Boardman River Trout Spawning Redd Survey

Transcription

1 Boardman River Trout Spawning Redd Survey Nate Winkler, Biologist Conservation Resource Alliance Traverse Highway, Suite 1180 Traverse City, MI

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3 What?

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5 Spawning and Spawning Cues Photoperiod Temperature Flow/discharge

6 Why? Implications for Management Once methodology is refined, can provide an estimate of adult spawning escapement (Beland 1996; Daubleand Watson 1997; Riemanand Myers 1997; Maxell 1999; Muhlfield et al. 2006) An estimate of population growth rates through analysis of reddquantity data coupled with age data (Isaak and Thurow 2006) Determine spatial and temporal spawning distribution (i.e work windows) Identification of habitat otherwise suitable for spawning but for whatever reason do not have redds associated (Beland 1996)

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11 Methods

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15 Results Became a presence/absence analysis (identification of under-seeded areas) indicating either a lack of or an abundance of spawning habitatthough it is unknown at this point what kind of recruitment is being attained between the two reaches Browns created discrete, textbook redds Brook trout and maybe small brown trout created pots and smears on substrate, sometimes in uncountable numbers of pockmarks on gravelly shoals and sediment with fine wood material In new channel, spawning activity primarily limited to margins of channel. In upper reach, spawning activity occurred throughout the channel (more heterogeneity in bedform and higher amount of wood) Standing up and poling canoe with polarized sunglasses gave great perspective on channel bottom Provided insight regarding niches utilized by trout in which to spawn

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28 Summary of Redds/Pots Observed (preliminary) Upper Section (Forks Campground to Ranch Rudolf Canoe Takeout) Redd Numbers Observed 95 1,194 Pot Numbers Observed numerous x9 Length of Survey (Mileage) 4.54 miles (~23,971 ) Dates Observed (2016) October 21, 24, 28, 29 November 1, 4 Lower Section (Brown Bridge- Upper Riffle to Midway Through Former Impoundment) 44 1, miles (~13,200 ) November 4, 5, 11, 14 December 10

29 Upper Reach (Redds)

30 Upper Reach (Pots)

31 Lower Reach (Redds)

32 Lower Reach (Pots)

33 Recommendations Develop shorter survey reaches to capture temporal spawning behavior, or get more help to survey longer reaches Electrofishareas where our work occurs in relation to spawning habitat to show whether our work provides cover to a variety of lifestages Develop brook trout spawning redd survey protocol (none found in literature) Obtain coverage in November Set up remote cameras in gravel shoals to observe spawning activity and obtain actual numbers of spawners utilizing a given area Perform Wolman pebble counts in areas showing high spawning activity Develop methodology to parse out new reddsfrom old without having to geo-reference each one, especially the smears and pots Develop way to mark individual redds/pots/smears (i.e. colored rocks)

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38 Primary Implications Trout preferred to spawn mainly in riffles very near (large) stones, woody debris, or channel banks as noted by Syrjunenet. al, 2014 Placing large wood and sometimes stone in rivers for habitat and stabilization is our stock and trade Redd surveys can identify where MORE wood, etc. needs to be placed if many other spawning requirements are met Example-if there is no cover but the gravel is appropriate in size Example-where there is too large of material to spawn on (boulders/cobbles), installation of large wood can capture smaller gravels and cause it to form beds of spawning-appropriate material Easily understood concept for funders Another aspect is sedimentation-can provide empirical evidence that excessive sedimentation from road/stream crossings and banks can lead to negative effects on spawning habitat (and vice versa if repaired)

39 THANK YOU VERY MUCH Nate Winkler, Biologist Conservation Resource Alliance Traverse Highway, Suite 1180 Traverse City, MI