First occurrence of the mysid Hemimysis anomala in an inland lake in North America, Oneida Lake, NY

Spatial, seasonal, and diel distribution patterns of Hemimysis anomala in New York State's Finger Lakes

“…The maximum seasonal density of Hemimysis at the reference site was substantially higher (N2500 ind./m 3 ) than population densities reported in other systems (Brooking et al, 2010;Ketelaars et al, 1999). The time of the day we collected our monthly samples (3 h after sunset) may have actually underestimated Hemimysis density as the greatest densities during our diel study from 19 to 20 June were observed later in the night.…”

“…1). Rivers and canals provide a continuous, surface-water connection between the Finger Lakes and lakes where Hemimysis is established (Brooking et al, 2010;Walsh et al, 2010). The two largest Finger Lakes, Seneca Lake (Lake SA = 175 km 2 ;Z max = 186 m) and Cayuga Lake (Lake SA = 172 km 2 ; Z max = 133 m), connect to each other and the Erie Canal via the Seneca-Cayuga Canal (Schaffner and Oglesby, 1978).…”

“…Hemimysis could have been present at abundances that were below detection, but there were several aspects of our methodology that minimized the potential for a false negative. We targeted our night, littoral collections to exploit the preference of Hemimysis for rocky substrate and complex structures, an effective detection strategy in Seneca Lake and other lakes (Brooking et al, 2010;Ketelaars et al, 1999;Walsh et al, 2010;Wittmann and Ariani, 2009). We also collected multiple horizontal tows at the surface-a preferred method to quantify Hemimysis-allowing us to search 4.5 m 3 -8.25 m 3 of water per lake (assuming 100% net efficiency), which is above the volumes expected to contain Hemimysis in rocky, littoral areas (Brooking et al, 2010;Walsh et al, 2010).…”

“…Since its detection in 2006, Hemimysis has become established in the lower Great Lakes (Pothoven et al, 2007;Walsh et al, 2010), the St. Lawrence River (Kestrup and Ricciardi, 2008), and Oneida Lake, New York (Brooking et al, 2010). Hemimysis has also rapidly expanded its range in Western Europe (Borcherding et al, 2006;Holdich et al, 2006;Wittmann and Ariani, 2009) due to intentional stocking and accidental dispersal through ship ballast and downstream currents (Bij de Vaate et al, 2002;Grigorovich et al, 2002).…”

“…Invasions of Hemimysis are associated with declines in the abundance and diversity of native zooplankton and may also alter levels of primary production and impact fish communities (e.g., Ketelaars et al, 1999;Borcherding et al, 2006). Given the wide and rapid spread of Hemimysis over the past decade in Europe, the risk of range expansion may be higher within the Great Lakes basin than first suggested (Brooking et al, 2010;Koops et al, 2010).…”