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salmonid
02-18-2014, 02:17 PM
Reading a paper today and thought this was pretty cool.


We observed 36 different life-history trajectories among Nass and Skeena steelhead, all different expressions of the anadromous life-history (Fig. 2). Individuals varied in the number of years they spend in fresh water, from 2 to 6 years, with 3 and 4 years being most common (Table 1). In addition, individuals varied in the number of years they spent in the ocean before migrating back to spawn, from 1 to 4 years (Table 1). Furthermore, some individuals made repeat spawning migrations (Table 1). An extreme example from the Skeena River is a female that spent 4 years in freshwater, 2 years in the ocean, migrated to spawn, migrated out to the ocean for another year, migrated again to spawn, back to the ocean for another year, and so on for a total of 4 spawning migrations and a total age of 12 years.

Life-history diversity and its importance to population stability and persistence of a migratory fish: steelhead in two large North American watersheds - Moore - Journal of Animal Ecology - Wiley Online Library (http://onlinelibrary.wiley.com/doi/10.1111/1365-2656.12212/abstract)