Effects of fish farming on microbial enzyme activities and densities: comparison between three Mediterranean sites.
OBJECTIVE
The effects of fish farming on microbial enzyme activities and heterotrophic bacterial density were investigated in three Mediterranean sites before and after the start of mariculture.


RESULTS
Microbial activities were measured on water and sediment samples by using fluorogenic substrates specific for leucine aminopeptidase, beta-glucosidase and alkaline phosphatase (AP); bacterial counts were determined by Marine agar plates.


CONCLUSIONS
Comparison of activity and abundance values obtained before and after the experiment showed that fish farming mainly affected the levels of microbial activities; they were significantly enhanced both in water and sediments, reaching an increase of 183.66 times for AP in Castellammare Gulf. After mariculture, no significant variations were recorded in heterotrophic bacterial density in the waters, while significant changes were observed in the sediments. Effects induced appeared to be extended not only to stations in which cages were located, but also to control sites far from the direct influence of fish farming.
Caruso
G
G
Istituto per l'Ambiente Marino Costiero, C.N.R., Messina, Italy. caruso@ist.me.cnr.it
Genovese
L
L
Mancuso
M
M
Modica
A
A
D000818:Animals; D017756:Aquaculture; D001419:Bacteria / Q000201:enzymology* / Q000254:growth & development*; D001492:Bass / Q000254:growth & development*; D015169:Colony Count, Microbial; D019015:Geologic Sediments / Q000382:microbiology; D007931:Leucyl Aminopeptidase / Q000378:metabolism; D019083:Mediterranean Region; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D021541:Sea Bream / Q000254:growth & development*; D012623:Seawater / Q000382:microbiology; D001617:beta-Glucosidase / Q000378:metabolism
D010744:Phosphoric Monoester Hydrolases; D001617:beta-Glucosidase; D007931:Leucyl Aminopeptidase