A Multidisciplinary and Ecosystemic Approach in the Oristano Lagoon-Gulf System (Sardinia, Italy) as a Tool in Management Plans

fshr: a fish sex-determining locus shows variable incomplete penetrance across flathead grey mullet populations.

Sediment characteristics and macrofauna distribution along a human-modified inlet in the Gulf of Oristano (Sardinia, Italy)

A metabolic scope based model of fish response to environmental changes

1 - The work aims to study the feeding habits of Phalacrocorax carbo sinensis wintering in the Cabras and Mistras lagoons and to assess the impact of the cormorants colony on fish stocks. 2 - 438 bird flocks of Great Cormorant (Phalacrocorax carbo sinensis) wintering in the Cabras and Mistras lagoons (central-western Sardinia) (SPA ITB034008 and ITB034006 respectively) were analysed. 3 - Through the morphological analysis of undigested hard body parts, such as otoliths, it was possible to trace to the preyed species and their biomass and, then, to the average daily consumption of cormorants. 4 - The trophic spectrum was dominated almost exclusively by euryhaline, gregarious fish species. Mugilidae, and particularly Liza ramada with a percentage index of relative importance (%IRI) of 75.28 and L. saliens (%IRI = 17.78) were the most important preys, while Dicentrarchus labrax (%IRI = 3.53) was of secondary importance. Other species, as Diplodus vulgaris (%IRI = 0.06), Sparus aurata (%IRI = 0.01), Solea solea (%IRI = 0.04) and Anguilla anguilla (%IRI = 0.01), completed the diet. 5 - The Daily Food Intake (DFI) was estimated in 478.4 ± 18 g/day. The overall amount of biomass preyed by the cormorants during the entire wintering season was calculated in about 422 tons. Considering the Cabras lagoon area, it was possible to estimate an amount of fish taken equal to 189.4 Kg/ha during the same period.

Ichthyophonus sp. is reported for the first time in Mugil capito (thinlip grey mullet) and Li a saliens (leaping grey mullet). The fungus was also found in L. aurata (golden grey mullet), Dicentrarchus labrax (sea bass), Sparus aurata (gilthead sea bream) and Scophthalmus maximus (turbot), whereas Mugil cephalus (grey mullet) was not parasitized. In fish sampled periodically, the highest prevalences were observed in sea bass and the lowest in turbot. Among the fish sampled occasionally, the fungus was found associated to an epizootic in thinlip grey mullet. Ichthyophonus was never found in fish weighing <0·5 g. An increase in the prevalence of infection with the age of turbot and gilthead sea bream was observed. Gilthead sea bream and sea bass showed higher prevalences in a closed system than in open and semi‐intensive systems. Multinucleate spherical spores, hyphae and endospores of Ichthyophonus sp. parasitized different organs of thinlip and leaping grey mullets, though infection intensity was maximal in the spleen. In the remaining fish, the fungus was found mainly in the trunk kidney, where it appeared frequently in a necrotic form. Ichthyophonus sp. can be considered a potential threat for marine fish aquaculture, especially in culture conditions which may favour the introduction and transmission of the fungus.

1 - Sardinia Island (Italy), even if relatively small, has over 100 lagoons totalling some 12,000 ha. Yet their potential yield remain often unexpressed because they are subjected to environmental stress and degradation. As far as benthic communities are concerned, one of the main disturbances is certainly the accumulation of shell detritus, which progressively modifies the way benthic organisms interact with the sediment. 2 - An experimental dredging study was therefore performed in the Calich lagoon (NW Sardinia), due to its particular interest for fishing activities and potential semi-intensive mollusc culture. Changes in benthic community structure were examined in two areas of the lagoon by analysing both the demographic profile of several abundant species and the features of sedimentary matrix immediately after the cleaning operations and seven months later. Data obtained were compared with those collected in undisturbed areas of the lagoon. This allowed us to evaluate the effects of dredging operations on the benthic assemblages unaffected by natural temporal shifts of the system. 3 - Univariate and multivariate analyses indicated a strong relationship between macrofaunal community structure and intensity of the cleaning activities. At the dredged sites benthic fauna was not depleted but did exhibit higher diversity and evenness indexes than at the undisturbed sites. This seemed to be a consequence of decrease in the density of some abundant species at the dredged sites. Furthermore, a general reduction of total organic content was observed in the upper sediment layer. Lastly, the cleaning method employed is discussed in relation to its potential for impacting the benthos.

The fish assemblage of the Obidos lagoon was studied between January 1993 and December 1994 based on beach seine catches. Forty-one species were identified, with Gobius niger, Syngnathus acus, Atherina boyeri, Dicentrarchus labrax, Liza aurata, Chelon labrosus and Symphodus bailloni the most common species. The community was dominated by the families Atherinidae, Mugilidae and Gobiidae, which is characteristic of temperate and tropical estuaries and coastal lagoons. Community ordination analysis outlined three major fish assemblages along a longitudinal environmental gradient, determined by salinity, sediment and turbidity. Euryhaline fish species, such as Liza ramada and Mugil cephalus, were particularly abundant in the upper part of the lagoon. The middle area was dominated by estuarine resident species, namely G. niger, A. boyeri, S. acus and S. bailloni, while in the lower part of the lagoon the fish assemblage was composed of inshore marine species. The seasonal pattern was mainly induced by the annual cycle of resident species and by the migration of juveniles moving between coastal areas and the lagoon. If human activities related to keeping the mouth of the lagoon open to the sea ceased, the nursery function of this estuarine system would be affected, with a dominance of euryhaline fish species expected throughout the lagoon.

Abstract. The existence of a pleomorphic development cycle is demonstrated in epitheliocystis organisms obtained from fish of the following families: Sparidae, Sparus aurata L.; Mugilidae, Liza ramada (Risso), Liza aurata (Risso) and Mugil cephalus L.; Cichlidae, Tilapia mossambica (Peters) and Tilapia aurea × nilotica; and Serranidae, Dicentrarchus labrax L. Ultrastructure of the successive developmental stages, primary long cells, intermediate long cells and small cells are described as well as the division process between stages. An additional stage, the round cell, was found in infected chloride cells. The affinities between epitheliocystis organisms and known chlamydial organisms of vertebrates and invertebrates are discussed.

Determination of trace metals in fish species of the Ria de Aveiro (Portugal) by electrothermal atomic absorption spectrometry

Micropalaeontological analyses of benthic foraminiferal assemblages were carried out on stratigraphic sections from the Late Miocene of Sinis Peninsula (Capo San Marco, western Sardinia, Mediterranean Sea). Biotic index values and the relative abundance of the most abundant foraminiferal species have been used for a palaeoenvironmental reconstruction. The palaeoenvironmental significance of foraminiferal assemblages indicates a shallower trend from an upper bathyal-circalittoral environment to coastal lagoon facies that are characterized by variable salinity and some fluvial run-off episodes during the pre-Messinian Salinity Crisis stage. After a subaerial exposure, a siliciclastic carbonate platform developed at the start of the Messinian Salinity Crisis. The re-establishment of marine conditions during the Upper Messinian is marked by fossiliferous marly limestone and sandy marls (cfr. Terminal Carbonate Complex) bearing microfaunas (benthic foraminifera, ostracods, rare planktonic taxa) and macrofauna intercalated in siliciclastic fluvial deposits. During the Messinian stages, the paleoecological conditions in the Sinis Basin were intermittently suitable for sustaining marine biotas, indicating that this basin was not uninterruptedly desiccated.

Genetic divergence and phylogenetic relationships among five species of the Mugilidae family (Liza saliens, Liza aurata, Liza ramada, Chelon labrosus, and Mugil cephalus) were investigated, in the present study, on samples taken from Messolongi lagoon in Greece, using allozyme electrophoresis. Ten enzymic systems corresponding to 22 genetic loci were assayed, among which, four were found to be polymorphic in Liza saliens, Liza aurata, and Chelon labrosus, seven in Liza ramada, while only two were polymorphic in Mugil cephalus. Several loci showed different electrophoretic patterns among the species and thus, they can be useful in species taxonomy as diagnostic markers, as well as for further evolutionary studies. It must be underlined that among them the aGPD-2* locus proved to be species-specific, while the other ones can be also used in various combinations for the same purpose. The observed heterozygosity wasfound to range from 0.020 to 0.051. Allele frequencies of all loci were used to estimate Nei's (1972) genetic distance, which was found to range between 0.249 and 1.171 among the five species studied. UPGMA and NJ trees, obtained by genetic distance matrix methods, as well as, a tree based on the discrete character parsimony analysis were found to exhibit the same topology. Our result show that the three species of the genus Liza are clustered together, Chelon labrosus being closer to the previous clade, while Mugil cephalus being more distinct.

Concentrations of five heavy metals (Hg, Cd, Pb, Cu and Zn) in edible tissues of four fish species (Cyprinus carpio, Platichthys flesus, Liza aurata, Mugil cephalus) collected from Natural Reserve Area called Sarikum Lake were determined by ICP-MS (Agilent 7700x). The order of heavy metal concentration was observed as: Zn> Cu > Hg > Pb > Cd. The heavy metal levels were species specific and significantly different. The highest concentrations of Hg, Cd and Zn were found in flathead grey mullet, European flounder and common carp, respectively. The higher concentrations of Pb and Cu are present in golden grey mullet. The concentrations of Cd are in range of 0.019-0.027 µg g-1 in common carp, 0.028–0.040 µg g-1 in European flounder, 0.020-0.034 µg g-1 in golden grey mullet and 0.16-0.27 µg g-1 in flathead grey mullet tissues. Concentration of Cd in M. cephalus was limit value and precautions need to be taken in order to prevent future heavy metal contamination, but other metals were lower than those in certified values. Keywords: Cyprinus carpio, Platichthys flesus, Liza aurata, Mugil cephalus, Sarikum Lake

This study was conducted between June and September of 2008 to determine the technical characteristics of setlining for European seabass in the central Aegean Sea, Çeşme. Experiments were carried out by 4 different baits; Annular sea bream (Diplodus annularis) and flathead grey mullet (Mugil cephalus) were used as the live baits while picarel (Spicara sp.) and elegant cuttlefish (Sepia elegans) were used as the dead baits. During the study it was observed that 19% of the tackles captured European seabass, 9% of them captured by-catch species and 27% of those were detached. Finally 45% of the tackles didn’t catch any individuals. Among the weight based distribution of captured species European seabass composed the majority with 79%. On the other hand it was found that 70% of the European seabasses were captured with flathead grey mullet as being the most efficient bait for European seabass setlining in the central Aegean Sea.

Metallothioneins failed to reflect mercury external levels of exposure and bioaccumulation in marine fish – Considerations on tissue and species specific responses

The worsening of the ecological situation in the last years resulted in the decrease of biodiversity and general fish productivity of the saltish-water Shabolatsky estuary, placed in Danube-Dniester interfluves. It doesn’t allow to use it effectively for the traditional pasturable cultivation of mullet fish.The aim of the work was to study the features of feeding, food relations and growth of indigenous species of mullet (stripped mullet, leaping grey mullet, golden mullet) and soiuy mullet acclimater at the pasturable cultivation under conditions of Shabolatsky estuary. The collection of ichthyological material was realized in 2012-2014. At the study of mullet feeding were used standard methods that allowed to assess season changes of qualitative and quantitative parameters of feeding and food relations of mullet: stripped mullet - Mugil cephalus, golden mullet – Liza aurata, leaping grey mullet – Liza saliens, soiuy mullet – Liza haematocheilus.For the first time there was given the qualitative characteristics of feeding and food relations of different types of mullet in season and age aspects. It was demonstrated, that leaping grey mullet and golden mullet of all age groups in all seasons of a year prefer animal food; stripped mullet and soiuy mullet – detritus and vegetable food. The most similarity was inherent to the qualitative compositions of rations of yearlings of all mullet species in the spring period (feeding similarity index FSI – 63,0-76,5). In summer the food composition changed (decreased for animal plankton and increased for zoobenthos). The tension of food relations decreased (FSI – 49,8-75,0). In autumn the most similarity of the food character was typical for second-year golden mullet and leaping grey mullet on the one side and second-year and third-year stripped mullet and soiuy mullet (up to 75-89% of detritus and vegetable food) on the other one. At the same time golden mullet and leaping grey mullet essentially differed from stripped mullet and soiuy mullet by the food character. The decrease of zooplankton and zoobenthos production, noticed in Shabolatsky estuary in last years resulted in the decrease of the growth speed of leaping grey mullet and golden mullet. At the same time essential reserves of detritus of vegetable food provide the intensive growth of striped mullet and soiuy mullet.In the existent situation it is expedient to use striped mullet and soiuy mullet detritophages as main objects of the pasturable mullet cultivation to provide the maximal fish productivity of the water body.