Preliminary Evaluation of the Use of Nitrogen Stable Isotope Ratios to Establish Escapement Levels for Pacific Salmon

Bilby, Robert E.; Fransen, Brian R.; Walter, Jason K.; Cederholm, Carl J.; Scarlett, W. J.

doi:10.1577/1548-8446(2001)026<0006:peotuo>2.0.co;2

Cited by 69 publications

(66 citation statements)

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“…Since growth and production of stream-rearing salmonids can be limited by food availability (Chapman 1966) these findings imply that cross-boundary nutrient inputs may be important for fisheries. Understanding these cross-species interactions can also help inform ecosystem-based management (Bilby et al 2001, Wipfli and Baxter 2010, Levi et al 2012). …”

Section: Discussionmentioning

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: Discussionmentioning

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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“…1) only during floods in the fall and after removal of the trap in winter, so that the number of salmon arriving at Naibetsu River is variable seasonally and yearly. The maximum biomasses of carcasses below the dam were 0.5, 0.6, 2.5, and 7.5 kg 100 m -2 in 1999-2000, 2000-2001, 2001, respectively (Ito et al 2005.…”

Section: Study Sitementioning

confidence: 99%

“…Salmon carcasses contribute to the abundance and biomass of freshwater invertebrates and fishes (Kline et al 1997;Cederholm et al 1999;Bibly et al 2001;Wipfli et al 2003).…”

Section: Lowest Effective Biomass Of Salmon Carcassesmentioning

confidence: 99%

Effect of salmon carcasses on egg production of a freshwater amphipod, Jesogammarus jesoensis: a field observation

Kusano¹,

Ito²

2005

Limnology

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The effect of salmon carcasses on egg production of a freshwater amphipod, Jesogammarus jesoensis, was examined by comparing populations with and without a supply of carcasses in Naibetsu River in Hokkaido, northern Japan. The female body length in the population with carcasses became larger in the years when carcasses were abundant, being significantly larger than that in the population without carcasses. No evidence, however, was found that carcasses influenced the ratio of brooding females to mature females. Every year, the clutch size in the population with carcasses was larger than the clutch size without carcasses. Because clutch size showed a significant correlation with female size, the larger clutch size was considered to be a result of the larger female size. In addition, however, comparison of clutch size using analysis of cavariance revealed that clutch size in the population with carcasses was larger than that without carcasses, even for the same body size. Egg size showed no difference between populations and for different years. These results indicate that salmon carcasses influence egg production of J. jesoensis by increasing female body size and by increasing the investment in each clutch per unit of body size.

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“…The productivity of the system is also linked to the timing of the salmon runs and the proportion of early-run and late-run spawners. Bilby et al (2001) found that the nitrogen stable isotope ratio of one-year-old coho salmon increased with the number of spawners the previous autumn, up to a saturating level. A better understanding of the positive feedbacks between spawning salmon and stream productivity could improve estimates of the number of spawners required to maintain salmon production and could uncover more interactions between fishes and their habitat.…”

Section: Phil Trans R Soc Lond B (2002)mentioning

confidence: 99%

Multiple states in river and lake ecosystems

Dent

Cumming

Carpenter

2002

Phil. Trans. R. Soc. Lond. B

136

116

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Nonlinear models of ecosystem dynamics that incorporate positive feedbacks and multiple, internally reinforced states have considerable explanatory power. However, linear models may be adequate, particularly if ecosystem behaviour is primarily controlled by external processes. In lake ecosystems, internal (mainly biotic) processes are thought to have major impacts on system behaviour, whereas in rivers, external (mainly physical) factors have traditionally been emphasized. We consider the hypothesis that models that exhibit multiple states are useful for understanding the behaviour of lake ecosystems, but not as useful for understanding stream ecosystems. Some of the best-known examples of multiple states come from lake ecosystems. We review some of these examples, and we also describe examples of multiple states in rivers. We conclude that the hypothesis is an oversimplification; the importance of physical forcing in rivers does not eliminate the possibility of internal feedbacks that create multiple states, although in rivers these feedbacks are likely to include physical as well as biotic processes. Nonlinear behaviour in aquatic ecosystems may be more common than current theory indicates.

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Preliminary Evaluation of the Use of Nitrogen Stable Isotope Ratios to Establish Escapement Levels for Pacific Salmon

Cited by 69 publications

References 0 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

Effect of salmon carcasses on egg production of a freshwater amphipod, Jesogammarus jesoensis: a field observation

Multiple states in river and lake ecosystems

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