Nutrient fluxes and the recent collapse of coastal California salmon populations
Migratory salmon move nutrients both in and out of fresh waters during the different parts of their life cycle. We used a mass-balance approach to quantify recent changes in phosphorus (P) fluxes in six coastal California, USA, watersheds that have recently experienced dramatic decreases
in salmon populations. As adults, semelparous Chinook (Oncorhynchus tshawytscha) and coho (Oncorhynchus kisutch)
salmon imported 8.3 and 10.4 times more P from the ocean, respectively, than they exported as smolts, while iteroparous steelhead (i.e., sea-run rainbow trout, Oncorhynchus mykiss) imported only
1.6 times more than they exported as kelts and smolts. Semelparous species whose life histories led them to import more nutrients were also the species whose populations decreased the most dramatically in California in recent years. In addition, the relationship between import and export
was nonlinear, with export being proportionally more important at lower levels of import. This pattern was driven by two density-dependent processes — smolts were larger and disproportionately more abundant at lower spawner abundances. In fact, in four of our six streams we found
evidence that salmon can drive net export of P at low abundance, evidence for the reversal of the “conveyor belt” of nutrients.
Document Type: Research Article
NOAA Fisheries, Southwest Fisheries Science Center, Santa Cruz, CA 95060, USA.
USGS California Cooperative Fish and Wildlife, Humbolt State University, Arcata, CA 95521, USA.
California State Department of Fish and Game, 32330 North Harbor Drive, Fort Bragg, CA 95437, USA.
Campbell Timberlands Management, LLC, P.O. Box 1228, Fort Bragg, CA 95437, USA.
Publication date: July 6, 2011
More about this publication?
Published continuously since 1901 (under various titles), this monthly journal is the primary publishing vehicle for the multidisciplinary field of aquatic sciences. It publishes perspectives (syntheses, critiques, and re-evaluations), discussions (comments and replies), articles, and rapid communications, relating to current research on cells, organisms, populations, ecosystems, or processes that affect aquatic systems. The journal seeks to amplify, modify, question, or redirect accumulated knowledge in the field of fisheries and aquatic science. Occasional supplements are dedicated to single topics or to proceedings of international symposia.
- Information for Authors
- Submit a Paper
- Subscribe to this Title
- Terms & Conditions
- Sample Issue
- Reprints & Permissions
- ingentaconnect is not responsible for the content or availability of external websites