The ODAS Italia 1 oceanographic buoy is moored in the Ligurian Sea, 37 nm from Genoa, along the Genoa-Cape Corse transect (43° 48.90' N-09° 06.80' E), over a 1270 m deep sea bottom. The underwater ...portion of the buoy is 37 m long and 0.60 m in diameter, acting as a small island for colonization of fouling organisms and as a fish-aggregating device (FAD). The role of the buoy in attracting and maintaining fish assemblages was investigated by visual censuses in different seasons at depths of 0-40 m. Fish from seven families, comprising 12 species, of which three are benthic, were recorded with maximum abundance in summer. Fouling was studied from samples collected on the buoy and on immersed panels. The fouling community of the buoy consisted of 34 algae and 100 animal species, including three fish. The settlement processes of the fouling community on the panels, in particular on those exposed for over 70 months at 12 m and 33 m depth, are described based on counts of settled organisms, the covering index of each taxa and biomass assessments. On the panels, 63 species were identified. The fouling biomass, on the panel submerged for 70 months, assessed as wet weight, reached 2.8 kg/m^sup 2^ at 12 m depth and 4.8 kg/m^sup 2^ at 33 m depth. Observations of benthic organisms settled directly on the buoy were made between 1988 and 1989 and when the buoy was retrieved and brought back to shore on April 15, 1991 after 52 months at sea. At this time, the fouling community along the full 37 m length of the buoy was sampled, and 91 taxa, including 83 species, were identified. Several of the species present on the buoy are shallow, coastal species, some with a very short larval period. Possible ways of colonization by such species are discussed. Despite seasonal changes, the pelagic fish community was more stable over the period of 11 years of study than the benthic community settled on the buoy (that is still developing).PUBLICATION ABSTRACT
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The main themes of the Symposium were biodiversity in enclosed and semi-enclosed seas and artificial habitats, and the restoration of degraded systems. These themes are highly relevant today both ...from a basic scientific point of view and from an applied approach. The papers dealing with the first theme represent current research and concerns about marine biodiversity in enclosed seas and will have wide appeal to all those interested in understanding and preserving the biodiversity of the seas and in particular of the Mediterranean and Black Seas. The papers in the second theme represent a synthesis of up-to-date knowledge on artificial habitats and how they can contribute to protection of coastal marine ecosystems, to enhancement of species diversity and biological resources and to restoration of degraded marine environments.
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Visual census activities were implemented on a monthly basis from February 1989 to December 1998 to analyze trends in the fish population on the Loana artificial reef. This reef is located in the ...Ligurian Sea off the coast of Italy. Researchers documented gradual increases in the values for species richness per census and the Shannon-Wiener diversity index. Analyses of the evolution of the community have identified the arrival of several new species, including Phycis phycis, Epinephelus marginatus, Muraena helena, and Parablennius gattorugine. Other species have disappeared from the region, including Gobius cruentatus. Gradual increases in the density of certain species typically favoring hard substrata have also been documented. Observed data underscored the long-term nature of reef community stabilization processes.
Thirty months after the construction of the Loano artificial reef a study of fish abundance was started. The method used both direct censuses at monthly intervals and limited fishing activity with ...longlines and trammels. The monthly census was carried out by two divers in the central
part of the artificial reef made up of pyramids, each consisting of five concrete cubic blocks with 2-m sides. The census was carried out in two main phases: first the observer counted the fish moving around him for 15 min and then he explored the holes and the internal corridors. The second
phase consisted of a 25-m crosswise movement between two pyramids. Observations were carried out over a period of 2 years, from February 1989 to February 1991, and 66 species of fish and invertebrates of fishing importance were caught and/or observed in the Loano artificial reef; 41 species
(of which three were Crustaceans and two Cephalopods) were censused during the above-mentioned dives. The most numerous families were Sparidae and Labridae, followed by Serranidae. The predominance of the first two families seems to be one of the general characteristics of rocky sea-bed fish
communities in the northwest Mediterranean. Seasonal changes in the qualitative and quantitative assemblages of fish are described. An important contribution to these changes was the appearance of juveniles, mainly in the latter half of the summer and in the autumn. It was in this period that
the maximum fish density occurred, while the minimum was registered in June. The number of fishes increased with the age of the artificial reef and the evolution of macrobenthos settlement. In particular the development of algae improved the reef's attractiveness to the Labridae species.
The aim of this study is to increase our knowledge of short-term (month) and long-term (3 year) trends in communities settled on hard artificial substrata at different depths off Loano (Lat. ...44°07′22″ Long. 8°16′25″). An artificial reef complex was built
in response to protection, mitigation and restoration needs in an area subjected to illegal trawling, destruction of seagrass beds and the discharge of muddy material. The reef complex consisted of large concrete blocks (2 × 2 × 2 m) arranged in pyramids and single small concrete
blocks (1.2 × 1.2 × 1.2 m). Short-term observations were intended to show seasonal changes in the settlement periods for exploitable resources such as oysters (Ostrea edulis). The long-term investigations were intended to show the pattern of sessile biota development, climax
stages and interaction with fishes. To accomplish these objectives, asbestos panels (20 × 30 × 0.4 cm) were immersed for 1, 3, 6, 9 and 12 months at four stations in different depths. Photographic and removal sampling have been used since 1986. Results indicated consistent increases
in biomass, cover and number of sessile species with time of panel immersion. Decreases were observed in relation to depth, particularly from stations at −18 m to −30 m. Similar patterns of community development occurred over all 3 years. After 1 year the community was dominated
by encrusting bryozoans, serpulids, hydroids, barnacles, ascidians, bivalves and algae (also Corallinaceae), although they occurred in different proportions according to depth. Mussels were never dominant, as has been described for other artificial reefs in the Adriatic (Ancona) and Middle
Tyrrhenian Sea (Fregene). The activity of the sea-urchins Paracentrotus lividus and Arbacia lixula in cleaning the substrata is described. Five years after the immersion of concrete blocks a climax has not yet been reached. The community is still changing: in particular large
algae and sponges are increasing.
An Offshore Buoy as a Fad in the Mediterranean Relini, Marco; Relini Orsi, Lidia; Relini, Giulio
Bulletin of marine science,
09/1994, Volume:
55, Issue:
2
Journal Article, Conference Proceeding
Peer reviewed
The role of a large offshore buoy in attracting and maintaining fish assemblages was investigated. The ODAS (Oceanographic Data Acquisition System) 1 buoy was a 42 m long vertical cylinder, 80 cm in ...diameter, with a stabilizing disk at its tip. The buoy remained 4 years in the Ligurian
Sea from winter 1987 onward, moored by chains to the bottom at 1,100 m, 30 miles off the coast. Twenty underwater observations carried out in different seasons at depths of 0-40 m showed the presence of at least 10 fish species (Naucrates ductor, Seriola dumerili, Polyprion americanus,
Thunnus thynnus, Trachurus sp., Balistes carolinensis, Schedophilus ovalis, Centrolophus niger, Parablennius spp.) with a maximum presence during summer. Numerical censuses, sizes and behavioral notes about the associated fish are presented. More detailed observations on Naucrates
ductor (length/frequency distributions, sex ratio, feeding behavior) are given.
Coal Ash for Artificial Habitats in Italy Sampaolo, Armando; Relini, Giulio
Bulletin of marine science,
09/1994, Volume:
55, Issue:
2
Journal Article, Conference Proceeding
Peer reviewed
Experiments were carried out on ash derived from an ENEL coal combustion power plant for use as a component in artificial reef blocks. After preliminary laboratory tests to establish the optimum ...block hydrated lime-coal ash ratio and to determine their leaching capability in sea water,
systematic physical, chemical and biological tests were carried out on reef models in an experimental plant. Ash and concrete cubic blocks (20 × 20 × 20 cm), the latter used as reference, were arranged in pyramid shaped reef models inside two trial tanks supplied with flowing sea
water. After one year of tests encouraging results have been obtained. No weathering, volume variation or swelling were found; on the other hand, marked compressive strength and sonic velocity increases were recorded. In the tank (water and blocks) chemical tests showed no significant leaching
phenomena for chemical elements of environmental concern while laboratory tests showed the blocks' limited leaching capability (ppm) for macrocomponents such as Al, Si, Ca and to a lesser extent (ppb) for hazardous elements like As, Cr, Se, Tl. Studies on biocolonization clearly showed that
benthonic settlement on ash blocks was more evident than on concrete ones and that there was a greater number of species and biomass quantity. Chemical tests also showed no bioaccumulation phenomena.
. As part of a wider study on the settlement and recruitment of Chthamalus spp. in Europe, this study investigated whether chthamalid cyprids can be separated by length on a European scale. Variation ...in cyprid length with latitude and temporal variation at selected localities were also examined. The lengths of cyprids collected between 1996 – 1999 on nine rocky shores in Europe are reported. Elminius modestus cyprids were found only at Roscoff, NW France and could be distinguished due to their carapace shape and length. They showed a unimodal length distribution, measuring between 450 and 625 µm, with no variation in length between the two sampling dates (1997 and 1998). Based on carapace shape and length, the remaining cyprids in the collections were identified as one of three chthamalid species, Chthamalus montagui, Chthamalus stellatus or Euraphia depressa. Bimodal length distributions of chthamalid cyprids were seen on some shores, while others had a single small‐sized modal group (representing C. montagui on Atlantic shores and/or E. depressa in the Mediterranean) separated from a few distinctly larger cyprids (C. stellatus). Metamorphs collected simultaneously with cyprid collections were identified as C. stellatus or C. montagui, except at Roscoff, where E. modestus were also found. In southern Portugal, where all metamorphs collected were C. montagui and adult C. montagui were the dominant barnacles, most cyprids measured between 350 and 550 µm long and this size distribution coincides with the distribution expected for C. montagui. Cyprids collected on these four more southerly Portuguese shores had the same modal length class (475 µm) and this remained constant between successive years at Luz and Albufeira, Algarve. The smallest (350 µm long) wild chthamalid cyprids found were from southern Portugal and Italy. In Spain, France and Ireland the smallest chthamalid cyprid was 425 µm long. The results from the present study support the hypothesis that on Atlantic shores cyprids of C. montagui can be separated from those of C. stellatus based on size, although there is some variation in cyprid length with latitude as well as temporal variation at selected localities.
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