1,721,065 research outputs found
Molecular systematics of the Atlanto-Mediterranean Solea species
No full textWithin the genus Solea, four sister lineages have been evolved that actually correspond to the species S. vulgaris, S. senegalensis, S. kleini and S. lascaris. The existence of S. aegyptiaca and S. impar is not supported and these species can be synonymized under S. vulgaris and S. lascaris, respectively. This pattern of taxonomy agrees fully with that proposed by Ben-Tuvia (1990; Journal of Fish Biology 36, 947-960) based on morphological features. In addition, mtDNA data contradict the widely accepted relatedness between S. kleini and S. lascaris based on the shared enlarged forenostril on the blind side. A sample of soles clearly related to S. senegalensis was caught in the Gulf of Taranto (Ionian Sea), representing the most western finding of this species in the Mediterranean Sea. (C) 2000 The Fisheries Society of the British Isles
Oxygen and carbon isotope profiles from Nassa mutabilis shells (Gastropoda): accretion rates and biological behaviour
No full textRecent state of demersal resources in the Adriatic Sea
No full textA picture of the recent situation and changes in demersal resources of the Adriatic Sea (GSA 17) is reported on the basis of the long –term monitoring of demersal communities performed in the framework of the international trawl survey MEDITS (1996-2010). GIS maps of distribution of 78 species are also reported
Time series ad biology of Trisopterus minutus capelanus (Lacepede, 1800) in the North and Central Adriatic Sea
No full textThe paper examines data of 40 trawl surveys carried out in the North and Central Adriatic Sea from 1982 to 2004 to describe the distribution area, the abundance and some details of the biology of Trisoterus minutus capelanus (Osteichthyes, Gadidae). Their trends during time are also analyse
Reproductive cycle of the common sole Sole vulgaris Quensel, 1806, in the northern Adriatic Sea
No full textAnatomical and cytotogical modifications of the ovary of Solea vulgaris Quensel from the northern Adriatic Sea were studied over a one-year period. Seven stages of ovarian development were observed. The gonadosomatic index increased rapidly during the reproductive season from December to March, when the majority of oocyte growth (>20010-6m in diameter) occurred. Hydrated oocytes immediately before spawning reach 136010-6m. During spring, summer and autumn (from April to November) previtellogenic oocytes (<20010-6m) occurred
Temporal and spatial distribution of some elasmobranchs in the Northern and Central Adriatic Sea
No full textData collected from trawl survey, carried out in the Northern and Central Adriatic Sea, were analysed in order to know about the spatial distribution of Myliobatis aquila, Mustelus mustelus and Squalus acanthias. Distribution areas with relation to different seasons were discussed
The relationship among catch, fishing effort, and measures of fish stock abundance: implications in the Adriatic Sea
No full textRelationships among catch, fishing effort, and measures of fish stock abundance have several implications for fisheries research. In this context, spatial and seasonal aspects are of significant importance for management decisions, especially when effort regulation schemes are used. In this paper, the multispecies trawl fishery in the Northern and Central Adriatic Sea was investigated, taking into account the heterogeneous distribution of fish stocks. Two approaches are presented depending on the availability (or not) of fishery-independent indices of stock abundance. The empirical results indicate that (i) aggregation and targeting behaviours affect catches by modifying the relationship between abundance and catch per unit effort and (ii) these relationships are not homogenous across space. Data from the Adriatic Sea is still insufficient to guarantee reliable estimations. However, these preliminary results call into question management decisions being made on the basis of catch per unit effort. Furthermore, the high heterogeneity between the northern and central areas of the sea basin calls for the adoption of spatially explicit management systems
Nursery areas of some demersal species in the Adriatic Sea (GSA 17): prospects of management
No full textPrediction of nursery areas localization of some demersal species was studied in Northern and Central Adriatic Sea using geostatistical tools and data from trawl surveys time series. The investigated species are: Eledone cirrhosa (Cephalopoda, Octopodidae), Lophius budegassa (Teleostei, Lophiidae), Merluccius merluccius (Teleostei, Merlucciidae) and Nephrops norvegicus (Crustacea, Nephropidae). Protection of these areas through limitation of fishing pressure is discussed
Mitochondrial DNA variation, phylogenetic relationships, and evolution of four Mediterranean genera of soles (soleidae, pleuronectiformes)
No full textTo increase knowledge about the systematics and evolution of Mediterranean soles, we assessed mitochondrial DNA variation, molecular phylogeny, and evolution in eight species from the genera Solea, Microchirus, Monochirus, and Buglossidium by large ribosomal subunit (16S) and cytochrome b (cytb) sequence analysis. Relevant molecular features are the great variation of base composition among species at the third codon in cytb and the heterogeneity of the nucleotide substitution rate. Phylogenies recovered using 16S nucleotide and cytb amino acid sequences agree with those based on morphology in assessing monophyly of Solea species and ancestry of Buglossidium luteum, but they are against the intergeneric differentiation of Microchirus and Monochirus. Conversely, phylogenetic trees based on cytb nucleotide sequences yielded relationships among taxa regardless of their evolutionary histories. The incongruities between morphological and molecular issues suggest the need for reassessing the systematic value of some morphological characters. Approximate estimates of the divergence time of Mediterranean soleid lineages range from 40 to 13 Mya (Oligocene-Miocene), indicating an ancient origin for the group
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