Pacific salmon effects on stream ecosystems: a quantitative synthesis

Janetski, David J.; Chaloner, Dominic T.; Tiegs, Scott D.; Lamberti, Gary A.

doi:10.1007/s00442-008-1249-x

Cited by 202 publications

(293 citation statements)

References 68 publications

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“…along the temperate coasts of the northern Pacific Ocean. Because salmon gain .95% of their body mass in the ocean, return to freshwater to spawn and then die, the marine-derived nutrients they transport can be substantial to nutrient-poor freshwater streams and lakes (Naiman et al 2002, Schindler et al 2003, Janetski et al 2009). While most research has focused on import of nutrients (e.g., Verspoor et al 2011, Hocking et al 2013, it is noteworthy that salmon can also drive export of nutrients from streams through the engineering effects of spawning adults, which can flush invertebrates downstream ).…”

Section: Introductionmentioning

confidence: 99%

Effects of subsidies from spawning chum and pink salmon on juvenile coho salmon body size and migration timing

Nelson

Reynolds

2015

Ecosphere

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Abstract. Organisms transporting nutrients from highly productive ecosystems can subsidize food webs and alter ecosystem processes. For example, the carcasses and eggs of migratory Pacific salmon (Oncorhynchus spp.) provide a high-quality food source that could potentially benefit other species of salmon rearing in fresh water. We investigated relationships between spawning chum (O. keta) and pink (O. gorbuscha) salmon density, and the body size and age of juvenile coho salmon (O. kisutch) in 17 streams on the central coast of British Columbia, Canada. Chum salmon density was the most consistently important and positive correlate of coho body size, in comparison with pink salmon density, juvenile coho salmon density, and numerous characteristics of habitats. This was shown by comparisons both among and within streams, and between sites above and below natural barriers to spawning chum and pink salmon. In addition, streams that had higher chum and pink salmon spawning densities had a higher proportion of age 0 coho (less age 1), suggesting earlier juvenile coho salmon migration to the ocean with increased spawning salmon nutrient availability. Most of the coho salmon sampled had little or no direct contact with spawning chum and pink salmon, which suggests an indirect, time-delayed influence on coho salmon body size.

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Section: Introductionmentioning

confidence: 99%

Effects of subsidies from spawning chum and pink salmon on juvenile coho salmon body size and migration timing

Nelson

Reynolds

2015

Ecosphere

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“…Migrations of anadromous fish are a relatively well-studied example of a resource pulse that influences a diversity of ecological characteristics, including trophic productivity and habitat structure, through their spawning activities (Richey et al 1975, Moore et al 2007, Jones et al 2010). Though our understanding of this system is growing (Janetski et al 2009), there remain some unresolved questions including two that we address in this paper. First, there is little known with regards to the enrichment potential of low densities (0.1-1.0 kg/m 2 ) of spawning fish (Janetski et al 2009), which is characteristic of many populations across their native range (Gresh et al 2000).…”

Section: Introductionmentioning

confidence: 99%

“…Though our understanding of this system is growing (Janetski et al 2009), there remain some unresolved questions including two that we address in this paper. First, there is little known with regards to the enrichment potential of low densities (0.1-1.0 kg/m 2 ) of spawning fish (Janetski et al 2009), which is characteristic of many populations across their native range (Gresh et al 2000). Second, there is some uncertainty regarding the mechanisms by which adult salmon influence the productivity of higher trophic levels.…”

Section: Introductionmentioning

confidence: 99%

Linking resource availability and habitat structure to stream organisms: an experimental and observational assessment

et al. 2014

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An experiment and a mark‐recapture field study of juvenile coho salmon (Oncorhynchus kisutch) were conducted to identify controls of key energy flow chains in river food webs. In the small‐scale experiment, we investigated the individual and interactive effects of physical habitat structure (PHS) as small wood and resource availability (tissue of adult Chinook salmon, O. tshawytscha) on nutrients, algae, invertebrates, and fish predators including juvenile coho. In the field, we quantified the effects of natural variation in prey availability (invertebrate drift biomass), PHS (wood), and local fish density on summer growth of juvenile coho across multiple stream reaches. Adding salmon tissue to experimental channels resulted in strong bottom‐up effects on select invertebrates including increased population biomass of chironomids and baetids, the numerically dominant invertebrates, and faster growth of juvenile coho. We link the enhanced growth of coho to chironomid productivity: for instance, adult chironomid flux was 4.3× higher and coho consumption of these animals 3× higher in salmon‐subsidized channels. PHS in experimental channels was associated with reduced algal biomass, potentially in response to increased invertebrate consumption, and invertebrate flux or export. The field study revealed coho growth was negatively related to PHS and total fish density and positively related to Diptera drift biomass; however, the effects of fish density and drift biomass on coho growth were relatively weak. The field study also indicated that prey resource availability and coho growth were associated with differences in canopy cover, with prey biomass and coho growth 2–4× higher in reaches receiving more sunlight. As in the experiment, coho in natural stream reaches predominantly fed on adult chironomids and other Diptera, indicating that these taxa and life‐stages are a key link between the benthic food web and mobile vertebrate predators. Our study showed that bottom‐up processes initiated by salmon subsidies and possibly light flux determined key trophic interactions in the Cedar River food web. Moreover, we speculate that PHS may modify some of these interactions indirectly through its effects on the movement of organisms through the environment.

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“…A considerable body of research has investigated the effects of the salmon's unique life history, which couples offshore marine productivity to coastal ecosystems (Gende et al 2002, Naiman et al 2002. However, the net effects of spawning salmon can vary (Harding et al 2014); salmon can subsidize freshwater and riparian habitats through excretion and egg and carcass deposition (Kline et al 1990, Cederholm et al 1999, Janetski et al 2009, and can export nutrients with juvenile emigration and disturbance as adults dig and defend nests (Moore et al 2007, Kohler et al 2013. Although considerable amounts of salmon-derived nutrients imported into coastal watersheds are retained, large proportions are also exported downstream to estuaries (Gende et al 2004, Mitchell and Lamberti 2005, Cak et al 2008.…”

Section: Introductionmentioning

confidence: 99%

From earth and ocean: investigating the importance of cross‐ecosystem resource linkages to a mobile estuarine consumer

Harding

Reynolds

2014

Ecosphere

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Abstract. Externally derived resources often contribute to the structuring of ecological communities.Estuaries are one of the most productive ecosystems in the world and provide an ideal system to test how communities may be shaped by resource subsidies because they occur at the intersection of marine, freshwater and terrestrial habitats. Here we tested the effects of both terrestrial-and salmon-derived subsidies, in addition to other factors such as habitat area, on the diet (inferred from stable isotopes), abundance and size of a mobile estuarine consumer, the Dungeness crab (Metacarcinus magister). Crab trap surveys encompassed 19 watersheds over two seasons in the central coast of British Columbia, Canada, which spanned natural gradients in estuary size, watershed size, riparian tree composition, and Pacific salmon spawning density. Stable isotope ratios of crab tissue confirmed the predictions that estuarine nutrient regimes can be strongly affected by upstream watershed size, salmon density, and the dominance of nitrogen-fixing red alder (Alnus rubra). There were more crabs in larger estuaries and the largest crabs were found in estuaries below the largest watersheds. The proportional contributions of terrestrial-and salmon-derived subsidies to the diet of Dungeness crabs increased with watershed size and salmon density, respectively. These results confirmed that resource subsidies can constitute large proportions of the Dungeness crab's diet, that crab abundance is determined by habitat size, but that crab size is affected by the magnitude of terrestrial resource influx.

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Pacific salmon effects on stream ecosystems: a quantitative synthesis

Cited by 202 publications

References 68 publications

Effects of subsidies from spawning chum and pink salmon on juvenile coho salmon body size and migration timing

Effects of subsidies from spawning chum and pink salmon on juvenile coho salmon body size and migration timing

Linking resource availability and habitat structure to stream organisms: an experimental and observational assessment

From earth and ocean: investigating the importance of cross‐ecosystem resource linkages to a mobile estuarine consumer

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