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Cutaneous ulcerative skin lesions in a complex of invasive Gulf of Mexico lionfish (Red Lionfish Pterois volitans, Devil Firefish P. miles, and the hybrid Red Lionfish × Devil Firefish) became epizootic beginning in mid‐August 2017. Herein, we provide the first pathological descriptions of these lesions and summarize our analyses to elucidate the etiology of the disease. We examined ulcerated and normal fish through gross pathology and histopathology, bacterial sampling, and unbiased metagenomic next‐generation sequencing. We tracked prevalence of the disease, and we used biological health indicators (condition factor, splenosomatic and hepatosomatic index) to evaluate impacts to health, while considering sex and age as potential risk factors. Typical ulcerative lesions were deep, exposing skeletal muscle, and were bordered by pale or reddened areas often with some degree of scale loss. Only incidental parasites were found in our examinations. Most fish (86%; n= 50) exhibited wound healing grossly and histologically, confirmed by the presence of granulation tissues. A primary bacterial pathogen was not evident through bacterial culture or histopathology. Metagenomic next‐generation sequencing did not reveal a viral pathogen (DNA or RNA) but did provide information about the microbiome of some ulcerated specimens. Compared with clinically healthy fish, ulcerated fish had a significantly lower condition factor and a higher splenosomatic index. Disease prevalence at monitored sites through July 2021 indicated that ulcerated fish were still present but at substantially lower prevalence than observed in 2017. Although some common findings in a number of specimens suggest a potential role for opportunistic bacteria, collectively our suite of diagnostics and analyses did not reveal an intralesional infectious agent, and we must consider the possibility that there was no communicable pathogen. Impact StatementAn outbreak of ulcers affected lionfish in the Gulf of Mexico. The disease occurred coincident to declines in invasive lionfish populations but could be contagious to native fish. Sick fish were examined to determine the cause. Findings were inconclusive but bacteria and environmental factors should be further investigated. An outbreak of ulcers affected lionfish in the Gulf of Mexico. The disease occurred coincident to declines in invasive lionfish populations but could be contagious to native fish. Sick fish were examined to determine the cause. Findings were inconclusive but bacteria and environmental factors should be further investigated.

In 1995, eight female pumas from Texas (Puma concolor stanleyana) were introduced into five areas in South Florida to remediate morphological and biomedical correlates of inbreeding depression that threatened the long-term survival of Florida panthers (P. c. coryi). Initial analysis of the results of this genetic introgression initiative has highlighted its success, including growth of the population, increased genetic heterozygosity, and reduced frequencies of physical traits associated with inbreeding, including cryptorchidism. However, panthers remain isolated from other puma populations and natural gene flow is not currently plausible. Using data collected from 65 panthers in the post-genetic introgression era (1998–2020), we assessed the benefits accrued to male panther reproductive parameters via this management initiative, the effect of genetic variables, and compared results to historic data. Microsatellite data were used to determine individual heterozygosity levels and qualify panther genetic ancestry as admixed (i.e., panthers descended from crosses with female Texas puma) or canonical (i.e., panthers that comprised most of the population prior to genetic introgression). A total of 47 admixed and 10 canonical panthers were identified; mean individual heterozygosity of canonical panthers (0.39) was significantly different from admixed panthers (0.63; t54= 4.7, P-value < 0.001). Admixed panthers exhibited higher mean values for total testicular volume, structurally normal spermatozoa, and total sperm in comparison to canonical panthers. The progressive improvement of sperm metrics demonstrates that the benefits of genetic introgression continue to have a positive impact on the population >25 years since the release of the Texas pumas. However, the Florida panther population remains small, isolated, and vulnerable to deterministic and stochastic events that warrants continued monitoring to assess when additional genetic introgression initiatives will need to be implemented in the future.

Mortality from being struck by a motorized watercraft is considerable for many aquatic vertebrates around the world, including sea turtles. We studied stranded (i.e., dead, sick, or injured) sea turtles found in Florida, USA, during 1986–2014 and identified those with sharp force or blunt force injuries indicative of a vessel strike. About a third of stranded loggerheads (Caretta caretta), green turtles (Chelonia mydas), and leatherbacks (Dermochelys coriacea) had a vessel‐strike injury (VSI). The frequency of this injury was lower but still substantial for stranded Kemp's ridleys (Lepidochelys kempii; 26.1%) and hawksbills (Eretmochelys imbricata; 14.8%). Over the study period, the annual number of stranded loggerheads, green turtles, and Kemp's ridleys with a VSI increased as did the annual number of vessels registered in Florida. Eighty‐one percent of the stranded turtles with a VSI were found in the southern half of Florida and 66% of those were found along the southeast coast. By coastal county, the proportion of stranded sea turtles with a VSI was positively related to the mean annual number of registered vessels. The percentage occurrence of a VSI was highest for adult loggerheads, green turtles, and leatherbacks, and reproductively active individuals appeared to be particularly vulnerable to these injuries. We conducted necropsies on 194 stranded sea turtles with a VSI and concluded that this injury was the cause of death or the probable cause of death in ≥92.8% of these cases. During 2000–2014, we estimate that the mean annual numbers of stranded sea turtles that died from a VSI were 142–229 loggerheads, 101–162 green turtles, 16–32 Kemp's ridleys, 4–6 leatherbacks, and 2–4 hawksbills. Considering that only about 10–20% of sea turtles that died likely washed ashore, the overall annual mortality may have been 5–10 times greater than that represented by strandings. Most of the significant clusters of stranded sea turtles with a VSI occurred at inlets or passes and the probability that a stranded sea turtle had a VSI decreased with increasing distance from inlets or passes, navigable waterways, and marinas. We suggest focusing initial management efforts on reducing watercraft‐related mortality for all sea turtle species around 8 inlets in southeast Florida, reproductively active loggerheads and green turtles along the coast of southeast Florida, and Kemp's ridleys and adult male loggerheads at passes along the coast of southwest Florida. Published 2019. This article is a U.S. Government work and is in the public domain in the USA. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society Watercraft‐related mortality of sea turtles in Florida is substantial and reproductively active adults appear to be particularly vulnerable. Initial efforts to reduce this mortality should focus on southeast Florida, especially around 8 inlets where this mortality is particularly high.

AbstractSixteen darter species, including the federally endangered Boulder Darter Etheostoma wapiti, are known to occur in the Elk River, a large, flow-regulated tributary of the Tennessee River, Tennessee–Alabama. Since the construction of Tims Ford Dam (TFD) in 1970, habitat modification caused by cold, hypolimnetic water releases and peak-demand hydropower generation has contributed to population declines and range reductions for numerous aquatic species in the main-stem Elk River. We developed Bayesian hierarchical multispecies occupancy models to determine the influence of site- and species-level characteristics on darter occurrence by using presence–absence data for 15 species collected from 39 study sites. Modeling results indicated that large-river obligate species, such as the Boulder Darter, were 6.92 times more likely to occur for every 37-km increase in the distance downstream from TFD. In contrast, small-stream species were 2.35 times less likely and cosmopolitan species were 1.88 times less likely to occur for every 37-km increase in distance downstream from TFD. The probability of occurrence for darter species also had a strong negative relationship with the absence of cobble and boulder substrates and the presence of high silt levels, particularly for species that require boulder substrates during spawning. Although total darter species richness was similar across all 39 sample sites, the composition of darter assemblages varied substantially among locations, presumably due in part to species-specific habitat affinities and hydrothermal conditions. The use of multispecies occupancy models allowed us to account for the incomplete detection of species while estimating the influence of physical habitat characteristics and species traits on darter occurrences, including rarely observed species that would have been difficult to model individually.Received August 23, 2015; accepted May 31, 2016 Published online August 12, 2016

Sixteen darter species, including the federally endangered Boulder Darter Etheostoma wapiti, are known to occur in the Elk River, a large, flow-regulated tributary of the Tennessee River, Tennessee–Alabama. Since the construction of Tims Ford Dam (TFD) in 1970, habitat modification caused by cold, hypolimnetic water releases and peak-demand hydropower generation has contributed to population declines and range reductions for numerous aquatic species in the main-stem Elk River. We developed Bayesian hierarchical multispecies occupancy models to determine the influence of site- and species-level characteristics on darter occurrence by using presence–absence data for 15 species collected from 39 study sites. Modeling results indicated that large-river obligate species, such as the Boulder Darter, were 6.92 times more likely to occur for every 37-km increase in the distance downstream from TFD. In contrast, small-stream species were 2.35 times less likely and cosmopolitan species were 1.88 times less likely to occur for every 37-km increase in distance downstream from TFD. The probability of occurrence for darter species also had a strong negative relationship with the absence of cobble and boulder substrates and the presence of high silt levels, particularly for species that require boulder substrates during spawning. Although total darter species richness was similar across all 39 sample sites, the composition of darter assemblages varied substantially among locations, presumably due in part to species-specific habitat affinities and hydrothermal conditions. The use of multispecies occupancy models allowed us to account for the incomplete detection of species while estimating the influence of physical habitat characteristics and species traits on darter occurrences, including rarely observed species that would have been difficult to model individually. Received August 23, 2015; accepted May 31, 2016 Published online August 12, 2016

Daclizumab is a monoclonal antibody that reduces inflammation in multiple sclerosis (MS). Through a retrospective analysis, our objective was to determine whether daclizumab treatment reduces the rate of brain structure atrophy in comparison to a mixture of other disease-modifying therapies (mainly different interferon β preparations). We analyzed MRI examinations (1332 scans from 70 MS cases) obtained between 2000 and 2011 in a single center and processed with an automated brain segmentation method. We used mixed-effects multivariable linear regression models to determine whether a median of 4.3 years of daclizumab therapy in 26 patients altered rates of brain-volume change, controlling for variations in MRI protocol. The control group consisted of 44 patients not treated with daclizumab. We found that supratentorial brain volume declined by 5.17ml per year (95% confidence limits: 3.58–6.77) off daclizumab therapy. On daclizumab, the annual rate of volume loss decreased to 3.72ml (p=0.01). The rate of ventricular enlargement decreased from 1.26 to 0.42ml per year (p<0.001). Focused analysis suggests that reduction in gray matter atrophy rate most likely underlies these results. In summary, in this retrospective analysis, daclizumab therapy substantially decreased the rate of brain atrophy in relapsing-remitting MS in comparison to other disease-modifying therapies, predominantly interferon β.

Current approaches to assessing the potential effects of river regulation and water use on stream fish communities are based on physical habitat simulation and are not feasible for estimating these effects over large spatial scales. We developed a channel classification for streams in the lower Flint River basin, Georgia, based on gross channel morphology and geology and evaluated its usefulness at 23 study sites representing the four channel types in the basin. Our channel classification separated stream channel types based on dominant geology (upland residuum versus Ocala limestone) and channel form (confined versus unconfined). Fish were sampled and habitat measured at the study sites in spring, summer, and winter from 2001 to 2004, a period that included some of the lowest and highest seasonal flows ever recorded. The channel types differed with respect to diurnal variability in temperature and dissolved oxygen concentration as well as habitat characteristics (substrate, large wood). Statistical habitat modeling indicated that channel unit (e.g., pool, riffle) availability could be predicted accurately for each channel type using streamflow, with errors rates that averaged 0.7% across channel unit types. Comparisons between the accuracy of species presence and fish abundance models fit using habitat characteristics to those fit using geomorphic channel characteristics indicated similar model accuracy with slightly less bias (6% on average) for the geomorphic channel characteristics models. Our results indicate that the channel types were useful for predicting changes in habitats and stream fish presence and abundance in response to changing streamflow. Channel classification is potentially a useful and cost-effective approach to quantifying changes in the physical environment in response to varying streamflow. Additionally, channel classification could be combined with dynamic fish population models to evaluate the effects of river regulation and water use across large spatial scales.

River regulation and development are the foremost problems threatening lotic fishes and other aquatic biota in the United States. The operation of hydroelectric facilities can influence both habitat availability and environmental stability in downstream reaches. We evaluated the relative influence of habitat complexity and environmental stability on fish assemblage structure at unregulated and hydropower-regulated reaches of the Flint River in southwestern Georgia. The availability of different habitat types was highly variable at the regulated reach owing to large, daily fluctuations in discharge. Habitat-specific fish assemblages also differed between reaches, as a greater number of species occupied identical habitat types at the unregulated reach, most notably in shallow, slow-flowing habitats. Differences in fish assemblage structure between study reaches in comparable habitat types were explained equally well by patterns of habitat structure and variability. Within-reach patterns of fish assemblage structure were best explained by patterns of habitat structure at both study reaches. However, the relative influence of habitat complexity and habitat stability differed within each study reach, habitat variability influencing fish assemblage structure to a greater extent at the regulated reach than at the unregulated reach. These differences suggest that both habitat structure and variability influence Flint River fish assemblages and that flow regulation associated with hydropower operation primarily affects riverine fish communities by increasing environmental variability. Thus, flow management plans for regulated rivers based on minimum flows may be most effective when implemented in conjunction with plans that reduce the spatial and temporal variability of habitat availability, particularly in shallow, slow-flowing habitats.