A monogenean flatworm Gyrodactylus jennyae Paetow, Cone, Huyse, McLaughlin & 24 Marcogliese, 2009 was previously described as a pathogen on bullfrog Lithobates 25 catesbeianus Shaw, 1802, in a Canadian captive population originating in Missouri, U.S.A. 26 The ITS barcoding of G. jennyae showed relatedness to Asian Gyrodactylus macracanthus 27 Hukuda 1940, a parasite of the Asian loach Misgurnus anguillicaudatus Cantor, 1842. The 28 resulting suggestion that the globally invasive pet-trade of fish may be a mechanism for 29 arrival of Gyrodactylus species to North America provided the framework for the current 30 study. The present study was undertaken following the discovery of two other species of 31 Gyrodactylus in a population of illegally introduced M. anguillicaudatus in New York State. 32 Here the invasion hypothesis was tested via DNA sequencing of the ITS of the two 33 Gyrodactylus species obtained from M. anguillicaudatus from New York, termed 34 Gyrodactylus sp. A and Gyrodactylus sp. B. Both Gyrodactylus sp. A and Gyrodactylus sp. B 35 were closely related to G. jennyae and G. macracanthus, and all belong to a molecularly well-36 supported monophyletic Asian freshwater group. In conclusion, this invasive fish has 37 trafficked at least three parasite species to the U.S.A., one of them also found on frog. This 38 route from the Asian wetlands to other continents is similar to that of amphibian chytrid fungi 39 of genus Batrachochytrium Longcore, Pessier & Nichols, 1999. 40 41 Keywords 42 Intercontinental parasite dispersal 43 Molecular systematics 44 Aquatic invasive species 45 Chytrid fungus 46 47 4 (2005) estimated that there are 50,000 foreign plant or animal species in the United States 73 alone, and that 42% of endemic species are endangered or threatened because of aliens. The 74 authors concluded that the total economic damages and losses caused by invasive species add 75 up to an estimated $120 billion per year in the U.S.A. alone. 76 This study maps a complex case of an introduced and rapidly spreading Asian fish in 77 North America, accompanied by East Asian parasites. The starting point of this narrative was 78 as follows. A monogenean flatworm species Gyrodactylus jennyae Paetow, Cone, Huyse, 79 McLaughlin and Marcogliese 2009 was described as a new pathogenic parasite on the 80 American bullfrog Lithobates catesbeianus Shaw, 1802 in North America. The bullfrog itself 81 is widely trafficked (Mata-López et al. 2010). Paetow et al. (2013) also demonstrated that G. 82 jennyae infection increased the mortality of the tadpoles associated with fungal disease 83 Batrachochytrium dendrobatidis Longcore, Pessier & Nichols, 1999, making matters worse. 84 This fungal disease is considered one of the main reasons for the contemporary decline of 85 global amphibian populations (Collins and Crump 2009). The question was raised about the 86 origin of this newly described Gyrodactylus species, which are monogenean ectoparasites of 87 fish, seldom found on amphibians. Records on amphibians were reviewed in P...

The Mohawk River and New York State Barge Canal run together as a series of permanent and temporary impoundments for most of the distance between Rome and Albany, New York. The downstream or lower section is composed of two permanent impoundments, the middle section of a series of temporary (seasonal) impoundments, and the upper section of a series of permanent impoundments. In the middle section, movable dams are lifted from the water during winter and the wetted surface area decreases by 36–56%. We used boat electrofishing during spring 2014 and 2015 to compare the relative abundance of fish populations and the composition of fish assemblages between the permanently and seasonally impounded sections of the Barge Canal and to infer the effects of the two flow management practices. A total of 3,264 individuals from 38 species were captured, and total catch per unit effort (CPUE) ranged from 46.0 to 134.7 fish/h at sites in the seasonally impounded section, compared with 140.0–342.0 fish/h in the permanent lower section and 89.0–282.0 fish/h in the permanent upper section. The amount of drawdown explained 55% of the variation in total CPUE and was a highly significant predictor variable. Mean total CPUE in the seasonally impounded section was significantly lower (by about 50%) than that in either permanently impounded section, and the assemblage composition differed significantly between sections. The relative abundance of many lentic species was markedly lower in the seasonally impounded section, while the relative abundance of several native cyprinids and the percentage of individuals belonging to species that are native to the watershed was greater in this section. Overall, these findings suggest that winter dam removal in impounded rivers may reduce the abundance of fish but may also create more natural riverine conditions that favor some native species. Received January 28, 2016; accepted August 5, 2016 Published online October 14, 2016

Warm water stream fish assemblages (2005) and habitat variables (2004 and 2005) were examined fromMay to September at 108 sites in the Tonawanda and Johnson Creek Watersheds of Western New York. Seventy species and > 27,500 fishes were identified; ~98% were from Families Cyprinidae, Centrarchidae, Catostomidae and Percidae. Data were analyzed at 16 spatial scales using best subsets and backward stepwise multiple linear regression to explore associations between individual fish species ≥9% of total catch and fish assemblage variables [catch per unit effort (CPUE), species richness, Simpson's diversity] with six habitat variables (pool type, maximum depth, substrate size, instream wood, bank cover, aquatic vegetation). CPUE was the only fish assemblage variable related to habitat variables, especially aquatic vegetation and pool type. Only two species (johnny darter, Etheostoma nigrum; round goby, Neogobius melanostomus) were significantly associated with habitat variables. The results reflected inherent difficulties understanding the complexities of habitat use by warm water stream fishes and their assemblages and how to manage them on a broad scale.

Objective:The American Eel Anguilla rostrata historically was one of the most common fish species in Atlantic coast watersheds, but extensive dam construction and other factors caused a widespread population decline. One of the watersheds where American Eels have declined considerably is the Mohawk River in eastern and central New York. Recent attempts to characterize the distribution and abundance of American Eels in this watershed have been ineffective, and the extent to which a series of locks and dams on the Hudson River and lower Mohawk River limits use of the watershed is unclear. Methods:We developed a model between environmental DNA (eDNA) quantity and American Eel abundance in the Hudson River watershed in which the DNA concentration in water samples explained up to 65% of the variability in eel density and 56% of the variability in eel biomass. We then used this relationship to interpret eDNA data collected twice from 36 sites across the Mohawk River watershed in 2021 and make inferences about the distribution and abundance of American Eels.Result: American Eel DNA was detected almost exclusively in the downstream-most 4 km of the Mohawk River within a series of barriers. The concentration of DNA was reduced by approximately 80% across each successive upstream barrier before becoming too low to detect consistently. Our data suggest that eel population density was high in the Hudson River estuary and declined rapidly in the lower Mohawk River, and the species was nearly absent or undetectable in the Mohawk River and its tributaries upstream of the Crescent Dam and the Waterford Flight of Locks. Conclusion:Barriers appear to be largely restricting American Eels from using over 99% of the Mohawk River watershed. Therefore, improvements in fish passage at dams and hydroelectric facilities in the region could help the American Eel to regain access to this part of its native range.