Factors influencing coastal cutthroat trout (Oncorhynchus clarkii clarkii) seasonal survival rates: a spatially continuous approach within stream networks

2009 ◽  
Vol 66 (4) ◽  
pp. 613-632 ◽  
Author(s):  
Aaron M. Berger ◽  
Robert E. Gresswell

Mark–recapture methods were used to examine watershed-scale survival of coastal cutthroat trout ( Oncorhynchus clarkii clarkii ) from two headwater stream networks. A total of 1725 individuals (≥100 mm, fork length) were individually marked and monitored seasonally over a 3-year period. Differences in survival were compared among spatial (stream segment, subwatershed, and watershed) and temporal (season and year) analytical scales, and the effects of abiotic (discharge, temperature, and cover) and biotic (length, growth, condition, density, movement, and relative fish abundance) factors were evaluated. Seasonal survival was consistently lowest and least variable (years combined) during autumn (16 September – 15 December), and evidence suggested that survival was negatively associated with periods of low stream discharge. In addition, relatively low (–) and high (+) water temperatures, fish length (–), and boulder cover (+) were weakly associated with survival. Seasonal abiotic conditions affected the adult cutthroat trout population in these watersheds, and low-discharge periods (e.g., autumn) were annual survival bottlenecks. Results emphasize the importance of watershed-scale processes to the understanding of population-level survival.


2010 ◽  
Vol 1 (2) ◽  
pp. 86-92 ◽  
Author(s):  
John P. Bigelow ◽  
Wendy M. Rauw ◽  
Luis Gomez-Raya

Abstract We investigated the effectiveness of two acclimation protocols for 8-month-old Lahontan cutthroat trout Oncorhynchus clarkii henshawi, reared at Lahontan National Fish Hatchery in terms of survival during a week-long challenge in water from saline, alkaline Walker Lake, Nevada. Fish were acclimated for 0 (control), 3, and 8 d by increasing the ratio of lake water to hatchery water. For the 3-d acclimation treatment, 50% of the tank water was replaced with lake water each day. For the 8-d treatment, 33% of the water was replaced with lake water on the first through fourth day of acclimation. Survival during acclimation (i.e., prior to the challenge) was lowest for fish acclimated 3 d. Median survival time during the lake water challenge was 8 h for unacclimated fish, and 8 and 12 h for fish surviving the 3- and 8-d acclimation treatments, respectively. No fish survived the entire week-long challenge. Compared with no acclimation, 3- and 8-d acclimation decreased the hazard of mortality during the challenge. Increased fork length also reduced the hazard of death. Our results indicate acceptable survival rates cannot be achieved for subyearling, hatchery-reared Lahontan cutthroat trout stocked in Walker Lake without acclimation or with the acclimation methods employed in this study. Our results indicate that the acclimation method might be improved by the use of longer fish, longer acclimation, and better control of water temperature, ammonia concentration, and alkalinity.



Author(s):  
Robert Al-Chokhachy ◽  
Mike Lien ◽  
Bradley B. Shepard ◽  
Brett High

Climate change and non-native species are considered two of the biggest threats to native salmonids in North America. We evaluated how non-native salmonids and stream temperature and discharge were associated with Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) distribution, abundance, and body size, to gain a more complete understanding of the existing threats to native populations. Allopatric Yellowstone cutthroat trout were distributed across a wide range of average August temperatures (3.2 to 17.7ºC), but occurrence significantly declined at colder temperatures (<10 ºC) with increasing numbers of non-natives. At warmer temperatures occurrence remained high, despite sympatry with non-natives. Yellowstone cutthroat trout relative abundance was significantly reduced with increasing abundance of non-natives, with the greatest impacts at colder temperatures. Body sizes of large Yellowstone cutthroat trout (90th percentile) significantly increased with warming temperatures and larger stream size, highlighting the importance of access to these more productive stream segments. Considering multiple population-level attributes demonstrates the complexities of how native salmonids (such as Yellowstone cutthroat trout) are likely to be affected by shifting climates.



<em>Abstract</em>.—There has been considerable interest in the systematics and classification of Cutthroat Trout since the 1800s. Cutthroat Trout native to western North America (currently classified as <em>Oncorhynchus clarkii</em>) have historically been grouped or separated using many different classification schemes. Since the 1960s, Robert Behnke has been a leader in these efforts. Introductions of nonnative trout (other forms of Cutthroat Trout, and Rainbow Trout <em>O. mykiss</em>) have obscured some historical patterns of distribution and differentiation. Morphological and meristic analyses have often grouped the various forms of Cutthroat Trout together based on the shared presence of the “cutthroat mark,” high scale counts along the lateral line, and the presence of basibranchial teeth. Spotting patterns and counts of gill rakers and pyloric caeca have in some cases been helpful in differentiation of groups (e.g., Coastal Cutthroat Trout <em>O. c. clarkii</em>, Lahontan Cutthroat Trout <em>O. c. henshawi</em>, and Westslope Cutthroat Trout <em>O. c. lewisi</em>) currently classified as subspecies. The historical genetic methods of allozyme genotyping through protein electrophoresis and chromosome analyses were often helpful in differentiating the various subspecies of Cutthroat Trout. Allozyme genotyping allowed four major groups to be readily recognized (Coastal Cutthroat Trout, Westslope Cutthroat Trout, the Lahontan Cutthroat Trout subspecies complex, and Yellowstone Cutthroat Trout <em>O. c. bouvieri </em>subspecies complex) while chromosome analyses showed similarity between the Lahontan and Yellowstone Cutthroat trout subspecies complex trout (possibly reflecting shared ancestral type) and differentiated the Coastal and Westslope Cutthroat trouts from each other and those two groups. DNA results may yield higher resolution of evolutionary relationships of Cutthroat Trout and allow incorporation of ancient museum samples. Accurate resolution of taxonomic differences among various Cutthroat Trout lineages, and hybridization assessments, requires several approaches and will aid in conservation of these charismatic and increasingly rare native fishes.



2020 ◽  
Vol 94 (2) ◽  
Author(s):  
James P. Losee ◽  
Simon R. M. Jones ◽  
Caitlin A. E. McKinstry ◽  
William N. Batts ◽  
Paul K. Hershberger




2013 ◽  
Vol 83 (5) ◽  
pp. 1161-1182 ◽  
Author(s):  
F. A. Goetz ◽  
B. Baker ◽  
T. Buehrens ◽  
T. P. Quinn


2014 ◽  
Vol 71 (11) ◽  
pp. 1680-1694 ◽  
Author(s):  
Helen M. Neville ◽  
Douglas P. Peterson

We contrasted various genetic analyses to evaluate their utility and constraints for detecting movement of cutthroat trout (Oncorhynchus clarkii) through restored culverts in different field settings: population-level metrics of genetic variability (heterozygosity and allelic richness); Bayesian clustering and assignment of individual genotypes from age 1+ fish; and a novel “sib-split” approach, where movement patterns are extracted from the spatial distribution of young-of-year (YOY) full-sibling groups inferred via pedigree reconstruction. Family structure greatly influenced population-level and individual clustering results in our small headwater populations, even though field sampling was implemented to avoid siblings. Sib-split, which uses family structure to detect movement, uncovered passage of YOY just weeks after emergence. When retrospectively applied to older individuals, it proved essential in interpreting clustering patterns and captured passage in several families of 1- and 2-year-olds. Where family structuring may negatively affect genetic analyses or, alternatively, be prominent enough to allow application of sib-split is difficult to predict a priori; we discuss benefits and limitations of all approaches under different ecological, spatial, and management scenarios.



2014 ◽  
Vol 5 (1) ◽  
pp. 183-190 ◽  
Author(s):  
Peter D. Bangs ◽  
James J. Nagler

Abstract Knowledge of the state of sexual development is important for management of coastal cutthroat trout Oncorhynchus clarkii clarkii, a fish species targeted for sport fishing throughout its range along the Pacific coast of North America. The purpose of this study was to compare the nonlethal methods of ultrasound imaging, body lipid content, and the measurement of plasma vitellogenin and estradiol levels for assessing the reproductive status of female coastal cutthroat trout. This was examined in a population living in Florence Lake, Alaska, during the spring–early autumn period of the annual reproductive cycle. All methods, except body lipid content, were effective at determining maturity status in either the spring (ultrasound imaging), or spring and autumn (plasma vitellogenin and estradiol). These approaches could be useful for conducting nonlethal assessments of length- or age-at-maturity on populations of coastal cutthroat trout that are small, have conservation concerns, or are heavily utilized by anglers.



2019 ◽  
Vol 76 (11) ◽  
pp. 2057-2068
Author(s):  
Mariah P. Mayfield ◽  
Thomas E. McMahon ◽  
Jay J. Rotella ◽  
Robert E. Gresswell ◽  
Trevor Selch ◽  
...  

Multistate modeling was used to estimate survival and movement of brown trout (Salmo trutta) and westslope cutthroat trout (Oncorhynchus clarkii lewisi) in relation to copper concentrations in the mining-impacted Clark Fork River, Montana. Survival probability in the uppermost river segment, where dissolved copper concentrations frequently exceeded acute criteria for aquatic life (range: 31–60 days > 13.4 μg·L–1), was 2.1 times lower for brown trout and 122 times lower for westslope cutthroat trout compared with survival rates in the lowermost segment that had relatively low dissolved copper (0 days exceedance of acute concentration). Lowest survival for both species occurred in the spring–summer period when dissolved copper concentrations were elevated coincident with higher discharge. Movement among study segments was generally low, and cutthroat trout showed low movement into the uppermost river segment with the most elevated copper levels. Both species showed high rates of movement into tributaries, which coincided with their respective spawning migrations rather than as an apparent avoidance of elevated copper levels. The linkage between survival rate and level of copper exposure for both trout species suggests that additional removal of tailings deposits could improve survival rates.



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