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understanding northern pike distribution in Browns Park, and were also captured in subsequent regular seine sampling in autumn 2006 (more below). Smallmouth bass distribution and abundance in Lodore Canyon in the 1994-1996 period was extremely restricted, as only a single Smallmouth bass was collected from 1994 to 1996 by electrofishing and was found in reach LD3. Smallmouth bass distribution and abundance in Lodore Canyon increased dramatically in the 2002 to 2004 period compared to 1994 to 1996 (Fig. 16). By the 2002-2004 period, Smallmouth bass occupied all Lodore Canyon reaches and increased in abundance in a downstream fashion, where they constituted > 6% of the fish community in LD4 and > 10% of the fish community in Whirlpool Canyon. In 2005 and 2006, abundance of Smallmouth bass remained similar and low in upper reaches of Lodore Canyon, but was lower in lower Lodore Canyon (relative abundance reduced by nearly 50% in 2005-2006 compared to 2002-2004), and declined substantially in Whirlpool Canyon in 2005. Seine and drift net samples showed that smallmouth bass reproduction was first detected in lower Lodore Canyon in 2002 (N = 4, 13 to 85 mm TL) and was more progressively widespread in subsequent years. This is supported by the sampling of Fuller (2005) in the nearby lower Yampa River, who found that smallmouth bass abundance increased from 0.15 fish/hr captured in 2001 to 36 fish/hr in 2004. The upstream range expansion of smallmouth bass in the Green River in Lodore Canyon continued through 2005 when small age-0 bass were noted nearly to the head of Lodore Canyon in autumn, and into Browns Park in 2006. Prior to 2001, higher base flows prevailed and temperatures were cooler. Perhaps warm water conditions promoted successful smallmouth bass reproduction and higher levels of channel catfish abundance beginning in 2002 in Lodore Canyon. Cooler and higher flow conditions in 2005 may also have prevented smallmouth bass from successfully spawning in Browns Park until the relatively warm year of 2006. Anderson (2002; 2005) also found increased abundance of young smallmouth bass in the Yampa River in 2001, 2003, and 2004 when summer water temperatures were elevated (no sampling conducted in 2002). Size structure of smallmouth bass captured in 2002 to 2004 suggested a population invading from downstream, as the few fish present upstream were relatively large (Fig. 35, in 27