15 research outputs found
The Tenter-Hooks of Temptation : The Debate Over Theatre in Post-Revolutionary America
In Royall Tyler’s 1787 play The Contrast, the innocent and simple Yankee Jonathan unknowingly attends a playhouse, mistaking it for a hocus pocus show. The historian and eighteenth-century theatre manager, William Dunlap, later criticized Tyler’s play because his hero was a clown who misrepresented the new nation that the Revolutionary War created. Tyler’s satirical portrait of his hero, however, is not an attack on the Yankee, but rather a symbol of the ideological conflicts within America. Jonathan repeats the religious charges against theatre, but he also joins in the fun at the playhouse. He is simple and honest, but he does not have a mind of his own. Thus, Tyler both supported and critiqued the arguments against theatre from the 1780s and 90s. The Contrast is not only a play about theatre, but it is about the new American. Jonathan represents the common man, but his ignorance reveals that the common man could be dangerous. The debate over theatre at the end of the eighteenth century exemplified this paradox. Republicanism meant freemen should have the right to choose their own entertainment, yet it also meant freemen had the right to be protected from dangerous elements of society
Methodological Bias in Estimates of Strain Composition and Straying of Hatchery‐Produced Steelhead in Lake Michigan Tributaries
Steelhead Oncorhynchus mykiss were first introduced into the Great Lakes in the late 1800s. Subsequently, natural recruitment of steelhead from spawning runs in streams across the basin has been regularly supplemented by hatchery production of strains derived from widely dispersed locales within the species’ native range. Estimates of hatchery contributions to the spawning runs of naturalized populations may be underrepresented by observations of marked fish, as not all hatchery fish are marked prior to release. To assess the potential bias in estimates of the hatchery contribution to steelhead spawning runs in four major rivers in Michigan, we used scale pattern analysis (SPA) to identify nonmarked hatchery fish and multilocus genotypes to estimate the proportional contributions of each hatchery strain to spawning runs. The four hatchery strains currently stocked are significantly genetically distinct (mean FST = 0.077), making it possible to identify specific strains by use of likelihood‐based assignment tests. The differences between direct (mark observations) and indirect (SPA and genetic analysis) estimates of hatchery contribution were mainly due to variations in the percentage of hatchery fish marked by states prior to release and the potential for confusion between certain marks and injuries. By combining direct and indirect assessment methodologies, we estimated that the percentage of hatchery fish returning to the four rivers ranged from 13% to 31% of total spawning runs. The large contribution of hatchery fish to nonstocked rivers differed significantly from expectations of strain‐specific stocking rates across the Lake Michigan basin and for individual streams, indicating high amounts of straying into Michigan streams.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141020/1/nafm1288.pd
Status Review for Anadromous Atlantic Salmon (Salmo salar) in the United States
https://digitalmaine.com/commerce_feddocs/1003/thumbnail.jp
Evidence of Limited Recruitment of Pallid Sturgeon in the Lower Missouri River
Pallid Sturgeon Scaphirhynchus albus are endemic to the Missouri and Mississippi river basins and are rare throughout their range. The species was listed as federally endangered with little to no evidence of natural recruitment. Since population augmentation was initiated as a recovery objective in the early 1990s, thousands of hatchery-origin Pallid Sturgeon have been stocked in the lower Missouri River (Gavins Point Dam [river kilometer 1,305.1] to the confluence of the Mississippi River [river kilometer 0.0]). Efforts to discriminate natural reproduction and recruitment of wild-origin Pallid Sturgeon from hatchery-origin fish has been hampered by tag loss in hatchery-origin sturgeon, inconsistent documentation of hatchery parental crosses, and the failure to collect tissue samples for genotyping all broodstock. However, the recent reconstruction of missing parental genotypes from known hatchery-origin progeny and from cryopreserved milt made it possible to examine Pallid Sturgeon recruitment. Therefore, our objectives were to 1) determine the likelihood that unmarked Pallid Sturgeon captured from the lower Missouri River were the result of natural recruitment and 2) examine the length distribution of wild- and hatchery-origin fish to determine if a difference exists by origin and examine the life-stage distribution. Genetic analysis showed that from 2003 to 2015, 358 ‘‘presumptive wild-origin’’ Pallid Sturgeon were captured in the lower Missouri River and the comparison between the length distributions of wild- and hatchery-origin fish did not provide any additional clarification into potential wildorigin fish. Low recruitment may be due to a small breeding population, high mortality of early life stages, hybridization with Shovelnose Sturgeon Scaphirhynchus platorynchus, or transport of drifting free embryos or larvae into inhospitable habitats. Determining what factors are limiting recruitment is the important next step for the recovery of Pallid Sturgeon in the lower Missouri River
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Session B7- Evaluating brook trout genetic response to population isolation
Brook trout (Salvelinus fontinalis) reside in a range of habitats including headwater streams where populations may become periodically isolated. Demographic consequences of population isolation include increased potential for localized extinction. Genetic consequences for population isolation, or populations of sustained small numbers, include increasing susceptibility to inbreeding, the expression of negative fitness traits, and overall loss of genetic variability, which may increase the risk of localized extinction. Reestablishment of connectivity -with larger populations through periodic gene flow into these small populations may act to offset loss of genetic diversity. Restoring population connectivity and degraded headwater habitats, especially those that historically harbored wild brook trout populations has been a focus of restoration efforts. To understand the degree of genetic isolation among headwater brook trout populations, we examined how variability in connectivity between brook trout populations bas resulted in the partitioning of genetic variation within a number of headwater brook trout populations in two locations: Nash Stream, New Hampshire, and Pennsylvania. Both locations bad multiple headwater brook trout populations, but varied by how populations were potentially isolated. In Nash Stream, potential causes of isolation were culverts or waterfalls. In Pennsylvania, isolation could be due to larger geographic distance, culverts or dams, or areas of poor stream quality. In both locations, overall estimates of variation in allele frequency among populations were high, indicating that populations were significantly genetically different, but the effect of the different barrier types varied based on the likely amount of gene flow allowed. For example, in Pennsylvania, significant correlations of genetic diversity were only observed with the presence of impaired stream sections, but not geographic distance or barrier effect. Understanding the effects of barriers on genetic diversity and gene flow can be useful to guide efforts to restore connectivity between populations
New York Brook Trout Genotypes
Genotypes, in Convert format, for all Brook Trout individuals analyzed
Brook Trout Locality GPS Coordinates
GPS coordinates and locality information for Brook Trout collection sites across western New York State
Local and Regional Evaluation of Smallmouth Bass Population Genetic Structure in the Susquehanna River Basin
Smallmouth bass (Micropterus dolomieu) in the Susquehanna River basin have been displaying characteristics of disease and endocrine disruption (ED) for several years, including gross lesions and the presence of intersex. Since the initial observations of disease and ED, a wide range of potential environmental stressors have been identified including pathogens, water quality, and contaminants. Because of the life history characteristics of smallmouth bass in this system, which often spawn in smaller tributaries to the Susquehanna River and overwinter in the main-stem, it is challenging to link processes and ecological conditions in the river and the surrounding landscape that may be contributing to the observed disease and ED. To do so requires gaining an understanding of how smallmouth bass move throughout the river system and to define how they may function collectively as a population(s). Although a radio-telemetry study on two tributaries and a section of the Susquehanna River demonstrated movements relating to spawning and overwintering, resulting in intermixing of tributary and river-tagged fish, the population-level implications of these movements are unclear. One approach to address this question is through the use of highly variable genetic markers to quantify genetic variation within smallmouth bass from numerous sites within the Susquehanna River basin. This study aims to use population genetic tools to evaluate the structure and connectivity of smallmouth bass populations at both a local and regional scale across the Susquehanna River basin. Genetic samples were collected from 24 sites, including main-stem river sites that were paired with tributary locations to assess local gene flow between main-stem and tributary systems. A total of 1,034 fin clips were collected for genetic analysis during prespawn conditions and are being analyzed with microsatellite markers to investigate differences within and among populations. Laboratory analysis is currently underway, and results aim to provide information on the connectivity and genetic structure of populations as they may correlate to observed disease and other health characteristics and therefore aid in management
Minimal Captive Introgression in Wild Brook Trout (Salvelinus fontinalis) Populations in the Loyalsock Creek Watershed, Pennsylvania
Due to increased anthropogenic pressures on many fish populations, stocking wild populations with hatchery individuals has become a common management practice. Stocking has been the subject of much controversy due, in large part, to the potential for captive individuals to breed with wild stocks. By modulating the abundance of locally adapted gene complexes and introducing maladaptive genotypes, genetic introgression can cause declines in wild population fitness, resiliency, and accelerate local population extirpation. However, the rate of introgression in highly stocked river systems has not been rigorously evaluated, and so the relative risk of genetic erosion from stocking is unknown. We quantified the proportion of introgressed individuals in 30 populations of wild brook trout (Salvelinus fontinalis) distributed throughout the Loyalsock Creek watershed in Pennsylvania. Genetic assignment tests were used to determine the origin (wild vs. captive) for 1748 wild-caught and 300 hatchery brook trout. These assignment tests generated the probability of an individual fish belonging to either a simulated wild or simulated hatchery population. Fish with intermediate probabilities of wild descent were classified as introgressed, with cutoff values determined through simulation of first-generation crosses between wild and hatchery individuals. Even though streams in Loyalsock Creek are annually stocked with high densities of adult trout, we found minimal evidence for genetic introgression in the populations studied. Over 93% of all wild-caught individuals assigned to wild origin, and only 5% of wild-caught fish showed evidence of recent introgression. There was variation in introgression across populations; however, average within-site wild probability was 97%. Our results suggest that introgression with hatchery fish can occur at low rates, even in heavily managed ecosystems. However, results from this study should be viewed cautiously. Higher rates of introgression are not uncommon in other species of salmonids, and introgression may be more common under different environmental conditions. Further, we did not evaluate potential declines in wild brook trout fitness from competition with hatchery individuals, and so negative effects of stocking could still occur despite limited introgression
New York Brook Trout Fst Values
Pairwise Fst values and associated p-values between all Brook Trout populations analyzed