Diversity of life history traits, growth, and lipid storage in migratory variants of steelhead and rainbow trout (Oncorhynchus mykiss) in Kamchatka, Russia

Abstract

Partial migration in salmonids provides access to freshwater and marine feeding environments varying in productivity. To test the hypothesis that partial migration drives differences in growth and energy storage with differential consequences for females than males, we assigned Oncorhynchus mykiss sampled on the western Kamchatka Peninsula, Russia to one of five life history contingents based on scale patterns. Stable isotopes, obtained from a subset of fish, indicated different foraging by fish showing oceanic and coastal anadromous life histories. In younger fish, body size was largest in anadromous fish feeding on the high seas, intermediate for those feeding in coastal environments, and smallest for non-anadromous fish feeding in rivers. Older fish converged on large (oceanic) and small (coastal, freshwater) body sizes. Somatic lipid content, also collected for a subset of fish, averaged 2.5% across all life histories. Percent lipid was highest in females of ocean and males of coastal and freshwater life histories. Taken together, migratory patterns predictably influenced growth but may limit compensatory lipid storage in females, especially for the rare life histories.

Diverse migration patterns of anadromous white-spotted charr Salvelinus leucomaenis revealed from otolith microchemistry

“…Recent studies, however, have attempted to explore the diversity within migratory communities on a continuum. Terms like "migration continuum", "life-history contingent", or "differential migration" have been introduced to describe some intermediate patterns where individuals vary in distance or timing of migration (Cucherousset et al 2005;Quinn 2021;Zimmerman et al 2022). For example, brown trout Salmo trutta exhibit a migration continuum that varies across ranges, ages, and cohorts, mainly in response to environmental changes (Cucherousset et al 2005).…”