Data from: Simulating nutrient release from parental carcasses increases the growth, biomass and genetic diversity of juvenile Atlantic salmon

McLennan, Darryl1; Auer, Sonya K.1; Anderson, Graeme J.1; Reid, Thomas C.1; Bassar, Ronald D.2; Stewart, David C.3; Cauwelier, Eef3; Sampayo, James3; McKelvey, Simon4; Nislow, Keith H.5; Armstrong, John D.3; Metcalfe, Neil B.1

Published May 31, 2019 on Dryad. https://doi.org/10.5061/dryad.c6v3838

Data files

May 31, 2019 version files 132.51 KB

Macroinvertebrate biomass and abundance.xlsx
11.40 KB
Salmon focal cohort - density and biomass (age 0+ & 1+).xlsx
10.31 KB
Salmon focal cohort - fork length & body mass (age 0+).xlsx
44.39 KB
Salmon focal cohort - fork length & body mass (age 1+).xlsx
26.96 KB
Salmon focal cohort - fork length & body mass (age 2).xlsx
16.62 KB
Salmon second cohort - density and biomass (age 0+).xlsx
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Salmon second cohort - fork length (age 0+).xlsx
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Abstract

1. The net transport of nutrients by migratory fish from oceans to inland spawning areas has decreased due to population declines and migration barriers. Restoration of nutrients to increasingly oligotrophic upland streams (that were historically salmon spawning areas) have shown short-term benefits for juvenile salmon, but the longer-term consequences are little known. 2. Here we simulated the deposition of a small number of adult Atlantic salmon Salmo salar carcasses at the end of the spawning period in five Scottish upland streams (‘high parental nutrient’ treatment), while leaving five reference streams without carcasses (‘low parental nutrient’ treatment). All streams received exactly the same number of salmon eggs (n = 3,000) drawn in equal number from the same 30 wild-origin families, thereby controlling for initial egg density and genetic composition. We then monitored the resulting juvenile salmon and their macroinvertebrate prey, repeating the carcass addition treatment in the next spawning season. 3. Macroinvertebrate biomass and abundance were five times higher in the high parental nutrient streams, even one year after the carcass addition, and led to faster growth of juvenile salmon over the next 2 years (but with no change in population density). This faster growth led to more fish exceeding the size threshold that would trigger emigration to sea at 2 rather than 3 years of age. There was also higher genetic diversity among surviving salmon in high parental nutrient streams; genotyping showed that these effects were not due to immigration but to differential survival. 4. Synthesis and applications: This 2 year field experiment shows that adding nutrients that simulate the presence of small numbers of adult salmon carcasses can have long-term effects on the growth rate of juvenile salmon, likely increasing the number that will migrate to sea early and also increasing their genetic diversity. However, the feasibility of adding nutrients to spawning streams as a management tool to boost salmon populations will depend on whether the benefits at this stage are maintained over the entire life cycle.03-May-2019

Macroinvertebrate biomass and abundance

Data corresponding to the analyses of macroinvertebrate abundance (individuals min-1) and biomass (mg dry mass min-1) when focal fish were age 0+ (May-June 2016) and age 1+ (March 2017) in streams with low (0) and high (1) parental nutrient levels. Please see Table S1 in Supplementary Information for further details of each stream.

Salmon focal cohort - density and biomass (age 0+ & 1+)

Data corresponding to the analyses of density (individuals m-2) and biomass (g m-2) of juvenile Atlantic salmon (focal cohort) captured at age 0+ (July 2016) and age 1+ (July 2017) in streams with low (0) and high (1) parental nutrient levels. Please see Supplementary Information for further details of each stream.

Salmon focal cohort - fork length & body mass (age 0+)

Data corresponding to the analyses of fork length (mm) and body mass (g) of juvenile Atlantic salmon (focal cohort) at age 0+ in streams with low (0) and high (1) parental nutrient levels. Please see Supplementary Information for further details of each stream.

Salmon focal cohort - fork length & body mass (age 1+)

Data corresponding to the analyses of fork length (mm) and body mass (g) of juvenile Atlantic salmon (focal cohort) at age 1+ in streams with low (0) and high (1) parental nutrient levels. Please see Supplementary Information for further details of each stream.

Salmon focal cohort - fork length & body mass (age 2+)

Data corresponding to the analyses of fork length (mm) and body mass (g) of juvenile Atlantic salmon (focal cohort) at age 2+ in streams with low (0) and high (1) parental nutrient levels. Please see Supplementary Information for further details of each stream.

Salmon focal cohort - fork length & body mass (age 2).xlsx

Salmon second cohort - density and biomass (age 0+)

Data corresponding to the analyses of density (individuals m-2) and biomass (g m-2) of juvenile Atlantic salmon (second cohort) at age 0+ in streams with low (0) and high (1) parental nutrient levels. Please see Supplementary Information for further details of each stream.

Salmon second cohort - fork length (age 0+)

Data corresponding to the analysis of fork length (mm) of juvenile Atlantic salmon (second cohort) at age 0+ in streams with low (0) and high (1) parental nutrient levels. Please see Supplementary Information for further details of each stream.