You are here

Salmon carcasses increase stream productivity more than inorganic fertilizer pellets: A test on multiple trophic levels in streamside experimental channels

TitleSalmon carcasses increase stream productivity more than inorganic fertilizer pellets: A test on multiple trophic levels in streamside experimental channels
Publication TypeJournal Article
Year of Publication2010
AuthorsWipfli, MS, Hudson, JP, Caouette, JP, Mitchell, NL, Lessard, JL, Heintz, RA, Chaloner, DT
JournalTransactions of the American Fisheries Society
Volume139
Pagination824–839
Abstract

Abstract.–-Inorganic nutrient amendments to streams are viewed as possible restoration strategies for reestablishingnutrients and stream productivity throughout the western coast of North America, where salmonruns and associated marine-derived nutrient subsidies have declined. In a mesocosm experiment, we examinedthe short-term (6 weeks) comparative effects of artificial nutrient pellets and salmon carcasses, alone (low andhigh amounts) and in combination, on stream food webs. Response variables included dissolved nutrientconcentrations, biofilm ash-free dry mass (AFDM) and chlorophyll-a levels, macroinvertebrate density,growth and body condition of juvenile coho salmon Oncorhynchus kisutch, and whole-body lipid content ofinvertebrates and juvenile coho salmon. Most of the response variables were significantly influenced bycarcass treatment; the only response variable significantly influenced by fertilizer pellet treatment was solublereactive phosphorus (SRP) concentration. Ammonium-nitrogen concentration was the only response variableaffected by both (low and high) levels of carcass treatment; all others showed no significant response to thetwo carcass treatment levels. Significant treatment3time interactions were observed for all responses exceptnitrate; for most responses, significant treatment effects were detected at certain time periods and not others.For example, significantly higher SRP concentrations were recorded earlier in the experiment, whereassignificant fish responses were observed later. These results provide evidence that inorganic nutrient additionsdo not have the same ecological effects in streams as do salmon carcasses, potentially because inorganicnutrient additions lack carbon-based biochemicals and macromolecules that are sequestered directly orindirectly by consumers. Salmon carcasses, preferably deposited naturally during spawning migrations, appearto be far superior to inorganic nutrient amendments for sustaining and restoring stream productivity, includingfish production, and should be chosen over artificial nutrient additions when feasible and practical.

DOI10.1577/T09-114.1
Username Tag: