tailieunhanh - Lake Trout Ecosystems in a Changing Environment - Chapter 3

Phục hồi chức năng của hồ cá hồi ở Great Lakes: bài học quá khứ và những thách thức trong tương lai Hồ cá hồi Salvelinus namaycush, trước khi thực dân các dân tộc châu Âu, đã có nguồn gốc trong năm Great Lakes, xảy ra khắp hồ Superior, hồ Michigan, hồ Huron, hồ Ontario, và trong lưu vực phía đông của hồ Erie. Cuộc sống đặc điểm lịch sử của quần thể Đại Hồ mở rộng phạm vi đối với các loài. . | chapter three Rehabilitation of lake trout in the Great Lakes past lessons and future challenges Charles C. Krueger Great Lakes Fishery Commission Mark Ebener Great Lakes Fishery Commission Contents The lake trout fishery and its management 1800-1950S Rehabilitation management 1950s to present Causes for the slow recovery Status of rehabilitation Lake Superior Lake Huron Lake Michigan Lake Erie Lake Ontario New management approaches Pulse stocking Creation of spawning areas Transplantation of adults Management lessons and future challenges Conclusion Acknowledgments References Lake trout Salvelinus namaycush before colonization by European peoples were native to each of the five Great Lakes occurring throughout Lake Superior Lake Michigan Lake Huron and Lake Ontario and in the eastern basin of Lake Erie. Life history characteristics of Great Lakes populations span the range for the species. For example spawning typically occurs in the fall but some populations may spawn as early as August Hansen et al. 2004 by CRC Press LLC 1995 or even in the spring Bronte 1993 . Age at first maturity is also highly variable across the lakes. For some shallow-water populations in Lake Superior age at first maturity can be as late as age 9 or beyond and some individuals may not spawn every year . Rahrer 1967 Swanson and Swedburg 1980 . This maturity schedule is comparable to those of some populations from Precambrian Shield lakes Martin and Olver 1980 or northern Arctic lakes. On the other extreme lake trout in lakes Erie and Ontario at the southern edge of their native range mature at age 3 and all fish are mature at age 5 or 6 Cornelius et al. 1995 Elrod et al. 1995 . These life history differences can dramatically affect the speed with which populations respond to management actions such as fishery regulations and stocking. The native lake trout of the Great Lakes used a diversity of semiisolated spawning habitats from shallow near-shore reefs to deep offshore shoals to .