Flathead Catfish Pylodictis olivaris have been either intentionally or accidentally introduced into Atlantic Slope drainages extending from Florida to Pennsylvania and have quickly become established. In Pennsylvania, Flathead Catfish were first detected in the Schuylkill River at the Fairmont Dam in 1999 and in the Susquehanna River at Safe Harbor Dam in 2002. The species has since moved throughout the respective basins, with subsequent detections during 244 riverine surveys in these drainages. Fishway and electrofishing surveys in the tidal Schuylkill River, a Delaware River tributary, have documented an increase in abundances since 2004, when the surveys were first implemented. Hoop-net surveys in nontidal large-river reaches found mean (±SD) catch rates varying from 0.00 to 4.51 ± 4.38 fish/series. A Bayesian hierarchical Poisson regression model indicated that Flathead Catfish abundance decreased as the distance from the initial point of detection increased, demonstrating a general pattern of fish expansion upstream from the point of detection. The distance downstream of the nearest dam, although not significant, had a relatively high posterior probability of being negatively correlated with Flathead Catfish abundance. Ongoing and future targeted surveys should help to better understand changes in the distribution and abundance of Flathead Catfish in these systems.

中文翻译：

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美国特拉华州和萨斯奎汉纳河的侵袭性平头Cat鱼数量丰富的范围扩大和影响因素

平头head鱼Pylodictis olivaris已被有意或无意地引入了从佛罗里达州延伸至宾夕法尼亚州的大西洋斜坡排水系统，并迅速建立起来。在宾夕法尼亚州，首次在1999年的Fairmont大坝的Schuylkill河和2002年的Safe Harbor大坝的Susquehanna河中发现了head鱼。此后，该物种在各个流域中移动，随后在这些排水渠的244次河川调查中被发现。自2004年首次实施调查以来，在特拉华河支流潮水Schuylkill河上进行的鱼道和电捕鱼调查表明，丰度有所增加。非潮汐大河段的环网调查发现平均捕获量（±SD）在0.00至4.51±4.38鱼/系列之间。贝叶斯分层Poisson回归模型表明，扁平头Cat鱼的丰度随着距检测起点的距离增加而降低，这表明从检测点到上游的鱼类扩展的一般模式。最近的水坝下游的距离虽然不显着，但具有较高的后验概率，与with鱼的丰度负相关。正在进行的和将来的有针对性的调查应有助于更好地了解这些系统中平头Cat鱼的分布和丰度变化。与Flat鱼的丰度负相关的后验概率较高。正在进行的和将来的有针对性的调查应有助于更好地了解这些系统中平头Cat鱼的分布和丰度变化。与Flat鱼的丰度负相关的后验概率较高。正在进行的和将来的有针对性的调查应有助于更好地了解这些系统中平头Cat鱼的分布和丰度变化。