Rapport nr 77: Vattenkvalitet och bottenfauna kring tre åländska fiskodlingar sommaren 1990
LAURÈN-MÄÄTTÄ, C (1990)
LAURÈN-MÄÄTTÄ, C
1990
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This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:951-649-845-0
https://urn.fi/URN:ISBN:951-649-845-0
Tiivistelmä
Areas adjacent to three fish farms in the Åland archipelago, N. Baltic Sea, were investigated with regard to Secchi depth, oxygen, total phosphorus and nitrogen, chlorofyll-a content, organic content of the sediment and bottom fauna; abundance, biomass and species composition. The effects correlate with the sensitivity of the area. Accordingly, the effects were slightest in the area with the strongest currents. However, due to the increased fish production of the farm same changes in oxygen content and abundance of the indicator species Pontoporeia affinis could be stated. The other two areas were small bays with sills, and here the effects were more profound. Sampling showed that the chlorofyll-a and nutrient contents were quite high in the mid-summer. One of the bays was occasionally more or less deplete of oxygen near the bottom over a vast area, and the other one suffered of oxygen depletion in the inner deepest area. The areas with temporary oxygen depletion had none or only a poor benthic infauna.