a-forest-fire/754350 "2016-05-08T23:45:22Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![PurpleClogs](https://avatars.discourse-cdn.com/v4/letter/p/f04885/32.png) [@PurpleClogs](https://boards.straightdope.com/u/PurpleClogs)\
**Post date:** [May 8, 2016, 11:45pm UTC](https://boards.straightdope.com/t/do-fish-ever-die-due-to-a-forest-fire/754350/1 "2016-05-08T23:45:22Z")

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During or soon after a bad forest fire, do fish ever die from cooking in the heated water, oxygen depletion, burned up vegetation at the shoreline or covering the pond, overhead burnt trees dropping into the water, or rain or fire hoses poisoning the water with charred runoff?

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**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\
**Post date:** [May 9, 2016, 12:13am UTC](https://boards.straightdope.com/t/do-fish-ever-die-due-to-a-forest-fire/754350/2 "2016-05-09T00:13:16Z")

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[Here you go.](http://www.uwyo.edu/barnbackyard/_files/documents/resources/wildfire2013/waterqualityerosion2013wywildfire.pdf)

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**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\
**Post date:** [May 9, 2016, 12:47am UTC](https://boards.straightdope.com/t/do-fish-ever-die-due-to-a-forest-fire/754350/3 "2016-05-09T00:47:40Z")

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The fire retardant they use is [toxic to fish](http://www.care2.com/greenliving/toxic-forest-fire-retardant-usage-requires-more-review-says-judge.html).

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**Author:** ![burpo\_the\_wonder\_mutt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/burpo_the_wonder_mutt/32/365_2.png) [@burpo\_the\_wonder\_mutt](https://boards.straightdope.com/u/burpo_the_wonder_mutt)\
**Post date:** [May 9, 2016, 1:34am UTC](https://boards.straightdope.com/t/do-fish-ever-die-due-to-a-forest-fire/754350/4 "2016-05-09T01:34:51Z")

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[Smoke and ash raise the pH of water in ponds and streams](http://www.northernrockiesfire.org/effects/aqimme.htm). That can’t be good.

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**Author:** ![penultima\_thule](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/penultima_thule/32/3833_2.png) [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\
**Post date:** [May 9, 2016, 11:43pm UTC](https://boards.straightdope.com/t/do-fish-ever-die-due-to-a-forest-fire/754350/5 "2016-05-09T23:43:32Z")

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> [@PurpleClogs](#):
>
> During or soon after a bad forest fire, do fish ever die from cooking in the heated water, oxygen depletion, …

Doesn’t need to be a bad fire either. The impact of heat causing oxygen depletion is known here as [Black water](http://www.theage.com.au/victoria/creeping-flow-of-dirty-water-killing-fish-in-states-rivers-20110125-1a4cg.html) and can devastate fish stocks a long way downstream of the source.

Interestingly enough the linked above event in 2011 was caused when the river forests were flooded in high summer as demanded by green groups for “environmental flows”. When the high river levels required to cause the flooding of the forests fell back to normal summer flows the forests drained of the now black water and killed fish for hundreds of kms.

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**Author:** ![enipla](https://avatars.discourse-cdn.com/v4/letter/e/54ee81/32.png) [@enipla](https://boards.straightdope.com/u/enipla)\
**Post date:** [May 11, 2016, 11:27pm UTC](https://boards.straightdope.com/t/do-fish-ever-die-due-to-a-forest-fire/754350/6 "2016-05-11T23:27:14Z")

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My County department is doing a Community Wildfire Protection Plan (CWPP).

It identifies high risk areas and how to protect them. One of the inputs to the data models is endangered fish species.

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**Author:** ![mmmiiikkkeee](https://avatars.discourse-cdn.com/v4/letter/m/edb3f5/32.png) [@mmmiiikkkeee](https://boards.straightdope.com/u/mmmiiikkkeee)\
**Post date:** [May 12, 2016, 3:00pm UTC](https://boards.straightdope.com/t/do-fish-ever-die-due-to-a-forest-fire/754350/7 "2016-05-12T15:00:41Z")

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> [@penultima\_thule](#):
>
> Doesn’t need to be a bad fire either. The impact of heat causing oxygen depletion is known here as [Black water](http://www.theage.com.au/victoria/creeping-flow-of-dirty-water-killing-fish-in-states-rivers-20110125-1a4cg.html) and can devastate fish stocks a long way downstream of the source.

Those black water events are driven mainly by excessive organic material decomposing via bacteria aided by high water temperatures all contributing to drops in dissolved oxygen; they’re not fire-induced. The heat from a fire usually does little to raise the water temperature while it’s burning. A fire may indirectly lead to future temperature elevations by reducing the canopy cover, but that’s not the same thing. In cooler less eutrophic areas (like the north American rockies), typical forest fires generally have little impact on fish populations.