Summary:Cage Aquaculture's Environmental Effects

Cage aquaculture in the ocean ouputs large amounts of waste into the surrounding environment. The effluent from the cages has elevated levels of nutrients, waste feed, feces and by-products such as medications for the fish. The effluent has a negative impact on the local environment. The degree of impact depends on the water movement around the cages, the assimilation capacity of the environment around the cages and the rate at which the effluent is produced. The effects of effluent on the environment is considered inconsequential to the inputs from industry and agriculture however. That being said, the ocean floor around the cages tend to be hypereutrophic and completely anoxic up to the surface. They release sulfides and other toxins into the water as a result of reduction in the anoxic conditions of the excess organics in the sediment. The long term effects of these conditions are not known. There are no standards by which to compare internationally the effects of the cages and it is hard to determine the effects, if any, on areas away from the immediate area surrounding the cages. There needs to be work done on how to reduce feed waste, and how to quantify the effects of the cages on the surrounding environment. To complete this project, more information is needed on operations other than cage salmon in Norway.

Bibliography:

Record 1

ASFA: Aquatic Sciences and Fisheries Abstracts

Organic enrichment of sediments from salmon farming in Norway:

environmental factors, management practices, and monitoring

techniques

Carroll, ML*; Cochrane, S; Fieler, R; Velvin, R; White, P

Aquaculture [Aquaculture]. Vol. 226, no. 1-4, pp. 165-180. 31 Oct

2003.

Record 2

ASFA: Aquatic Sciences and Fisheries Abstracts

The environmental impacts of marine fish cage farms in the eastern

Adriatic.

Katavic, I

Ribarstvo [Ribarstvo]. Vol. 61, no. 4, pp. 175-194. 2003.

Record 3

ASFA: Aquatic Sciences and Fisheries Abstracts

The degradation of fish-cage waste in sediments during fallowing

McGhie, TK*; Crawford, CM; Mitchell, IM; O'Brien, D

Aquaculture [Aquaculture]. Vol. 187, no. 3-4, pp. 351-366. 20 Jul

2000.

Record 4

ASFA: Aquatic Sciences and Fisheries Abstracts

The environmental impact of an offshore aquaculture system in the Gulf

of Gaeta: a first approach.