1,720,964 research outputs found
Record of the bluespotted cornetfish Fistularia commersonii Rüppell, 1838in the Ligurian Sea (NW Mediterranean)
No full textThe record of one adult female of the bluespotted cornetfish Fistularia commersonii Rüppell, 1838, caught using trawl nets in
coastal waters near Sanremo, Western Ligurian Sea, in October 2007 is reported. This record confirms the rapid spread of the
species and suggests a possible fast expansion toward French and Spanish waters by means of the Western Mediterranean
Northern Current. Previous records in Italian waters apparently indicate a pioneer phase of colonization by adult fish and a
stabilized phase, with adult and young fish, four years later
Non native marine fish in Italian waters
No full textAbout thirty species of non native marine fi sh appeared in Italian waters during the last fi fty years, a consistent fraction of the total number recorded in the same period in the whole Mediterranean by the CIESM Atlas of Exotic Fish (Golani et al., 2002; 2004; 2007 plus online updating 2005, 2008). Th is number represents an approximation because abundant material is still waiting to be studied. In the present notes I take into account a sample (Table 1) hopefully suffi cient to characterize diff erent groups, in order to separate casual events from those which have ecological signifi cance
First record of the yellow sea chub Kyphosus incisor in the Mediterranean
No full textThe presence of herbivorous fish of the family Kyphosidae in the Mediterranean has increased with the first record of the
species Kyphosus incisor which occurred in July 2009 at Camogli, eastern Ligurian Riviera
Biology and fishery of Eledone cirrhosa in the Ligurian Sea
No full textBiological information for Eledone cirrhosa has been reassessed through two series of trawls in the framework of the Research Projects MEDITS (summer) and GRUND (autumn) over a 10-year period of surveys in the Ligurian Sea. This information covers aspects such as life span and growth and mortality rates. The sum of samples obtained in the two different seasons allowed the analysis of consistent length frequency distributions and resulted in distinguishing recruits/juveniles from adults of two different ages, i.e. E. cirrhosa is a relatively long living cephalopod, whose reproduction occurs in the second or third year of life. By sampling in different bathymetric strata, different densities
on shelf and slope fishing grounds were measured and their displacements with changing season were monitored. The most important stratum in terms of summer densities was in the range 100–200m depth, which includes the shelf edge, at 150 m. In a relatively narrow strip of seabed, covered by the shelf-edge detritic assemblage and adjacent muddy bottom assemblage VTC (80–150 m), the recruitment of E. cirrhosa occurs from January onwards, while till recent times a specific trawling targeting juveniles used to be carried out in late spring and summer months. In autumn E. cirrhosa is mainly concentrated in shallower waters where trawling activity does not specifically target this species. Trends in numbers and biomass derived by the two series of surveys, and in particular those during autumn series have revealed a significant decrease over the studied time interval. Therefore, the possible relationship between large-scale environmental factors and/or exploitation, was investigated and a positive relationship between summer biomass and winter NAO index was found, even if the cause of such relationship
remains unexplained. However, trends of E. cirrhosa landings reported in other studies of the north-western Mediterranean resulted in a similar relationship, thus reinforcing the hypothesis of climatic factors influencing the success of the fishery of this biological resource. A tentative stock assessment, based on relative yield-per-recruit functions, taking into account the two different lengths at first capture and corresponding to mesh sizes of 20 or 40mm (juveniles and adults nets), showed overexploitation and underexploitation, respectively. A
preliminary study of density indices by vital phase also demonstrated a correlation between summer spawners and autumn juveniles of the following year, thus providing evidence of a stock–recruitment relationship
Medusivorous fishes of the Ligurian sea 1. Chub mackerels and other pelagic fish species sometimes "Have the Medusa" Pelagia noctiluca
No full textDuring blooms of Pelagia noctiluca periodically occurring in the Ligurian Sea (North Western Mediterranean), a natural mark,
formed by the jellyfish pigments, characterizes fish eating this species
Exploring relationships between recruitment of European hake(Merluccius merluccius L. 1758) and environmental factors in theLigurian Sea and the Strait of Sicily (Central Mediterranean)
No full textThis paper explores the relationships between the spatial patterns of the distribution of the young hakes of the year (YOY) and the
oceanographical features in two areas of the Central Mediterranean (the Ligurian Sea and the Strait of Sicily), characterised by the occurrence of straits and channels. Comparative and correlative approaches were used to investigate coupling between biological and physical patterns. Density indices of the YOY were derived from annual trawl surveys from 1994 to 2004 in spring and autumn. Mean
patterns of theYOYdistributionswere comparedwith the mesoscale oceanographical features reported in literature.No evident trends in recruitment strength were found in either areas. Inter-annual variability in YOYabundance in the Ligurian Sea was higher than in the Strait of Sicily. The location of nursery grounds in the study areas coincides with zones of relatively higher production, where upwelling and other enrichment processes regularly occur. The presence of predictable eddies and the frontal systems play a major role in the localization of nursery areas in the Strait of Sicily, maintaining their stable position throughout the years. The strongest transport of southern waters from the Tyrrhenian to the Ligurian Sea, due to the East Corsica Current, which is negatively correlated to winter North Atlantic Oscillation, is associated with the highest abundance of hake recruits in the nurseries of the Northern Ligurian Sea
La collezione malacologica del Regio Museo di Storia Naturale dell'Università di Genova: uno studio preliminare
No full textLarge pelagic fish, swordfish, bluefin and small tunas, in the Ligurian Sea: biological characteristics and fishery trends.
No full textThis article presents a review and summary of the data on large pelagic fish, collected over the period
1990–2007, thanks to national and European Community research programmes. Swordfish are present in
the Ligurian Sea at all life history stages. Time series of longline fishing catch per unit effort (CPUE) values
showa good exploitation status, possibly related to the dismission of past questionable fishing technics (e.g.
‘spadare’ nets). CPUE values were also negatively related to North Atlantic oscillation: climatic factors
probably had synergic effects. Bluefin is present in the Ligurian Sea with mainly schools of young fish
aged 1–4 years, which feed on small pelagic fish and on the Ligurian krill Meganyctiphanes norvegica.
Recent limitations on catches have severely reduced local fishing activities. Following the dismission of
purse seiners, artisanal hook-based fisheries should be maintained, regardless of the length of fish caught,
as a way of monitoring stock status. The two most abundant species of small tuna, Sarda sarda and
Auxis rochei rochei, are present in the Ligurian Sea at all life stages. In particular, Auxis rochei rochei
is a commercially neglected species which, in terms of larval occurrence, is the most abundant in the
Mediterranean. Physiomorphological and genetic studies have been recently carried out in order to improve
forthcoming exploitation
Trace element concentrations in the muscle of Red Shrimp Aristeus antennatus (Risso, 1816) (Crustacea, Decapoda) from Ligurian Sea (NW Mediterranean: variations related to the reproductive cycle.
No full textConcentrations of total and organic mercury, cadmium, lead, copper, iron, manganese and zinc were determined in
the muscular tissue of 135 specimens of Aristeus antennatus (Risso, 1816) collected during a 3-year period in the Ligurian sea (NW Mediterranean). The aim of the present work was to study the relationships between the concentrations of these trace elements and the main biological parameters characterising the organisms, i.e. sex and size with special attention to the sexual maturity of the female specimens. Mercury is the only element showing a
significant correlation with the size of the specimens, and for this reason it could give some indications about the age of the shrimps. However, comparison between females collected at four different reproductive phases shows that reproductive individuals are characterised by higher levels of mercury with respect to non-reproductive individuals of
the same size
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