Fig 1.
Site locations in Akkeshi-Ko estuary, Hokkaido, Japan.
Aquaculture areas are roughly outlined in white, based on 2011 Esri aerial imagery. Numbers indicate regions for the mobile epifauna study.
Fig 2.
Photographs and schematics of long-line oyster aquaculture.
Photograph of the surface of Akkeshi-ko estuary (A) and underwater photograph of long-line aquaculture in Hokkaido, Japan (B). Schematic of long-line oyster aquaculture (C) and close-up of individual aquaculture lines (D).
Table 1.
One-way ANOVA comparisons and Tukey’s post-hoc tests for the sessile epibiont study.
Table 2.
Two-way ANOVA comparisons and Tukey’s post-hoc tests for the mobile epifauna study.
Fig 3.
Seagrass beds beneath aquaculture have higher sessile polychaete biomass than reference seagrass beds.
NMDS plot showing a Bray-Curtis similarity matrix of biomass for eelgrass-associated fouling phyla (A). Mean (± SE) biomass of sessile polychaetes (B) and red algae (C) among treatments in the sessile epibiont study. Different lower-case letters denote statistical differences between treatments by Tukey’s post-hoc tests (adjusted for multiple comparisons), whereas NS indicates non-significant results.
Fig 4.
Reference seagrass beds have significantly higher epiphyte biomass than seagrass beds beneath aquaculture.
Mean (± SE) seagrass canopy height (A), blade width (B), stem density (C), above-ground biomass (D), epiphyte biomass per cm2 (E), and SOM (F) between reference and aquaculture sites. Different lower-case letters denote statistical differences between treatments/regions by Tukey’s post-hoc tests (adjusted for multiple comparisons), NS indicates that there were no differences, and an asterisk indicates a significant interaction.
Fig 5.
Seagrass epifaunal communities beneath aquaculture are significantly different than reference seagrass communities.
NMDS plots showing Bray-Curtis similarity matrices of seagrass epifaunal communities including sessile polychaetes (A), without sessile polychaetes (B), and with only amphipods (C). Open circles are reference sites and filled circles are aquaculture sites.
Table 3.
Total number of epifauna collected in each region in the mobile epifauna study.
R = reference sites and A = aquaculture sites.