scholarly journals Differential migration in Pacific salmon and trout: Patterns and hypotheses

2021 ◽  
Vol 8 (1) ◽  
pp. 1-18
Author(s):  
Thomas P. Quinn
Keyword(s):  
Life History ◽  
Pacific Salmon ◽  
Life History Evolution ◽  
Partial Migration ◽  
Differential Migration ◽  
Natural Ecosystems ◽  
Paper Briefly ◽  
Migration Distance ◽  
Fishery Exploitation ◽  
Life History Patterns

AbstractMigrations affect the population dynamics, life history, evolution, and connections of animals to natural ecosystems and humans. Many species and populations display partial migration (some individuals migrate and some do not), and differential migration (migration distance varies). Partial migration is widely distributed in fishes but the term differential migration is much less commonly applied, despite the occurrence of this phenomenon. This paper briefly reviews the extent of differential migration in Pacific salmon and trout (genus Oncorhynchus), a very extensively studied group. Three hypotheses are presented to explain the patterns among species: 1) phylogenetic relationships, 2) the prevalence of partial migration (i.e., variation in anadromy), and 3) life history patterns (iteroparous or semelparous, and duration spent feeding at sea prior to maturation). Each hypothesis has some support but none is consistent with all patterns. The prevalence of differential migration, ranging from essentially non-existent to common within a species, reflects phylogeny and life history, interacting with the geographic features of the region where juvenile salmon enter the ocean. Notwithstanding the uncertain evolution of this behavior, it has very clear implications for salmon conservation, as it strongly affects exposure to predators, patterns of fishery exploitation and also uptake of toxic contaminants.

Life-History Evolution in Uncertain Environments: Bet Hedging in Time

2006 ◽  
Vol 168 (3) ◽  
pp. 398
Author(s):  
Wilbur ◽  
Volker H. W. Rudolf
Keyword(s):  
Life History ◽  
Life History Evolution ◽  
Bet Hedging ◽  
Uncertain Environments ◽  
History Evolution

scholarly journals Sex, age, molt strategy, and migration distance explain the phenology of songbirds at a stopover along the East Asian flyway

2021 ◽  
Vol 75 (1) ◽  
Author(s):  
Jonas Wobker ◽  
Wieland Heim ◽  
Heiko Schmaljohann
Keyword(s):  
East Asian ◽  
Russian Far East ◽  
First Year ◽  
Large Set ◽  
Differential Migration ◽  
Breeding Area ◽  
Migration Distance ◽  
Stopover Site ◽  
Evolutionary Response ◽  
Migrant Birds

Abstract Sex- and age-specific differences in the timing of migration are widespread among animals. In birds, common patterns are protandry, the earlier arrival of males in spring, and age-differential migration during autumn. However, knowledge of these differences stems mainly from the Palearctic-African and Nearctic-Neotropical flyways, while detailed information about the phenology of migrant birds from the East Asian flyway is far scarcer. To help fill parts of this gap, we analyzed how migration distance, sex, age, and molt strategy affect the spring and autumn phenologies of 36 migrant songbirds (altogether 18,427 individuals) at a stopover site in the Russian Far East. Sex-differential migration was more pronounced in spring than in autumn, with half of the studied species (6 out of 12) showing a protandrous migration pattern. Age-differences in migration were rare in spring but found in nearly half of the studied species (11 out of 25) in autumn. These age effects were associated with the birds’ molt strategy and the mean latitudinal distances from the assumed breeding area to the study site. Adults performing a complete molt before the onset of autumn migration passed the study site later than first-year birds undergoing only a partial molt. This pattern, however, reversed with increasing migration distance to the study site. These sex-, age-, and molt-specific migration patterns agree with those found along other flyways and seem to be common features of land bird migration strategies. Significance statement The timing of animal migration is shaped by the availability of resources and the organization of annual cycles. In migrant birds, sex- and age-differential migration is a common phenomenon. For the rarely studied East Asian flyway, we show for the first time and based on a large set of migrant songbirds that earlier migration of males is a common pattern there in spring. Further, the timing and extent of molt explained age-differential migration during autumn. Adults molting their complete plumage at the breeding area before migration showed delayed phenology in comparison to first-year birds, which perform only a partial molt. This pattern, however, reversed with increasing migration distance to the study site. Since our results agree with the general patterns from the other migration flyways, similar drivers for differential migration may act across different flyway systems, provoking a similar evolutionary response.

scholarly journals Gene Trees versus Species Trees: Reassessing Life-History Evolution in a Freshwater Fish Radiation

2010 ◽  
Vol 59 (5) ◽  
pp. 504-517 ◽  
Author(s):  
Jonathan M. Waters ◽  
Diane L. Rowe ◽  
Christopher P. Burridge ◽  
Graham P. Wallis
Keyword(s):  
Life History ◽  
Freshwater Fish ◽  
Life History Evolution ◽  
Gene Trees ◽  
Species Trees ◽  
History Evolution
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