Search   in
between years and
Vertical diel dynamic of fish assemblage associated with an artificial reef (Northern Adriatic Sea)
Antonello Sala, Gianna Fabi and Sarine Manoukian

The vertical diel activity of a fish assemblage inhabiting the Senigallia artificial reef (northern Adriatic Sea, Italy) was evaluated from July to November 1996 using enhanced hydroacoustic techniques. Extensive seabed mapping of the area was done using a multibeam echosounder to obtain background imagery of the reef structures and identify the most suitable locations for placing stationary acoustic transducers. Three acoustic transducers were placed inside the reef area, while a fourth was located in the open sea outside the area. Data analysis was conducted on three different depth layers: surface, midwater and bottom. In each layer, diel fish biomass inside the reef showed two peaks, one in the early morning and the other in the late evening. Slightly different behaviour was observed outside the protected area. Comparison of the layers showed that fish biomass was not homogeneously distributed along the water column throughout the sampling period. There were high values in the middle and bottom layers until the end of August. However, no significant biomass variations in time were observed outside the reef where low values were always recorded in each layer.

Keywords: Adriatic Sea, artificial reef, fish biomass, multibeam sonar, split-beam hydroacoustic.
Contents of this volume Sci. Mar. 71(2) : 355-364 Back PDF
Please, send comments to
ICM (CSIC) - Passeig Marítim de la Barceloneta, 37-49. E-08003 Barcelona (Spain)