Within-stream release-site fidelity of steelhead trout from Lake Erie hatchery stocks

Straying of salmonids in Lake Erie is not well understood despite the economic importance of these recreational fisheries, which are sustained by stocking approximately 2 million steelhead trout (Oncorhynchus mykiss) yearlings annually. The occurrence of straying in hatchery-reared salmonid populations can be influenced by stocking strategies, such as within-stream stocking location. Conneaut Creek provides a unique opportunity to evaluate the extent of release-site fidelity of adult steelhead trout from Lake Erie, because it is equally stocked by Ohio and Pennsylvania at different distances from the stream mouth. Adult steelhead trout were collected from two Conneaut Creek sites, Conneaut Ohio (2 km from Lake Erie) and Albion Pennsylvania (61 km from Lake Erie), in spring and fall of 2009. Elemental signatures of yearling otoliths measured by laser-ablation-inductively-coupled-plasma-mass-spectrometry were used to identify hatchery stocks. The state-specific hatchery stocks were identified with high confidence using discriminant analysis (Sr and Ba concentrations in nine otolith regions; Ohio 100.0%, Michigan 86.1%, New York 92.4%, and Pennsylvania 93.2% using jackknifed mean correct assignment). Adult steelhead trout (N = 174) collected in spring and fall at Conneaut Ohio included both Ohio and Pennsylvania-stocked fish, but no Ohio-stocked steelhead trout were collected at the Pennsylvania site in either season. Of the classified adult steelhead trout, 13.8% were identified as strays from other states (New York and Michigan). These results confirm strong release-site fidelity between Ohio and Pennsylvania stocked steelhead trout and provides fishery managers with sound scientific data to refine their stocking practices.