Ridurre lo scarto nella pesca con reti da posta: il caso di studio nella AMP delle isole Egadi

Sebbene la selettività nel tramaglio sia assodata, rimangono solitamente catturati dalla rete individui di specie bentoniche che non hanno rilevanza ai fini della commercializzazione ma svolgono ruoli ecologici rilevanti nell'ecosistema marino. Oltre che il danno ecologico, la cattura di invertebrati del benthos costituisce un aggravio di lavoro per i pescatori che impiegano molto tempo per la pulizia delle reti. L'obiettivo generale di questo lavoro è la riduzione della cattura "indesiderata" di invertebrati del benthos, migliorando la selettività ed aumentando ulteriormente la sostenibilità della pesca con il tramaglio. Nello specifico si è voluto sperimentare l'installazione di una "greca" sulla parte terminale del tramaglio. Si tratta di una fascia di rete mono-panno montata alla base dell'attrezzo, prima della lima dei piombi, allo scopo di minimizzare la cattura di specie accessorie e il rischio di danneggiamento degli organismi bentonici. Sono state impiegate 2 imbarcazioni provviste di attrezzo sperimentale in ciascuna delle tre differenti aree di indagine (Favignana, Marettimo, Trapani), per un totale di 48 uscite. Le prove di pesca sono state condotte all’interno dell’Area Marina Protetta Isole Egadi. E’ stato previsto che ogni barca impieghi un attrezzo sperimentale di 1000 metri di lunghezza in cui si alternano 50 metri di tramaglio standard (pannello interno con maglia di 31,25 mm di lato, pannelli esterni con maglia di 180 mm di lato), con pezze delle stesse caratteristiche a cui è stata aggiunta una “greca” di 35 cm di altezza, di maglia di 50 mm di lato. Dal confronto delle catture di specie commerciali e non commerciali ottenute con il tramaglio sperimentale, valutando le differenze di cattura tra le pezze con "greca" e quelle armate in maniera tradizionale, si è osservato che si ha una riduzione degli organismi bentonici nonché delle specie commerciali. L'attrezzo risulta in generale più selettivo nei confronti della rete tradizionale.

Phylogeny and phylogeography of the family Hyalidae (Crustacea: Amphipoda) along the northeast Atlantic coasts

The family Hyalidae comprises more than one hundred species, distributed worldwide. They are common and abundant in the littoral and shallow sublittoral habitats and they play an important role in the coastal food chain. Most studies about this family were dealing with taxonomy and ecology, while very little is known about phylogenetic relationship among genera and species. In the present study we aim to achieve the first approach of the phylogenetic patterns of this family in NE Atlantic Ocean and Mediterranean Sea, and to perform the first insight into the phylogeography Apohyale prevostii along both the North Atlantic coasts. In order to do that, eight species belonging to the genera Apohyale, Hyale, Serejohyale and Protohyale were investigated using the mitochondrial COI-5P barcode region. Specimens were collected along European and Moroccan Atlantic rocky shores, including Iceland, the British Isles, Macaronesia and in the Mediterranean Sea. Sequences of A. prevostii, from the NW Atlantic Ocean, available in BOLD and GenBank, were retrieved. As expected, phylogenetic analyses showed highly-divergent clades, clearly discriminating among different species clusters, confirming their morphology-based identifications. Although, within A. perieri, A. media, A. stebbingi, P. (Protohyale) schmidtii and S. spinidactylus, high genetic diversity was found, revealing putative cryptic species. The clade of A. prevostii and A. stebbingi appears well supported and divided from the other two congeneric species, and P. (Protohyale) schmidtii shows a basal divergence. The north-western Atlantic coasts were recently colonized by A. prevostii after the last glacial maximum from the European populations showing also a common haplotype in every population analysed. The use of the COI-5P as DNA barcode provided a good tool to underline the necessity of a revision of this emblematic family, as well as to discern taxonomically the possible new species flagged with this molecular device.

Megistobenthic faunal diversity of the Antalya Gulf: Crustacea

The spatio-temporal distribution of megistobenthic crustacean assemblages from the Antalya Gulf, located in the Levantine Sea is described. In order to provide a comprehensive overview of the spatio-temporal patterns of the crustacean community, 3 transect including depth of 10, 25, 75, 125 and 200 m, were studied between 2014 and 2015 to investigate their association with a set of environmental parameters in representative months of each season (spring, summer, autumn and winter). For its economic importance in Levantine waters, a focus analysis of deep-water rose shrimp Parapenaeus longirostris (Lucas, 1846) was done, to investigate the length frequency composition of the population of the Antalya Gulf. A total of 58 crustacean species were encountered in the study area, of these species identified, 18 species were recognized as alien species in the Mediterranean Sea. Throughout the year the most frequent species of the study were the hermit crab Pagurus prideaux (Leach, 1815) and Parapenaeus longirostris (Lucas, 1846) followed by the Indo-Pacific swimming crab Charybdis longicollis (Leene, 1938) and by the invasive shrimp Marsupenaeus japonicus (Spence Bate, 1888). Few species contributing to a high amount to the total biomass were found throughout the year. These species were Charybdis longicollis and Parapenaeus longirostris. Stations of the study area showed similar values of diversity indices of benthic crustacean community among the three transect. The highest values of faunistic indices were detected in autumn and winter (October and February), and also varied along the depth gradient, with the highest values found between 25 and 75 meters. The multivariate analyses conducted on the abundance data point out major differences between depths and between seasons. Therefore, according to cluster analysis and ordination over abundance and biomass, three main crustacean assemblages were detected: the first corresponding to shallow bottoms (10, 25 meters), the second corresponding to intermediate waters (75 meters) and the last to deeper waters (125, 200 meters). Depth was the main factor governing the distribution of megistobenthic crustacean in the area. Besides the depth, the structure of the sediment is the most important factor in determining the crustacean assemblage. Therefore, all factors governing the crustacean distribution were found to be related to the bottom depth. The population of Parapenaeus longirostris in the Antalya Gulf showed significant differences in depth. It was found that females dominated the population of the study area (65.11%), and were significantly larger than males for each cohort identified. The size-weight relationships revealed a slight negative allometry in growth, a bit more pronounced in females than in males.

Nuovi suoni di balenottera comune (Balaenoptera physalus) nel Mediterraneo occidentale

Fin whale (Balaenoptera physalus) is the only misticeto commonly observed in the Mediterranean. The males emit sounds, classic pulse products in sequences called songs, at 20Hz for sexual purposes: sounds are produced during the spring for migration to the Tirreno-Ligurian-Provençal basin, the summer feeding area, and during the autumn, when there is a migration to the south to meet the winter breeding season. This area in the Mediterranean sea is unknown. The east coast of the Iberian Peninsula is a migration area. The study was conducted by analyzing through Adobe Audition 3.0 and XBAT softwares files audio of 30 minutes recorded in 2006, in 2011 and 2012 at the level of the Columbretes Islands, in the western Mediterranean sea, using two hearing aids: the MARU, used in 2006 and the EAR, used in 2011 and 2012. From the analysis have emerged that, in addition to songs with pulses of 20 Hz, there are new sounds of fin whale never previously recognized: the VFPs (Variable Frequency Pulses), higher-frequency pulses emitted, between 50 and 120Hz and the ramps, a set of 7-8 pulses, pertaining to a particular song, of increasing frequency. Further studies are needed to understand the importance of these new sounds.

Spatio-temporal diversity of Megistozoobenthos in the Antalya Gulf and relationships with environmental features

Antalya Gulf is situated in the Levantine Sea, the second biggest and most eastern basin in the Mediterranean Sea. This area is an ultra-oligotrophic basin, strongly affected by anthropogenic inputs, in particular in the fishing areas. For this characteristic, in the Levantine Sea, there is a strong pressure on the natural resources and benthic assemblages. Furthermore, many alien species enter from Suez Canal and are well established in the area. All these pressures are leading to a degradation of the Levantine Sea. For this reason it is important to have tools to study and monitoring the functioning of the marine ecosystem. Benthic organisms are superior to many other biological groups for their response to environmental stresses. The variability of benthic assemblages on a site can reflect, in an integrative mode, the entire functioning of the marine ecosystem. In this study, that wants to analyze the spatial and temporal distribution of the benthic macrofaunal assemblages of Antalya Gulf, 90 benthic species divided in 8 taxa (Annelida, Cnidaria, Echinodermata, Echiura, Mollusca, Porifera, Sipunculida and Tunicata) were found. All the analyses conducted on the entire benthic class and later on Mollusca and Echinodermata separately highlighted the importance of depth on structuring benthic community.

Inference of Raja miraletus population structure using mitochondrial and nuclear DNA: comparing the resolution power of molecular markers in exploring species and population boundaries

This study focused on the role of oceanographic discontinuities and the presence of transitional areas in shaping the population structure and the phylogeography of the Raja miraletus species complex, coupled with the test of the effective occurrence of past speciation events. The comparisons between the Atlantic African and the North-Eastern Atlantic-Mediterranean geographic populations were unravelled using both Cytochrome Oxidase I and eight microsatellite loci. This approach guaranteed a robust dataset for the identification of a speciation event between the Atlantic African clade, corresponding to the ex Raja ocellifera nominal species, and the NE Atlantic-Mediterranean R. miraletus clade. As a matter of fact, the origin of the Atlantic Africa and the NE Atlantic-Mediterranean deep split dated about 11.74MYA and was likely due to the synergic influence currents and two upwelling areas crossing the Western African Waters. Within the Mediterranean Sea, particular attention was also paid to the transitional area represented by Adventura and Maltese Bank, that might have contributed in sustaining the connectivity of the Western and the Eastern Mediterranean geographical populations. Furthermore, the geology of the easternmost part of Sicily and the geo-morphological depression of the Calabrian Arc could have driven the differentiation of the Eastern Mediterranean Sea. Although bathymetric and oceanographic discontinuity could represent barriers to dispersal and migration between Eastern and Western Mediterranean samples, a clear and complete genetic separation among them was not detected. Results produced by this work identified a speciation event defining Raja ocellifera and R. miraletus as two different species, and describing the R. miraletus species complex as the most ancient cryptic speciation event in the family Rajidae, representing another example of how strictly connected the environment, the behavioural habits and the evolutionary and ecologic drivers are.

Climate warming and vegetation response after Heinrich event 1 (16 700–16 000 cal yr BP) in Europe south of the Alps

Chironomids preserved in a sediment core from Lago di Origlio (416 m a.s.l.), a lake in the foreland of the Southern Swiss Alps, allowed quantitative reconstruction of Late Glacial and Early Holocene summer temperatures using a combined Swiss–Norwegian temperature inference model based on chironomid assemblages from 274 lakes. We reconstruct July air temperatures of ca. 10 °C between 17 300 and 16 000 cal yr BP, a rather abrupt warming to ca. 12.0 °C at ca. 16 500–16 000 cal yr BP, and a strong temperature increase at the transition to the Bølling/Allerød interstadial with average temperatures of about 14 °C. During the Younger Dryas and earliest Holocene similar temperatures are reconstructed as for the interstadial. The rather abrupt warming at 16 500–16 000 cal yr BP is consistent with sea-surface temperature as well as speleothem records, which indicate a warming after the end of Heinrich event 1 (sensu stricto) and before the Bølling/Allerød interstadial in southern Europe and the Mediterranean Sea. Pollen records from Origlio and other sites in southern Switzerland and northern Italy indicate an early reforestation of the lowlands 2000–1500 yr prior to the large-scale afforestation of Central Europe at the onset of the Bølling/Allerød period at ca. 14 700–14 600 cal yr BP. Our results suggest that these early afforestation processes in the formerly glaciated areas of northern Italy and southern Switzerland have been promoted by increasing temperatures.

A 2000 year long seasonal record of floods in the southern European Alps

Knowledge of past natural flood variability and controlling climate factors is of high value since it can be useful to refine projections of the future flood behavior under climate warming. In this context, we present a seasonally resolved 2000 year long flood frequency and intensity reconstruction from the southern Alpine slope (North Italy) using annually laminated (varved) lake sediments. Floods occurred predominantly during summer and autumn, whereas winter and spring events were rare. The all-season flood frequency and, particularly, the occurrence of summer events increased during solar minima, suggesting solar-induced circulation changes resembling negative conditions of the North Atlantic Oscillation as controlling atmospheric mechanism. Furthermore, the most extreme autumn events occurred during a period of warm Mediterranean sea surface temperature. Interpreting these results in regard to present climate change, our data set proposes for a warming scenario, a decrease in summer floods, but an increase in the intensity of autumn floods at the South-Alpine slope.