Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2025
Erindi/veggspjald / Talk/poster V89
Höfundar / Authors: Hildur Magnúsdóttir, Rakel Guðmundsdóttir, Hjalti Karlsson, Stefán Áki Ragnarsson, Andreas Macrander, Karólína Einarsdóttir, Jónas Páll Jónasson og Hrönn Egilsdóttir
Starfsvettvangur / Affiliations: 1. Hafrannsóknastofnun
Kynnir / Presenter: Hildur Magnúsdóttir
It has been widely demonstrated that open net-pen salmon farming can result in a range of localised impacts on the seafloor both under pens and in their nearest vicinity. However, far-field impacts on fjords are much more subtle and harder to detect but may over time cause an overall degradation of ecosystem health. Fjord ecosystems play many essential roles in ecosystem services, e.g. as a habitat for juveniles of important fishery species. Thus, monitoring of fjord ecosystems is of utmost importance, particularly on a fjord-by-fjord basis as they can vary in their natural sensitivity to accumulation of organic matter. In Iceland the growth of net-pen salmon farming has been rapid. In the last ten years (2014-2024), annual production of farmed salmon in the country has increased from 2,847 t to 45,684 t and is confined to the Westfjords and Eastfjords. The carrying capacity for salmon biomass of each fjord is assessed individually, based on projected accumulation of organic matter within the fjord and the sensitivity of its environment to the effects of such accumulation. After aquaculture has started, monitoring of the far-field impact of net-pens includes oceanographic parameters (temperature, salinity, oxygen content, nutrients), benthic invertebrate diversity and changes in community composition (NQI1 and other diversity indices), sediment grain size and organic content, as well as detailed microsensor measurements of sediment cores (oxygen, redox, H2S, and pH).