Northernmost occurrence of the offshore rockfish, <i>Pontinus kuhlii</i> (Scorpaeniformes: Scorpaenidae), in the Mediterranean sea

An adult male specimen of the offshore rockfish, Pontinus kuhlii (Bowdich, 1825), was caught off the coast of Alghero (NW Sardinia, Italy) in August 2004. That capture represents the second documented record of this Atlantic migrant in Italian waters, after more than a century from the first report. Furthermore, the new specimen is the largest specimen of this species ever recorded in the Mediterranean Basin and the most northern capture for this geographic area. Morphologic and meristic characters of the collected fish are described and the existence of a Mediterranean population is hypothesized

A Machine learning approach to the study of a red coral <i>Corallium rubrum</i> (l.) population = Un'Applicazione del machine learning per lo studio di una popolazione di corallo rosso <i>Corallium rubrum</i> (L.)

This study deals with the application of a machine learning algorithm (a classification tree) to assess the weight of Corallium rubrum (Cnidaria, Octocorallia) ramifications on the basis of the number of apices. Our approach can be easily applied to obtain in situ estimates of weight and basal diameter of colonies. Future developments include the integration with image acquisition and processing hardware

<i>Gobius ater</i> Bellotti (<i>Pisces, Perciformes</i>): specie valida ed inclusa nella fauna italiana

Gobius ater Bellotti (1888), hitherto known from Nice and Balearic Island, is also inc1uded in the Italian ichthyofauna. It was found on Posidonia beads near Alghero (Sardinia). The study of its morphological characters confirms that this is a good species well different from G. niger L

Composizione biochimica di quattro specie fitoplanctoniche impiegate in acquicoltura

The protein, lipid, carbohydrate, and amino acid content of four algae of the genus Chlorella, Dunaliella, Nannochloris and Tetraselmis was determined: each species was grown on Walne's media containig two different levels of nitrogen. The results show how tbe media influenced the biochemical composition of the algae

Definizione degli elementi conoscitivi e progettuali per l'istituzione di aree marine protette

La sensibilizzazione alla tutela ambientale, fatto prioritario per la creazione di parchi, riserve od oasi naturali, deve inevitabilmente passare attraverso l'acquisizione di tutte le componenti del sistema, macro e microscopiche, e del loro ruolo nel contesto ambientale. Ci riferiamo qui a quel processo cognitivo che va sotto la denominazione di "analisi strutturale o formale degli ecosistemi", un metodo che rappresenta l'opposto all'approccio naturalistico-descrittivo che negli anni passati ha avuto così grande spazio e che è stato il massimo responsabile della diffusione di una visione statica dell'ambiente che fatichiamo a toglierci di dosso

Suspended culture of Ostrea edulis in the Calich lagoon (North western Sardinia, Italy): preliminary results

Suspended culture is a widespread farming method used for many bivalve species such as mussels, oysters and scallops. In the Mediterranean, this technique is mainly practised in lagoons or in sheltered coastal areas using floating lines from which molluscs are suspended in several ways. In this study, the European flat oyster (Ostrea edulis Linné, 1758) was grown in suspended lantern nets in the Calich lagoon (Sardinia, Mediterranean Sea) from March 2004 to March 2005. Two distinct groups of 6 lanterns each were hung to longline ropes near the mouth (station 1) and in the central portion of the lagoon (station 2). In each lantern (diameter=50cm; height=30cm), 90 O. edulis specimens were grown and, in order to ensure good water circulation inside the lantern net, fouling organisms were removed every month. Overall mortality, shell length (anterior-posterior axis), shell width (maximum distance on the lateral axis, between both valves of the closed shell) and total wet weight of a 180 specimen oyster sample (30 from each lantern) were recorded every 2 months at each site. In addition, water temperature, salinity, dissolved oxygen, and pH were monitored monthly by means of a multi-parametric probe at both sites (between 10a.m. and 12p.m.). One-way ANOVA was used to test for differences in oyster final mean morphometric characters recorded at the 2 growing stations. Chi-square test (with Yates correction for continuity) was performed to compare survival rates at the end of the trial. From an initial mean shell length of 49.5±4.6mm, O. edulis growth rate showed a similar trend at both the stations. Nevertheless, ANOVA detected significant differences (F=7.10; p<0.01) in final mean oyster length values (83.7±6.5mm at station 1 vs 81.7±7.6mm at station 2). Significant differences (F=9.74; p<0.01) were also found in final mean oyster width (28.4±3.1mm at station 1 vs 27.5±2.8mm at station 2) and weight (F=4.00; p<0.05) values (91.4±16.7g at station 1 vs 87.7±18.3g at station 2). Moreover, chi-square test revealed a significantly different survival rate (χ2=10.04; p<0.01) between the 2 groups (57.4% at station 1 vs 47.6% at station 2).Water temperature, salinity, dissolved oxygen, and pH monthly values recorded at the 2 growing stations were almost identical. Thus, the observed differences in oyster growth and survival seemed not to be due to the hydrological variables considered. Instead, they could probably be related to mechanical and chemical effects of water renewal by coastal waters, which may have led to different seasonal seston food supplies at the 2 sites. The suspended culture of the European flat oyster described in this paper can increase the mollusc production of the Calich lagoon by growing a valuable bivalve species which is naturally scarce in this biotope. In fact, our preliminary results showed good survival and growth rates of O. edulis especially near the mouth of the lagoon. Furthermore, this farming technique could be a possible source of economic benefits for local fishermen and, above all, a low impact aquacultural activity compatible with the environment

Suspended culture of <i>Ostrea edulis</i> in the Calich lagoon (North western Sardinia, Italy): preliminary results

Suspended culture is a widespread farming method used for many bivalve species such as mussels, oysters and scallops. In the Mediterranean, this technique is mainly practised in lagoons or in sheltered coastal areas using floating lines from which molluscs are suspended in several ways. In this study, the European flat oyster (Ostrea edulis Linné, 1758) was grown in suspended lantern nets in the Calich lagoon (Sardinia, Mediterranean Sea) from March 2004 to March 2005. Two distinct groups of 6 lanterns each were hung to longline ropes near the mouth (station 1) and in the central portion of the lagoon (station 2). In each lantern (diameter=50cm; height=30cm), 90 O. edulis specimens were grown and, in order to ensure good water circulation inside the lantern net, fouling organisms were removed every month. Overall mortality, shell length (anterior-posterior axis), shell width (maximum distance on the lateral axis, between both valves of the closed shell) and total wet weight of a 180 specimen oyster sample (30 from each lantern) were recorded every 2 months at each site. In addition, water temperature, salinity, dissolved oxygen, and pH were monitored monthly by means of a multi-parametric probe at both sites (between 10a.m. and 12p.m.). One-way ANOVA was used to test for differences in oyster final mean morphometric characters recorded at the 2 growing stations. Chi-square test (with Yates correction for continuity) was performed to compare survival rates at the end of the trial. From an initial mean shell length of 49.5±4.6mm, O. edulis growth rate showed a similar trend at both the stations. Nevertheless, ANOVA detected significant differences (F=7.10; p&lt;0.01) in final mean oyster length values (83.7±6.5mm at station 1 vs 81.7±7.6mm at station 2). Significant differences (F=9.74; p&lt;0.01) were also found in final mean oyster width (28.4±3.1mm at station 1 vs 27.5±2.8mm at station 2) and weight (F=4.00; p&lt;0.05) values (91.4±16.7g at station 1 vs 87.7±18.3g at station 2). Moreover, chi-square test revealed a significantly different survival rate (χ2=10.04; p&lt;0.01) between the 2 groups (57.4% at station 1 vs 47.6% at station 2).Water temperature, salinity, dissolved oxygen, and pH monthly values recorded at the 2 growing stations were almost identical. Thus, the observed differences in oyster growth and survival seemed not to be due to the hydrological variables considered. Instead, they could probably be related to mechanical and chemical effects of water renewal by coastal waters, which may have led to different seasonal seston food supplies at the 2 sites. The suspended culture of the European flat oyster described in this paper can increase the mollusc production of the Calich lagoon by growing a valuable bivalve species which is naturally scarce in this biotope. In fact, our preliminary results showed good survival and growth rates of O. edulis especially near the mouth of the lagoon. Furthermore, this farming technique could be a possible source of economic benefits for local fishermen and, above all, a low impact aquacultural activity compatible with the environment

Osservazioni sulla diversità della fauna ittica costiera in zone soggette a differenti regimi di tutela nell'area marina protetta dell'isola dell'Asinara = Observations on the diversity of coastal fish fauna in zones with different protection measures in the Asinara Island marine protected area

In order to assess the effects of protection, coastal fish assemblages from 3 zones with different protection levels were investigated by visual census in the Asinara Island MPA (North-western Sardinia). On the whole 45 species of Teleosts from 18 families were observed. Labrids and Sparids were more abundant in both species richness and density. Significant differences in densities of Diplodus sargus and D. vulgaris in the 3 zones, due to both the protection measures and the geographic exposure, were found

On the circalittoral benthic communities in the Asinara Marine Park = Sui popolamenti circalitorali dell'Isola dell'Asinara

This work reports the results of various surveys made in the North Weslern part of Asinara National Park. It was oriented to the description of deep benthic communities. A conspicuous number of rare species and biogeographically interesting populations for the Mediterranean Sea are present in this area, in particular coralligenous formation are present in typical form as well as in enclave and platlorms

Morphometric relationships and annual gonad index of the edible Sea urchin <i>Paracentrotus lividus</i> from North Western Sardinia = Relazioni morfometriche e indice gonadico annuale del riccio di mare commestibile <i>Paracentrotus lividus</i> nel nord ovest Sardegna

Weight/diameter, weight/height and height/diameter morphometric relationships were calculated for a shallow rocky Paracentrotus lividus population sampled monthly near Alghero (Italy) from November 2004 to October 2005. Gonad index (GI) of the sea urchins was also evaluated. Statistical analyses showed significant differences of GI between 2 distinct periods of the year: late fall-winter and spring-late summer