Chemical composition and release rate of waste discharge from an Atlantic salmon farm with an evaluation of IMTA feasibility

Chemical composition and release rate of waste
discharge from an Atlantic salmon farm with an
evaluation of IMTA feasibility
Xinxin Wang1,*, Kjersti Andresen1
, Aleksander Handå2
, Bjørn Jensen3
,
Kjell Inge Reitan1
, Yngvar Olsen1
1
Trondheim Biological Station, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim,
Norway
2
SINTEF Fisheries and Aquaculture, 7465 Trondheim, Norway
3
Lerøy-Midnor, 7247 Hestvika, Norway
ABSTRACT: The carbon (C), nitrogen (N) and phosphorus (P) compositions of salmon feed, fish
and faeces were studied at a salmon farm in Badstuvika (63° 31’ N, 9° 9’ E) in central Norway.
These data were used to estimate the release rates of wastes from 2 salmon cages and the qualities
of particulate wastes as food resources for integrated multi-trophic aquaculture (IMTA). About
38% of feed C, 43% of feed N and 24% of feed P were retained as fish biomass. About 62% of feed
C, 57% of feed N and 76% of feed P were lost into the environment. Around 40% of feed C was
respired as CO2, and 39% of feed N and 24% of feed P were excreted as dissolved inorganic nitrogen and phosphorus, respectively. About 19% of feed C, 15% of feed N and 44% of feed P were
released as particles. The chemical composition of feed was independent of time (p > 0.05). The
faecal C content increased with increasing fish weight (r2 = 0.14, p < 0.05); however, other faecal
chemical components showed no apparent relationships with fish weight (p > 0.05). Our results
suggested that P digestibility of feed may be 30%, but more information is still needed to reach
conclusions on this. The C content of faeces was 70% of that of feed and the N content of faeces
was 50% of that of feed. The P content was far higher than that of feed. The lipid, docosahexaenoic acid and eicosapentaenoic acid contents of faeces were comparable to those of some
phytoplankton species. The results suggested that both feed and faeces are adequate food for blue
mussels and sea cucumbers co-cultured with salmon, and the nutrient content may meet their
nutritional requirements.
KEY WORDS: Mass balance · Chemical composition · Faeces · Integrated multi-trophic
aquaculture · Salmon farming · Salmo salar


https://www.int-res.com/articles/aei2013/4/q004p147.pdf


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