Food resource partitioning between two sympatric temperate wrasses

The present study analysed two sympatric wrasses, Thalassoma pavo and Coris julis, with similar sizes and morphologies, that are widespread in the reef habitats of the Mediterranean and the eastern Atlantic coast. Ocean warming has induced the northward movement of T. pavo, whereas C. julis has been moving to deeper habitats. In addition, under conditions of high slope of the sea bottom, T. pavo occupies shallow habitats and C. julis is in greater abundance in deeper habitats. By investigating stomach contents and prey availability in the benthos, we assessed whether the two wrasses exploit food resources by choosing different prey within the same habitat both under co-existence and segreg…

Trace elements and PAHs in surface sediments and biota from a contamination hot spot (Augusta Bay, Italy): potential export to the adjoining coastal marine areas

First Data on the Mysid Community in the “Stagnone di Marsala” (Western Sicily)

First data on the spatial and temporal distribution of the mysid community in the “Stagnone di Marsala” (western Sicily) from January to December 1996 are reported. The assemblage consists mainly of five species which are common in the Mediterranean Sea: Diamysis bahirensis (55.2%), Siriella armata (18.6%), S. clausii (15.8%), Mysidopsis gibbosa (9.8%) and Mesopodospis slabberi (0.6%). Population structure is described for each species and the reproductive period inferred. A sharp increase in abundance occurred in the spring, while the minima occurred during autumn-winter. The D. bahirensis dominated from March to October and S. clausii in the winter. A large difference, which was mainly qu…

Effects of predator and shelter conditioning on hatchery-reared white seabream Diplodus sargus (L., 1758) released at sea

Abstract The behavioural deficit of hatchery reared (HR) fish used for stock enhancement is the main cause of their low survival in the wild. In this study the effects of predator and shelter conditioning on survival and dispersal of HR white seabream ( Diplodus sargus ) released at sea were investigated. The hypotheses were that conditioned white seabream would avoid predators more efficiently and would be more capable to shelter, showing higher survival and smaller dispersal than naive fish. Six thousand HR white seabream (6.32 ± 0.93 cm total length) were allocated in twelve plastic tanks and divided in four experimental groups: three groups were conditioned with a predator, a refuge or …

Experimental rearing of the sea urchinParacentrotus lividusfed with discards of the lettuceLactuca sativain a sea-based system

Small-sized specimens (test diameter: 16.64 ± 0.93 mm, mean ± SE) of the sea urchin Paracentrotus lividus were fed with fresh discards of the lettuce Lactuca sativa during a 24-week experiment in a sea-based system. At the end of the experiment, stock survival was high (88.8 ± 6.6%). Sea urchin test diameter and total weight grew by 35% and 56%, respectively, while gonad somatic index, after an initial decrease, increased by 3.2%. Moreover, more than 90% of specimens achieved the gonad colour that the market demands. These results support the exploitation of L. sativa as the main ingredient in a manufactured diet for echinoculture of P. lividus. Employing diets formulated with discard ingre…

Fatty acid composition of a cultured sturgeon hybrid (Acipenser naccarii · A. baerii)

Analyses of fatty acids from the dorsal muscle of Acipenser naccarii · A. baerii sturgeon hybrid were carried out. The data were compared with those reported in the literature for other sturgeons reared for human consumption. This hybrid would seem to be of great nutritional interest, its flesh being more beneficial for human health than those of other cultured sturgeons. In fact, the level of polyunsaturated fatty acids (PUFAs) was very high (34.7 ± 0.67%), being similar to that of monounsaturated fatty acids (37.9 ± 0.83%). Moreover, the PUFAs-n3/PUFAs-n6 ratio (6.74) was noticeably higher in this hybrid than in the other cultured sturgeon species. There were also high contents of EPA (C2…

Highly contaminated areas as sources of pollution for adjoining ecosystems: The case of Augusta Bay (Central Mediterranean).

An assessment of trace element and polycyclic aromatic hydrocarbon (PAH) contamination based on surface sediments collected in summer 2012 was carried out in Priolo Bay adjoining one of the most polluted areas of the Mediterranean Sea, the industrial Augusta harbour (Italy, Central Mediterranean). Inorganic and organic contaminants were generally not remarkable. Occasional elevated concentrations of Hg, Cd, Ni and PAHs exceeding sediment quality guidelines were detected in the northern sector of Priolo Bay, close to Augusta harbour, possibly as a result of water drainage of industrialised and urbanised areas and/or potential direct export of contaminated material from Augusta harbour, whose…

Use of fresh vegetable discards as sea urchin diet: effect on gonad index and quality

This study evaluated the exploitation of unprocessed agricultural discards in the form of fresh vegetable leaves as a diet for the sea urchin Paracentrotus lividus through the assessment of their effects on gonad yield and quality. A stock of wild-caught P. lividus was fed on discarded leaves from three different species (Beta vulgaris, Brassica oleracea, and Lactuca sativa) and the macroalga Ulva lactuca for 3 months under controlled conditions. At the beginning and end of the experiment, total and gonad weight were measured, while gonad and diet total carbon (C%), nitrogen (N%), δ13C, δ15N, carbohydrates, lipids, and proteins were analyzed. The results showed that agricultural discards pr…

Fatty acid composition of a cultured sturgeon hybrid (×)

Abstract Analyses of fatty acids from the dorsal muscle of Acipenser naccarii  ×  A. baerii sturgeon hybrid were carried out. The data were compared with those reported in the literature for other sturgeons reared for human consumption. This hybrid would seem to be of great nutritional interest, its flesh being more beneficial for human health than those of other cultured sturgeons. In fact, the level of polyunsaturated fatty acids (PUFAs) was very high (34.7 ± 0.67%), being similar to that of monounsaturated fatty acids (37.9 ± 0.83%). Moreover, the PUFAs- n 3/PUFAs- n 6 ratio (6.74) was noticeably higher in this hybrid than in the other cultured sturgeon species. There were also high cont…

Lipid and fatty acid biomarkers as proxies for environmental contamination in caged mussels Mytilus galloprovincialis

Mussels (Mytilus galloprovincialis) were transplanted from a reference site (Syracuse harbour) to an impacted site (Augusta Bay) from January to July 2013 to assess the biochemical response of caged mus- sels to high trace element and polycyclic aromatic hydrocarbon (PAH) contamination, using lipid and fatty acid (FA) biomarkers. Sediment and mussels were analysed to assess contaminant bioavailability in the study sites and bioaccumulation in mussel tissue. Trace elements (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, V, Zn) and PAHs were significantly higher in mussels from Augusta than in those from Syracuse, mirror- ing the different environmental contamination. The biological impact quotient (BIQs…

Turning waste into gold: Sustainable feed made of discards from the food industries promotes gonad development and colouration in the commercial sea urchin Paracentrotus lividus (Lamarck, 1816)

Abstract Development of sustainable aquaculture practices is a suitable solution to reduce the pressure on overexploited stocks of the Mediterranean sea urchin, Paracentrotus lividus, and to respond to the increasing market demand. To move forward the Blue Growth and following the principles of circular economy, a three-month feeding experiment was conducted to test a sustainable feed based on food processing discards on sea urchins. Two feed formulations differing on the proportions of the two main ingredients (endive outermost leaves and European anchovy discards in a ratio of 60:40 and 80:20 respectively) were prepared and tested on P. lividus gonad yield, development and quality. The re…

Formulation of a new sustainable feed from food industry discards for rearing the purple sea urchin Paracentrotus lividus

The lack of suitable feeds for echinoculture has led to use natural resources already widely exploited by human activities. To move towards a higher sustainability of echinoculture, this study proposes a sustainable feed for Paracentrotus lividus. Two experimental formulations were obtained using discarded endive (Cichorium endivia) leaves and anchovy (Engraulis encrasicolus) industry discards in different proportions, and agar as a binder. The evaluation of the feed stability showed that the feed was stable for 72 hr, allowing a suitable feeding for sea urchins. Both formulations showed a proper nutritional value and fatty acid profile, corresponding to the features of the main ingredients…

Caratterizzazione del pattern lipidico e degli acidi grassi del muscolo dell’ibrido Acipenser naccarii (Bonaparte, 1836) x A. baerii (Brandt, 1869) e del reciproco A. baerii x A. naccarii.

Muscle phospholipids and tryglicerides were measured in two sturgeon (Acipenseridae) hybrids. Fatty acid composition of the two lipidic fractions showed a strong similarity between the two hybrids.

Trace element and PAH bioaccumulation in caged mussels (Mytilus galloprovincialis) from an industrial area (Augusta Bay, SE Sicily)

Crustacea Decapoda from Ustica (Southern Tyrrhenian Sea): species distribution and sampling approach.

The decapod crustacean fauna of Ustica Island (Sicily, southern Tyrrhenian Sea) has been investigated in summer 2002 with the aid of many different sampling methods: suction device, pushnet, skid trawl, trammel net, traps, underwater observation, interviews. All the substrata occurring around the island from 0 to about -30 m were surveyed: midlittoral rock, infralittoral rock, pebbles, seagrass (Posidonia oceanica) bed, sand, detritic bottom, submerged cave. Fiftyseven species were collected in the investigated localities. Abundance and frequency of all species in the samples and in each surveyed biotope are given. The performance of each sampling method has been evaluated, in terms of numb…

Biogenic habitat shifts under long-term ocean acidification show nonlinear community responses and unbalanced functions of associated invertebrates

Este artículo contiene 8 páginas, 4 figuras.

Comparison of growth performance and biometric relationships in two reciprocal sturgeon hybrids reared in net cages (Sicily, Mediterranean)

This study was designed to investigate growth performance in two sturgeon hybrids reared in two quadrangular floating cages moored in an artificial pond, representing the first experience of sturgeon culture performed at Southern Mediterranean latitudes. The research was carried out from December 2000 to July 2001 and tested the growth performance, feeding parameters and biometric relationships. The sturgeons were randomly collected from the cages on a monthly basis, and total length, standard length (SL) and wet weight (WW) were recorded. The specific daily growth rate (SGRW) as somatic WW, food conversion ratio and condition factor (CF) were calculated. Biometric relationships, as linear …

Osservazioni preliminari sulle variazioni nictemereli della comunità a Misidacei dello Stagnone di Marsala. (Sicilia Occidentale)

The first data on day-night variability of the mysid assemblage in the Stagnone di Marsala (Western Sicily) are reported. The fluctuations of populations structure are shown for each species.