The behavior and ecology of Pacific salmon and trout

“Such an influence would manifest most in chum and pink salmon: small individuals were probably most abundant because 9 Mar Ecol Prog Ser 557: 1–15, 2016 these species immigrate over a short period of time, grow rapidly, and suffer high mortality (Quinn 2005).”

“Salmon have been either likewise exterminated or dramatically diminished in watersheds to the south along the coast (Slaney et al. 1996, Northcote and Atagi 1997, Gresh et al. 2000, Quinn 2005, Price et al. 2009).”

“We hypothesize several factors that may influence travel speeds of juvenile salmon: (i) species—coho and Chinook salmon often reside in coastal waters closer to their river of origin than steelhead and sockeye salmon [5,8], so may reasonably be slower during their Figure 1.”

“All fry leave the river shortly after commencing external feeding (Heard 1991; Quinn 2005).”

“Rainbow trout in the Iliamna Lake system spawn in streams, but fish represent‐ ing a wide range of sizes and ages occur simultaneously in both lake and stream habitats during the summer (Arostegui & Quinn, 2018; M. C. Arostegui, unpublished data).”

“disperse to some other patch on the landscape (Quinn 2005).”

“Steelhead typically have larger eggs than smaller residents (Quinn 2005), which can Environ Biol Fish”

“, 1993) or high flows (Tschaplinski, 1987), or could represent an adaptive life-history strategy (Healey, 1991; Quinn, 2005).”

“Fraser River populations having less than 5% of the adult return spending 3 years at sea (ocean-age-3), on average, were excluded from this analysis because mean age at maturity changed very little from year to year, possibly in response to other factors such as physical constraints imposed by spawning habitat (Quinn…”

“These background levels of natural straying may be adaptive by allowing populations to expand into new habitats and by supplementing populations with low genetic diversities (Quinn 2005).”

“Second, Pacific salmon are anadromous, meaning that they undertake migrations between freshwater breeding grounds and marine feeding grounds (Groot and Margolis, 1991; Hendry et al., 2004a; Quinn, 2005).”

“Jill (1-ocean female) and freshwater-maturing female Chinook salmon are rare, presumably because females require a greater energetic investment in reproduction (Sloat et al. 2014a) than males, which are more typically limited by access to mates than by gamete production (Quinn 2005).”

“Because of their ecological and commercial importance, salmonids have been the chief focus of the debate over flow management (Quinn 2011; Milner et al. 2012).”

“Differences among populations have also been observed in marine migration patterns, timing of return to freshwater to spawn and timing of spawning (Halupka et al. 2003; Quinn 2005).”

“During their reproductive migration, however, salmon of many populations must first navigate from the open sea to the proximity of their specific river, a process that is unlikely to be mediated by olfactory cues given the distances involved (Quinn 2018).”

“2006) – has been restricted to a few groups and species (Tuset et al. 2016a; Quinn 2018).”

“Specific to salmon, it is thought that growth and mortality during the first period at sea is a primary determinant of later adult salmon abundance from that cohort (Pearcy 1992, Beamish & Mahnken 2001, Beamish et al. 2004, Quinn 2005).”

“Temperature is a critical factor shaping salmon growth and survival [44,45] and can act as a selective force shaping key life-history events, such as timing of breeding, hatching and development [46].”

“Although the vertical distribution of salmon changes on seasonal and diel scales, and is affected by many physiological and ecological factors [46, 49, 75], tagging and fisheries studies consistently indicated that Chinook salmon are located deeper in the water column than other salmonids.”

“Varying egg size, incubation rate, and timing of emergence and differences in rearing lake habitat lead to differences in juvenile life histories (Quinn 2005).”

“Although the precise mechanisms remain unclear, such fitness declines have been observed after as little as one or two generations in captivity (Araki et al. 2007).”

“1963), CWTs ( 1 mm sections of coded magnetized wire that are inserted into the cranial cartilage of juveniles) have revealed stock structure, marine distributions, and smolt–adult survival in salmonids (Quinn 2005).”

“…nerka, and chum O. keta, salmon), males are larger, on average, than females and more variable in size (Beacham and Murray 1985, Blair et al. 1993, Quinn 2005), but in those breeding at lower densities (coho O. kisutch and Chinook O. tshawytscha, salmon), males are often smaller than females…”

“…spp., Salmo spp.) provide a unique opportunity for investigating islands of divergence because they return to their natal streams with high fidelity, thereby providing extensive opportunities for local adaptation on small spatial scales (Hendry et al. 2000; Quinn 2005; Pavey et al. 2010).”

“Mean smolt sizes vary from 50 to 140 mm among sockeye salmon populations (Quinn, 2005), so an aggregate”

“Water depth is often positively related to density and distribution of salmonids, especially coho salmon (Lonzarich and Quinn 1995; Quinn 2005), and has been identified as a source of cover from wading and diving predators (Harvey et al.”

“Natural stray rates are typically 3-5% (Quinn 2005), whereas straying rates of 83 Page 4 of 49”

“Initiation of migration generally occurred after several years of residence in freshwater, and this is common in anadromous fishes (Quinn 2005).”

“…of the degradation of salmonid spawning habitat as a key driver for high mortality in freshwater systems, and a key contributor to this trend is commonly thought to have been the enhanced accumulation of fine sediment in river beds (e.g. Lisle, 1989; Quinn, 2005; Armstrong et al., 2003).”

“required to exploit different environments may be particularly responsive to natural selection (Crozier and others 2008; Quinn 2005).”

“From a commercial perspective, our plan would not be reasonable for Chinook and coho salmon (O. tshawytscha and kisutch), which spend much of their lives along the near shore waters of western North America and thus are continuously vulnerable to fishing by multiple jurisdictions.”

“Steelhead exhibit a great deal of life-history diversity, including both anadromous and resident forms, iteroparity and semelparity, and variation in both freshwater and saltwater residence time (Quinn 2005).”

“Because mortality can be high in the early life of salmonids (Healey 1991; Bradford 1995; Quinn 2005), the asynchrony we observed in juvenile Chinook salmon could be attributed to differential survival between movers and stayers in their respective early rearing habitats.”

“The well-known habitat requirements of salmon and trout [13] provide an ideal setting for testing predictions about the influence of spatial processes on species’ distributions and abundances.”

“Chinook salmon are affected by factors such as predation, temperature stress, loss of refuge in a river, and ocean conditions (e.g., Groot and Margolis 1991; Quinn 2005).”

“They play a key ecological role in lakes, rivers, and streams as aquatic predators contributing to top-down influences on food webs (Quinn 2005).”

“Thus more flooding may promote higher gene flow if, as hypothesized by Quinn (2005), dispersal will be higher among populations occupying less stable rivers.”

“Similar to the hypothesis for the Eastern Cascades, higher temperatures could lead to increased straying of adults and during the later stages of migration, increased flooding events in winter could decrease river stability and increase the dispersal of returning adult steelhead (Quinn 2005).”

“These salmon still return to their natal stream as adults; however, they have higher rates of straying compared to sockeye and chinook, who spend several years in the freshwater before going out to the ocean (Quinn 2005).”

“Bears are by far the dominant predator of salmon (Levi et al., 2015; Quinn, 2018),”

“The typical salmonid female lays large, demersal eggs in freshwater that hatch after several months; incubation duration is mediated by temperature and genetically controlled development rate (6).”

“501 502 Timing of spawning also varies widely among species, populations, and years (Quinn 2005) and each 503 salmon species has a slightly different optimal temperature for growth and survival (Murray and McPhail 504 1988, Beacham and Murray 1990).”

“For example, anadromous Coastal Cutthroat Trout are iteroparous and remain nearshore in the marine environment (Trotter 1989); Chinook Salmon are semelparous and pelagic, and they require rapid marine growth to optimize the tradeoff between mortality risk and body size for reproduction (Quinn 2005).”

“Steelhead populations in North America are generally divided into coastal and inland genetic lineages [11, 31].”

“Unlike Atlantic and Pacific salmon, who migrate over hundreds of kilometres offshore (Hansen and Quinn 1998; Quinn 2005), anadromous salmonids of the genus Salvelinus tend to remain closer to their natal stream during marine migrations (e.”

“Juvenile salmon are active visual predators, capturing individual prey in the water column and from the substrate (Quinn 2005).”

“It is unclear if straying reflects a failure to return home or a decision to spawn elsewhere, but in either case, straying has been essential for the persistence and distribution of salmon [35].”

“The transition from freshwater to marine environments is one of the most physiologically demanding phases for salmon [57], and overall marine survival appears to depend on rapid early marine growth [58].”

“A trade-off may be lower survival because of increased predation, variable prey availability and other risks in the marine environment (Quinn, 2005).”

“…in salmonids is a complex and critical life- history component that is influenced by genetic background, developmental thresholds, ecological conditions such as flow regimes and temperature, olfactory cues, and hormonal changes (Dodson et al., 2013; Quinn, 2005; Quinn et al., 2016; Ueda, 2011).”

“Yet, six6 was also significant in Sockeye Salmon, a species not known to be iteroparous (Quinn, 2005), and this association was detected in two populations compared to the larger number of populations”

“40e60 km/day) into Bristol Bay, where they progressively segregate into their natal drainage basins (Quinn, 2005).”

“[6] The iconic anadromous Chinook salmon has adapted its reproductive life stage to accommodate a relatively predictable annual hydrograph in many snowmelt-dominated western North American mountain streams [e.g., Quinn 2005; Waples et al., 2008].”

“Many anadromous salmonids spend several years at sea before returning to freshwater to spawn (Fleming 1998; Quinn 2005).”

“Quinn TP. 2005.”

“Coldwater (streams with maximum daily mean temperatures <22°C; Lyons et al. 1996) fish communities generally are dominated by salmonids, which are stenothermic, have low tolerance for poor water quality, and are highly mobile (Quinn 2005, Richter and Kolmes 2005).”

“The productivity parameter was based on literature values (10), and smolt capacity was set to ensure a sufficient number of individuals in each category to calculate statistical averages in any given year.”

“Unique environmental conditions experienced by each population have been linked to distinct life-history strategies employed by different groups in order to maximize fitness (Ricker, 1972; Quinn, 2005; Eliason et al ., 2011).”

“However, all of these factors influence survival of fish in the wild (Plaut 2001; Quinn 2005) and are of direct relevance to studies of tag effects.”

“It has been reported that the prevalence of straying varies greatly depending on hatcheries, rivers, release sites, and origin of fish (Quinn 1993, 2005).”

“Juvenile steelhead and Chinook salmon did not always hold in the coldest areas of the refuge, and both species tended to cluster in areas that met their species-specific habitat requirements (Everest and Chapman 1972; Quinn 2005).”

“The high FST values observed between all other populations and regions in this study reflect the large geographic range surveyed in addition to the extreme philopatry of the species which results in strong genetic differences across even small geographic scales [57].”

“Dorsal humps also serve as a shield to protect spawning fish during bouts of male-male aggression while fighting for female proximity [57], while condition factor provides a general indication of overall fish health [59].”

“Moreover, the highly predictable spatial and temporal patterns in availability of different salmon species and populations (Quinn 2005) offer bears the opportunity to move between nearby spawning areas as salmon abundance changes (Deacy et al.”