Yea I’m deff not anti brown either, Real brown trout that come from their native range are unmistakably beautiful.
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They also ironically face the same invasive species problems brookies do here in the states.
Rainbow trout (Oncorhynchus mykiss) has become by far the most frequently farmed freshwater fish species in Turkey, whereas very little is known about its es...
www.frontiersin.org
The only issue with “restoring” a stream with the idea of brown trout persisting on after you do projects is the question of what are you restoring for?
So many people think that stream restorations are aimed at the trout that they love when in all reality no one besides the volunteers cares about the actual trout. Sure the grant funders are happy to say they are helping the trout but if it doesn’t improve the TMDL big time most grant funders in the Susquehanna basin aren’t going to fund you.
So we all assume these projects are for the trout but the funders get their reductions in nitrogen, phos, and sediment and what ever happens beyond that happens. The truth is the brown trout act similarly to the AMD, but to a lesser extent of course, in terms of limiting populations of the target species the restoration was meant to help in the first place like sculpins, mayflies, darters, native brook, hellbenders, crayfish, and many more. They impair their populations as seen below.
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Hellbenders are harmed by invasive trout they have not evolved chemical signaling defenses against.
https://ag.purdue.edu/extension/hellbender/Documents/Gall_InnatePredator.pdf
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sculpins
-“ Some salmonids may also induce behavioral shifts in sculpins, leading to reduced foraging. For example, in stream enclosures, growth of large sculpins was reduced in the presence of nonnative brown trout Salrno trutta but not in the presence of native brook trout Salvelinus fontinalis despite a lack of difference in diet composition or invertebrate availability among treatments (Zimrnerman and Vondracek 2007, this issue).
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“Species introductions have adversely affected a number of sculpin populations via predation (White and Harvey 2001),”
ja_adams013.pdf (usda.gov)
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Endangered candy darter
For anglers who use minnows for trout bait, a brightly colored 3-inch fish could spell trouble.
www.wvgazettemail.com
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Endangered guyandotte crayfish harmed by brown trout an WV stopping stocking them overtop of populations.
The past two years haven’t been the greatest for West Virginians who like to fish for brown trout.
www.wvgazettemail.com
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mayflies: Invasive brown trout caused trophic cascade by depleting native galaxids, altering may flow behavior, and algae blooms that in eloped the bottom of the streams resulted. Shows how powerful the food web disturbances can be.
Experiments in laboratory stream channels compared the behaviour of Deleatidium mayfly nymphs in the absence of fish with that in the presence of either native common river galaxias (Galaxias vulgaris Stokell) or introduced brown trout (Salmo trutta L.). Galaxias present similar predation risks...
pubmed.ncbi.nlm.nih.gov
-brown trout reduce sensitive mayfly species populations.
Request PDF | Impact of introduced trout on Nesameletus mayfly populations measured using electrofishing | Despite the widespread introduction of salmonid fishes for sports fisheries their effects on recipient invertebrate communities are not well... | Find, read and cite all the research you...
www.researchgate.net
In summation, brown trout disrupt entire food webs as invaders outside their native range similar to AMD but to a lesser extent I would guess. So we look at the end out come as just clean water with either brown or brook trout as anglers. However, if brown trout are left it really is JUST clean water in the end because the native food web will still be limited to an extent by the invasive brown trout. The bay appreciates it, the PhD who devoted his life to hellbenders is happy the water is cleaner but sees it as only a half measure because his larval hellbenders are getting eaten. Not saying we can remove in even close to a majority of the scenarios, I’m just highlighting what’s at stake in the situations where you could. The reality is most of theses browns are here to stay but to preserve what’s truly special(intact food web) in areas where we can, we have to realize that clean water alone won’t save us and what the real cost of invasive species are. Clean cold water and great habitat hasn’t saved kettle, pine, cedar, and many others. You can’t get it any better than up there and invasive species are still winning the battle and so much more than brook trout are being lost it’s the destruction of an entire ecosystem.