David A. Schmetterling

Seasonal movements of fluvial westslope cutthroat trout in the Blackfoot River drainage, Montana

Abstract I studied the seasonal movements and habitat use of fluvial westslope cutthroat trout Oncorhynchus clarki lewisi from 1997 to 1999 in the Blackfoot River drainage in western Montana to help guide restoration efforts and lead to a better understanding of this subspecies. Of 22 radio-tagged fish, 16 migrated during the spawning period (mean length, 371 mm). Ten of the 22 fish were tracked over a 2-year period, and 2 of these fish migrated in both 1997 and 1998. Migrations to tributaries occurred during the rising limb of the hydrograph in both years and lasted for an average of 10 d (range, 1–14 d) in 1998. Migratory fish moved both upriver and downriver to reach spawning tributaries during both years. In 1998 the mean distance traveled to access tributaries was 31 km (range, 3–72 km). Fish staged at the mouths of tributaries for up to 14 d before entering near the peak in the hydrograph. They remained in tributaries for an average of 27 d (range, 4–63 d), the duration varying with size of tributar...

Summer Movements within the Fish Community of a Small Montane Stream

Abstract We studied movements by fishes in Chamberlain Creek, Montana, from 24 July to 16 August 2001. We operated six weirs with two-way traps and one additional upstream trap, separated by 14–1,596 m, to quantify the timing, direction, and distance of movements and to estimate fish populations in the study reaches. We trapped and marked 567 fish of seven species, including 368 westslope cutthroat trout Oncorhynchus clarkii lewisi and 172 sculpin (slimy sculpin Cottus cognatus and an unidentified species similar to mottled sculpin C. bairdii). We recaptured 173 westslope cutthroat trout and detected net movements as long as 1,581 m (median, 91 m). Bidirectional movements for 116 westslope cutthroat trout ranged from less than 18 to more than 1,581 m (median, 64 m). Sculpin moved as far as 209 m (median, 26 m). We estimate that 14% of sculpin and 48% of westslope cutthroat trout were mobile during the study. We captured all species more frequently at night or twilight (n = 296) than during the day (n = 83...

Reconnecting a Fragmented River: Movements of Westslope Cutthroat Trout and Bull Trout after Transport Upstream of Milltown Dam, Montana

Abstract Milltown Dam annually impedes the migration of 11 fish species, and data suggest that fish that migrate to the dam do not spawn once their migration is impeded. Densities of westslope cutthroat trout Oncorhynchus clarki lewisi and bull trout Salvelinus confluentus are low near Milltown Dam, but their annual presence at the dam suggests the potential to reestablish fluvial life history forms and enhance local or upriver populations. Operating a fish trap at Milltown Dam in 2000 and 2001, I captured westslope cutthroat trout and bull trout, implanted 42 with radio transmitters, and transported them upstream of Milltown Dam. I monitored the implanted fish to determine posttransport movements and spawning. Most of the fish captured continued upstream to spawn, and many migrations exceeded 100 km after transport. Several fish encountered pre- or postspawning problems, including entrainment in irrigation ditches, predation by nonnative northern pike Esox lucius, angler harvest, and fallback over Millto...

Redd Characteristics of Fluvial Westslope Cutthroat Trout in Four Tributaries to the Blackfoot River, Montana

Abstract Westslope cutthroat trout Oncorhynchus clarki lewisi spawned in May 1998 as flows subsided after peak discharges in four tributaries to the Blackfoot River in western Montana. For 32 redds, water depths averaged 12.9 cm and velocities averaged 56 cm/s. Spawning occurred in substrate sizes ranging from 6 to 110 mm. Redd pits averaged 0.61 m long, and the total redd length averaged 1.34 m. Of the redds studied, 75% were upstream of the tailout of glides, 21% were found in riffles, and the remaining 9% were near the tailout of midchannel scour pools. Despite differences in stream characteristics, redd attributes were remarkably similar among streams. I found a wider variability in fluvial westslope cutthroat trout spawning habits than was previously reported for Montana.

Comparison of Surgical Staples and Silk Sutures for Closing Incisions in Rainbow Trout

Abstract The effects of surgical staples on incision healing and long-term fish growth are largely unknown. To determine these effects, we implanted 50 rainbow trout Oncorhynchus mykiss with dummy radio transmitters, closed incisions with either silk sutures or steel staples, and monitored these fish for 6 months. Surgeries with staples were performed twice as fast as suture surgeries. Incisions closed with staples had three times less epidermal infection than sutured incisions. Fish with staples lost significantly fewer visible implant tags and had a lower incidence of abdominal bloating, two signs of systemic stress, than did fish with sutures. Six months after surgery, treatment and control groups had grown equally. The lower incidence of local and systemic infection caused by staples and the faster speed with which they can be applied suggest stapling is a better method than suturing for closing incisions.

Freshwater Sculpins: Phylogenetics to Ecology

Abstract Freshwater sculpins (Cottidae) are a diverse and ecologically important component of cool- and coldwater ecosystems throughout the northern hemisphere. More than 60 sculpin species occur in a variety of habitats, and sculpin distributions range from highly localized to widespread. Despite the frequently high biomass of sculpins and their numerous ecosystem functions, the traditional fisheries management emphasis on sport fishes has led to a general neglect of small-bodied, nongame fishes, such as sculpins, in both research and management. Ironically, in many coldwater ecosystems, salmonids are used as umbrella species to conserve and protect all aquatic vertebrates; however, many management and conservation goals may be better met by focusing on sculpins. This module arose from a symposium entitled “Ecology and Phylogeny of Freshwater and Diadromous Sculpin,” which was held at the 2005 annual meeting of the American Fisheries Society in Anchorage, Alaska, and which brought together researchers st...

Efficacy of Three Denil Fish Ladders for Low-Flow Fish Passage in Two Tributaries to the Blackfoot River, Montana

Abstract We evaluated the efficacy of three Denil fish ladders retrofitted to three irrigation diversions in two tributaries to the Blackfoot River, Montana. Fish ladders were 2.4–6.1 m long, with slopes of 9.6–15.8% and mean velocities of 18–140 cm/s. We captured westslope cutthroat trout Oncorhynchus clarki lewisi, brown trout Salmo trutta, bull trout Salvelinus confluentus, and slimy sculpins Cottus cognatus upstream of the fish ladders (treatment groups), and in three nearby stream reaches without a ladder (control groups). Fish were marked and then released downstream of the fish ladders (treatment) or immediately downstream of their capture reaches (control). Fish lengths were similar between treatment and control sites (t-tests; P > 0.05). We resampled the reaches 5–7 d after marking and recaptured similar numbers of marked westslope cutthroat trout and brown trout in both treatment and control sections (χ2 = 0.13; df = 2; P = 0.94). No slimy sculpins were recaptured in treatment or control section...

Abundance and Diversity of Fishes Migrating to a Hydroelectric Dam in Montana

Abstract Although many potamodromous fishes make extensive migrations, dams that block their upstream movements are not often mitigated with passage facilities. Over several months in 1998 and 1999 we studied the numbers of all fish species attempting to migrate beyond Milltown Dam, a hydroelectric dam on the Clark Fork River, Montana. Using a radial-gate raceway as a fish trap, we captured 13 fish species known to seasonally congregate below Milltown Dam. In 1998 we captured over 17,000 fish, representing 9 species; in 1999 we captured 12 species and more than twice the 1998 catch by sampling 6 weeks longer. Trapping in both years began on March 10 and was concluded November 17. In 1998 we found that spring migrations were related to spawning behavior for rainbow trout Oncorhynchus mykiss and largescale suckers Catostomus macrocheilus; and in 1999 we additionally noted the spawning-related migrations of westslope cutthroat trout O. clarki lewisi, longnose suckers C. catostomus, and northern pikeminnows P...

Summer Stream Temperatures Influence Sculpin Distributions and Spatial Partitioning in the Upper Clark Fork River Basin, Montana

The upper Clark Fork River basin of western Montana supports a poorly understood sculpin (Uranidea spp.) fauna that has perplexed ichthyologists and fish ecologists since the late 1800s. During our study, the basin contained three sculpin taxa whose taxonomy was under revision. All three taxa were formerly referred to the genus Cottus but are now treated as Uranidea. Our goal was to improve understanding of the distribution and ecology of two of the taxa. From 2006 to 2009, we sampled 144 reaches in 31 streams and rivers to determine distributions of each taxa across the study area and within streams. We collected habitat data in 2007 and stream temperature data from 2006–2009 to identify correlates of sculpin distributions. In streams where both taxa occurred, Rocky Mountain Sculpin Uranidea sp. cf. bairdii were downstream and Columbia Slimy Sculpin U. sp. cf. cognata were upstream with a syntopic zone in between. Summer stream temperatures strongly influenced sculpin distributions, with mean August 2007 water temperatures increasing in order of reaches characterized as: Columbia Slimy Sculpin-dominated, syntopic, Rocky Mountain Sculpin-dominated, and no sculpin. Columbia Slimy Sculpin occurred in cold tributaries of the Blackfoot, Clark Fork, and Bitterroot rivers and in two coldwater refugia in the mainstem Bitterroot River. In contrast, Rocky Mountain Sculpin occupied warmer downstream segments of many Blackfoot and Clark Fork river tributaries as well as some mainstem reaches of both rivers but were absent from the Bitterroot River drainage. Persistence of the taxa will likely depend, both directly and indirectly, on future water temperatures, and thus, sculpins are appropriate targets for researching and monitoring biological changes resulting from climate change.

Table 3 Adams_et_al_2015

Table 3. Minimum, average, and maximum daily water temperature values for each reach during summer 2007. Stream names and reach codes are as in Tables 1 and 2. Sites are organized by sculpin group: no sculpin (none); Rocky Mountain sculpin (RMS) or Columbia slimy sculpin (CSS) only; or both species (syntopic). Daily summary statistics (mean, sample size [N], SD, and SE) by group are given for each temperature metric. Numbers in blue were estimated based on linear regressions (see text).