The behavior and ecology of Pacific salmon and trout

“…and steelhead have been published despite their importance for understanding the metapopulation dynamics of these fish and their potential utility for informing expectations about the stray rates of hatchery-origin salmon and steelhead (Quinn 2005; Keefer and Caudill 2014; Fullerton et al. 2016).”

“Examples are if migrants and non-migrants nest in different habitats (Morrissey 2004; Quinn 2005) or if reproduction occurs at different times.”

“According to many authors, ripe specimens that manage without travel to the sea make the populatonal reserve ensuring the survival of the species in dramatic change of the environment and in suboptimum conditions (Reist, 1989; Quinn and Adams, 1996; Hendry and Stearns, 2004; Quinn, 2005).”

“Whereas homing to natal streams and consequent within-basin adaptation are well documented for philopatric taxa like salmonids (Groot & Margolis, 1991; Quinn & Myers, 2004; Quinn, 2005), the existing evidence does not support a similar philopatric scenario for lampreys (Petromyzontiformes), an ancient taxonomic group…”

“This reproductive strategy has been described for a variety of vertebrate taxa (Morbey and Ydenberg 2001), including fishes such as Pacific salmon Oncorhynchus spp. (Morbey 2000; Quinn 2005), Redhorse Moxostoma spp. (Reid 2006), and Rainbow Smelt Osmerus mordax (Lischka and Magnuson 2006).”

“Assuming a generation time of 5 years for chum and Chinook salmon (Quinn 2005), approximately 2000 generations have passed, suggesting that the collections could be at equilibrium.”

“The migration timing patterns we observed in shoreline and channel habitats are generally similar to those reported for other large estuaries within the region (Quinn 2005; Weitkamp et al. 2014).”

“Iteroparous species like steelhead/rainbow trout have resident freshwater forms and a broader period of spawning (Quinn, 2018), both of which translate to a greater period of overlap with the parasite.”

“…suggesting detrimental effects not only to the Chinook salmon considered here, but also to other species of salmon, trout and char that require cold water from snowmelt runoff and are regulated at multiple life stages by density-dependent growth, survival, and reproduction (Quinn, 2005).”

“Salmon spawn in fresh water, mostly in fastflowing tributary streams (Jonsson & Jonsson, 2011; Quinn, 2018).”

“For example, growth can determine smolting age, size and age at migration, overwinter mortality, return timing, sexual maturity, success on the spawning grounds and emergence time of embryos, among others (Quinn, 2005; Levings, 2016).”

“This developmental compensation is wide-spread in salmonids, and contributes to stabilizing the timing of hatch and emergence in the face of variable thermal environments during incubation (Brannon 1987; Quinn, 2005).”

“Although several exceptions exist, fish are generally larger bodied in large and fast flowing rivers (Langerhans, 2008; Quinn, 2005), and body length of returning salmonids may increase with both water discharge and spawning migration length (Power, 1981; Schaffer & Elson, 1975), possibly more so for discharge (Jonsso…”

“Jacks were identified from their otoliths as fish with a marine age of 1 year (Flain & Glova, 1988; Quinn, 2005).”

“Chum salmon stray at relatively high rates compared to other Pacific salmon (Quinn 2011), leading to patterns of genetic variation that are not always well captured by classical island models.”

“The Chinook salmon male precocial resident life history is well known (Quinn 2011), and it is therefore not surprising that several age 2 unsampled males had successfully reproduced.”

“In North America, Chinook salmon exhibit highly variable life history strategies, especially with regard to downstream migration timing (Quinn 2005).”

“Finally, elevated river temperatures can reduce survival of eggs, juvenile, and pre-spawn adult salmonids (Quinn 2005; Martins et al. 2011) and reduce feeding performance among juvenile steelhead (Sauter and Connolly 2010).”

“salmon, trout, charr, freshwater whitefish and grayling; Nelson 2006) are predicted to provide numerous examples of local adaptation because of their high fidelity of returning to spawn in their natal streams, which results in highly structured populations (Quinn 2005), and the wide diversity of environments the salmo…”

“Coho salmon ( Oncorhynchus kisutch ), Chinook salmon ( O. tshawytscha ), and rainbow and steelhead trout ( O. mykiss ) are three species of salmonid fishes distributed around the Pacific Rim (22).”

“Downstream/freshwater survival rates from release to salt water are likely to vary considerably by watershed and probably average between 50% and 90% (Bradford 1995; Quinn 2018).”

“(b) Immune functions are often differentially expressed genes under domestication Domestication is expected to result in changes to immune systems of salmonids for reasons relating to, often intentional, selection for resistance to pathogens present in artificial environments and relaxed selection for resistance to ce…”

“, fish [135], mollusks [132], insects [252], mammals [253]).”

“…Amphipoda), and aquatic insect larvae (Trichoptera, Ephemeroptera, Plecoptera) are abundantly available to both freshwater and coastal contingents (Kuzishchin et al. 2020b), and consumption of seasonally pulsed resources may homogenize their isotopic signatures (Arostegui and Quinn 2018).”

“We also examined morphological signs of migration (smoltification), including silver-colored body and an accumulation of black pigments along the outer edges of the dorsal and caudal fins (Quinn, 2018).”

“Since migration timing of anadromous salmonids is in fl uenced by both genetics and environmental conditions (see reviews by Banks 1969; Dodson 1997; Quinn 2005), and our study locations are major migration corridors for multiple populations of Chinook salmon (Fraser et al. 1982), it was challenging…”

“The role of host dispersal can be inferred from the infection level of the migratory (anadromous) form because such individuals are known to undertake long-distance upstream migration before spawning (Quinn, 2018).”

“For simulations in this paper, the number of offspring produced (Noff) for each breeding female was randomly drawn from a uniform distribution ranging from 2,500 to 6,500, which is typical of salmonids (Quinn, 2011, p. 117).”

“Pacific salmon are anadromous, gaining 99% of their biomass in the ocean before returning to their natal streams to spawn en masse and subsequently die of rapid senescence (Quinn, 2005).”

“Delays in spawning have been documented in many salmon species due to warm water temperatures (Webb and McLay 1996; Richter and Kolmes 2005; Quinn 2018).”

“…with conspecifics, predator avoidance [Hodgson and Mathewson, 1978; Johnson and Nelson, 1978; Demski and Northcutt, 1996; Hueter et al., 2004; Kasumyan, 2004; Gardiner et al., 2012; Collin et al., 2015], and navigation [Rooker et al., 2008; Gardiner et al., 2015; Nosal et al., 2016; Quinn, 2018].”

“Migration between spawning habitats suitable for egg and juvenile development and feeding habitats suitable for larger fish are common (Hesthagen & Sandlund, 2004; Quinn, 2005; Jonsson & Jonsson, 2011).”

“There is also a broad range in female salmonid sizes and, therefore, differences in bed sediment mobilization capabilities (Kondolf & Wolman 1993; Kondolf 2000; Quinn 2011).”

“Steelhead spend their first years in their natal streams where they compete for food and space and migrate to the ocean once they reach a certain size (Keeley 2001; Quinn 2005; Kendall et al. 2015).”

“First, most Sockeye Salmon populations use lakes to feed and grow for 1–2 years prior to seaward migration (Burgner 1991; Quinn 2005).”

“Site selection is tightly linked with philopatry in salmon, as they characteristically home to natal rearing locations (Healey, 1991; Quinn et al., 1999; Quinn, 2005).”

“Indeed, the general responsiveness of spawning salmonids to river and groundwater exchange, at a range of scales, is well known (Tautz and Groot 1975; Leman 1993; Geist et al. 2002; Quinn 2005).”

“Some individual O. mykiss spend their entire lives in freshwater streams and rivers and are referred to as rainbow trout (Quinn 2005; Pearse et al. 2007, 2009; Zimmerman and Reeves 2000).”

“At sea, both typically range in size from 20 to 56 cm (Jonsson and Jonsson 2007; Quinn 2018) but larger specimens are common in some areas.”

“Juvenile Chi-nook Salmon consume benthos during the rearing period in nearshore coastal areas prior to their seaward migration (Chapman and Wang 2001; Healey 1991), as food availability tends to be higher in estuarine coastal habitats than in freshwater areas (Quinn 2005).”

“Here, we focus on the microbiome of Chinook salmon (Oncorhychus tshawytscha), an anadromous and semelparous salmonid recognized as the largest species in its genus (Rounsefell 1958; Quinn 2018; Ohlberger et al. 2018).”

“Specifically, we assumed discrete generations, which is not typical for most salmonid species, where age- at- maturity can vary (Quinn, 2018).”

“As timing of reproduction is one of the most critical adaptations of animal populations to their environment, the ideal spawning time of fish species or populations should result in emergence of juveniles at a date that optimizes their survival (Quinn, 2018).”

“First, pools were considered a low-disturbance location, especially at their upstream end, as salmon tend to spawn in faster flowing areas (e.g., riffles and pool tail-outs; Quinn, 2005).”

“…represent potential high-quality rearing habitat for all three species of salmon given overhanging banks and vegetation, eelgrass beds, and depth of the pools (approximately 2 m at high tide), all of which provide shelter from predators (Simenstad et al. 1982; Quinn 2011; Carr-Harris et al. 2015).”

“In 492 addition, kelts increased in length during reconditioning, which would be expected to result in an 493 increase in fecundity (Quinn 2005, Seamons and Quinn 2010).”

“The factors assessed are known to influence local densities and individual growth opportunities (Bjornn and Reiser 1991; Quinn 2005; Myrvold and Kennedy 2015a,b).”

“This study reports the occurrence and details of spawning by Coastal Cutthroat Trout Oncorhynchus clarkii clarkii in Indian Creek in the Elwha River, Washington, in October and November.”

“This was eloquently phrased by TP Quinn (2005): ‘One cannot understand water management in the Colombia River system or forestry on the Oregon coast without understanding salmon’.”

“Further movement is associated with seasonal changes in stream flow (Quinn 2005), competitive displacement (Gowan and Fausch 1996), and habitat patch quality assessment (Kahler et al.”

“mykiss (hereafter, collectively referred to as “salmon”) are renowned for their life history diversity across all stages of the life cycle (Groot and Margolis 1991; Quinn 2005; Beamish 2018).”

“Juveniles grow in the river before migrating to the ocean to feed and grow, returning to natal areas once mature to spawn and die (Quinn 2018).”

“Chinook salmon are born in freshwater streams across the Pacific Rim, spend several months to more than a year in freshwater, migrate to the ocean as juveniles to spend 1–6 years feeding and growing, then return to their natal river to spawn (Quinn, 2005).”

“Unlike congeners that rely heavily on freshwater for juvenile rearing, pink salmon use freshwater only for spawning and embryonic development and spend the rest of their life history in coastal, estuarine habitats and at sea (Keefer & Caudill, 2014; Quinn, 2018).”

“Chinook salmon ( Oncorhynchus tshawytscha ) are anadromous, sem-elparous, and philopatric fish that complete long-distance migrations up rivers to spawn (Quinn, 2018; Birnie-Gauvin et al., 2021).”

“Wild-born Pacific salmon outmigrate from freshwater to saltwater as fry in the spring and early summer (Quinn 2018).”

“Pacific salmonids ( Oncorhynchus spp.) are of profound recreational, ecological, and economic importance throughout their range (Quinn 2018).”

“In the process, spawners deposit large amounts of carcass, 44 egg, and waste materials (Naiman et al. 2002; Quinn 2005) and dislodge benthic invertebrates 45 that are, in turn, preyed upon by fish (Peterson and Foote 2000).”

“Individuals move, disperse and migrate in order to feed, establish home ranges, accomplish life-history events and evade predators and harsh environmental conditions (Linløkken, 1993; Lucas & Baras, 2001; Northcote, 1984; Quinn, 2018).”

“We tracked these factors because Coho Salmon, like all Pacific salmon, are sensitive to temperature (Brett 1952, Sandercock 1991, Quinn 2005), and macroinvertebrates make up the bulk of their diet (Nielsen 1992, Robillard 2006, Rosenfeld and Raeburn 2009).”

“Identifying the timing of juvenile growth can therefore give important insights into the ecology of a population because it is shaped by life histories, environmental conditions, community composition and food availability (Quinn, 2018; Thompson & Beauchamp, 2016).”