Ecosystemic Effects of Salmon Farming Increase Mercury Contamination in Wild Fish

deBruyn, Adrian M.H.; Trudel, Marc; Eyding, Nicola; Harding, Joel; Mcnally, Heather; Mountain, Robert; Orr, Craig; Urban, Diane J.; Verenitch, Sergei S.; Mazumder, Asit

doi:10.1021/es0520161

Cited by 37 publications

(25 citation statements)

References 21 publications

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“…Wild fish populations at aquaculture sites are subject to several anthropogenic impacts, including fishing (Akyol and Ertosluk, 2010) or aquaculture-originated contaminants (DeBruyn et al, 2006;Bustnes et al, in press). …”

Section: Waste Feed As a Trophic Subsidy With Compositional Side-effementioning

confidence: 99%

Waste feed from coastal fish farms: A trophic subsidy with compositional side-effects for wild gadoids

Fernandez‐Jover

Martínez-Rubio

Sánchez-Jérez

et al. 2011

Estuarine, Coastal and Shelf Science

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Section: Waste Feed As a Trophic Subsidy With Compositional Side-effementioning

confidence: 99%

Waste feed from coastal fish farms: A trophic subsidy with compositional side-effects for wild gadoids

Fernandez‐Jover

Martínez-Rubio

Sánchez-Jérez

et al. 2011

Estuarine, Coastal and Shelf Science

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“…This may also increase levels of pollutants such as mercury in the tissues of long-term residents beneath farms (deBruyn et al 2006). Biological evidence (increased liver somatic index) in farm-associated saithe Pollachius virens (Skog et al 2003) and the results of tagging studies in southern Norway (Bjordal & Skar 1992, Bjordal & Johnstone 1993 suggest that saithe reside in the vicinity of specific farms for several months.…”

Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 99%

High connectivity of salmon farms revealed by aggregation, residence and repeated movements of wild fish among farms

Uglem¹,

Dempster²,

Bjørn³

et al. 2009

Mar. Ecol. Prog. Ser.

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Marine fish farms are widespread in coastal waters throughout the world, yet how they modify the movement patterns of wild fish species is largely unknown. We determined the spatiotemporal distribution of saithe Pollachius virens in a fjord system with intensive salmon cage aquaculture in Norway. Abundances of 8000 to 18 000 saithe were estimated around 2 salmon farms in the fjord using an underwater video system. Residence of saithe around fish farms and movements among farms and throughout the fjord were studied using implanted acoustic transmitters and an extensive array of automatic receivers. Of the saithe equipped with acoustic tags, 63% were observed daily at one or more of the 3 farms in the fjord over a 3 mo period. When resident at a farm, saithe spent 8 to 10 h d -1 close to the sea-cages. Periods of residence at specific farms were interspersed with rapid and frequent movements to adjacent farms 1.6 to 4.7 km away. Of 24 tagged saithe, 15 moved among farms 2 to 21 times during the 3 mo period. If the movement patterns of the tagged fish are representative of the movements of untagged saithe, we estimate that fish from 2 different farms resulted in a total (± SE) of 167 112 ± 41 764 and 7768 ± 1831 inter-farm movements during the 3 mo period. Thus, fish farms should be considered as connected, not only through ocean currents, but also through wild fish movements. If saithe share pathogens with farmed salmonids, their behaviours imply that they have the potential to act as vectors for diseases and parasites among salmon farms.KEY WORDS: Aquaculture · Sea-cage · Aggregation · Movement · Pollachius virens · Tagging · Tracking Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 384: [251][252][253][254][255][256][257][258][259][260] 2009 sea lice infestations of wild salmonids (Bjørn et al. 2001, Krkosek et al. 2007). An additional impact involves the attraction and aggregation of large amounts of wild fish by salmon farms (e.g. Carss 1990, Dempster et al. 2009). The importance of this phenomenon for the management of wild fish populations and fish farming environments is gathering momentum (Dempster & Sanchez-Jerez 2008).Wild fish are resident near farms over a sufficient period to drive some physiological changes, such as modifying diets, fat content and tissue fatty-acid distributions (Skog et al. 2003, Fernandez-Jover et al. 2007). This may also increase levels of pollutants such as mercury in the tissues of long-term residents beneath farms (deBruyn et al. 2006). Biological evidence (increased liver somatic index) in farm-associated saithe Pollachius virens (Skog et al. 2003) and the results of tagging studies in southern Norway (Bjordal & Skar 1992, Bjordal & Johnstone 1993 suggest that saithe reside in the vicinity of specific farms for several months. Because of this, wild fish may also act as a source of pathogens to cultured fish in farms (e.g. Sepúlveda et al. 2004). However, little direct evidence exists to assess whether wild fish trans...

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“…The dietary shift in turn leads to increased condition, higher body fat concentration, and modified ω3:ω6 fatty acid composition of body tissue, which changes to mirror the composition of lost feed (Fernandez-Jover et al 2007a). Residence in the vicinity of farms by wild fish may also lead to consumption of feed-based pharmaceuticals or increased bio-accumulation of heavy metals (deBruyn et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Coastal salmon farms attract large and persistent aggregations of wild fish: an ecosystem effect

Dempster

Uglem²,

Sánchez-Jérez³

et al. 2009

Mar. Ecol. Prog. Ser.

149

143

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Coastal aquaculture is a globally expanding enterprise. Currently, 1200 salmon farms operate in coastal Norway, yet their capacity to aggregate and subsequently modify wild fish distributions is poorly known. Aggregations of wild fish at 9 farms and 9 control locations were counted on 3 separate days in June to August 2007. On each sampling occasion, 6 counts were made at 5 distinct depth-strata at each farm and control location. Wild fish were 1 to 3 orders of magnitude more abundant at farms than at control sites, depending on the location. Gadoid fish (Pollachius virens, Gadus morhua and Melanogrammus aeglefinus) dominated farm-associated assemblages and were present across a wide range of sizes, from juveniles to large adults. Estimated total farmaggregated wild fish biomass averaged 10.2 metric tonnes (t) per farm across the 9 farms (range: 600 kg to 41.6 t). Applied across the geographical range of Norway's 1200 salmon farms, our estimates indicate that salmon farms attract and aggregate over 12 000 t of wild fish into a total of just 750 ha of coastal waters on any given day in summer. Possible consequences of these persistent, substantial aggregations of wild fishes at farms include a heightened potential for the transfer of pathogens from salmon farms to wild fish and among adjacent salmon farms, and altered availability of wild fish to fisheries. Restrictions on fishing in the immediate surrounds of salmon farms may avoid farms acting as ecological traps, particularly for species with depressed populations such as G. morhua, which are highly attracted to farms.

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Ecosystemic Effects of Salmon Farming Increase Mercury Contamination in Wild Fish

Cited by 37 publications

References 21 publications

Waste feed from coastal fish farms: A trophic subsidy with compositional side-effects for wild gadoids

Waste feed from coastal fish farms: A trophic subsidy with compositional side-effects for wild gadoids

High connectivity of salmon farms revealed by aggregation, residence and repeated movements of wild fish among farms

Coastal salmon farms attract large and persistent aggregations of wild fish: an ecosystem effect

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