ESF



Examining Brook Trout Habitat Use and Distribution in the Ausable River, NY Final Report to the Edna Bailey Sussman Foundation, 2016Carrianne E. Pershyn, M.S. CandidateDepartment of Environmental and Forest BiologyState University of New York College of Environmental Science and Forestry12/01/2016BackgroundBrook trout are the state fish of New York, and have been identified as a species of greatest conservation need. These fish occur in healthy watersheds in areas that will likely have some resistance to climate change, and one of their last strongholds is in the northeastern US. This makes the fish ecologically valuable, as well as the intact habitats in which they live. Brook trout are well loved by eastern anglers, though they are not present in all prized fly angling waters, nor are they the largest species in the rivers of the east. Despite the large proportion of public and large tracts of privately held land in the northeast, brook trout here are facing major human-induced threats, including habitat fragmentation, increasing summer water temperatures, and competition from nonnative and introduced species. The Eastern Brook Trout Joint Venture (EBTJV) and Interactive Catchment Explorer () have identified the eastern and central Adirondack region of New York State as having a high proportion of intact brook trout habitat and also a high probability of continued occupancy with increases in summer temperatures between 2 and 6 degrees Celsius. Management priorities, as laid out by the EBTJV include protection of intact populations, collecting finer scale catchment level data, improving water quality and reducing fragmentation, and building partnerships for research and conservation. It is therefore important to understand the historical and current status of brook trout in these intact watersheds in order to understand and predict their future persistence in this region. IntroductionThe Ausable River in New York’s Adirondack Mountains is home to extraordinary trout fisheries, and anglers from around the world travel to fish these waters. The Ausable watershed is 512 square miles and two branches of the river drain from the interior of the Eastern High Peaks Zone of the Adirondacks, join in the town of Ausable Forks, and flow in a northerly direction where the river spills into Lake Champlain. The headwaters of the east branch Ausable River are located within the Adirondack Mountain Reserve (AMR), a 7,000-acre private reserve with extensive public access created in 1887 to protect scenic lands and mountains of the Adirondacks from lumbering and environmental degradation. The streams and lakes that form these headwaters exhibit pristine habitat that has remained intact since the AMR was created. When the east branch leaves the AMR property, it flows for 28 miles before it meets the confluence with the west branch, and is classified by NYSDEC as recreational. There are extensive public fishing rights on this segment of the river, and DEC stocks the river with brook, brown, and rainbow trout. There are a number of tributary streams that flow into the main stem, all with varying degrees of land use, from protected wild forest to logging and private residential lands. Recent water quality and fish surveys conducted on the waters of the AMR build on previous knowledge of the fisheries in these waters and raised questions on current trends. The Upper Lake has a historic population of brook trout, lake trout, and round whitefish, with the recreational fishery enhanced with stocked brook trout since the 1970s. In the past five years, anglers reported fewer captures of stocked trout, and are instead capturing wild brook trout. The fishing committee and managers at the AMR were interested in understanding the population status of wild fish, and I was subsequently invited to focus my research on these questions. In summer 2015, my field season included a study of the streams on the property, and in 2016, I completed a 14-week internship at the AMR and along the upper east branch, under the supervision of William Curtis and Newell Grant of the AMR and Dr. Neil Ringler at SUNY-ESF. This was a continuation of work completed in 2015, and the data collection continued through the end of October 2016. The data I collected from my 2015 and 2016 field season enables me to both characterize the Ausable Lakes system with a focus on the streams to gain an understanding of population dynamics, habitat, and recruitment to lake populations as well as examining changes in fish populations along the river continuum. Another goal of the project was to estimate the population of the Upper Lake and determine whether fish are wild or stocked. As I studied the streams and lakes on the AMR property, I began to wonder if the streams along the remainder of the east branch had healthy brook trout populations, and how the fish assemblages change overall along the longitudinal gradient of the river. Initially, I hypothesized that 1) the lake population is self-sustaining, consisting mostly of wild fish that use high-quality habitat in the adjoining streams for spawning and juvenile development, 2) that water temperature and pool availability affect the density of juvenile trout in streams, and finally 3) Fish species richness and relative abundance will increase from the headwaters downstream towards the confluence of the east and west branch, with primarily brook trout/sculpin dominated communities in the headwaters, and more diverse communities with less brook trout in downstream habitats.Sampling Sites and MethodsStream Sampling: There are approximately 50 streams that flow into the east branch from the headwaters at Marcy Swamp to the confluence with the west branch at Ausable Forks. I focused my efforts at the AMR on four streams, and I conducted fish community and habitat surveys on 17 other tributaries that drain into the east branch Ausable River downstream from the AMR property (table 1 and fig. 1). Fish were sampled from the confluence with Upper Ausable Lake or the east branch, upstream to the first natural barrier or culvert with Smith-Root backpack electroshocker units, using multiple-pass depletion electrofishing with block nets on 50 to 100 meter stream reaches. All fish captured were identified to species, measured, and salmonids were weighed. In addition, from July to November 2015 and May to October 2016, Onset HOBO Water Temperature Pro v2 Data Loggers were installed in pools of the four streams at AMR (Sawtooth, Otis, Cedar, and Crystal Brooks), and water temperature readings were recorded at 30-minute intervals. Habitat surveys of stream width, depth, velocity, substrate, % canopy cover, and forest type were recorded at 5-10 meter intervals along all study streams. In addition, water quality data were measured at each stream, including water temperature, dissolved oxygen, pH, and conductance. Lake sampling: Previous gill net surveys on Upper Ausable Lake from 2010 to 2015 targeted lake trout, but also caught brook trout and lake whitefish. These surveys showed very low abundances of stocked brook trout (based on fin clips), and subsequently led to a halt in stocking of brook trout in spring 2015. In order to survey the full species assemblage and estimate population density of brook trout in Upper Ausable Lake, a mark-recapture study was conducted using Oneida-style trap nets were set for 48-hour sets at five sites from May 11-19, 2016 and repeated at the same sites on October 10-16, 2016. Nets were set near the mouths of Otis, Crystal, and Cedar Brooks, as well as near two potential spawning sites. All fish were identified to species, counted, and all salmonids were measured and weighed, with scale samples collected for aging purposes, and then were given a temporary caudal fin clip before being released. All marked fish that were recaptured were noted. 36061650036791903084525Figure 1. Stream locationsFigure 1. Stream locationsTable 1. Streams, brook trout presence, and diversity on 21 Ausable tributariesStream NumberStream Name*Brook trout present?Species richness S-W Index of Diversity**1Cedar Brook*Yes10.002Crystal 1*Yes61.193Otis (Lost Brook)*Yes31.004Sawtooth*Yes30.955Deer CreekYes41.096Crystal Brook 2Yes41.177Mossy CascadeYes81.688Flume BrookYes61.449John's BrookNO51.3410Phelps Brook (Beede)Yes61.3811Porter BrookNO61.2412Walton BrookYes31.0413Dart BrookNO71.6314Gulf BrookNO51.3715Cascade BrookYes71.3716Clifford BrookNO81.8317Styles BrookNO61.3818Phelps Brook 2Yes51.0219Lewis BrookYes81.6820Otis Brook 2NO41.2921Rocky BranchYes111.95*denotes 2015 sample event**Shannon-Weiner index of diversity, where values near 0 are representative of low diversity, and values of 1 and above represent sites with high diversity. This index takes species abundance and evenness into account in the sample.Preliminary ResultsIn my 2016 field season, I collected 16,608 fish from Upper Ausable Lake, and 1,037 fish from 17 different tributary streams along the east branch. Of these, brook trout were abundant in the lake, (n=88), abundant in the four AMR tributaries, and present in 10 of 17 study streams outside of AMR property. Table 1 summarizes the stream names and reports brook trout presence-absence, overall species richness or the number of species caught per stream, and the Shannon-Weiner index of diversity, which takes into account the total number of species and their abundances. Within the tributaries, as few as one, and as many as eleven species were caught per stream. Three species of juvenile salmonids were caught across the watershed. At the AMR, only juvenile brook trout were caught, along with slimy sculpin, dace, creek chub, and tessellated darter (Appendix, Fig 2). Species richness increased from upstream to downstream reaches and five additional species were caught in downstream tributaries (common shiner, tessellated darter, white sucker, brown trout, and rainbow trout), and adult trout were caught in these streams. In the trap net surveys of Upper Ausable Lake, a total of 13 species were caught, all native to New York State except for a single rainbow trout. Total catch by season is summarized in Table 2, appendix. In May, 67 brook trout were caught with three recaptures, and 21 brook trout were caught in October (one recapture). The recapture rate of marked brook trout for both sampling events was 4.3%, and my initial estimate of the total population of brook trout in the lake, using the Schnabel estimator for May catch data is 850-900 fish. Based on the low recapture rate, however, I will research alternative methods of reaching a confident population estimate, and comparing them statistically. Of all the brook trout captured in trap net surveys, only two fish had one of the special fin clips given to stocked fish, suggesting the remainder were wild fish. Future WorkPreliminary results show tributaries with healthy populations of juvenile brook trout, and the lake with large adults spawning near stream mouths and in sufficient lake spawning habitat. This supports my first hypothesis that the lake population is self-sustaining, consisting mostly of wild fish that use streams for juvenile development. I will focus next on aging some of my fish using scale samples, in order to create an age structure analysis for stream and lake fish. I will also continue to work with the extensive habitat dataset that I collected to compare brook trout presence and abundance to physical habitat variables such as temperature and pool availability, in order to further explore hypothesis 2. Additionally, I will extend this analysis outside of the AMR, using the physical habitat variables and water quality information collected this fall along the river gradient that I sampled outside of AMR. I will explore the possibility of creating a habitat suitability index for brook trout, and also using multivariate statistical methods to compare sites by habitat variables and local land use (private preserve, logging preserve, actively/recently logged). Finally, I preserved the fin clips from all marked fish, and will consider partnering with someone to do a genetic analysis of these fish to compare relatedness between stream and lake populations and to determine if there are unique strains of native Brook Trout at AMR. The fish communities in tributaries change markedly along the river continuum, and the data presented here support hypothesis 3 that fish species richness and diversity increases from the headwaters downstream. I plan to expand this dataset and analysis to include data from preliminary surveys completed in 2014 on 11 other streams on the AMR property, as well as incorporating historical data from as far back as 1929 (Greeley, 1930) to note how stream communities have changed over time. This far reaching preliminary assessment of the east branch Ausable River allows for future comparisons of fish community and habitat change. This study will provide baseline data that can guide management and future research in the Ausable River watershed. It may allow for the prediction of future conditions under different climate change scenarios, and could also help answer questions about whether the east branch can support wild trout populations. The Edna Bailey Sussman Foundation will continue to be acknowledged in all products of this work, including presentations at conferences, in posters, on the ESF website, in my thesis and published works resulting from this study. AcknowledgementsI am extremely grateful to the Edna Bailey Sussman Foundation for the generous support of my summer internship with the Adirondack Mountain Reserve. I am also appreciative of John Schuler, Roger Roumpf, and Kevin Strait, as well as William Curtis and Newell Grant of the Fishing Committee at AMR, for the resources granted to me to for the access of AMR property and the tremendous opportunity to study their unique and well protected resource. The study was expanded down the length of the east branch with the support of NYSDEC Region 5 staff, the Ausable River Association, and the permission of various private landowners. In addition, the support, guidance, and field assistance of Dr. Margaret Murphy was critical to the completion of my project, and I wouldn’t be involved in this project without her direction and field assistance. Dr. Neil Ringler has been especially supportive of my work and I am extremely grateful at his willingness to allow me to work on my thesis part-time while working as a young professional in the environmental field. Finally, I am grateful to my various field assistants, Margaret, Barbara, Janelle, Nicole, Cassie, and Ben, for their gift of long days in the field and heavy lifting to help me pursue my passion.References and Appended Figures"Department of Environmental Conservation."?Wild, Scenic and Recreational Rivers - NYS Dept. of Environmental Conservation. N.p., n.d. Web. 22 Nov. 2016."Department of Environmental Conservation." Spring 2016 Trout Stocking for Essex County - NYS Dept. of Environmental Conservation. N.p., n.d. Web. 09 Oct. 2016. Carlson, Douglas M., Robert A. Daniels, and Jeremy J. Wright.?Atlas of Inland Fishes of New York. Albany: New York State Museum, 2016. Print. Record 7.Fausch, Kurt D., et al. "Landscapes to riverscapes: bridging the gap between research and conservation of stream fishes a continuous view of the river is needed to understand how processes interacting among scales set the context for stream fishes and their habitat."?BioScience?52.6 (2002): 483-498.Greeley, J.R. 1930. Fishes of the Lake Champlain watershed. Pp 48-87. In: E. Moore(ed.). A Biological Survey of the Champlain watershed. Supplemental to the Twenty-third Annual Report New York State Conservation Department (1929). Albany, NY.Sheldon, A. L. (1968). Species diversity and longitudinal succession in stream fishes.?Ecology, 193-198.Vannote, R. L., Minshall, G. W., Cummins, K. W., Sedell, J. R., & Cushing, C. E. (1980). The river continuum concept. Canadian Journal of Fisheries and Aquatic Sciences, 37(1), 130–137.Table 2. Total trap net catch by species, Upper Ausable Lake, 2016Common nameMayOctoberTotalbrook trout67 (recaptured=3)21 (recaptured=1)88round whitefish112common shiner5,6741,6027,276white sucker2,7244393,163lake chub1,93421,936brown bullhead7201,5432,263longnose dace5530553Pumpkinseed1011,0811,182creek chub227092slimy sculpin17017black nose dace12618n. redbelly dace707rainbow trout011Grand Total11,8324,76616,598Figure 2. Species composition by % abundance from upstream to downstream tributaries (left to right) along the east branch Ausable River.4530098552200Figure 3. Selected photos from field research clockwise from top left: Carrianne electrofishing in summer, view of Upper Ausable Lake, Crystal Brook at AMR, and adult brook trout captured in trap net, October, 2016. ................
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