Does fine sediment source as well as quantity affect salmonid embryo mortality and development?

• Published in: The Science of the total environment Vol. 541; pp. 957 - 968
• Main Authors: Sear, D.A., Jones, J.I., Collins, A.L., Hulin, A., Burke, N., Bateman, S., Pattison, I., Naden, P.S.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.01.2016
• Subjects: Agriculture; Animals; Atlantic salmon; Brown trout; Channels; Damage; Embryo, Nonmammalian; Embryos; Environmental Monitoring; Fine sediment; Fitness; Geologic Sediments - analysis; Mortality; Organic matter; Rivers; Roads; Salmo salar; Salmo salar - growth & development; Salmo trutta; Sediment sources; Sediments; Trout; Trout - growth & development; Water Pollutants - analysis; Sediment sources; Organic matter; Atlantic salmon; Fine sediment; Brown trout
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2015.09.155

Fine sediments are known to be an important cause of increased mortality in benthic spawning fish. To date, most of the research has focussed on the relationship between embryo mortality and the quantity of fine sediment accumulated in the egg pocket. However, recent evidence suggests a) that the source of fine sediment might also be important, and b) that fitness of surviving embryos post-hatch might also be impacted by the accumulation of fine sediments. In this paper, we report an experiment designed to simulate the incubation environment of brown trout (Salmo trutta) and Atlantic salmon (Salmo salar). During the experiment, the incubating embryos were exposed to different quantities of fine (<63μm) sediment derived from four different sources; agricultural topsoils, damaged road verges, eroding river channel banks and tertiary level treated sewage. Results showed that mass and source are independently important for determining the mortality and fitness of alevin. Differences between species were observed, such that brown trout are less sensitive to mass and source of accumulated sediment. We demonstrate for the first time that sediment source is an additional control on the impact of fine sediment, and that this is primarily controlled by the organic matter content and oxygen consumption of the catchment source material. [Display omitted] •We expose two salmonid fish species to different sediment loads and sources.•We examine egg mortality and alevin fitness in response to sediment mass and source.•We find that sediment source as well as mass effects spawning habitat quality.•Brown trout are less sensitive to sediment compared to Atlantic salmon.•Organic matter is the main factor determining the impact of a sediment source.