title: How does coarse gravel augmentation affect early-stage Chinook salmon Oncorhynchus tshawytscha embryonic survivorship?
abstract: Early-stage Chinook salmon Oncorhynchus tshawytscha embryos were incubated in artificial redds that mimicked hyporheic conditions in gravel-augmented habitat to assess survivorship. Two complementary experiments were conducted where units varied along gradients of (1) increasing interstitial flow velocity (0·05-2·50 cm s⁻¹) in a uniformly coarse (particles ≥22 mm) sediment mixture and (2) increasing sediment porosity with interstitial flow velocity held constant. Embryonic survivorship increased moderately along a gradient of interstitial flow velocity, while survivorship among units with varying sediment porosities was consistent. No evidence for flow-induced agitation and mortality was observed. Results suggest that high interstitial flow velocities may confer a moderate advantage for incubating salmonid embryos when conditions that typically reduce embryonic mortality (i.e. low concentrations of fine particles) are ideal.
authors: Bren School of Environmental Science and Management, University of California, Santa Barbara, Santa Barbara, CA 93106, USA. utz.ryan@gmail.com
authors: R M
authors: RM
authors: Utz
authors: C F
authors: CF
authors: Mesick
authors: B J
authors: BJ
authors: Cardinale
authors: T
authors: T
authors: Dunne
mesh_terms: D000818:Animals; D003247:Conservation of Natural Resources / Q000379:methods*; D017753:Ecosystem; D045483:Rivers; D012474:Salmon / Q000196:embryology* / Q000502:physiology*