The influence of phylogeny, size and behaviour on patterns of covariation in salmonid life histories.

Evaluated covariation in 8 life history traits within the Salmonidae. Principal components analysis defined a primary tactic ranking salmonids from large, early-maturing, semelparous individuals bearing few, large, rapidly developing eggs to the opposite suite of characters in small, iteroparous individuals. The analysis also defined a secondary cline from anadromous to freshwater forms, and a tertiary tactic describing variation in development. Clustering of species on the basis of life history traits reflected taxonomic affiliations. Life history traits appear to co-evolve and form successful life history strategies best suited to the biology and environment of a given taxon. Migratory behaviour and life histories are closely linked. The correspondence between behaviour and life histories may lead to unanticipated but nevertheless successful life history strategies. -Authors