Search

The aesthetic appeal of marine reserves and the facilities provided, together with the increased public awareness of nature, all contribute to creating massive tourism in MPAs. Human activities are being changed inside MPAs in two ways: humans as top predators are generally being removed, but in turn they could come back at great numbers as visitors. Many authors have studied the impact of visitors, and the results highlight that the consequences can be very substantial and may represent a severe threat to the overall diversity of marine communities. To date, the documented effects of human recreational activities on natural communities are restricted to assessing the consequences of trampling over intertidal and upper infralittoral areas, boat anchoring in seagrass meadows and tropical reefs, or SCUB A-diving. In this paper we review the available literature world-wide on the effects of human recreational activities in marine communities. The objective is to address the extent of these impacts and to highlight the gaps of knowledge to be filled in order to optimise decision making on research, monitoring, and management of Mediterranean MPAs. A specific plan for managing tourism use in each Mediterranean MPA should be designated. These strategies should be implemented through education, training, and changes in legislation and policy.

The short-term response of Mediterranean upper infralittoral macroalgal species to experimental human trampling was investigated. Disturbances of six different intensities were applied within the integral reserve of the Ustica Island marine protected area (Italy, Mediterranean Sea). The dominant macroalgal species Cystoseira brachicarpa v. balearica and Dictyota mediterranea were strongly affected by human trampling. Higher levels of disturbance significantly affected both algal percentage cover and canopy at an increasing rate. Three months after trampling, for both variables it was highlighted that the algal recovery from disturbance was incomplete, being significantly different among trampling intensities. The current study revealed that in the short-term it was not possible to identify critical levels of trampling that are sustainable for this shallow community.

Mollusc assemblages of three concrete artificial reefs (ARs) in the Gulf of Castellammare were compared with those of two nearby natural reefs (NRs). The reefs were located in areas characterized by different degrees of water transparency, with average annual Secchi disk visibility ranging from clear (>20 m) to turbid waters (

Developing embryos and sexually mature follicles of the male portion of ovotestis proved to be a suitable material as a source of cleaving cells for advanced cytological investigations on the sacoglossan species Oxynoe olivacea Rafinesque, 1819 (Mollusca: Opisthobranchia). O. olivacea has a diploid chromosomal number of 30 made up of 15 pairs of which six are metacentric/submetacentric (M/SM), four subtelocentric (ST) and five on the borderline between SM and ST. Correspondingly, 15 bivalents occur in spermatocytes at Metaphase I. Constitutive heterochromatin is scarce and restricted to small C-bands seen in five pachytene bivalents. The use of combined silver staining and fluorescent in situ hybridization (FISH) with a Paracentrotus lividus (Echinodermata) 4.3 kilobase (kb) rDNA probe (prR14) consisting of sequences from the 3′ end of 18S rDNA to the 3′ end of 26S rDNA, revealed that nucleolus organizer regions (NORs) are situated terminally on one arm of a small metacentric pair. The telomeric (TTAGGG) n sequence did not hybridize with termini of O. olivacea chromosomes.

The mussel Brachidontes pharaonis (Fisher P., 1870) (Bivalvia: Mytilidae) has a diploid chromosomal set of 28 made up of 14 pairs of which eight are mono-armed (ST) and six bi-armed (M+SM). Fourteen bivalents occur in spermatocytes both at pachytene and metaphase-I. The use of combined silver and CMA3 staining reveals that nucleolus organizer regions (NORs) are located terminally on the long arm of a small subtelocentric chromosome pair (pair 14) and are compartmentalized in GC base pairs. A Paracentrotus lividus (Echinodermata) 4.3 kilobase (kb) rDNA probe (prR14) consisting of sequences from the 3′ end of 18S rDNA to the 3′ end of 26S rDNA was used to map the rDNA loci of B. pharaonis by fluorescence in situ hybridization. The results obtained with this technique confirm that NORs are located terminally on two small subtelocentric chromosomes (pair 14) and establish that the difference in dimension of homologous NORs is due to difference in the number of rDNA copies.

Marine protected areas (MPAs) may be important for protecting the marine environment, but they may also have substantial socio-cultural impacts about which very little is currently known, or acknowledged. In the Mediterranean, few data are available on the socio-economic consequences of MPAs. The present study reviews the existing data on MPAs in Spain, France, Italy and Greece. A general increase in tourist activities in Mediterranean MPAs is evident, as are increases in the abundances of larger fish species, although there are no data indicating yields for fisheries increase adjacent to MPAs. A large increase in the number of divers and vessels using MPAs has already had impacts on natural benthic communities as a result of diver damage, mooring and the feeding of large fish by divers. Emphasis has been given in only a few MPAs to promoting public awareness of these impacts. Although the conservation of nature should be considered the fundamental objective of MPAs, neglecting their social, cultural and economic impacts has at times led to poor local consensus, if not hostility. We believe that planning and managing MPAs should be conducted on a multidisciplinary basis. Nonetheless, no single model can be considered valid for the whole Mediterranean. The very variable characteristics of coastal areas, from those of small uninhabited islands to those of cities, require different weightings to be assigned for each factor in order to achieve a durable equilibrium and realize the original objectives of each MPA. Only with such flexibility of management will it be possible to reach a greater understanding of the MPA system and create a lasting consensus in favour of conservation, a consensus which would mean an overwhelming majority of people actively avoiding damaging nature and preventing others from doing so. This paper was realized with funds from the EU CEC DGXII–MAST III contract number: MAS3-ct97–0155.

The capability to detect and predict the responses of marine populations and communities to the establishment of marine protected areas (MPAs) depends on the ability to distinguish between the influences of management and natural variability due to the effects of factors other than protection. Thus, it is important to understand and quantify the magnitude and range of this natural variability at each scale of observation. Here we review the scale of responses of target populations and communities to protection within Mediterranean MPAs, against their ‘normal’ spatio-temporal heterogeneity, and compare those with documented cases from other temperate and tropical marine ecosystems. Additionally, we approach the problem of the relative importance of habitat structure, considered as a set of biological and physical elements of the seascape hierarchically arranged in space at multiple scales, to drive natural variability. We conclude that much more effort has to be made to characterize heterogeneity in relation to Mediterranean MPAs, and to quantify and explain relationships between target species and their habitats as sources of such variability. These studies should be based on sound sampling designs, which (1) generate long-term data sets, and would ideally (2) be based on a Mediterranean-wide comparison of a number of protected and unprotected localities, (3) be designed from a multi-scaled perspective, and (4) control for factors other than protection, in order to avoid their confounding effects. The need for appropriate spatial and temporal replication, nested designs and power analysis is advocated.

Seasonal histological changes were monitored in the course of one year to describe the development of the gonads of Pagellus acarne, collected in the Strait of Messina. This species is a protandric hermaphroditic fish bearing ovotestes, where the testis and ovary are segregated in two separate portions. One hundred and forty specimens of P. acarne, measuring from 18 to 22 cm in body length, were sampled with monthly periodicity. Both gona‐dosomatic index computation and histological monitoring reveal that spawning occurs in summer. The sex ratio is 2.1:1 in favour of males.

Very few studies have addressed the effect of protection on macrozoobenthos in marine protected areas, and particularly for sites in the Mediterranean Sea. In the present study, the molluscan assemblages associated with photophilic algal communities of the Marine Reserve of Ustica Island, were investigated. A survey was carried out along transects from 1 to 15 m in depth, during the spring of 1996 at three different sites, subjected to different levels of reserve protection. Species richness and number of individuals reflected the level of protection, and both variables were significantly higher in the integral (most heavily protected) part of the reserve compared with the less well protected buffer areas. Species diversity values showed no correlation with the level of protection. The results reported here do not agree with previous findings on the ‘reserve effect’ involving large‐sized macrozoo‐benthic species. However, the data reported, together with a study on polychaetes from the same study...

Most carbonate rocky shores of NW Sicily are marked by a coalescence of shells of the gastropod Dendropoma in a construction that is variably developed as a response to wave impact. Here, we review all the available information on these constructions and find that the fossil reefs are reliable sea-level indicators. The thickness of the reef samples never exceeds 30–40 cm below sea-level, whereas all 14 C dates fall within a range of few centuries. Some small fragments ejected by violent sea storms date back to 2500 years cal BP. No samples older than 6200 years cal BP have been detected so far. The present distribution of Mediterranean vermetid platforms should result from a northward migration related to the long term effect of the Holocene sea surface temperature (SST) warming. Some consideration on the morphology of the reefs and the comparison with the available data point out that Dendropoma reefs are excellent biological indicators of sea-level fluctuations especially when detected and sampled in tectonically stable areas as those in NW Sicily.

The results of a year's survey on the parasitic infestation of the gastrointestinal tract of three species of benthic fish, namely Serranus scriba, Mullus surmuletus, and Scorpaena porcus, living in a restricted coastal seaground in the N/W sector of the Gulf of Palermo, are reported and critically discussed. Fish populations were sampled monthly by means of a trammel net, according to the local fishing usage. As many as nine helminth species, five of them trematodes and four nematodes, were collected from the gastrointestinal tract of 625 individuals. Infestation was most intense in M. surmuletus, with a peak in the spring. S. scriba was especially parasitized during the spring and summer, whereas S. porcus showed no appreciable variations over the year, but only a slight increase in the spring. A positive relation of the degree of infestation to feeding habits, and especially to crustacean prey, was demonstrated. M. surmuletus and S. scriba are very likely final hosts of H. fabri, whereas S. po...

Recent ecological studies have shown a strong relation between temperature, echinoids and their grazing effects on macro-algal communities. In this study, we speculate that climate warming may result in an increasingly favourable environment for the reproduction and development of the sea urchin Arbacia lixula. The relationship between increased A. lixula density and the extent of barren grounds in the Mediterranean Sea is also discussed.

The peracarid Crustacea belonging to Cumacea, Tanaidacca, Isopoda and Amphipoda, inhabiting aegagropylae of Rytiphloea tinctoria were studied throughout a year in the Stagnone Sound (western Sicily, Italy). The dominant groups, tanaids (61.7%) and amphipods (32.8%), were represented by 6 and 28 species, and showed complementary trends during the 12 months, reaching their maximum of abundance in spring and autumn, respectively. Tanaids were mainly represented by Apseudes intermedius Hansen, 1895 and Parapseudes latifrons (Grube, 1864), and amphipods by Elasmopus pocillimanus (Bate, 1862), Leptocheirus guttatus (Grube, 1864), Lysianassa longicornis Lucas, 1849 and Maera inaequipes (A. Costa, 1857). These species, often found in open coastal waters, showed different seasonal trends in the Stagnone, probably in relation to their ecological requirements and life cycle. Evidence is provided that these aegagropyla formations are not only a temporary refuge for the peracaridan communities in the sometimes stressed environmental conditions of the Stagnone. In fact, they are a complex microcommunity where species are present constantly in both sexes and at all stages of development. The formations are also the result of an interaction between alga and peracarid crustaceans, which moreover play a major role among the other small invertebrates.

In the Mediterranean, fishing bans generally allow the recovery of populations of sea urchin predators, such as the seabreams Diplodus sargus and D. vulgaris, promoting the transformation of overgrazed communities into ones dominated by erect macroalgae. However, in the marine reserve on Ustica Island (SW Italy) the opposite trend has occurred in the upper infralittoral community, and urchin barrens formed after the cessation of fishing activities. We hypothesized that (1) the natural scarcity of the 2 seabream species leads to a low predation rate on sea urchins at Ustica, and (2) predation rate varies with depth, due to differences in the predator assemblages. Tethering experiments were conducted to test these hypotheses by comparing the predation rates at different depths at Ustica and 2 other locations in Sicily characterized by erect macroalgae communities and low urchin densities. Differences in the assemblages of predators, relative vulnerability of the 2 species of sea urchin present (Paracentrotus lividus and Arbacia lixula), and sea urchin density were also assessed. Despite large variation in predator abundance among locations, there was no difference in predation rate on tethered urchins. Predation by fish was found to be higher in locations where seabreams were abundant, while predation by the starfish Marthasterias glacialis, usually considered a minor sea urchin predator, was found to be the major source of mortality at Ustica. The paucity of predatory fish at Ustica was consistent with the high abundances of urchins and persistence of barrens habitat. The high predation rate on urchins by M. glacialis at Ustica suggests that. this species might play an important role in controlling urchin populations in the future.

We investigated, with a series of field and laboratory observations, the possible effect of the starfish Marthasteria glacialis predation on the operational sex ratio (OSR), i.e. the number of sexually mature males divided by the total number of sexually mature adults of both sexes at any one time, of the edible sea urchin Paracentrotus lividus. The OSR was estimated three times during the sea urchin summer spawning period (July 2004, June 2005 and July 2006) on barren substrates of Ustica Island Marine Protected Area (Southern Tyrrhenian Sea, Italy). Four sites were selected: two characterized by high M. glacialis density (take zone C) and two controls with low starfish density (no-take zone A). Mature sea urchins were independently collected by SCUBA diving and sexed. The adult sex ratio was skewed towards males at high M. glacialis density sites, whereas it was balanced (1:1) at predator low-density sites. Results of sex-selective feeding experiments in the laboratory showed that females of P. lividus were more vulnerable to M. glacialis predation. These outcomes underline the possible importance of M. glacialis in regulating the OSR of P. lividus populations.

The feeding behaviour of the shelled sacoglossan Oxynoe olivacea was investigated to better understand the role and importance of this species in influencing encroachments of the alien alga Caulerpa taxifolia in the Mediterranean sea. We tested whether this slug preferred, as preliminary field observations suggested, an aggregative feeding behaviour and which part of the algal thallus, phylloid vs rhizoid, it preferred. Results showed that O. olivacea fed in groups and actively selected phylloid. This outcome poses important questions regarding the possibility that this species, fragmenting the alga thallus, could enhance dispersion and regeneration of C. taxifolia.

Seagrass colonise new areas via the dispersion of seeds or vegetative fragments. Independent of the manner of colonization, habitat requirements need to be met for the successful establishment of seagrasses. Here we report on the colonization process of Posidonia oceanica in a highly disturbed area: a gas pipeline trench at Capo Feto (SW Sicily, Italy). A trench dredged through a P. oceanica bed was back-filled with rubble added from dump barges leading to the formation of a series of rubble mounds on the seabed. Over time, these mounds became colonised with P. oceanica. In order to understand the pattern of P. oceanica colonization, shoot density was quantified over 3 years (2001-2003) on different mound locations (crests, sides, valleys). Seagrass coalescence was observed only in valleys between mounds where shoot density averaged 133 +/- 50 shoots m(-2), while values for sides and crests were significantly lower (30.5 +/- 14 and 5.8 +/- 2.6 shoots m(-2), respectively). Although sediment accumulated on both crests and valleys, a significantly thicker sediment layer was recorded in the valleys (9.8 +/- 0.4 cm) than on crests (1.1 +/- 0.2). Plaster dissolution rate (an indicator of the hydrodynamic regime) tended to decrease from crests to valleys but even in the valleys, the currents were still higher than in the adjacent vegetated control location. This pattern was constant over time and depths. This is the first study to report on P. oceanica vegetative recruitment on artificial rubble after a disturbance event. It appears that the valleys between the rubble mounds are suitable for seagrass recruitment as sediment deposited between the rubble provides the necessary resources for plant settlement and growth. Once the seagrass patches are established, they may start a positive feedback of attenuation of currents, sediment accumulation and seagrass patch expansion.

This paper provides information on spawn morphology and egg features of the stenophagous planktotrophic Mediterranean sacoglossan Oxynoe olivacea. Smith and Fretwell’s hypothesis, predicting that individuals of the same population growing in the same environmental conditions and varying in size should spawn eggs of a constant size, was tested in a population of O. olivacea living in the Straits of Messina. To determine whether (a) spawn mass size, (b) total egg number per spawn, and (c) egg size were related to parent size of O. olivacea, 21 egg masses (seven egg masses deposited by seven different 20 mm animals, seven egg masses deposited by seven different 25 mm animals and seven egg masses by seven different 30 mm animals) were randomly chosen and examined. Results showed that both spawn mass width and number of eggs per spawn mass increased across O. olivacea body size and apart from the significant variation of the short capsule diameter, there was no consistent variation of egg features in O. olivacea. In conclusion the species allocates constant amounts of energy to individual embryos and thus supports the prediction designed by Smith and Fretwell.

The ecological importance of marine algae is widely known but in shallow coastal areas the composition and structure of algal communities may be affected by different human activities. Recovery from different trampling disturbances of two competing morphological groups (i.e. macroalgae and algal turfs) and effects of macroalgal canopy removal on the dominant associated fauna were examined using controlled trampling experiments. Six months after trampling disturbance was removed, the two morphological groups closely resembled control (untrampled) conditions, both in terms of cover and canopy (%). In particular, macroalgal recovery seemed to be very rapid: the higher the impact on the system the more rapid the recovery rate. In the short-term, the removal of macroalgal fronds (i.e. canopy) caused evident changes in invertebrate and crypto-benthic fish densities although these indirect effects were species- specific. Erect macroalgae are very sensitive to disturbance and even relatively low intensities of human use may be non-sustainable for this shallow assemblage. The present findings suggest some interesting options for the management of Mediterranean rocky shallow areas. This is crucial for coastal areas that are intended to be maintained in natural condition for conservation purposes.

Summary 1To better understand the role and importance of body size in hermaphroditic mating system theory, the mating behaviour of the shelled sacoglossan Oxynoe olivacea was studied. This simultaneous hermaphrodite exhibits bilateral and unilateral sperm transfer and thus it is particularly suitable for studies on hermaphrodite sexual conflict. 2In this study three hypotheses on body size were tested: that O. olivacea partner size has an effect on (i) mating mode choice, (ii) duration of mating modes, and (iii) choice of sexual role. Furthermore, we tested Charnov's hypothesis that in O. olivacea, like many simultaneous hermaphrodites, a sexual conflict exists and the male role is preferred. 3A laboratory experiment was done to test the aforementioned hypothesis and to observe the general mating behaviour of O. olivacea. Pairs of similar (S) and different (D) sizes were considered for a total of five different treatments (S1, S2, S3, D1, D2). 4During the five copulatory treatments O. olivacea mated up to 93 times. Specifically, pairs of the same size mated with bilateral sperm transfer while unilateral copulation was common in pairs of slightly differing size. Contrary to predictions, animals of small body size started mating in the female role. O. olivacea showed an active alternation of sexual roles and thus did not specialize in one particular sexual role. 5This study produced evidence of a relationship between mating mode and body size in O. olivacea and highlighted the need for new studies on this simultaneously hermaphroditic species.

The opisthobranch order Sacoglossa (Ascoglossa) is a relatively widespread group of stenophagous sea slugs comprising about 250 species. Sacoglossan are deemed as marine specialist herbivores and are often among the rarest components of inshore communities being strongly entrained upon the life histories of their algae. 1 The close association between these molluscs and their food algae has invoked terms such as co-evolution 2 and provides a fascinating biological puzzle, distinct from other photosymbiotic associations in several ways. Moreover, physiological adaptations as functional kleptoplasty (� chloroplast symbiosis) and the capability of taking up and concentrating secondary metabolites from the algal food have been described. 3,4 The majority of species feed upon siphonalean green algae, 5,6 and the stenophagy is plesiomorphic, feeding being restricted to the green, siphonalean algal genus Caulerpa 7,8 for the entire suborder Oxynoacea. The most representative species in the Mediterranean is the endemic Oxynoe olivacea (Rafinesque, 1819) characterized by small size (20 mm long), an extreme host-specificity, a cryptic coloration and a planktotrophic veliger larvae. 9 Over the last century the algal genus Caulerpa has been undergoing prolific growth in the coastline of Mediterranean Sea. 10 In particular, the tropical algae Caulerpa taxifolia (Vahl) C. Agardh and the Lessepsian migrant Caulerpa racemosa (Forsk.) Agardh are rapidly colonizing the coastal water of the Mediterranean Sea. 11,12 The rapid expansion of these algae could be attributable to their functional plasticity to different environments, 13,14 and to anthropogenic and climatic causes: probably unusual endogenous or exogenous factors are encouraging their spread in the Mediterranean sea, 15 which is becoming a new favourable environment for tropical species. 16,17 These invasions may cause serious ecological problems, such as habitat alterations and changes in the dynamics of macrobenthic assemblages. 18 The marked stenophagy of O. olivacea could make this sacoglossan a potentially important biological control agent of allochthonous Caulerpa populations. 9 The siphonalean, stoloniferous C. taxifolia and C. racemosa represent, in fact, potential host species to the suctorial O. olivacea, a species so far specialized on the autochthonous Caulerpa prolifera (Forskal) Lamouroux. The aim of this study is to investigate food preferences of the native O. olivacea using C. prolifera, C. taxifolia, and C. racemosa as food items. Thirty specimens of adult Oxynoe olivacea were collected with Caulerpa taxifolia from Punta Faro, in the Straits of Messina, on November 2000, and brought back to the laboratory. In the same months, samples of Caulerpa prolifera and Caulerpa racemosa were collected at Santa Panagia Bay (south east Sicily) and maintained in aquaria. Prior to experimentation, all specimens were acclimated for two weeks: during this period, they were kept in aquaria with circulated natural seawater, at ambient light and temperature regimes. Furthermore all O. olivacea were maintained on a diet exclusively of C. prolifera and C. racemosa, because they came from a C. taxifolia meadow and probably needed to acclimatize to the other two algae. After two weeks, a series of choice experiments were conducted to assess whether or not slugs preferred to consume either native or host algae. Before starting experiments all specimens were starved for 2 h. Then, one slug was placed in the centre of a 20-cm dish with filtered seawater and containing equal masses of the three species of Caulerpa (~6 g wet weight) set randomly at an angle of 120°. All 30 O. olivacea were tested independently, thus ensuring the independence of data. The number of animals reaching and staying on an alga was recorded until no more changes occurred, as this can be considered an index of feeding preferences recorded. 19 The results of all experiments were combined and analysed by non-parametric statistics using chi-square analysis: the observed and the expected frequencies of animals on each algal species were calculated. All slugs chose one food and thus were included from the computation of chi square analysis. Most animals used in the food preference experiments headed towards the foods and started feeding immediately; a smaller number were engaged in crawling or orientating behaviours before feeding. The experiments lasted from 30 to 70 min. The observed frequencies of animals on each algal species showed a clear tendency for Oxynoe olivacea to prefer the native Caulerpa prolifera to the introduced Caulerpa taxifolia and Caulerpa racemosa. This resulted in a highly significant chi-square test (Table 1, P

Biogeographia vol. XXII - 2001 (Pubblicafo il 1 ottobre 2001) Biogeogratia degli ambienti costieri Distribuzione delle piattaforrne a molluschi Vermetidi nel Mar Mediterraneo TIZIANA DIELL DARIO PELLINO. SILVANO RIGGIO Dzpzrtinzezzro di Biolagizz Arzinzzzle, Uni:/er:it¢‘z a’z' Pd/£77710, Vizz Arc/Jz'mfi, 18 - L90123 Przlemzo (lmlizz) INTRO DUZION E Un tipico reef ‘ e um formazione rocciosa “vivente” formata dalla stretta aggtegazione di organismi animali e Vegetali muniti di rivestirnenti schelem'ci estemi, Che si eleva da un basso fondo marino, :1 volts emergcndo sulla superficie in forma di scogliera. Nel corso della sua crescita, legata allo sviluppo degli organismi costruttori, ogni recfmodjfica progressivamente Fambicnte locale, sia fisicamente, in quanto crea nuovi spazi su scala tridirnensionale, chr: ecologicamente, in virtil della moltitudine di microambienti che si segregano nelle varie parti della struttura e che ospitzmo popolamenti diversi (‘Sage-rstrom, 1987; Bianchi e Morri, 1996). Lungo Yestensione deile scogliere le associazioni biotiche si djstribuiscono e selezionano in Funzione delia distanza relativa dallhcqua, della profondite e/0 deifaltezza relativa sul livello medio del mare, e (161 substrate di impianto. Ogni reef crea nuove nicchie, con l’eiTetto di aumentare sia l’eter0geneit£z spzzzizzle che la liiotliverzvitfz [om/2 Indipendentcmente dalle loro origini e posizioni geografiche, le biocostruzioni mostrano alcune caratteristiche comuni. Quests possono tiassumersi nelle seguenti: rilievo topografico positive; deposizione di mgteriale scheletrico; tasso di crescita piil o meno elevato; erosione Che pub essere pari al tasso di crescita; struttura complessa; profilo orizzontale fittamente dentellato; alto tasso cli formazione di sedirnento detritico; elevata diversite dei popolamenti associati. ‘ In itaiiano tmducibile — anchc se impropriamente » con bnrricrn.

The most notable features of the biotic colonization and fishing yield of artificial reefs are a straightforward response to local environmental conditions. When applying this assumption to the artificial reefs of north-west Sicily, the features that distinguish the reefs from each other are largely consistent with the major hydrographic characteristics of the Gulf of Castellammare, the Bay of Carini and the Gulf of Palermo. The differences in environmental conditions in the three biotopes have made it possible to compare the colonization of artificial reefs in unpolluted oligotrophic water (Bay of Carini), eutrophic water (Gulf of Palermo) and water with heavy siltation rates (Alcamo Marina artificial reef area in the Gulf of Castellammare).

Most of the plans for fish stock replenishment recently undertaken in Sicily have focused on the Gulf of Castellammare. Reasons for choosing this biotope for a restocking plan include the size of the Gulf (300 km2), the importance and traditional role of its fisheries and the existence of information describing the local marine environment. The Gulf of Castellammare is the widest bay in Sicily and fishing has always played a major role in the local economy. Today income from fishing complements that from tourism.

Sicilian cave drawings from the Grotta del Genovese, Isle of Levanzo (west Sicily) ca. 12 000 B.C. show silhouettes of dolphins, tuna, groupers and bass which, together with remains offish (tuna, groupers, bass and others), limpets and oysters from Grotta dell Uzzo, north-western Sicily, indicate the importance of fish and shellfish in the diet of coastal populations of that time (Villari, 1992a, 1992b). Remains of turtles (Caretta caretta), tuna and sharks are evidence of fishing activity during this period (Villari, 1995).

During the bionomic survey carried out in the course of 1968 on the biogenic platform bordering the rocky shore of Mount Pellegrino in the Bay of Palermo (northwestern Sicily) some individuals of a species of Synapseudes Miller (1940) were found in samples of Tanaidacea taken during the winter at station no. 1. This find is of considerable interest as no Synapseudes species had hitherto been described from the Mediterranean, although the presence of this genus on the coast of southern France has been mentioned by Bellan-Santini (1962, 1969). Careful examination of the specimens revealed that they belonged to a new species, which was named after Prof. Sueo M. Shiino in gratitude for his kind assistance and valuable suggestions.

Floating fish aggregating devices (FADs) have long been used to attract fish in NW Sicily since antiquity. Recently, a number of changes have been made to the type of material employed to construct FADs, with the aim of increasing their effectiveness. In this paper we compare the catches made at eight experimental floating FADs (polypropylene ropes frayed at the ends) with those obtained at eight traditional FADs in the Gulf of Castellammare. A total of 672 samples were collected during summer and autumn in 1995 and 1996 at the 16 FADs using a surrounding net. Visual observations of fishes associated with the FADs were also conducted to obtain qualitative information about the spatial distribution of species. A total of 1632 specimens weighing 144 kg and belonging to eight species were caught during the survey. Seriola dumerili, Caranx crysos, C. rhonchus and Coryphaena hippurus were the most frequent and abundant species accounting for 96% of the total catch. Average fish abundance and weight, characterised by high variance, were significantly higher at the sites with experimental FADs than at the sites with traditional FADs. S. dumerili was the only species with higher catches around the experimental FADs. Some spatial and temporal variations in fish abundance and size were also detected. Younger individuals of S. dumerili were observed to show high affinity for the experimental FAD tufts., No disponible