Rapporto tecnico sul metodo di produzione di un contenitore “porta otoliti” in resina epossidica a partire da un modello commerciale

Nell'ambito delle attività del Programma Nazionale di raccolta Dati Alieutici, per la raccolta dei dati primari di tipo biologico, tecnico ambientale e socio economico nel settore della pesca, l’IAMC - CNR UOS di Mazara del Vallo e Capo Granitola partecipano a dare attuazione al Programma Nazionale attraverso la raccolta ed analisi di campioni biologici provenienti da catture commerciali (ex modulo Campbiol) e da survey scientifici a mare (MEDITS e MEDIAS). A tal fine, tra l'altro, ogni anno si rende necessario il reperimento di un gran numero di particolari vaschette per la conservazione di otoliti di specie ittiche quali Engraulis encrasicolus e Sardina pilchardus, specie di particolare interesse economico in Mediterraneo e i cui stock vengono annualmente monitorati dal CNR. Si è cercato in prima battuta di acquistare i contenitori “porta otoliti” in questione, ma gli stessi non sono stati trovati in commercio. E’ stato quindi necessario avviare una produzione propria dell’articolo partendo da un modello/esemplare in nostro possesso, cercando con le opportune accortezze di realizzare un clone sia dal punto di vista morfometrico che da quello chimico/meccanico per scongiurare problemi di deformazioni nel tempo che potrebbero causare la perdita dei campioni raccolti

CYCLOSTRATIGRAPHY: A METHODOLOGICAL APPROACH

Aim of this study is a synthetic description of the most used methodologies of cylostratigraphic analysis for the astronomical calibration of sedimentary sequences. The different numerical solutions of the insolation curve and, in particular, the most used astronomic curve La90 (1,1) are analyzed. Then, a detailed description of the methodologies for the astronomic calibration of different sedimentary sequences i) on the basis of a litho-stratigraphic approach and ii) on the basis of a spectral analysis applied to faunal and geochemical climate-sensitive records, is proposed.&nbsp

Importancia de los fenómenos físicos y la disponibilidad de nutrientes en el control de la concentración de clorofila estimada por satélite en el área costera de afloramiento del Canal de Sicilia

The northern sector of the Sicilian Channel is an area of favourable upwelling winds, which ought to support primary production. However, the values for primary production are low when compared with other Mediterranean areas and very low compared with the most biologically productive regions of the world’s oceans: California, the Canary Islands, Humboldt and Benguela. The aim of this study was to identify the main factors that limit phytoplankton biomass in the Sicilian Channel and modulate its monthly changes. We compared satellite-based estimates of chlorophyll a concentration in the Strait of Sicily with those observed in the four Eastern Boundary Upwelling Systems mentioned above and in other Mediterranean wind-induced coastal upwelling systems (the Alboran Sea, the Gulf of Lions and the Aegean Sea). Our results show that this low level of chlorophyll is mainly due to the low nutrient level in surface and sub-surface waters, independently of wind-induced upwelling intensity. Further, monthly changes in chlorophyll are mainly driven by the mixing of water column and wind-induced and/or circulation-related upwelling processes. Finally, primary production limitation due to the enhanced stratification processes resulting from the general warming trend of Mediterranean waters is not active over most of the coastal upwelling area off the southern Sicilian coast.El sector norte del Canal de Sicilia es un área de vientos favorables para el afloramiento, lo cual debe favorecer la producción primaria. Sin embargo, los valores de producción primaria son bajos comparados con otras áreas del Mediterráneo y muy bajos comparados con las regiones biológicamente más productivas de los océanos a nivel mundial: California, Canarias, Humboldt y Benguela. El objetivo de este estudio fue identificar los principales factores que limitan la biomasa del fitoplancton y modulan sus cambios mensuales. Comparamos estimas de la concentración de clorofila a basadas en satélite en el estrecho de Sicilia, con las observadas en los cuatro sistemas orientales de afloramiento mencionados anteriormente y en otros sistemas costeros del Mediterráneo en los que el viento favorece los afloramientos (Mar del Alborán, Golfo de León y Mar Egeo). Nuestros resultados muestran que la baja producción primaria es debida principalmente a la baja entrada de nutrientes en aguas superficiales, independientemente de la intensidad del afloramiento causado por el viento. Por otro lado, los cambios mensuales en la producción primaria se deben a la mezcla de la columna de agua y afloramientos asociados al viento y/o procesos de circulación en la zona. Finalmente, la limitación de la producción primaria debida al aumento del proceso de estratificación resultante de la tendencia general de calentamiento de las aguas del Mediterráneo, no es activa a lo largo de la mayor parte del área de afloramiento en la costa sur de Sicilia

Environmental Conditions along Tuna Larval Dispersion: Insights on the Spawning Habitat and Impact on Their Development Stages

Estimated larval backward trajectories of three Tuna species, namely, Atlantic Bluefin Tuna (Thunnus thynnus, Linnaeus, 1758), Bullet Tuna (Auxis Rochei, Risso, 1801) and Albacore Tuna (Thunnus alalunga, Bonnaterre, 1788) in the central Mediterranean Sea, were used to characterize their spawning habitats, and to assess the impact of changes due to the major environmental parameters (i.e., sea surface temperature and chlorophyll-a concentration) on larval development during their advection by surface currents. We assumed that the environmental variability experienced by larvae along their paths may have influenced their development, also affecting their survival. Our results showed that the Tuna larvae underwent an accelerated growth in favorable environmental conditions, impacting on the notochord development. In addition, further updated information on spawning and larval retention habitats of Atlantic Bluefin Tuna, Bullet and Albacore Tunas in the central Mediterranean Sea were delivered

Valutazione dello stato della biodiversità in aree antropizzate: applicazione della metodologia BRUV (Baited Remote Underwater Video) per lo studio della componente nectonica dell'ecosistema

Uno studio di valutazione dello stato della biodiversità focalizzato sulla componente nectonica e finalizzato alla determinazione dell’abbondanza e della composizione in specie del popolamento marino costiero si può avvalere di diversi strumenti e metodologie, le quali possono essere più o meno invasive sull’ecosistema oggetto dello studio. È possibile ad esempio applicare delle metodologie di pesca sperimentale, i.e. di prelievo degli organismi dal loro ambiente al fine di riconoscere e quantificare la presenza delle specie nectoniche nell’area di studio. Esistono tuttavia metodologie meno distruttive che permettono la raccolta di dati attraverso una stima visiva dell’abbondanza e della composizione delle specie direttamente nel loro ambiente naturale. Di queste metodologie fanno parte i censimenti visivi in situ (Samoilys M.A. 1997), i quali hanno il vantaggio di permettere la raccolta dati nel rispetto della biodiversità, evitando eventi mortali e/o fortemente stressanti agli individui oggetto dello studio. Questo fa si che tali metodologie risultino particolarmente utili in ambienti vulnerabili e/o soggetti a particolari vincoli protezionistici volti alla conservazione dell’ambiente marino, come le Aree Marine Protette (AMP), le quali in questo studio rappresentano delle zone di confronto caratterizzate da un limitato impatto antropico. Per tali ragioni, nell’ambito del progetto CISAS è stato scelto di portare avanti la valutazione dello stato del popolamento ittico attraverso una particolare tecnica di censimento visivo, la quale viene effettuata attraverso il sistema BRUV (Baited Remote Underwater Video)

Variability of water mass properties in the Strait of Sicily in summer period of 1998–2013

The Strait of Sicily plays a crucial role in determining the water-mass exchanges and related properties between the western and eastern Mediterranean. Hydrographic measurements carried out from 1998 to 2013 allowed the identification of the main water masses present in the Strait of Sicily: a surface layer composed of Atlantic water (AW) flowing eastward, intermediate and deep layers mainly composed of Levantine intermediate water (LIW), and transitional eastern Mediterranean deep water (tEMDW) flowing in the opposite direction. Furthermore, for the first time, the signature of intermittent presence of western intermediate water (WIW) is also highlighted in the northwestern part of the study area (12.235◦ E, 37.705◦ N). The excellent area coverage allowed to highlight the high horizontal and vertical inter-annual variability affecting the study area and also to recognize the permanent character of the main mesoscale phenomena present in the surface water layer. Moreover, strong temperature-salinity correlations in the intermediate layer, for specific time intervals, seem to be linked to the reversal of surface circulation in the central Ionian Sea. The analysis of CTD data in deeper water layer indicates the presence of a large volume of tEMDW in the Strait of Sicily during the summers of 2006 and 2009.peer-reviewe

Moving Toward a Strategy for Addressing Climate Displacement of Marine Resources: A Proof-of-Concept

Realistic predictions of climate change effects on natural resources are central to adaptation policies that try to reduce these impacts. However, most current forecasting approaches do not incorporate species-specific, process-based biological information, which limits their ability to inform actionable strategies. Mechanistic approaches, incorporating quantitative information on functional traits, can potentially predict species- and population-specific responses that result from the cumulative impacts of small-scale processes acting at the organismal level, and can be used to infer population-level dynamics and inform natural resources management. Here we present a proof-of-concept study using the European anchovy as a model species that shows how a trait-based, mechanistic species distribution model can be used to explore the vulnerability of marine species to environmental changes, producing quantitative outputs useful for informing fisheries management. We crossed scenarios of temperature and food to generate quantitative maps of selected mechanistic model outcomes (e.g., Maximum Length and Total Reproductive Output). These results highlight changing patterns of source and sink spawning areas as well as the incidence of reproductive failure. This study demonstrates that model predictions based on functional traits can reduce the degree of uncertainty when forecasting future trends of fish stocks. However, to be effective they must be based on high spatial- and temporal resolution environmental data. Such a sensitive and spatially explicit predictive approach may be used to inform more effective adaptive management strategies of resources in novel climatic conditions

Signals from the deep-sea: Genetic structure, morphometric analysis, and ecological implications of Cyclothone braueri (Pisces, Gonostomatidae) early life stages in the Central Mediterranean Sea

Cyclothone braueri (Stomiiformes, Gonostomatidae) is a widely distributed fish inhabiting the mesopelagic zone of marine tropical and temperate waters. Constituting one of the largest biomasses of the ocean, C. braueri is a key element in most of the ecological processes occurring in the twilight layer. We focused on the ecological processes linked to early life stages in relation to marine pelagic environmental drivers (temperature, salinity, food availability and geostrophic currents) considering different regions of the Central Mediterranean Sea. A multivariate morphometric analysis was carried out using six parameters with the aim of discerning different larval morphotypes, while a fragment of 367 bp representing the 12S ribosomal RNA gene was used to perform molecular analyses aimed at determining the intraspecific genetic variability. Analysis highlighted two geographically distinct morphotypes not genetically discernible and related to the different nutritional conditions due to spatial heterogeneities in terms of temperature and food availability. The body depth (BD) emerged as an appropriate morphometric parameter to detect the larval condition in this species. Molecular analysis highlighted a moderate genetic divergence in the fish population, showing the recurrence of two phylogroups not geographically separated