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Pelagic broadcast spawning cyprinids are a mobile group of fishes commonly found within semi-arid areas of the Great Plains of North America. In several species, upstream movements of 50 to 200 km have been reported and associated with reproductive migration. Long distance migrations also are associated with finding food and refuge. Goals of this study were to detect synchronous movement of Prairie Chub at specific life stages and relate movement to functions associated with migration (i.e., reproduction, feeding, and refuge). Movement was inferred by quantifying monthly occurrences of age groups using length frequency distributions among five sites in two rivers and supported with range-wide assessment of genetic structuring. Monthly occurrences of age groups among sites were related to reproductive season (i.e., gonadosomatic indices, ovarian condition) for assessing reproductive migration, to food consumption (i.e., gut content assessments) for assessing feeding migration, and to habitat associations (e.g., specific conductance) for assessing refuge migration. Spatial and temporal patterns in age-0, age-1 and age-2 fish occurrences and abundances suggested movement within only one river. Non-synchronized movements were more consistently associated with specific conductance following a high flow event, which was more consistent with a refuge function than reproductive season or food consumption. Our findings suggest that Prairie Chubs are capable of moving long distances, but movement was inconsistently associated with reproductive efforts as previously described. Without synchronized movements, we question whether movement is migration or dispersal and provide a contrasting narrative to the drift compensation theory used to describe broadcast spawning cyprinid migrations.

Purposes of this study were to assess population status and life history attributes of the Texas Shiner Notropis amabilis, a minnow endemic to the Edwards Plateau region in Texas and the Rio Grande drainage of U.S.A. and Mexico. Despite possible extirpation from three stream reaches, populations of Texas Shiners persist with abundances categorized as occasional and frequent among multiple and independent stream reaches, streams, and drainages. Therefore, Texas Shiner population is considered stable. Quantification of life history traits suggest Texas Shiner has a protracted reproductive season (i.e., 9 mo), a life span of 2 y, and feeds on primarily aquatic invertebrates. Protracted spawning seasons are consistent with Texas Shiner's reported associations with spring systems of the Edwards Plateau. Current and future conservation of N. amabilis and other spring-associated fishes are explicitly linked to spring complexes, although exact mechanisms of association are unknown.

It has long been recognized that the process of preserving biological specimens results in alterations of body shape, though detailed studies examining the degree to which morphological changes occur throughout the preservation process are lacking. We utilize geometric morphometric analyses, an increasingly common tool for examining shape variation in a wide variety of biological disciplines, to examine the effects of formalin and ethanol preservation on the body shape of 10 freshwater fish species over time: from fresh specimens to eight weeks after preservation. We found significant changes in body shape among fresh and formalin fixed specimens. Furthermore, changes in body shape continue to occur after subsequent ethanol preservation. Two fish species collected at multiple localities show significant morphological differences for a limited number of morphometric characters. However, the significance, or lack thereof, often changed inconsistently from one stage of preservation to another. We conclude that morphometric analyses would ideally be performed on fresh specimens. However, recognizing that this is not always feasible, it is important to be aware of the morphometric changes that can occur during preservation.

We report the occurrence of a single population of Etheostoma parvipinne (Goldstripe Darter) in a small, acidic, spring-fed stream within the Colorado River drainage following an extended period of below-average precipitation (January–September 2011), a wildland fire (September 2011), and subsequent debris and sediment flows (November 2011–May 2012). Goldstripe Darters were taken from Alum Creek (Bastrop County, TX) along with a cyprinid, a poeciliid, and several species of centrarchids in June 2012. Occurrence of Goldstripe Darters in Alum Creek provides a regional example of fish-community responses to wildland fires. In additio n, understanding the mechanism of long-term persistence in a single tributary on the periphery of a species range might offer insight into the origin of endemic fishes and persistence of disjunct fish populations within aquatic evolutionary refugia of central Texas.

Within its southwestern native range, Ameiurus nebulosus (Brown Bullhead) had been found in the Red River drainage within Oklahoma, Arkansas, and Louisiana but not Texas. We report for the first time the occurrence of Brown Bullhead within the Cypress River system of Texas, a tributary of the Red River. We tentatively conclude that the Cypress River system of Texas is within the natural range of Brown Bullhead, but we cannot exclude human introduction as a possible mechanism for its occurrence, given that Brown Bullhead are introduced worldwide.

Freshwater fish communities segregate along water temperature gradients attributed in part to temperature-mediated physiological processes that affect species fitness. In spring complexes of southwest USA, spring complexes with narrow range of water temperatures are dominated by a community of fishes (i.e., spring-associated fishes), whereas riverine habitats with wide-range of water temperatures are dominated by a different community of fishes (i.e., riverine-associated fishes). The purpose of this study was to test a prediction of the concept that temperature-mediated species performance is a mechanism in maintaining community segregation. We predicted that a spring-associated fish (Largespring Gambusia Gambusia geiseri) would feed first and more often in a pairing with a riverine-associated fish (Western Mosquitofish G. affinis) at an average spring temperature (23 °C) and that the riverine-associated fish would feed first and more often in a pairing with the spring-associated fish at a warm riverine temperature (30 °C). Among four trails consisting of 30 pairings, at the spring complex temperature (23 °C), Largespring Gambusia had a greater number of first feeds (mean ± 1 SD, 5.0 ± 0.82) than Western Mosquitofish (2.5 ± 1.73) and had greater mean number of total feeds (1.9 ± 0.31) than Western Mosquitofish (0.81 ± 0.70). At the riverine environment temperature (30 °C), Western Mosquitofish had a greater number of first feeds (5.25 ± 1.71) than Largespring Gambusia (2.5 ± 1.73) and had greater mean number of total feeds (2.78 ± 1.05) than Largespring Gambusia (0.94 ± 0.68). Our findings suggest that temperature-mediated species performance could be maintaining segregation between the two fish communities. This study benefits our understanding of distributional patterns and improves threat assessments of stenothermal aquatic organisms.

Previous work has shown that certain β(3)-peptides can effectively mimic the side chain display of an α-helix and inhibit interactions between proteins, both in vitro and in cultured cells. Here we describe a β(3)-peptide analog of GLP-1, CC-3(Act), that interacts with the GLP-1R extracellular domain (nGLP-1R) in vitro in a manner that competes with exendin-4 and induces GLP-1R-dependent cAMP signaling in cultured CHO-K1 cells expressing GLP-1R.

Advances in the foldamer field in recent years are as diverse as the backbones of which they are composed. Applications have ranged from cellular penetration and membrane disruption to discrete molecular recognition, while efforts to control the complex geometric shape of foldamers has entered the realm of tertiary and quaternary structure. This review will provide recent examples of progress in the foldamer field, highlighting the significance of this class of compounds and the advances that have been made towards exploiting their full potential.