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Distribution and abundance of Millicoma Dace in the Coos River Basin, Oregon.

This study describes the current distribution of Millicoma Dace (Rhinichthys cataractae) at a subset of sites in the Coos River basin, Oregon. The Millicoma Dace is a form of Longnose Dace (R. cataractae) endemic to the Coos River drainage in southwestern Oregon. Bisson and Reimers (1997) first described the unique characters of Millicoma Dace and nearby Umpqua Dace (R. evermanni) and found large morphological differences between these coastal Longnose Dace and those inhabiting Columbia River tributaries, likely resulting from prolonged geographical isolation. McPhail and Taylor (2009) conducted a phylogeographical maximum likelihood analysis that found that together the Umpqua and Millicoma Dace form a distinctive Oregon coastal clade within the R. cataractae species group (they originated from a common R. cataractae-like ancestor, and the Millicoma Dace likely diverged from the Umpqua Dace). They noted substantial genetic divergence of Millicoma Dace from Umpqua Dace and argued that the Millicoma Dace warrants specific taxonomic status.

A review of fish museum records from the Oregon State University Ichthyology Collection revealed 22 records for Millicoma Dace, collected from 18 locations in the Coos River drainage between 1961 and 1997 (Fig. 1). Based on recent ad hoc sampling, there was concern that the range of this species may have contracted, thereby necessitating a more robust assessment to determine the current species status and whether management action is required. Our objectives were to (1) describe the current distribution of Millicoma Dace at historically occupied sites and a selection of other sites in the Coos River basin; (2) estimate their abundance at occupied sites; and (3) describe current habitat conditions at the sampling locations that may affect capture probabilities.

METHODS

We sampled all 18 locations known to have supported Millicoma Dace historically, from 818 September 2014 (Fig. 2), and 17 additional locations for which there were no historical data, from 28 September to 8 October 2015 (Fig. 3). Historically occupied locations were those associated with verified specimens in the Oregon State University Ichthyology Collection. The additional 17 locations were in tributaries to the South Fork Coos River, upstream of the locations where the fish were historically documented, and were chosen to describe the upstream limits of Millicoma Dace distribution in this subbasin. Additional locations did not include downstream sites, as these lacked riffle habitat and/or were tidally influenced. At each location, we used single-pass backpack electro-fishing to sample a section (length) of stream that included both pool and riffle habitats. We flagged the upstream and downstream boundaries. We placed captured Millicoma Dace in an 18.9-L bucket of aerated stream water until the entire site was sampled. After sampling was completed, we measured each Millicoma Dace to the nearest 1 mm. If Millicoma Dace were collected at a location, we repeated the sampling on 1 more occasion, 1 to 3 d later. If no dace were collected at a site, we repeated the sampling on 2 more occasions. We recorded presence or absence of the other fish species collected, with the exception of Coho Salmon (Oncorhynchus kisutch), which we counted to satisfy National Oceanic and Atmospheric Administration 4(d)permit reporting requirements.

We collected habitat information at each location that we visited. We used a graduated measuring tape or laser rangefinder to measure stream width and sample length. We determined the approximate sample length for each sampling location by multiplying the average wetted stream width by 6, thus scaling the sampling area to the size of the stream channel. At each sampling location we included one or more pool and riffle sequences, to include the representative habitats available at a site. Thus our sample units were 6 times mean wetted stream width because habitat sequences in streams generally occur with a periodicity of approximately 5 to 7 times mean stream width (Gordon and others 1992).

At 3 transects at each site, we determined the site depth using a graduated measuring staff. At each transect we measured depth at 5 equally spaced locations across the channel. We calculated average site depth by summing these measurements and dividing by 15. We determined the dominant substrate type at these same 15 equally spaced points along these transects. At each point (10-cm circle), we recorded whether the majority of the substrate was fines (<0.06 mm), sand (0.06 to 2 mm), gravel (3 to 64 mm), cobble (65 to 256 mm), boulder (>256 mm), or bedrock (native consolidated rock), and assigned the dominant substrate type for the sampling site to the substrate category with the most entries. The substrate types were ocular estimates based on Oregon Department of Fish and Wildlife's stream survey protocols (Moore and others 2007). We estimated the cover provided by large wood and/or large boulders, expressed as a percentage of surface area of the site. We recorded the water temperature ([degrees]C) using a hand-held thermometer. We recorded the Universal Transverse Mercator coordinates for the start and end points at each site using a handheld Global Positioning System, and photographed each sampling location.

To estimate abundance and capture probability for Millicoma Dace at each sampling location, we used an N-mixture or binomial-mixture model, which uses data from spatially replicated populations (sampling sites) with temporally replicated counts of independent individuals (multiple sampling occasions) within a period of closure (assuming no immigration, emigration, or mortality) (Royle 2004; Kery and Schaub 2012). The N-mixture model allows us to estimate abundance, corrected for imperfect capture, using simple counts without individual marking. The capture of Millicoma Dace present at a site was modeled assuming a binomial distribution, whereas the variation in abundance among sites was assumed to follow a negative binomial distribution.

The N-mixture model also allowed us to evaluate evidence for the effect of covariates on both capture probability and abundance at a sample site. We included the following habitat covariates as potential predictors for the capture probability submodel: sample unit length, substrate type, stream temperature, percent cover, average depth, and sample unit area. We also evaluated the following habitat covariates as predictors for the abundance submodel: stream temperature, percent cover, average depth, sample unit length, substrate type, and sample unit area. Continuous covariates were standardized to a mean of zero and standard deviation of one to facilitate model fitting. We evaluated the effect of these variables by systematically fitting alternative submodels with and without the predictors and selected the best model using Akaike's Information Criteria with a small-sample bias adjustment (AICc; Burnham and Anderson 2002). During the model-selection procedure, the same covariate (for example, average depth) was not included simultaneously in both submodels to avoid model convergence and parameter identifiability problems. We calculated 95% confidence limits for the abundance estimates using the asymptotic variance for lambda, which represents the density of occurrences within a time interval, as described by Royle (2004). All models were fit using R package UNMARKED (Fiske and Chandler 2011). Goodness-of-fit of the best supported models was evaluated using a bootstrap goodness-of-fit test as implemented in R package AlCcmodavg (Mazerolle 2014).

RESULTS

We sampled 35 locations in the Coos River drainage and collected Millicoma Dace from 26 of these locations (Fig. 2, Fig. 3). We collected dace from 23 of these locations on both the 1st and 2nd sampling occasions, and the numbers of individuals caught were remarkably consistent across repeat sampling visits at these locations (Appendix).

We collected 11 non-target fish species during our sampling, including Speckled Dace (Rhinichthys osculus), Coastrange Sculpin (Cottus aleuticus), Riffle Sculpin (Cottus gulosus), Rainbow Trout (Oncorhynchus mykiss), Cutthroat Trout (Oncorhynchus clarkii), Coho Salmon (Oncorhynchus kisutch), Threespine Stickleback (Gasterosteus aculeatus), Redside Shiner (Richardsonius balteatus), Tyee Sucker (Catostomus tsiltcoosensis), Pacific Lamprey (Lampetra tridentata), and Western Brook Lamprey (Lampetra riclwrdsoni) (Appendix). No nonnative fishes were collected.

The abundance submodel in the 2 best-approximating N-mixture models included sample length or sample unit area (positive relationship) and the negative binomial dispersion parameter. The capture probability submodel in the 2 best-approximating N-mixture models included bedrock-dominated substrate (negative relationship). Model-averaged estimated capture probabilities for these models were 9% when substrate was bedrock dominated and 28% when substrate was dominated by boulder, cobble, or gravel substrates (Table 1). All other models had a AAIC > 3 (not well supported).

The model-averaged site-abundance estimates ranged from 1 to 560 Millicoma Dace per sampling location, with a total estimated abundance (sum of site estimates) of over 3200 dace at the sites we sampled combined (Table 2). Millicoma Dace were most abundant at sites in the West Fork Millicoma River subbasin.

The bootstrap goodness-of-fit test found that the best- and second-best-approximating models met the statistical distributional assumptions of the N-mixture model with chi square test p values of 0.57 and 0.38, respectively.

DISCUSSION

Our data suggest that Millicoma Dace have very specific habitat requirements. We collected Millicoma Dace only from riffles and rapids, primarily associated with (hiding under) cobble or boulder substrates. Currently, these habitat types are relatively uncommon in the basin. When the Coos River basin was previously logged (1880s-1950s), the timber was transported downstream using water stored behind splash dams. When the spillway of one of these dams was opened to release a large flood of water stored in the upstream reservoir, the stream bed was severely scoured, resulting in low habitat complexity and a stream substrate that was dominated by bedrock. This logging practice resulted in an environmental legacy which has been slow to reverse (Miller 2010). The majority of the stream channels in the study area had low channel gradient and were dominated by pools and glides. However, within these swift-water habitats, Millicoma Dace were widespread and relatively abundant at the site level throughout their historical range. We also documented a broader species distribution than historical records suggested. We only found Millicoma Dace associated with native fishes; we did not collect any nonnative fish during our surveys. Their secretive behavior of hiding under cobble and boulders, coupled with the relative rarity of swift-water habitats, is likely responsible for the prior perceived rarity of this species. Additionally, complex stream habitats with large wood and coarse substrate are currently uncommon in the basin, and many of the riffles and rapids in the drainage are dominated by bedrock. We typically captured Millicoma Dace from these habitats only in areas where cobble or boulders were present. Thus we believe that Millicoma Dace, which are strongly cover oriented, were probably more abundant historically.

We used N-mixture models to estimate Millicoma Dace abundance at the sampling locations. This type of model has most commonly been used with bird counts (Kery 2008; Kery and Royle 2010), but never, to our knowledge, has it been used with small, stream-dwelling fish-count data. The appeal of these models is the ability to estimate abundance and capture probability from sparse count data. These models assume that: (1) each sample site is closed between visits (no immigration, emigration, birth, or death); (2) capture probability is constant for all individuals present during a visit to a sample site; (3) the capture of individuals at a sample site is independent of others at that site; (4) the distribution of animals among sample sites is adequately described by the chosen parametric distribution (negative binomial); and (5) there are no false positives such as double counts or species misidentification. We believe that we met these assumptions. We conducted our surveys over a very short time period, thus meeting the assumption of closure. We collected and measured each Millicoma Dace during a single sample event, thus eliminating the possibility of double counting individuals during a sampling visit. The goodness-of-fit tests showed that we met the statistical distribution assumptions. Additionally, the accuracy of the N-mixture model depends on the number of visits, true capture probability, true abundance, and whether or not the closure assumptions have been met. A recent evaluation of the accuracy of the N-mixture model under various abundances, capture probabilities, and violations of assumptions found that N-mixture models are generally unbiased when the variation in counts (catches) between visits at a site is much less than the variation among sites (Duarte and Peterson, in review). The variation in catches between our site visits was <30% of the variation among sites, which suggests that the dace abundance estimates are likely unbiased.

The electrofishing capture probabilities for Millicoma Dace from our study ranged from 9% over bedrock substrates to 28% over non-bedrock substrates. These estimates were similar to capture probabilities reported by Peterson and others 2004 for stream-dwelling salmonids (mean 28%; range 20-57%) using electrofishing, by Price and Peterson (2010) for catfishes (3%), darters (7%), sculpins (11%), minnows (17%), and suckers (29%) using electrofishing, by Peterson and others (2015) for minnows (2326%) using minnow traps, but less than those reported by Dauwalter and Fisher (2007) for Smallmouth Bass (Micropterus dolomieu; 53%) using electrofishing.

A major limitation of our study is the broad confidence intervals around our abundance estimates. Although it would involve additional sampling effort, we could have increased the precision of the capture probability and abundance estimates with additional site visits (sampling occasions). This lack of precision will affect our ability to detect trends in abundance over time if/when sites are resampled in subsequent years. Additionally, the model predicts that dace were present at all 35 locations (abundance estimates greater than 0), even at sites where no dace were collected. However, note that at the 12 locations where no dace were collected, the 95% confidence limits include 0.

In summary, we conclude that despite being widespread, Millicoma Dace have very specific habitat requirements (swift-water habitats with coarse substrates) and are thus patchily distributed because of the relative rarity of these habitats in the basin. We suggest periodic surveys to assess the future status and trends of this species. These surveys would benefit by incorporating available habitat surveys and targeting sites within stream segments that have higher amounts of riffle habitat. Additionally, managers can use our model to identify, protect, or enhance habitats in the Coos River basin that Millicoma Dace require. If restoration projects are implemented in the basin to increase the quantity and quality of habitat for Millicoma Dace, we suggest addition of coarse substrates (cobble and boulders) to swift-water stream segments dominated by bedrock, or the addition of large wood to trap and hold these coarse substrates. Increasing the amount of physical structure in swift water habitats will also likely benefit other native fish species in this basin.

ACKNOWLEDGMENTS

We thank C Claire, J Feola, M Gray, J Heinrich, J Jackson, C Larochelle, D Markle, S Messerle, M Mims, A Pickens, H Verduyn, and G Vonderohe for field assistance, and B Bangs and E Gilbert for GIS assistance. The Bureau of Land Management provided funding for this study in 2015. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US Government. The Oregon Cooperative Fish and Wildlife Research Unit is jointly sponsored by the US Geological Survey, the US Fish and Wildlife Service, the Oregon Department of Fish and Wildlife, Oregon State University, and the Wildlife Management Institute.

LITERATURE CITED

BISSON PA, REIMERS PE. 1977. Geographic variation among Pacific Northwest populations of Longnose Dace, Rhinichthys cataractae. Copeia 1977:518-522.

BURNHAM KP, ANDERSON DR. 2002. Model selection and multimodel inference: A practical-theoretic approach, second edition. New York, NY: SpringerVerlag. 353 p.

DAUWALTER DC, FISHER WL. 2007. Electrofishing capture probability of Smallmouth Bass in streams. North American Journal of Fisheries Management 27:162171.

FISKE I, CHANDLER R. 2011. Unmarked: An R package for fitting hierarchical models of wildlife occurrence and abundance. Journal of Statistical Software 43:123.

GORDON ND, MCMAHON TA, FINLAYSON BL. 1992. Stream hydrology: An introduction for ecologists. West Sussex, England: Wiley and Sons Ltd. 429 p.

KERY M. 2008. Estimating abundance from bird counts: Binomial mixture models uncover complex covariate relationships. Auk 125:336-345.

KERY M, Royle JA. 2010. Hierarchical modeling and estimation of abundance and population trends in metapopulation designs. Journal of Animal Ecology 79:453-461.

KERY M, SCHAUB M. 2012. Bayesian population analysis using WinBUGS--a hierarchical perspective. Burlington, VT: Elsevier Press. 560 p.

MAZEROLLE MJ. 2014. AICcmodavg: Model selection and multimodel inference based on (Q)AIC(c). R package version 2.00. http://CRAN.R-project.org/ package=AICcmodavg. Accessed 10 March 2016.

MCPHAIL, JD, TAYLOR EB. 2009. Phylogeography of the Longnose Dace (Rhinichthys cataractae) species group in northwestern North America--the origin and evolution of the Umpqua and Millicoma Dace. Canadian Journal of Zoology 87:491-497.

MILLER RR. 2010. Is the past present? Historical splashdam mapping and stream disturbance detection in the Oregon Coastal Province [thesis]. Corvallis, OR: Oregon State University. 110 p.

* MOORE KMS, JONES KK, DAMBACHER JM. 2008. Methods for stream habitat surveys: Aquatic Inventories Project. Oregon Department of Fish and Wildlife Information Report 2007-01, Corvallis, OR. 67 p. Available from Oregon Department of Fish and Wildlife, 28655 Highway 34, Corvallis, OR 97333.

PETERSON JT, THUROW RF, GUZEVICH JW. 2004. An evaluation of multipass electrofishing for estimating the abundance of stream-dwelling salmonids. Transactions of the American Fisheries Society 133:462-475.

PETERSON JT, SCHEERER PS, CLEMENTS S. 2015. An evaluation of the efficiency of minnow traps for estimating the abundance of minnows in desert spring systems. North American Journal of Fisheries Management 35:491-502.

PRICE AL, PETERSON JT. 2010. Estimation and modeling of electrofishing and seining capture efficiency for fishes in wadeable warmwater streams. North American Journal of Fisheries Management 30: 481-498.

R DEVELOPMENT CORE TEAM. 2008. R: A language and environment for statistical computing, http:// www.R-project.org. Accessed 10 March 2016.

ROYLE JA. 2004. N-Mixture models for estimating population size from spatially replicated counts. Biometrics 60:108-115.

Submitted 10 May 2016, accepted 27 August 2016.

Corresponding Editor: James W Orr.

* Unpublished
APPENDIX. Fish catch and habitat details for Millicoma Dace sampling
locations. Fish codes: MD = Millicoma Dace; SD = Speckled Dace; CRS =
Coastrange Sculpin; RT = Rainbow Trout; RS = Riffle Sculpin; CT =
Cutthroat Trout; CO = Coho Salmon; SKB = Threespine Stickleback; RSS
= Redside Shiner; SU = Largescale Sucker; LAM = lamprey ammocoete.
See text for scientific names. Note, only 1 electrofishing pass
(presence-absence) was conducted at EF Millicoma River 5, Cox Creek,
and Williams River 10. EF = East Fork, WF = West Fork, SF = South
Fork.

                                                                Shock
                                              Water             time
Location                Subbasin           temperature   Pass   (min)

EF Millicoma River 1    Millicoma River       15.5        1      50
                        Millicoma River       14.5        2      50
EF Millicoma River 2    Millicoma River       16.0        1      45
                        Millicoma River       14.0        2      43
EF Millicoma River 3    Millicoma River       16.0        1      21
                        Millicoma River       16.0        2      27
EF Millicoma River 4    Millicoma River       15.0        1      43
                        Millicoma River       14.0        2      50
                        Millicoma River       14.0        3      46
EF Millicoma River 5    Millicoma River       13.0        1      20
WF Millicoma River 1    Millicoma River       14.0        1      27
                        Millicoma River       15.0        2      29
WF Millicoma River 2    Millicoma River       16.0        1      30
                        Millicoma River       15.5        2      26
WF Millicoma River 3    Millicoma River       16.5        1      43
                        Millicoma River       16.5        2      58
WF Millicoma River 4    Millicoma River       14.0        1      37
                        Millicoma River       16.0        2      28
WF Millicoma River 5    Millicoma River       14.5        1      25
                        Millicoma River       13.0        2      23
WF Millicoma River 6    Millicoma River       14.0        1      44
                        Millicoma River       13.0        2      44
                        Millicoma River       13.0        3      44
Fall Creek              SF Coos River         15.0        1      45
                        SF Coos River         15.5        2      45
SF Coos River 1         SF Coos River         22.0        1      40
                        SF Coos River         22.0        2      45
SF Coos River 2         SF Coos River         20.5        1      40
                        SF Coos River         20.5        2      43
Cox Creek               SF Coos River         15.5        1      30
Tioga Creek 1           SF Coos River         17.5        1      45
                        SF Coos River         17.0        2      52
Tioga Creek 2           SF Coos River         15.5        1      35
                        SF Coos River         16.0        2      33
Tioga Creek 3           SF Coos River         12.0        1      26
                        SF Coos River         10.0        2      31
Tioga Creek 4           SF Coos River         16.0        1      45
                        SF Coos River         15.0        2      44
Tioga Creek 5           SF Coos River         11.5        1      30
                        SF Coos River         11.0        2      27
Tioga Creek 6           SF Coos River         11.5        1      35
                        SF Coos River         11.0        2      35
                        SF Coos River         11.5        3      33
Tioga Creek 7           SF Coos River         12.0        1      25
                        SF Coos River         11.0        2      21
                        SF Coos River         11.0        3      22
Tioga Creek 8           SF Coos River         13.0        1      18
                        SF Coos River         12.0        2      18
                        SF Coos River         12.0        3      16
Tioga Creek 9           SF Coos River         14.0        1      14
                        SF Coos River         14.0        2      16
                        SF Coos River         14.5        3      15
Tioga Creek 10          SF Coos River         12.0        1      18
                        SF Coos River         12.0        2      17
                        SF Coos River         12.0        3      15
Williams River 1        SF Coos River         13.0        1      52
                        SF Coos River         13.0        2      62
Williams River 2        SF Coos River         13.0        1      50
                        SF Coos River         12.5        2      45
Williams River 3        SF Coos River         13.0        1      64
                        SF Coos River         13.0        2      67
Williams River 4        SF Coos River         12.5        1      45
                        SF Coos River         11.0        2      42
Williams River 5        SF Coos River         12.0        1      60
                        SF Coos River         12.5        2      66
Williams River 6        SF Coos River         12.5        1      60
                        SF Coos River         13.0        2      62
Williams River 7        SF Coos River         13.0        1      50
                        SF Coos River         13.0        2      61
Williams River 8        SF Coos River         12.0        1      57
                        SF Coos River         11.5        2      72
Williams River 9        SF Coos River         12.0        1      24
                        SF Coos River         12.0        2      28
                        SF Coos River         12.0        3      24
Williams River 10       SF Coos River         11.0        1      22

                                           Length   Width    Dominant
Location                Subbasin            (m)      (m)     substrate

EF Millicoma River 1    Millicoma River      72       12      bedrock
                        Millicoma River      72       12      bedrock
EF Millicoma River 2    Millicoma River      84      14.1     bedrock
                        Millicoma River      84      14.1     bedrock
EF Millicoma River 3    Millicoma River     63.8     7.2      bedrock
                        Millicoma River     63.8     7.2      bedrock
EF Millicoma River 4    Millicoma River     54.2     7.5      bedrock
                        Millicoma River     54.2     7.5      bedrock
                        Millicoma River     54.2     7.5      bedrock
EF Millicoma River 5    Millicoma River      50       10      bedrock
WF Millicoma River 1    Millicoma River     81.4      16      bedrock
                        Millicoma River     81.4      16      bedrock
WF Millicoma River 2    Millicoma River     64.6      7       bedrock
                        Millicoma River     64.6      7       bedrock
WF Millicoma River 3    Millicoma River      83       12      bedrock
                        Millicoma River      83       12      bedrock
WF Millicoma River 4    Millicoma River      75      12.5     bedrock
                        Millicoma River      75      12.5     bedrock
WF Millicoma River 5    Millicoma River      60       10      bedrock
                        Millicoma River      60       10      bedrock
WF Millicoma River 6    Millicoma River      72      5.5      bedrock
                        Millicoma River      72      5.5      bedrock
                        Millicoma River      72      5.5      bedrock
Fall Creek              SF Coos River       48.6     8.1      boulder
                        SF Coos River       48.6     8.1      boulder
SF Coos River 1         SF Coos River        64       28      bedrock
                        SF Coos River        64       28      bedrock
SF Coos River 2         SF Coos River        66       11      gravel
                        SF Coos River        66       11      gravel
Cox Creek               SF Coos River       36.6     6.1      bedrock
Tioga Creek 1           SF Coos River       55.2     9.2      cobble
                        SF Coos River       55.2     9.2      cobble
Tioga Creek 2           SF Coos River        48       8       cobble
                        SF Coos River        48       8       cobble
Tioga Creek 3           SF Coos River       39.3     5.8      cobble
                        SF Coos River       39.3     5.8      cobble
Tioga Creek 4           SF Coos River        54       9       gravel
                        SF Coos River        54       9       gravel
Tioga Creek 5           SF Coos River       43.6      5       gravel
                        SF Coos River       43.6      5       gravel
Tioga Creek 6           SF Coos River       42.7     5.4      gravel
                        SF Coos River       42.7     5.4      gravel
                        SF Coos River       42.7     5.4      gravel
Tioga Creek 7           SF Coos River        34      5.2      gravel
                        SF Coos River        34      5.2      gravel
                        SF Coos River        34      5.2      gravel
Tioga Creek 8           SF Coos River        44      6.4      bedrock
                        SF Coos River        44      6.4      bedrock
                        SF Coos River        44      6.4      bedrock
Tioga Creek 9           SF Coos River        40      6.9      boulder
                        SF Coos River        40      6.9      boulder
                        SF Coos River        40      6.9      boulder
Tioga Creek 10          SF Coos River       38.8     5.4      cobble
                        SF Coos River       38.8     5.4      cobble
                        SF Coos River       38.8     5.4      cobble
Williams River 1        SF Coos River        54      8.9      cobble
                        SF Coos River        54      8.9      cobble
Williams River 2        SF Coos River       38.6     7.5      boulder
                        SF Coos River       38.6     7.5      boulder
Williams River 3        SF Coos River        55      7.9      bedrock
                        SF Coos River        55      7.9      bedrock
Williams River 4        SF Coos River        64      10.2     cobble
                        SF Coos River        64      10.2     cobble
Williams River 5        SF Coos River        72       19      cobble
                        SF Coos River        72       19      cobble
Williams River 6        SF Coos River        57      7.7      gravel
                        SF Coos River        57      7.7      gravel
Williams River 7        SF Coos River        48      6.3      cobble
                        SF Coos River        48      6.3      cobble
Williams River 8        SF Coos River        54      7.8      boulder
                        SF Coos River        54      7.8      boulder
Williams River 9        SF Coos River       44.5     7.3      gravel
                        SF Coos River       44.5     7.3      gravel
                        SF Coos River       44.5     7.3      gravel
Williams River 10       SF Coos River        55      4.4      cobble

                                           Average   Cover
Location                Subbasin            depth     (%)    MD    SD

EF Millicoma River 1    Millicoma River     0.22      20     19     x
                        Millicoma River     0.22      20     19     x
EF Millicoma River 2    Millicoma River     0.18      20     20     x
                        Millicoma River     0.18      20     14     x
EF Millicoma River 3    Millicoma River     0.18      20      4
                        Millicoma River     0.18      20      3     x
EF Millicoma River 4    Millicoma River     0.12      20      0     x
                        Millicoma River     0.12      20      2     x
                        Millicoma River     0.12      20      8     x
EF Millicoma River 5    Millicoma River     0.11      10      0
WF Millicoma River 1    Millicoma River     0.08      20     13     x
                        Millicoma River     0.08      20     22     x
WF Millicoma River 2    Millicoma River     0.32      20     12     x
                        Millicoma River     0.32      20     13     x
WF Millicoma River 3    Millicoma River     0.16      10     36     x
                        Millicoma River     0.16      10     43     x
WF Millicoma River 4    Millicoma River      0.1      20     10     x
                        Millicoma River      0.1      20     21     x
WF Millicoma River 5    Millicoma River     0.09      20      9     x
                        Millicoma River     0.09      20      4     x
WF Millicoma River 6    Millicoma River     0.13      20      0     x
                        Millicoma River     0.13      20      0     x
                        Millicoma River     0.13      20      3     x
Fall Creek              SF Coos River       0.15      20     13     x
                        SF Coos River       0.15      20     14     x
SF Coos River 1         SF Coos River       0.21      10     20     x
                        SF Coos River       0.21      10     16     x
SF Coos River 2         SF Coos River       0.11       5     33     x
                        SF Coos River       0.11       5     27     x
Cox Creek               SF Coos River        0.1       5      0
Tioga Creek 1           SF Coos River       0.09      25     16     x
                        SF Coos River       0.09      25     18     x
Tioga Creek 2           SF Coos River       0.16      20      1     x
                        SF Coos River       0.16      20      4     x
Tioga Creek 3           SF Coos River       0.13      10      4     x
                        SF Coos River       0.13      10      2     x
Tioga Creek 4           SF Coos River       0.08      10      4     x
                        SF Coos River       0.08      10      6     x
Tioga Creek 5           SF Coos River       0.07      10      1     x
                        SF Coos River       0.07      10      0     x
Tioga Creek 6           SF Coos River       0.17      10      0     x
                        SF Coos River       0.17      10      0     x
                        SF Coos River       0.17      10      0     x
Tioga Creek 7           SF Coos River       0.08       5      0     x
                        SF Coos River       0.08       5      0     x
                        SF Coos River       0.08       5      0     x
Tioga Creek 8           SF Coos River        0.1      10      0
                        SF Coos River        0.1      10      0
                        SF Coos River        0.1      10      0
Tioga Creek 9           SF Coos River       0.12      50      0     x
                        SF Coos River       0.12      50      0     x
                        SF Coos River       0.12      50      0     x
Tioga Creek 10          SF Coos River        0.1      25      0
                        SF Coos River        0.1      25      0
                        SF Coos River        0.1      25      0
Williams River 1        SF Coos River       0.08       5     23     x
                        SF Coos River       0.08       5     17     x
Williams River 2        SF Coos River       0.14      10     23     x
                        SF Coos River       0.14      10     12     x
Williams River 3        SF Coos River        0.1       5     26     x
                        SF Coos River        0.1       5     19     x
Williams River 4        SF Coos River       0.09       5      7     x
                        SF Coos River       0.09       5      9     x
Williams River 5        SF Coos River       0.12      10     15     x
                        SF Coos River       0.12      10     12     x
Williams River 6        SF Coos River       0.07       5     13     x
                        SF Coos River       0.07       5     13     x
Williams River 7        SF Coos River        0.1      10     15     x
                        SF Coos River        0.1      10     18     x
Williams River 8        SF Coos River       0.07      50      9     x
                        SF Coos River       0.07      50     11     x
Williams River 9        SF Coos River        0.1      10      0     x
                        SF Coos River        0.1      10      0     x
                        SF Coos River        0.1      10      0     x
Williams River 10       SF Coos River       0.18      10      0

Location                Subbasin           CRS   RS    RT    CT    CO

EF Millicoma River 1    Millicoma River     x     x     x
                        Millicoma River     x     x     x
EF Millicoma River 2    Millicoma River           x           x
                        Millicoma River           x           x
EF Millicoma River 3    Millicoma River     x           x
                        Millicoma River     x           x
EF Millicoma River 4    Millicoma River                 x
                        Millicoma River           x     x
                        Millicoma River           x     x
EF Millicoma River 5    Millicoma River           x     x
WF Millicoma River 1    Millicoma River     x     x     x
                        Millicoma River     x     x     x
WF Millicoma River 2    Millicoma River           x     x           2
                        Millicoma River     x     x     x
WF Millicoma River 3    Millicoma River           x     x           1
                        Millicoma River     x     x     x           3
WF Millicoma River 4    Millicoma River           x     x
                        Millicoma River           x     x
WF Millicoma River 5    Millicoma River           x     x
                        Millicoma River           x     x
WF Millicoma River 6    Millicoma River           x     x           1
                        Millicoma River     x     x     x
                        Millicoma River     x     x     x
Fall Creek              SF Coos River       x     x                 2
                        SF Coos River             x           x     1
SF Coos River 1         SF Coos River             x           x
                        SF Coos River             x           x
SF Coos River 2         SF Coos River                         x     1
                        SF Coos River                         x
Cox Creek               SF Coos River                         x
Tioga Creek 1           SF Coos River             x           x
                        SF Coos River             x           x
Tioga Creek 2           SF Coos River             x                 2
                        SF Coos River             x
Tioga Creek 3           SF Coos River       x           x
                        SF Coos River       x           x
Tioga Creek 4           SF Coos River       x     x
                        SF Coos River       x     x                 2
Tioga Creek 5           SF Coos River       x           x           0
                        SF Coos River                   x           1
Tioga Creek 6           SF Coos River       x           x           0
                        SF Coos River       x                       1
                        SF Coos River       x                       0
Tioga Creek 7           SF Coos River                   x           3
                        SF Coos River                   x           7
                        SF Coos River                   x           5
Tioga Creek 8           SF Coos River                   x     x     1
                        SF Coos River                   x     x     0
                        SF Coos River                   x     x     0
Tioga Creek 9           SF Coos River       x           x           1
                        SF Coos River       x           x           1
                        SF Coos River       x           x           0
Tioga Creek 10          SF Coos River                   x     x     3
                        SF Coos River                   x     x     2
                        SF Coos River                   x     x     1
Williams River 1        SF Coos River       x           x           0
                        SF Coos River       x           x           0
Williams River 2        SF Coos River       x                       0
                        SF Coos River       x                       0
Williams River 3        SF Coos River       x           x           0
                        SF Coos River       x           x           0
Williams River 4        SF Coos River       x     x     x           0
                        SF Coos River       x           x           0
Williams River 5        SF Coos River       x           x           0
                        SF Coos River       x           x           0
Williams River 6        SF Coos River       x           x           1
                        SF Coos River       x           x           0
Williams River 7        SF Coos River       x           x     x     1
                        SF Coos River       x           x           2
Williams River 8        SF Coos River       x           x           2
                        SF Coos River       x           x           1
Williams River 9        SF Coos River       x           x           3
                        SF Coos River       x           x           2
                        SF Coos River       x           x           2
Williams River 10       SF Coos River       x           x           2

Location                Subbasin           SKB   RSS   SU    LAM

EF Millicoma River 1    Millicoma River
                        Millicoma River
EF Millicoma River 2    Millicoma River
                        Millicoma River                 x     x
EF Millicoma River 3    Millicoma River
                        Millicoma River
EF Millicoma River 4    Millicoma River
                        Millicoma River
                        Millicoma River
EF Millicoma River 5    Millicoma River
WF Millicoma River 1    Millicoma River
                        Millicoma River
WF Millicoma River 2    Millicoma River
                        Millicoma River
WF Millicoma River 3    Millicoma River
                        Millicoma River
WF Millicoma River 4    Millicoma River
                        Millicoma River
WF Millicoma River 5    Millicoma River                       x
                        Millicoma River                       x
WF Millicoma River 6    Millicoma River
                        Millicoma River
                        Millicoma River
Fall Creek              SF Coos River             x
                        SF Coos River             x
SF Coos River 1         SF Coos River             x
                        SF Coos River             x
SF Coos River 2         SF Coos River             x
                        SF Coos River       x     x
Cox Creek               SF Coos River
Tioga Creek 1           SF Coos River       x     x
                        SF Coos River             x
Tioga Creek 2           SF Coos River
                        SF Coos River
Tioga Creek 3           SF Coos River
                        SF Coos River
Tioga Creek 4           SF Coos River                   x
                        SF Coos River                   x
Tioga Creek 5           SF Coos River
                        SF Coos River                   x
Tioga Creek 6           SF Coos River                   x
                        SF Coos River                   x
                        SF Coos River
Tioga Creek 7           SF Coos River
                        SF Coos River
                        SF Coos River
Tioga Creek 8           SF Coos River
                        SF Coos River
                        SF Coos River
Tioga Creek 9           SF Coos River
                        SF Coos River
                        SF Coos River
Tioga Creek 10          SF Coos River
                        SF Coos River
                        SF Coos River
Williams River 1        SF Coos River       x
                        SF Coos River       x           x
Williams River 2        SF Coos River       x           x
                        SF Coos River       x
Williams River 3        SF Coos River       x
                        SF Coos River       x
Williams River 4        SF Coos River
                        SF Coos River
Williams River 5        SF Coos River
                        SF Coos River
Williams River 6        SF Coos River                   x
                        SF Coos River
Williams River 7        SF Coos River
                        SF Coos River
Williams River 8        SF Coos River
                        SF Coos River
Williams River 9        SF Coos River
                        SF Coos River
                        SF Coos River
Williams River 10       SF Coos River


Paul D Scheerer

Oregon Department of Fish and Wildlife, 28655 Highway 34, Corvallis, OR 97333 USA; paul.scheerer[R]

oregonstate.edu

James T Peterson

US Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, 104 Nash Hall, Oregon State

University, Corvallis, OR 97331 USA

Shaun Clements

Oregon Department of Fish and Wildlife, 28655 Highway 34, Corvallis, OR 97333 USA

Caption: FIGURE 1. Approximate historical sampling locations for Millicoma Dace (Rhinichthys cataractae) from specimens in the Oregon State University Ichthyology Collection.

Caption: FIGURE 2. Sites where Millicoma Dace (Rhinichthys cataractae) were detected (black circles) and not detected (gray circles) in 2014. Site numbers refer to those listed in Table 2 for each tributary.

Caption: FIGURE 3. Sites where Millicoma Dace (Rhinichthys cataractae) were detected (black circles) and not detected (gray circles) in 2015, upstream of historical sites. Site numbers refer to those listed in Table 2 for each tributary. Note, we included Tioga Creek sites 1, 2, and 4 on this map, which were sampled in 2014.
TABLE 1. N-Mixture model parameter estimates, standard errors (SE),
and 95% confidence limits (CL).

Parameter                        Estimate   SE       Lower     Upper
                                                     95% CL    95% CL
Best-approximating model [DELTA]AICc = 0)
  Abundance submodel (log scale)
    Intercept                    3.0461     0.5846   2.0129    4.2338
    Sample length                1.6121     0.3672   0.9500    2.3930
    Dispersion                   1.5812     0.3106   1.0866    2.2875
  Capture probability submodel (logit scale)
    Intercept                    -0.9134    0.7519   -2.3893   0.4301
    Bedrock                      -1.5422    0.6265   -2.8197   -0.3540
Second-best-approximating model AAICc = 1.74)
  Abundance submodel (log scale)
    Intercept                    2.9112     0.5349   1.9547    4.0937
    Site area                    1.2413     0.3464   0.6026    1.9739
    Dispersion                   1.745      0.3373   1.2056    2.5219
  Capture probability submodel (logit scale)
    Intercept                    -1.0127    0.6930   -2.6240   0.1561
    Bedrock                      -0.9268    0.4876   -1.8893   0.0051
  Model-averaged estimates of capture probability
    Not bedrock                  0.2804     0.1388   0.0919    0.6001
    Bedrock                      0.0908     0.0408   0.0365    0.2084

TABLE 2. N-mixture model averaged estimates of Millicoma Dace
(Rhinichthys cataractae) abundance, standard deviation (SD), and 95%
confidence limits (CL). EF = East Fork, WF = West Fork, SF = South
Fork.

Site name              Estimate      SD    Lower    Upper
                                          95% CL   95% CL

EF Millicoma River 1        268   203.0       67      788
EF Millicoma River 2        243   180.2       60      721
EF Millicoma River 3         50    43.7       10      165
EF Millicoma River 4         48    37.5       12      147
EF Millicoma River 5          6     8.8        0       29
WF Millicoma River 1        250   187.7       62      721
WF Millicoma River 2        173   133.4       42      523
WF Millicoma River 3        560   412.9      144     1592
WF Millicoma River 4        221   165.6       55      664
WF Millicoma River 5         89    68.1       21      272
WF Millicoma River 6         18    15.9        4       61
SF Coos River 1             253   189.7       63      758
SF Coos River 2             132    96.3       50      386
Cox Creek                     3     5.7        0       18
Fall Creek                   58    43.2       21      173
Hoga Creek 1                 74    54.5       27      217
Tioga Creek 2                12     9.5        4       37
Tioga Creek 3                13    10.3        4       40
Tioga Creek 4                22    17.3        7       68
Tioga Creek 5                 3     3.3        1       11
Hoga Creek 6                  1     1.6        0        4
Hoga Creek 7                  1     1.4        0        4
Tioga Creek 8                 2     3.6        0       11
Tioga Creek 9                 1     1.4        0        4
Tioga Creek 10                1     1.4        0        4
Williams River 1             88    65.2       33      256
Williams River 2             77    56.2       30      226
Williams River 3            311   227.5       79      904
Williams River 4             35    27.0       12      107
Williams River 5             60    44.7       22      179
Williams River 6             57    42.4       21      168
Williams River 7             72    52.9       26      212
Williams River 8             43    32.4       16      130
Williams River 9              1     1.5        0        4
Williams River 10             3     4.4        0       14
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Article Details
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Author:Scheerer, Paul D.; Peterson, James T.; Clements, Shaun
Publication:Northwestern Naturalist: A Journal of Vertebrate Biology
Article Type:Report
Geographic Code:1USA
Date:Mar 22, 2017
Words:6487
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