The effect of salmon redd excavation on stream substrate and benthic community of two salmon spawning streams in Canterbury, New Zealand

Abstract

The effects of redd excavation by female quinnat salmon (Oncorhynchus tshawytscha walbaum) on the bentic invertebrate communities of two stable springfed spawning streams in the headwaters of the Rakaia River, South Island, New Zealand, were studied during January to September 1982. The gross effects of salmon spawning on the streams appear to be: the loss of instream macrophytes, algae and mosses, a loss of fines and detritus, and a modification of the pool-riffle character. Redd excavation may be associated with a reduction in benthic standing crop of up to 83.670, with only a minor effect on the benthic community structure. Benthic recolonisation rates were similar for both spawning streams, with almost complete recovery after 95 days.

Disturbance of freshwater habitats by anadromous salmon in Alaska

“…2). Thus, our study experimentally confirms previous observations that periphyton biomass is temporarily lower in salmon spawning locations after salmon spawning (Field-Dodgson 1987;Minakawa and Gara 1999;Peterson and Foote 2000). Although salmon spawning directly decreased algal biomass, it may The shading of the symbol indicates the time at which the sample was taken: black indicates "before", gray indicates "during", andwhite indicates "after" peak salmon spawning.…”

“…Although lacking rigorous controls, previous observational studies have suggested that these recently disturbed patches may be characterized by lower levels of fine sediment (Kondolf et al 1993;Montgomery et al 1996) and reduced abundances of benthic flora and fauna (Hildebrand 1971;Field-Dodgson 1987;Gara 1999, 2003;Peterson and Foote 2000).…”

Bed disturbance via foraging fish increases bedload transport during subsequent high flows and is controlled by fish size and species

“…With regard to fluvial systems, reviews by Statzner (2011), Rice et al (2012), and Albertson and Allen (2014) highlight the geomorphic capabilities of fish and macroinvertebrate fauna; but the number of studies is small and limited to a few species and impact mechanisms. The majority of research has focused on bed bioturbation during spawning by Salmonids (Field-Dodgson, 1987;Kondolf et al, 1993;Montgomery et al, 1996;Hassan et al, 2008), bed and bank bioturbation by crayfish (Statzner et al, 2003a;Zhang et al, 2004;Johnson et al, 2011;Harvey et al, 2014;Rice et al, 2014) and substrate consolidation through silk secretion by hydropsychid caddisflies (Cardinale et al, 2004;Johnson et al, 2009;. Rice et al (2012, their Figure 19.6) highlight a range of additional mechanisms by which fish and invertebrates might affect bed material conditions and thence sediment transport in gravel-bed rivers.…”

Eco-evolutionary dynamics in Pacific salmon

“…The importance of these salmon inputs for aquatic and terrestrial ecosystems has been documented in detail (see reviews in Willson and Halupka, 1995;Cederholm et al, 1999;Gende et al, 2002;Schindler et al, 2003;Janetski et al, 2009). In addition to the importance of salmon as a resource subsidy, they are also ecosystem engineers because of the disturbance caused by their nest digging activities (for example, Field-Dodgson, 1987;Peterson and Foote, 2000;Moore et al, 2004). The ecological importance of salmon suggests that this is a system where eco-evolutionary dynamics will be manifest (see also Kinnison and Hairston, 2007;Kinnison et al, 2008;Waples et al, 2010).…”

“…Another potential community-level effect of selection on salmon body size is related to their nest digging activity. By disturbing the local substrate, salmon nest digging results in short-term decreases in insect biomass (for example, Field-Dodgson, 1987;Moore and Schindler, 2008). The predictable disturbance also influences insect life histories, where emergence is timed to occur before salmon arrival, presumably to avoid mortality because of salmon nest digging activities (Moore and Schindler, 2010).…”