title: Broad-scale impacts of salmon farms on temperate macroalgal assemblages on rocky reefs.
abstract: Intensive fish culture in open sea pens delivers large amounts of nutrients to coastal environments. Relative to particulate waste impacts, the ecological impacts of dissolved wastes are poorly known despite their potential to substantially affect nutrient-assimilating components of surrounding ecosystems. Broad-scale enrichment effects of salmonid farms on Tasmanian reef communities were assessed by comparing macroalgal cover at four fixed distances from active fish farm leases across 44 sites. Macroalgal assemblages differed significantly between sites immediately adjacent (100m) to fish farms and reference sites at 5km distance, while sites at 400m and 1km exhibited intermediate characteristics. Epiphyte cover varied consistently with fish farm impacts in both sheltered and exposed locations. The green algae Chaetomorpha spp. predominated near fish farms at swell-exposed sites, whereas filamentous green algae showed elevated densities near sheltered farms. Cover of canopy-forming perennial algae appeared unaffected by fish farm impacts.
authors.affiliation: Institute for Marine and Antarctic Studies, University of Tasmania, GPO Box 252-49, Hobart, Tas 7001, Australia. Electronic address: Elizabeth.Oh@utas.edu.au.
authors.forename: E S
authors.initials: ES
authors.lastname: Oh
authors.affiliation: Institute for Marine and Antarctic Studies, University of Tasmania, GPO Box 252-49, Hobart, Tas 7001, Australia.
authors.forename: G J
authors.initials: GJ
authors.lastname: Edgar
authors.affiliation: Geography and Environmental Studies, University of Tasmania, GPO Box 252, Hobart, Tas 7001, Australia.
authors.forename: J B
authors.initials: JB
authors.lastname: Kirkpatrick
authors.affiliation: Institute for Marine and Antarctic Studies, University of Tasmania, GPO Box 252-49, Hobart, Tas 7001, Australia.
authors.forename: R D
authors.initials: RD
authors.lastname: Stuart-Smith
authors.affiliation: Institute for Marine and Antarctic Studies, University of Tasmania, GPO Box 252-49, Hobart, Tas 7001, Australia.
authors.forename: N S
authors.initials: NS
authors.lastname: Barrett
mesh_terms: D000818:Animals; D037421:Anthozoa; D017756:Aquaculture / Q000379:methods*; D000460:Chlorophyta / Q000502:physiology; D017753:Ecosystem; D004777:Environment; D009792:Oceans and Seas; D012474:Salmon; D012624:Seaweed; D013648:Tasmania
keywords: Aquaculture; Benthic macrofauna; Fishes; Invertebrates; Organic pollution; Tasmania