Connectivity & resident trout

Discussion in 'Gear Restrictions and Trout Fishing Regs' started by kzoofisher, Dec 24, 2020.

  1. kzoofisher

    kzoofisher

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    Merry Christmas all! I thought this might interest some of you to read over the winter (it isn't short) and couldn't remember if it had been posted here before. It bears on a topic that will probably come up more frequently in the next few years. Wasn't sure where to post it, doesn't have anything to do with regs but it isn't specific to any one part of the State either so it was either here or in the general trout fishing section and this section seems more inclined to receiving studies.
     

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  2. PunyTrout

    PunyTrout Staff Member Mod

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    Here's a snippet from the introduction:


    Nearly all rivers in the world have been impacted to some degree by dams. While providing benefits to society such as hydropower, flood control and water supply, dams alter rivers on many levels by fragmenting, inundating, and thermally or hydrologically altering habitats, often to the detriment of river fish populations and other lotic fauna (e.g. Cooper et al., 2017; Wang, Infante, Lyons, Stewart, & Cooper, 2010). However, much of this infrastructure is ageing, with nearly 75% of 49,000 large dams in the United States being more than 50 years old by 2020 (Cooper et al., 2017). As many dams ap-proach the end of their useful lives, and with considerable costs of maintaining old dams, dam removal opportunities presently abound and will continue to increase into the foreseeable future (Poff & Hart, 2002).Opportunities to remove dams or increase connectivity within river systems will often lead to changes in fish communities that should be considered prior to taking management action. These may include increased occurrence and production of downstream fishes in upstream reaches, and positive or negative responses of resident fishes to these changes. For example, by providing access to additional spawning habitat, increasing the connectivity of trib-utaries to North America's Great Lakes (hereafter Great Lakes) may result in greater reproduction for invasive species such as sea lam-prey Petromyzon marinus and round goby Neogobius melanostomus, a negative effect, but also increased reproduction of highly valued introduced Pacific salmonids currently stocked into the Great Lakes, namely Chinook salmon Oncorhynchus tshawytscha, coho salmon Oncorhynchus kisutch, and adfluvial rainbow trout or steelhead Oncorhynchus mykiss. Eggs and carcasses of migratory Pacific salmo-nids can provide an additional food resource for resident trout pop-ulations (Ivan, Rutherford, & Johengen, 2011), though the degree to which they produce a measurable increase in growth is less certain (Gerig, Weber, Chaloner, McGill, & Lamberti, 2018). Regardless of the geographic location, understanding how resident fish popu-lations will respond to dam removals or increased fish passage is needed to inform management decisions on dam removals and river connectivity, and for informing anglers on how fish populations might respond to river connectivity changes. For coldwater rivers in the Great Lakes region, the trout angling community's support for such actions may hinge on how they think resident trout populations will respond to these changes.Evaluations of the effects of river connectivity changes on res-ident trout populations are limited, hampering the ability of fishery managers to draw broad conclusions on effects of increased connec-tivity on resident trout populations. One study of juvenile salmonids in the Great Lakes region identified coho salmon as competitively superior to brown trout Salmo trutta and brook trout Salvelinus fon-tinalis (Fausch & White, 1986). Another could not detect an effect of steelhead on behaviour, growth or survival of brown trout (Kocik & Taylor, 1995, 1996), which contrasts with results from a long-term study by Nuhfer, Wills, and Zorn (2014) showing a 46% decline in survival of brown trout from age 0 to age 1 when steelhead were introduced into a low-gradient Michigan stream. Earlier studies im-plicated coho salmon and steelhead with declines in brook trout and brown trout populations at index sites (population estimation reaches) in Lake Superior tributaries (Peck, 2001; Stauffer, 1977). Such conclusions have been supported by later authors (Huckins, Baker, Fausch, & Leonard, 2008). Data from multiple locations and over longer time periods would provide a more robust characterisa-tion of resident trout population responses to Great Lakes salmo-nids that would have access to reaches following dam removal or fish passage installation, providing important information to fisher-ies managers or others needing to weigh trade-offs with regard to re-establishing river connectivity.Typically, the most downstream dam in a river system prevents migratory fish from accessing the system, but upstream dams can have similar negative hydrologic, geomorphic and biological effects. For example, dam removal in the Great Lakes region may provide non-native brown trout with access to reaches where native or resi-dent brook trout are the sole salmonid species present, with poten-tially negative consequences for brook trout populations. Previous research has often identified brown trout as competitively superior to brook trout (e.g. Fausch & White, 1981; Waters, 1983; Zorn & Wiley, 2010). Brown trout have been identified as one of the most invasive fish species, interacting with salmonids and native fishes in portions of North America, South America, Europe, New Zealand and other regions of the world (e.g. Budy & Gaeta, 2018; Casalinuovo, Alonso, Macchi, & Kuroda, 2018; Jones & Closs, 2018). The potential for negative effects of brown trout on native salmonid species has led to consideration or use of dams as management tools for isolating upstream populations of native salmonids from downstream non-na-tive populations (Fausch, Rieman, Dunham, Young, & Peterson, 2009; Rahel, 2013; Kirk, Rosswog, Ressel, & Wissinger, 2018). Long-term data from multiple locations would enable more robust estimates of brown trout effects on brook trout populations and the potential trade-offs of such management actions.We evaluated effects of increased salmonid species co-occur-rence (associated with fish passage) on resident trout in a broad array of streams to provide supportive data for fisheries management de-cisions on dam removal or fish passage in the Great Lakes region. Lacking multiple before-after studies, we focused on comparing attributes of resident trout populations between sets of streams where populations were or were not interacting with salmonid spe-cies that might be present if a dam was removed. More specifically, we compared resident trout populations between streams with and without Great Lakes access, and brook trout populations in Great Lakes inaccessible (land-locked) streams where brown trout were or were not present. We accomplished this by analysing electrofishing data from sites on 34 streams throughout Michigan that have been repeatedly sampled since 2002 under the Michigan Department of Natural Resources’ (MDNR) Status and Trends Program. Our ob-jectives were as follows: (1) to compare age-specific abundance, growth, and survival of resident brook trout and brown trout be-tween stream reaches with and without Great Lakes access to as-sess effects of Pacific salmonid species passage on resident trout; (2) | 3ZORN etal.to compare age-specific abundance, growth, and survival of brook trout between index reaches where brown trout did or did not occur to estimate potential effects of allowing brown trout access into brook trout streams; and (3) to compare overall abundance and bio-mass of salmonids between reaches without versus with Great Lakes access, and between land-locked brook trout streams without ver-sus with brown trout, to evaluate the hypothesis that total salmonid abundance would be higher in the latter scenarios where salmonid species richness was higher. The resident trout species we studied have wide-ranging distributions, with brook trout being present in 44 countries and brown trout in 59 countries (Fishbase, 2019). By quantifying potential effects of increased stream connectivity (and salmonid species richness) on these important and widely distrib-uted resident trout species, our findings provide managers and ecol-ogists useful information on effects of dam removal or fish passage actions for streams within the Great Lakes region and beyond.


    The paper continues in the pdf file linked above.
     
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  3. tincanary

    tincanary

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    What a great post, very valuable info in that pdf. Thanks for sharing.
     
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  4. kzoofisher

    kzoofisher

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    It's well worth thinking about before it's an issue on a stream you care a lot about. Already has been and will continue to be an issue on the Boardman. Someday, maybe/maybe not in my lifetime but someday, it will be an issue on the MO, Big Man, Betsie, AS... any stream that has a dam on it. A lot of dams most of us never heard of help keep browns out of brookie water in small streams.

    Take the Big M for instance and imagine no dams at Tippy and Hodenpyle. A whole lot of steelhead are going to be spending a year in streams that are primarily brook and brown fisheries now. There's some really good resident rainbow fishing up in there, too. Maybe those baby SH will be great, maybe it'll suck. Odds are very good it'll be both depending on which fisherman you ask. Now, that's a long time off because those are big dams and they produce electricity. But it'll happen very quickly when they stop being beneficial to the electric company. And if the first time you ever think about it is the day you hear the dam is coming out, be prepared to feel ignored.
     
  5. Boardman Brookies

    Boardman Brookies

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    The Boardman is completely overwhelmed with smolts now. You catch one brown or brookie to every 10-12 smolts. It is a shame.


    Sent from my iPhone using Michigan Sportsman
     
  6. Ranger Ray

    Ranger Ray Smells like, Victory! Premium Member

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    Everyone wants the dams gone, until it effects their resident trout. Seems like with when, not if, the carp invade the big lake, we'd be a little apprehensive to remove some of these dams.
     
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  7. kzoofisher

    kzoofisher

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    Very true. With the eventual removal of dams should barriers be put in place to prevent the mixing of some species? Or the expansion of invasive species? Keeping goby and lamprey from the upper Grand was a huge part of the discussion about 6th Street. BB is pretty clear on how he feels about steelhead filling the Boardman, too. A couple more snippets to peak the interest of anyone who hasn't read the whole paper.



    We think our overall findings of effects of Great Lakes access on resident trout populations are likely more robust than previous studies (e.g. Nuhfer et al., 2014) since analyses for each species were based on data from 25 or more rivers. Likewise, our conclusions re- garding fish passage or dam removal on land-locked reaches (i.e. ena- bling brown trout passage) are similarly robust, suggesting that fish passage or dam removal efforts in some streams could lead to brown trout reducing or replacing brook trout as the dominant trout species...

    This information will inform managers of Great Lakes tributaries on potential coldwater fish population changes from management activities that re-establish connectivity with the Great Lakes. Likewise, managers of fragmented land-locked waters can use our results to identify and prioritise connectivity projects when minimising risk to brook trout is necessary. Of course, effects of increased connectivity on resident trout are only part of the discussion as dam removal decisions involve other important considerations, such as costs for dam removal or future maintenance, available funding, sediment management, invasive species, migratory fish production, contaminant transport and the level of public support.
     
  8. Fishing Mike

    Fishing Mike

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    We need to remove barriers, as many as possible, as far down into our large river systems as possible in Michigan if we are going to improve our trout fisheries and make them more resilient into the future. Trout habitat across the US will continue to be negatively impacted by climate change and by mid century we can be uniquely positioned to have better, not worse, fisheries on large river systems (unlike projections for many western streams that arent controlled by large bottom draw dams) but we have to get rid of the dams that will only exacerbate warming trends. We will be the envy of nearly every other state, especially if this improves our trout, salmon and native species fisheries that will be made exponentially better by greater connectivity between our great lakes and rivers. I guess I'm really just talking about the Au Sable and Manistee here but there are at least 10 other systems that have hydro facilities that by mid century will be up for relicensing and will barely make an economic argument for continuing to generate power vs other renewable and actually green energy sources. Also, we know now that the bubbler systems installed don't make enough of a difference to justify keeping them in place to meet license requirements.

    There is no scenario that removing more dams, cooling larger stretches of river and opening up hundreds(?) of miles of more trout habitat will negatively impact our current trout fisheries enough to make the argument for keeping dams. So we catch a few more smolts? We will miles and miles of new, restored high gradient stream and this will provide so much more fishing opportunity and also habitat for our favored species to find niches in which to thrive. With the continuing increase in boat anglers this will be even more important.
     
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  9. The Mediocre Fisherman

    The Mediocre Fisherman

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    I’ve caught quite a few what I thought were goby in the upper Grand, hiding out among pretty much any rock near shore... or am I mistaken and these are sculpin?
     
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  10. slowpaya

    slowpaya Premium Member

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    dont see how we can keep them out,just a matter of time
     
  11. Stand By

    Stand By

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    If I had pictures of a few walleye I've seen in the upper Pine and posted them here, the tittabawassee and saginaw rivers would get a nice little brake from some of the walleye fishermen as they recover from thlaat spring's flooding. The Pike wasn't big enough to worry about a picture. I'm sure bigger ones move in from fletcher pond every spring.
     
  12. Martin Looker

    Martin Looker

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    Taking out the dams would improve fishing years down the road. In the meantime that thin open water is going to be warm. And what happens when the spring floods hit places like Midland?