The Ocean Ecology of Pacific Salmon and Trout

Chapter 7: Ocean Ecology of Steelhead

Katherine W. Myers


This chapter reviews information on the marine life history and ecology of steelhead—the ocean-migrating (anadromous) form of Rainbow Trout Oncorhynchus mykiss. While there are numerous scientific and common names for this species in North America and Asia (Table 1), the nomenclature in this chapter conforms to that accepted by western taxonomists. Both anadromous and freshwater resident forms of O. mykiss are best known as one of the world’s premier species for aquaculture (predominantly resident form) and recreational fisheries (both anadromous and resident forms), and as such are very economically important. Nevertheless, most of the research on the ecology of O. mykiss has been conducted in freshwater habitats. In accordance with the theme of this book, however, information about the freshwater life history and ecology of Rainbow Trout is included only where needed to clarify this review.

An earlier review of the ocean ecology of steelhead by Burgner et al. (1992) includes references to most of the early scientific literature on this topic. My review, therefore, emphasizes new information published during the period 1992–2017. The chapter is divided into five major sections: (1) General Biology, (2) Migration, Distribution, and Abundance, (3) Feeding and Growth, (4) Survival, and (5) Concluding Remarks, which includes suggestions for future research on the ocean life history and ecology of steelhead.