Impacts of salmon farming on Atlantic cod stocks Salcod

Informations

Funding country

Norway

Acronym

-

URL

-

Start date

1/1/2019

End date

12/31/2024

Budget

3,001,200 EUR

Fundings

Abstract

Fishermen have repeatedly claimed that salmon farms prevent Atlantic cod from using their traditional spawning grounds, and that this causes diminishing coastal cod populations. In the current project, impacts of salmon farming on cod stocks, we aim to get a holistic view of the impact of salmon farming on wild cod populations. To achieve this, despite Corona challengers, we have captured, acoustically tagged and released between 50-100 large spawning cod during winter, as well as around 50 larger coastal cod during autumn, annually since 2019. Migratory behavior and home range of these have in detail been investigated through a network of listening hydrophones, which also have been maintained continuously for the last three years (WP 1). We have also captured, sampled (e.g. to discriminate between Coastal and North East Arctic Cod), tagged and released more than 4500 juvenile cod. These will give us information about abundance, growth and behavior in young cod (WP 2). Physiological effects (e.g fatty acids and growth) in cod close and distant from fish farms (WP 3), as well as how cod uses sea floor and benthos, and how this again is influenced by intensive salmon farming activity (WP 4), have also been studied. In addition, we have reviewed the literature on effects of salmon farming on marine fish, including ongoing Norwegian research on cod. This well be the fundament for updated risk advice and will be published in the next IMR report on “Environmental effects of Norwegian fish farming” (WP 5). By implementing a before-after-control-impact (BACI) study design, working in northern Norwegian fjords with and without, but also by repeating the investigations above after establishment of a salmon farm, we hope to quantify the impact of salmon farms on cod survival, growth, migration, spawning and recruitment, and collate this in models, allowing us to make broad inferences about the underlying mechanisms and identify the pressures from salmon. Altogether, this will merge into improved advice to government, industry and population about how to secure aquaculture growth concurrent with preservation of wild fish and sustainable fisheries (WP 5 and 6). Establishment of the planned salmon farm in Frakkfjord have however been delayed. In accordance with the Norwegian Research Council (NRC), the NRC-project has therefore been temporary put on hold in 2022. Institute of Marine Research (IMR) has nevertheless kept on with parts of the project: we have tagged, sampled and released more cod both winter and autumn in the farm free Frakkfjord and also maintained the network of acoustic receivers. In addition, we have prepared and started a comparative study in the intensively farmed neighbor fjord, Langfjord: In autumn 2022 the fjord was acoustically instrumented, and we have tagged close to 500 cod, including more than 40 with acoustic tags. If the farm is further delayed, or do not come at all within the project period, this will give us valuable comparable cod-data in a fjord without- and with salmon farms and ensure as good as possible achievements of the project.