1,721,030 research outputs found
Preliminary study on the macrozoobenthic community in the Santa Gilla lagoon (Southern Sardinia, Italy).
No full textImpact of Phalacrocorax carbo sinensis (Aves, Palacrocoracide) on transitional environments in Central-Western Sardinia
No full textIMPACT OF Phalacrocorax carbo sinensis (AVES, PHALACROCORACIDE) ON TRANSITIONAL ENVIRONMENTS IN CENTRAL-WESTERN SARDINIA
1BUTTU S., 1MULAS A., 1PALMAS F.
1Dipartimento di Scienze della Vita e dell’Ambiente – Università degli Studi di Cagliari,
Via T.Fiorelli, 1 – 09126, Cagliari
[email protected]
Sardinia, for its peculiar environmental characteristics, the relative abundance and the quality of its lagoons and ponds, hosts the biggest wintering population of the Cormorant (Phalacrocorax carbo sinensis) on the Italian territory. Since the early ‘80s this species has began to rise considerably, probably due to conservation programs held in North Europe colonies. This fast population growth is cause of major concern among fishermen, afraid for the loss of the fish stocks.
In this work we analyse, through the mucous mixtures method (flock or bolus), the diet composition of the cormorants from the colony located in Cabras lagoon dormitory (ZPS ITB034008), to evaluate which species were more preyed and their impact on fisheries. The study of the diet was conducted during the wintering season 2010/2011, between October and March. A total of 438 pellets were collected. Through morphological analysis of hard body parts, such as otoliths found in the flock, it was possible to evaluate biomass and prey species composition as well as the average daily consumption.
The trophic spectrum was dominated almost exclusively by euryhaline fish species. The most important preys, by frequency of occurrence, belonged to Mugilidae (86%), Moronidae (7%), Atherinidae (4%) and Sparidae (3%) families. Regarding the qualitative composition of the diet, Mugilidae (mainly Liza spp. and Mugil spp. ) showed the highest index of relative importance (%IRI = 97,656). Moronidae (%IRI = 2,185) represented the second most important prey taxon, while Sparidae were the less (%IRI = 0,001). The values of percentage prey biomass of the entire wintering season amounted to 87% for Mugilidae and 10% for Moronidae, while the remaining 3% is represented by other prey taxa. Based on the data collected, it was estimated an average daily consumption (Daily Food Intake) of 478.4 g / day for example.
The Cabras lagoon represents the main Cormorants feeding area in Sardinia, with the highest concentration of specimens of the entire island. This fragile system seems to have reached, for some years, the carrying capacity in terms of presence of ichthyophagous birds, and it appears to have established a situation of balance between the various components of the ecosystem, which still requires constant monitoring
Methyl (6-Ethyldibenzo[d,f][1,3]dioxepin-6-yl)acetate
No full textStarting from 2,2'-dihydroxybiphenyl and an allenic ester, the title dibenzo-condensed dioxepine derivative was synthesized using a one-pot procedure
Egg-cases of Galeus melastomus (Chondrichthyes), Scyliorhinidae) in Sardinian waters
No full textIn this paper some morpho-biometric aspects of Galeus melastomus egg cases in Sardinian waters were analysed. The egg case
had a rounded vase-like shape and did not have tendrils. The mean length without posterior horns was 4.2 mm and mean width
was 1.6 mm. Egg cases from Sardinian waters were smaller than those from Atlantic and other Mediterranean areas
Occurrence of the non-indigenous species Dyspanopeus sayi (Crustacea: Brachyura) in a Mediterranean coastal lagoon (S. Gilla, Southern Sardinia).
Full text linkIntroduction of non-indigenous species (NIS) represents a worldwide threat to the integrity of the native communities, altering the natural distribution of the biota and impacting biodiversity. The Medi¬terranean Sea has been exceptionally susceptible to biological invasions and it is considered the world’s most invaded sea, hosting currently more than 700 NIS.
Among the Mediterranean NIS, the mud crab Dyspanopeus sayi (Smith, 1869), native to the Western Atlantic, was recorded only in recent years. The first record was from the Venice lagoon in 1991, where nowadays, it is the most common crab species. Most probably, it was introduced by shipping, as larvae in water ballast or accidentally through exchanges of aquaculture products. Since then, the species has spread into other areas, colonising different locations across the whole Mediterranean Sea.
We report here the first record of this species in a Sardinia lagoon (Santa Gilla lagoon, Southern Sardinia), obtained from samples collected during the investigation of the macrozoobenthic communities. Six stations were screened during four surveys, and three male specimens of the NI crab were found in the central area of the lagoon. The few records suggest that the introduction of the species could have been a recent event. However, as the sampling method used was not appropriate to collect vagile species like crabs, we cannot infer on the abundance of the species in this lagoon.
This finding, however, deserves particular attention since, within its native range, it is a common predator of shallow water bivalves. Moreover, in the Adriatic Sea, D. sayi has exterminated different prey mollusc species in a very small locally restricted area. We pinpoint here that, since the Santa Gilla lagoon is an im¬portant site for shellfish farming and aquaculture of commercial value bivalves species, an accurate search for abundance and potential impact of D. sayi on this lagoon is needed
A method for selective stimulation of leg chemoreceptors in whole crustaceans
Full text linkThe integration of sensory information with adequate motor outputs is critical for animal survival. Here, we present an innovative technique based on a non-invasive closed-circuit device consisting of a perfusion/stimulation chamber chronically applied on a single leg of the crayfish Procambarus clarkii. Using this technique, we focally stimulated the leg inside the chamber and studied the leg-dependent sensory-motor integration involving other sensory appendages, such as antennules and maxillipeds, which remain unstimulated outside the chamber.
Results show that the stimulation of a single leg with chemicals, such as disaccharides, is sufficient to trigger a complex search behaviour involving locomotion coupled with the reflex activation of antennules and maxillipeds.
This technique can be easily adapted to other decapods and/or other sensory appendages. Thus, it has opened possibilities for studying sensory-motor integration evoked by leg stimulation in whole aquatic animals under natural conditions to supplement, with a direct approach, current ablation/silencing techniques
The macrozoobenthic community of the Santa Gilla lagoon (southern Sardinia, Italy)
Full text link1 - Macrozoobenthos is one of the most significant communities of hydrobionts for assessing the ecological state of a water body. In spite of its importance, only few data concerning the macrobenthic community of Santa Gilla lagoon are available;
2 - Santa Gilla is one of the most important wetlands in Sardinia. The aim of this study is to give data on species composition of its macrozoobenthic community;
3 - Sampling has been carried out in 2010-2011 in July, October, January and April, in three stations located along a salinity gradient and the main environmental parameters were measured;
4 - A total of 13031 specimens belonging to 92 taxonomic groups and 5 main phyla (Anellida, Mollusca, Arthropoda, Cnidaria and Nemertea) were found. Among them, 52 different taxa were collected and pointed out for the first time in Santa Gilla lagoon in this work.
5 - Finally, seasonal and space differences were observed in the abundance values of the main taxonomic groups and in the diversity indices values
Studying the trimethylsilylation of alkylcatechols in Asian lacquers by analytical pyrolysis coupled with online micro-reaction sampler
No full textAsian lacquers are natural polymers obtained from the sap of trees of the Anacardiaceae family. Their main chemical components are long-chain alkylcatechols that form a complex polymeric network upon curing. Analytical pyrolysis is the most powerful tool to study these polymers from a chemical point of view. However, derivatisation of polar pyrolysis products, especially alkylcatechols, is needed to ensure their detection by gas chromatographic techniques. In this study, in situ trimethylsilylation using hexamethyldisilazane (HMDS) applied to the pyrolysis of urushi (Toxicodendron vernicifluum) and thitsi (Gluta usitata) lacquers was investigated to address the issue of partial derivatisation of alkylcatechols in flash pyrolysis conditions. By using an online micro-reaction sampler (MRS) coupled to pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), the derivatisation reaction was studied under controlled conditions. The reaction time between HMDS and lacquer pyrolysis products generated at 400 °C was investigated, proving that 12 s is sufficient for the complete trimethylsilylation of alkylcatechols. This information is crucial to understand the factors affecting in situ derivatisation, showing that slightly extending the contact time between the derivatising agent and the pyrolysis products is a relatively easy solution to partial derivatisation deriving from steric hindrance. This optimised procedure yields simpler chromatograms compared to flash pyrolysis and has high potential for the enhanced characterisation of these materials and the detection of lacquer molecular markers in samples containing complex mixtures of organic materials
Morphological variation among geographic populations of the rare finless eels Apterichtus anguiformis and Apterichtus caecus (Anguilliformes: Ophichthidae)
No full textMorphological analysis of recently collected specimens of the slender finless eel Apterichtus anguiformis (26 specimens) and the European finless eel Apterichtus caecus (14 specimens) in waters off the coast of Sardinia (central-western Mediterranean) confirmed their distinction from each other. Analysis also revealed a pronounced difference in mouth length in A. anguiformis from Sardinian waters when compared to the holotype and published data. To clarify their taxonomic status, morphological characteristics of the finless eels were analysed using morphometric and meristic characters. The morphometric differences between species were mainly related to the position of the anus and to cranial-related characters. Variation in meristic traits revealed differences in the number of operculum and pre-anal pores as well as the number of total vertebrae. Finally, we were able to capture specimens of these rare species using experimental trawl fishing gear, in which the entire cod-end was covered with a fine mesh net size of 8mm; this sampling approach would be a good sampling method for further studies
Geographical and bathymetrical distribution of red shrimps in Sardinian waters related to environmental conditions
No full textRed shrimps Aristaeomorpha foliacea and Aristeus antennatus are one of the most important and exploited resource in the western
Mediterranean. The aim of this work is to evaluate the geographical and bathymetrical distribution of the two species in Sardinian seas
and to identify a possible relationship with environmental conditions. We calculated the ratio between the two species and we
compared ratio values with hydrological data (temperature and salinity) to establish how water masses properties influence species
distribution. Our results indicate that A. antennatus prefers colder and less salty waters while A. foliacea prefers both higher
temperature and salinity
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