Angler Perception and Population Dynamics of the Northern Snakehead (Channa argus) in the Potomac River & Tributaries

Our research sought to address the extent to which the northern snakehead (Channa argus), an invasive fish species, represents a threat to the Potomac River ecosystem. The first goal of our research was to survey the perceptions and opinions of recreational anglers on the effects of the snakehead population in the Potomac River ecosystem. To determine angler perceptions, we created and administered 113 surveys from June – September 2014 at recreational boat ramps along the Potomac River. Our surveys were designed to expand information collected during previous surveys conducted by the U.S. Fish and Wildlife Service. Our results indicated recreational anglers perceive that abundances and catch rates of target species, specifically largemouth bass, have declined since snakehead became established in the river. The second goal of our research was to determine the genetic diversity and potential of the snakehead population to expand in the Potomac River. We hypothesized that the effective genetic population size would be much less than the census size of the snakehead population in the Potomac River. We collected tissue samples (fin clippings) from 79 snakehead collected in a recreational tournament held between Fort Washington and Wilson’s Landing, MD on the Potomac River and from electrofishing sampling conducted by the Maryland Department of Natural Resources in Pomonkey Creek, a tributary of the Potomac River. DNA was extracted from the tissue samples and scored for 12 microsatellite markers, which had previously been identified for Potomac River snakehead. Microsatellite allele frequency data were recorded and analyzed in the software programs GenAlEx and NeEstimator to estimate heterozygosity and effective genetic population size. Resampling simulations indicated that the number of microsatellites and the number of fish analyzed provided sufficient precision. Simulations indicated that the effective population size estimate would expect to stabilize for samples > 70 individual snakehead. Based on a sample of 79 fish scored for 12 microsatellites, we calculated an Ne of 15.3 individuals. This is substantially smaller than both the sample size and estimated population size. We conclude that genetic diversity in the snakehead population in the Potomac River is low because the population has yet to recover from a genetic bottleneck associated with a founder effect due to their recent introduction into the system

A Comparative Study of Suicidality and Its Association with Emotion Regulation Impairment in Large ASD and US Census-Matched Samples.

Evidence suggests increased rates of suicidality in autism spectrum disorder (ASD), but the research has rarely used comparison samples and the role of emotion dysregulation has not been considered. We compared the prevalence of parent-reported suicidality ideation and considered the role of emotion dysregulation in 330 psychiatric inpatient youth with ASD, 1169 community youth with ASD surveyed online, and 1000 youth representative of the US census. The prevalence of suicidal ideation was three and five times higher in the community and inpatient ASD samples, respectively, compared to the general US sample. In the ASD groups, greater emotion dysregulation was associated with suicidal ideation. Implications include consideration of emotion regulation as a potential mechanism and treatment target for suicidality in ASD

A Comparative Study of Suicidality and Its Association with Emotion Regulation Impairment in Large ASD and US Census-Matched Samples.

Evidence suggests increased rates of suicidality in autism spectrum disorder (ASD), but the research has rarely used comparison samples and the role of emotion dysregulation has not been considered. We compared the prevalence of parent-reported suicidality ideation and considered the role of emotion dysregulation in 330 psychiatric inpatient youth with ASD, 1169 community youth with ASD surveyed online, and 1000 youth representative of the US census. The prevalence of suicidal ideation was three and five times higher in the community and inpatient ASD samples, respectively, compared to the general US sample. In the ASD groups, greater emotion dysregulation was associated with suicidal ideation. Implications include consideration of emotion regulation as a potential mechanism and treatment target for suicidality in ASD