Partial migration in fishes: causes and consequences

Abstract

Partial migration, where only some individuals from a population migrate, has been widely reported in a diverse range of animals. In this paper, what is known about the causes and consequences of partial migration in fishes is reviewed. Firstly, the ultimate and proximate drivers of partial migration are reflected upon: what ecological factors can shape the evolution of migratory dimorphism? How is partial migration maintained over evolutionary timescales? What proximate mechanisms determine whether an individual is migratory or remains resident? Following this, the consequences of partial migration are considered, in an ecological and evolutionary context, and also in an applied sense. Here it is argued that understanding the concept of partial migration is crucial for fisheries and ecosystem managers, and can provide information for conservation strategies. The review concludes with a reflection on the future opportunities in this field, and the avenues of research that are likely to be fruitful to shed light on the enduring puzzle of partial migration in fishes.

Migration confers survival benefits against avian predators for partially migratory freshwater fish

“…Our data add further support by highlighting that in multi-predator systems, predation risk from birds can act additively to risk from piscivorous fishes to increase the costs of residency for our cyprinid model species. Given the prevalence of bird predation for a diverse array of migratory fishes, the importance of this force in shaping patterns of migratory dynamics has possibly been underestimated [19]. Incorporating additional predators into studies will clearly be fruitful for a range of migratory animals.…”

Telemetry and random‐walk models reveal complex patterns of partial migration in a large marine predator

“…However, in most animal populations only a proportion of the population migrates, with individuals selecting resident or migrant behavior, a process known as partial migration (Broderson et al 2008, Jahn et al 2010, Chapman et al 2012a. Partial migration appears to be ubiquitous among animal populations, but it is often unclear as to what drives the differences in migratory behavior.…”

“…Partial migration appears to be ubiquitous among animal populations, but it is often unclear as to what drives the differences in migratory behavior. However, a number of recent studies (particularly with birds) have started to reveal these driving factors, which include environmental conditions, resource distribution, body condition, reproductive state, and predation risk (e.g., Broderson et al 2008, Jahn et al 2010, Bunnefeld et al 2011, Chapman et al 2012a, Sanz-Aguilar et al 2012.…”

Residency, partial migration, and late egress of subadult Chinook salmon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) in Puget Sound, Washington

“…A number of diadromous species also exhibit alternative migratory behaviors that include resident forms of behavior similar to those of Puget Sound coho and Chinook salmon (Chapman et al, 2012a, Chapman et al 2012b. Striped bass (Morone saxatilis) have both resident fish that do not leave the natal river or estuary and migratory fish that travel long distances in coastal waters.…”

“…However, species and populations often vary greatly in the prevalence, duration, and spatial extent of their migrations (Quinn and Brodeur, 1991;Chapman et al, 2012a;Chapman et al, 2012b). Such variation (e.g., partial and differential migration) can affect the population's stability through alterations in exposure to predators, fisheries, and contaminants (Kerr et al, 2010;Gahagan et al, 2015).…”