Search

As climate-related impacts threaten marine biodiversity globally, it is important to adjust conservation efforts to mitigate the effects of climate change. Translating scientific knowledge into practical management, however, is often complicated due to resource, economic and policy constraints, generating a knowledge-action gap. To develop potential solutions for marine turtle conservation, we explored the perceptions of key actors across 18 countries in the Mediterranean. These actors evaluated their perceived relative importance of 19 adaptation and mitigation measures that could safeguard marine turtles from climate change. Of importance, despite differences in expertise, experience and focal country, the perceptions of researchers and management practitioners largely converged with respect to prioritizing adaptation and mitigation measures. Climate change was considered to have the greatest impacts on offspring sex ratios and suitable nesting sites. The most viable adaptation/mitigation measures were considered to be reducing other pressures that act in parallel to climate change. Ecological effectiveness represented a key determinant for implementing proposed measures, followed by practical applicability, financial cost, and societal cost. This convergence in opinions across actors likely reflects long-standing initiatives in the Mediterranean region towards supporting knowledge exchange in marine turtle conservation. Our results provide important guidance on how to prioritize measures that incorporate climate change in decision-making processes related to the current and future management and protection of marine turtles at the ocean-basin scale, and could be used to guide decisions in other regions globally. Importantly, this study demonstrates a successful example of how interactive processes can be used to fill the knowledge-action gap between research and management., This work was conducted under FutureMares EU project that received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 869300. The Mediterranean Marine Turtle Working Group was established in 2017 and is continuously supported by MedPAN and the National Marine Park of Zakynthos. The work of AC was supported by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “First Call for H.F.R.I. Research Projects to support Faculty members and Researchers and the procurement of high-cost research equipment grant” (Project Number: 2340).

The Marine Strategy Framework Directive (MSFD) aims to protect the marine environment and marine biodiversity across Europe more effectively. In the present study, the predicted distribution of striped dolphins of the Gulf of Corinth (Greece) is investigated for the first two periods of the MSFD (I: 2007-2012; II: 2013-2018). For the first time, anthropogenic variables are included in the striped dolphin distribution analysis, resulting from accounting for most of the variability. The results show that the predicted distribution is similar for both investigated periods. However, a small reduction of suitable areas in the Northern portion of the Gulf is observable for the second one, probably due to the expansion of fish farm activity in this zone. The MSFD and its consequent management actions didn’t appear to improve the protection of striped dolphins in the investigated area. Their review will be essential to assess which further management actions will be necessary to program to protect and conserve striped dolphins in the Natura 2000 area “Gulf of Corinth”. The present study shows that human activities are important for explaining stripe dolphins distribution and that their further development needs to be carefully taken into account while managing spatial planning.

Loggerhead turtles (Caretta caretta) spend most of their life in large marine areas occupying a variety of habitats where they are exposed to different types of threats. Among these, marine litter is known to pose a risk of entanglement or ingestion. Areas of risk exposure can be identified where the species overlap with litter accumulations, but gathering data on this highly mobile species and marine litter, especially in high sea areas, is challenging. Here we analysed five years of sea turtle and marine litter data collected by a network of research bodies along fixed trans-border transects in the Mediterranean Sea. Ferries were used as observation platforms to gather systematic data on a seasonal basis using standard protocols. The Sightings Per Unit of Effort was used as an index to compare loggerhead turtle sightings over time and space, and risk exposure areas were assessed based on seasonal overlap of species hot spots and high-density plastic areas revealed by Kernel analysis. In almost 180,000 km surveyed, 1258 sea turtles were recorded, concentrated mostly during all seasons in the central Adriatic Sea and Sardinia-Sicilian channels, and during spring in central Tyrrhenian. Plastic was the highest fraction of litter items detected. Several areas of higher risk exposure, both permanent and seasonal, were identified, mainly in the Adriatic Sea and during the spring-summer seasons. Records of both species and floating litter were highly variable, underlying the need for continuous long-term monitoring to develop sound conservation and management measures, especially in the identified areas of risk exposure.

A pilot study, using the dataset from the research network ‘FLT Med Net’, which regularly monitors transborder regions in the Mediterranean Sea using ferries as platform for systematic surveys, was undertaken to assess common bottlenose dolphin range and population trends within the Natura 2000 EU marine site “Tutela del Tursiops truncatus”. The site was recently designated by the Tuscany Region (Italy) within the requirement of the EU Habitats Directive. In order to evaluate the conservation status of bottlenose dolphin according to the surveillance scheme of the Directive, two six-year periods (2007-2012; 2013-2018) were compared to assess trends in distribution-occurrence (range); Sightings Per Unit of Effort and Density (population). In total, 18146 NM were surveyed along two fixed transects, recording 90 sightings of Tursiops truncatus and a total of 268 specimens. Between the two periods, slight but not statistically significant differences were assessed, with decreasing trend in range and population of the species; no variation was detected in mean group sizes. Travelling was the most common behaviour, and juveniles were present in 20% of the sightings, concentrated during spring and summer. The consistent FLT Med Net dataset was found to be appropriate to evaluate important parameters for the assessment of trends in the conservation status of Tursiops truncatus at the Natura2000 site scale.

Presence-only data are a typical occurrence in species distribution modeling. They include the presence locations and no information on the absence. Their modeling usually does not account for detection biases. In this work, we aim to merge three different sources of information to model the presence of marine mammals. The approach is fully general and it is applied to two species of dolphins in the Central Tyrrhenian Sea (Italy) as a case study. Data come from the Italian Environmental Protection Agency (ISPRA) and Sapienza University of Rome research campaigns, and from a careful selection of social media (SM) images and videos. We build a Log Gaussian Cox process where different detection functions describe each data source. For the SM data, we analyze several choices that allow accounting for detection biases. Our findings allow for a correct understanding of Stenella coeruleoalba and Tursiops truncatus distribution in the study area. The results prove that the proposed approach is broadly applicable, it can be widely used, and it is easily implemented in the R software using INLA and inlabru. We provide examples' code with simulated data in the supplementary materials.

The Sardinian and Sicilian Channels are considered hotspots of biodiversity and key ecological passages between Mediterranean sub-basins, but with significant knowledge gaps about marine mammal presence and potential threats they face. Using data collected between 2013 and 2019 along fixed transects, inter and intra-annual cetacean index of abundance was assessed. Habitat suitability, seasonal hot spots, and risk exposure for plastic were performed using the Kernel analysis and the Biomod2 R-package. 661 sightings of 8 cetacean species were recorded, with bottlenose and striped dolphins as the most sighted species. The north-eastern pelagic sector, the coastal waters and areas near ridges resulted the most suitable habitats for these species. The risk analysis identified the Tunis, Palermo, and Castellammare gulfs and the Egadi Island as areas of particular risk of plastic exposure. The study represents a great improvement for cetacean knowledge in this region and contributes to the development of effective conservation strategies.

Background The Mediterranean subpopulation of fin whale Balaenoptera physalus (Linnaeus, 1758) has recently been listed as Vulnerable by the IUCN Red List of threatened species. The species is also listed as species in need of strict protection under the Habitat Directive and is one of the indicators for the assessment of Good Environmental Status under the MSFD. Reference values on population abundance and trends are needed in order to set the threshold values and to assess the conservation status of the population. Methods Yearly summer monitoring using ferries as platform of opportunity was performed since 2008 within the framework of the FLT Med Network. Data were collected along several fixed transects crossing the Western Mediterranean basin and the Adriatic and Ionian region. Species presence, expressed by density recorded along the sampled transects, was inspected for assessing interannual variability together with group size. Generalized Additive Models were used to describe density trends over a 11 years’ period (2008–2018). A spatial multi-scale approach was used to highlight intra-basin differences in species presence and distribution during the years. Results Summer presence of fin whales in the western Mediterranean area showed a strong interannual variability, characterized by the alternance of rich and poor years. Small and large groups of fin whales were sighted only during rich years, confirming the favorable feeding condition influencing species presence. Trends highlighted by the GAM can be summarized as positive from 2008 to 2013, and slightly negative from 2014 to 2018. The sub-areas analysis showed a similar pattern, but with a more stable trend during the second period in the Pelagos Sanctuary sub-area, and a negative one in the other two sub-areas. Our findings further confirm the need for an integrated approach foreseeing both, large scale surveys and yearly monitoring at different spatial scales to correct and interpret the basin wide abundance estimates, and to correlate spatial and temporal trends with the ecological and anthropogenic drivers.

Land-based activities are, undoubtedly, the main source of marine litter, particularly in a highly populated closed sea basin, such as the Mediterranean Sea. Rivers, consequently, act as a pathway of mismanaged waste to the sea. While quantification of inputs is a difficult task, the assessment of abundance, composition trends and baselines, and the identification of sources and main sectors producing marine litter are of crucial importance to support the ability of policy makers to improve waste reduction measures. For this reason, the Joint Research Centre (JRC/RIMMEL) coordinated a network of several research bodies that monitored floating litter (> 2.5 cm) from fixed observation points located on rivers near the sea using the same systematic research protocol. In Italy, one of the surveyed rivers was the Tiber, the third longest river on the peninsula, which after running through the city of Rome divides into two branches before flowing into the Tyrrhenian Sea. Results of 1 year of monitoring, September 2016–August 2017, highlight that 82% of the floating items were plastic and belong to the food and cosmetic sector, and it was estimated that 85.4% (± 9.4) of litter items get into the sea each hour from the Tiber river canal in Fiumicino, of which approximately 30% were already fragmented.

Marine litter is a major form of pollution in the Mediterranean, but despite legislative requirements, additional information is still needed to evaluate basin-scale amounts, trends, and potential threats for the biota, especially for Habitats Directive listed species, such as cetaceans. Through repeated sampling of floating macro-litter along a fixed transect between Spain and Italy, this study provided detailed data within four marine sectors of the Western Mediterranean Sea, characterized by seasonal variability in oceanographic/ecological conditions and anthropogenic pressure. Moreover, we identified the areas of major overlap between high density of plastic and cetacean sightings. Litter was composed of plastic for more than 65%, with more diverse compositions occurring in the Balearic and Sardinian Sea compared to the semi-enclosed Bonifacio and Tyrrhenian sectors. The average amount of macro-litter ranged between 1.9 and 2.8 items km−2 and reached the highest values in spring/summer in all basins, suggesting a relationship with the increasing of touristic and maritime activities, both in coastal and offshore waters. The Balearic and Bonifacio sectors showed higher amounts and larger accumulation areas for plastic, likely due to a combination of multiple sources and oceanographic processes influencing the distributional patterns. Cetacean sightings were recorded in all sectors with fin whale (Balaenoptera physalus) and striped dolphin (Stenella coeruleoalba) as the most frequent species. The presence of cetaceans in areas with high densities of plastic emerged mostly during spring/summer in the Balearic and Bonifacio sectors, but other specific areas of potential exposure were identified, indicating the need for a dynamic definition of this threat.

We are grateful to the ACCOBAMS Secretariat for their support in this work, including a small grant for the analysis. The Mediterranean population of Cuvieŕs beaked whale (Ziphius cavirostris), a deep-diving cetacean, is genetically distinct from the Atlantic, and subject to a number of conservation threats, in particular underwater noise. It is also cryptic at the surface and relatively rare, so obtain robust knowledge on distribution and abundance presents unique challenges. Here we use multiplatform and multiyear survey data to analyse the distribution and abundance of this species across the Mediterranean Sea. We use a novel approach combining heterogeneous data gathered with different methods to obtain a single density index for the region. A total of 594,996 km of survey effort and 507 sightings of Cuvier’s beaked whales, from 1990 to 2016, were pooled together from 24 different sources. Data were divided into twelve major groups according to platform height, speed and sea state. Both availability bias and effective strip width were calculated from the sightings with available perpendicular distance data. This was extrapolated to the rest of the sightings for each of the twelve groups. Habitat preference models were fitted into a GAM framework using counts of groups as a response variable with the effective searched area as an offset. Depth, coefficient of variation of depth, longitude and marine regions (as defined by the International Hydrographic Organization) were identified as important predictors. Predicted abundance of groups per grid cell were multiplied by mean group size to obtain a prediction of the abundance of animals. A total abundance of 5799 (CV = 24.0%) animals was estimated for the whole Mediterranean basin. The Alborán Sea, Ligurian Sea, Hellenic Trench, southern Adriatic Sea and eastern Ionian Sea were identified as being the main hot spots in the region. It is important to urge that the relevant stakeholders incorporate this information in the planning and execution of high risk activities in these high-risk areas. Postprint

The Mediterranean marine region is considered one of the world’s biodiversity hotspots for conservation priorities due the high occurrence of rare and threatened species, endemism and high species richness. However, several pressure such as losses and alterations of habitats are ongoing and in order to increase conservation in this sea region, many marine protected areas were established, including Natura 2000 sites. The latter are areas designated under the Habitat and Bird Directives for the conservation of species in need of strict protection, so that they can reach a favourable conservation status. Species conservation status is also assessed through the IUCN (International Union for Conservation of Nature) Red List of Threatened Species. The aim of our study was to test whether IUCN Red List and the related Red List Index RLI (which aggregates in a single value all the information on conservation status of a particular set of species) can be used as a metrics to characterize MPAs, and orienting, consequently, local marine conservation policies. A pilot study was undertaken in the six Sicilian MPAs (Marine Protected Areas) and results highlighted that Egadi Island has a low RLI value (meaning that the MPA hosts many species with a threatened status) while the Capo Gallo MPA, at the opposite, as an high RLI value (i.e.less threatened species); the other four MPAs. Egadi, Pelagie, and Ustica showed similar distribution frequencies of Red List categories having similar RLI values. Biological resource use, natural system modifications, invasive species, and pollution all account for 90% of assessed threats. Outcomes of our study showed that IUCN indicators should be considered as a tool to: assess the conservation status of set of species in protected areas; drive prioritization in the decision process in order to support an effective management conservation plan; designate new MPAs.

To date, the principal assessment for the Loggerhead sea turtle (Caretta caretta) distribution in the Mediterranean Basin is given by beaches nests along the coasts. The Eastern Mediterranean Sea has been revealed an important foraging area for this protected species but temporal trends of its spatial distribution and anthropogenic threats are lacking. This study shows that the employment of ferry as platform of observation would represent a valid tool for monitoring Loggerhead sea turtle in remote marine area, and to pinpoint important areas for the conservation and assessment of the species. The results of the present study confirm the previous hypothesis of the areas selected by the species, which are neritic areas in the northern/middle Adriatic Sea and oceanic areas in the Ionian Sea.

The relationship between a species and its habitat is complex but it is essential to study the distribution and habitat use of a protected species in order to identify regions where human activities and disturbances are likely to impact its population. The Marine Strategy Framework Directive informs that studies focusing on spatial and temporal species distribution and ecosystem variations (including links between habitats and species of marine mammals) are recommended to achieve Good Environmental Status (GES) of the EU’s marine water by 2020. However, the current level of information on the spatial-temporal distribution of marine mammals is often lacking. The striped dolphin is the most abundant cetacean of the Mediterranean Sea; nevertheless its Mediterranean population is listed as "vulnerable" by IUCN experts. In order to investigate the spatial distribution of striped dolphin within the Adriatic-Ionian Region, a cooperative project among different research groups was set up and a multi-source data approach was employed. Presence data collected during monitoring activity carried out from 2008 to 2018 were analysed by means of Maxent. Main topographic variables as bathymetry, slope and distance from coastline were considered and five distribution models were performed to highlight suitable areas for striped dolphin within the entire study area. Models are presented and discussed. The results of this study show that to investigate the distribution of a species at a regional scale it is necessary to monitor area with different environmental characteristics. In this regards, cooperative regional projects represent an opportunity for pooling together data that taken singularly would not necessarily reflect the distribution of species at a larger scale, but that analysed together would allow to acquire information on suitable habitats at a regional level.

Marine litter is a major source of pollution in the Mediterranean basin, but despite legislative requirements, scant information is available for the ongoing assessment of this threat. Using higher size classes as proxy for litter distribution, this study gave a synoptic estimation of the amount, composition, and distribution of floating macro-litter in the Mediterranean. The average amount of macro-litter was in a range of 2-5 items/km2, with the highest in the Adriatic basin. Seasonal patterns were present in almost all study areas and were significant in the Ligurian Sea, Sardinian-Balearic basin, and Central Tyrrhenian Sea. Plastic accounted for > 80% of litter in all areas and seasons, with the highest proportion in the Adriatic Sea, Ligurian Sea, and Sicilian-Sardinian Channels; in the Bonifacio Strait, Tyrrhenian Sea, and Sardinian-Balearic basin, litter composition was instead more diverse. Spatial analysis suggested an almost homogeneous distribution of litter without evident regular aggregation zones.

While cetacean distribution and habitat is well investigated in some areas in the Mediterranean, only a few studies have been conducted so far in the central part of the Mediterranean basin. In order to fill this gap, a dedicated research program has been developed using ferries operating between Tunis and Genoa as platforms of opportunity to collect data on cetacean presence and distribution. The area was subdivided in three sub-regions: the Sardo-Tunisian channel, the eastern Sardinian margin and the international sanctuary for marine mammals Pelagos. During fall 2013, marine mammal observers surveyed 1900 nautical miles and recorded 39 encounters of 5 identified species including balaenopteridae, delphinidae, ziphiidae and physeteridae families. Bottlenose dolphin (Tursiops truncatus) and striped dolphin (Stenella coeruleoalba) were the most common species followed in decreasing occurrence by fin whale (Balaenoptera physalus), Cuvier’s beaked whale (Ziphius cavirostris) and sperm whale (Physeter macrocephalus). The distribution of bottlenose dolphin was restricted to the shallow waters of the Tunisian plateau over the continental shelf. Striped dolphins were sighted in the open sea waters and the eastern Sardinia margin. Large cetaceans as sperm whale and fin whale were mainly recorded over the canyon of Bizerte in the Sardo-Tunisian channel. Highest diversity index was reported in the Pelagos sanctuary even during autumn, confirming the area as a preferred habitat for several cetacean species. Our results also highlight the importance of the Sardo-Tunisian channel, where a relatively important diversity index has been computed, especially over the canyon of Bizerte. This study is the first to investigate cetacean diversity in pelagic central Mediterranean waters and highlights the insistent need to develop regular monitoring in this area.

Maritime traffic is one of many anthropogenic pressures threatening the marine environment. This study was specifically designed to investigate the relationship between vessels presence and cetacean sightings in the high sea areas of the Western Mediterranean Sea region. We recorded and compared the total number of vessels in the presence and absence of cetacean sightings using data gathered during the summer season (2009-2013) along six fixed transects repeatedly surveyed. In locations with cetacean sightings (N = 2667), nautical traffic was significantly lower, by 20%, compared to random locations where no sightings occurred (N = 1226): all cetacean species, except bottlenose dolphin, were generally observed in locations with lower vessel abundance. In different areas the species showed variable results likely influenced by a combination of biological and local environmental factors. The approach of this research helped create, for the first time, a wide vision of the different responses of animals towards a common pressure.

Cuvier’s beaked whale (Ziphius cavirostris, G. Cuvier 1823) is a poorly known species and many international agreements have asked for a better understanding of its biology for conservation purposes. In the present study, systematic cetacean surveys were carried out from ferries along a trans-regional fixed transect in the Central Tyrrhenian Sea (Civitavecchia, Latium – Golfo Aranci, Sardinia), just outside the southeastern border of the Pelagos Sanctuary. This research provided long-term, consistent data on Cuvier’s beaked whale during two research periods (1990–1992 and 2007–2011). The objective of the research was to compare the presence, distribution and habitat use of Cuvier’s beaked whale between the two investigated periods. Summer data (June–September) from the two periods were compared in terms of frequency of sightings, group size and spatial distribution related to the main ecogeographical features. A presence-absence model (generalized additive modelling) was performed to predict habitat suitability in the two study periods. The results highlight longterm site fidelity of Cuvier’s beaked whale in the Central Tyrrhenian Sea with encounter rates comparable to the ones reported for other key areas. Separate suitability models based on 1990s and 2000s data appeared to work for each individual time period but differences were evident between the two periods, indicating changes in habitat selection over time. Our findings of the study appear to expand the definition of suitable beaked whale habitat and underline how the temporal scale of the analysis can affect the results in habitat studies. Moreover, this research highlights the importance of the Central Tyrrhenian Sea marine region for Cuvier’s beaked whale and the ability of continuous monitoring to identify changes in cetacean frequency and distribution, necessary for adaptive conservation management approaches.

Cetacean strandings are a constant phenomenon that occurs on coastlines; mortality is related to several factors but commercial fishing is considered one of the main pressures, in the Mediterranean, that can impact small cetacean species such as common bottlenose dolphin (Tursiops truncatus) and striped dolphin (Stenella coeruleoalba). Since all eight species of cetaceans residing in the Mediterranean Sea are listed in the Habitats Directive, there is a legislative and management need to survey and report their conservation status every 6 years. The aim of this study was to assess the relationship, in Sicily, between strandings of two species and the fishery capacity, using records from 1995 to 2012. Positions and densities of all the strandings were compared with values of engine power from all the fishing vessels registered in 48 Sicilian ports. In addition, the relationship between strandings and the wild population at sea was investigated. Results showed that trends of fishing capacity and strandings both decreased, with a strong positive association. Trends were also confirmed when data were grouped into “6-year periods” or into different geographical sub-areas. Strandings were clustered near ports with higher fishing capacities; S. coeruleoalba records were distributed more homogenously along the coastline compared to T. truncatus, whose strandings were mostly distributed on the southern coastline, where the fishing capacity of bottom otter trawls was greater. The ratio between the two cetacean species was similar both for strandings and at-sea populations. Results show that fishing capacity is a pertinent indicator of pressure/threat to small cetacean species, and stranding records could complement at-sea data to assess population status within the framework of EU Directives.

1. Cetaceans are key biological indicators of the status of marine waters and are protected under an extensive legislative framework. Research about these highly dynamic species is challenging, so seasonal cycles and patterns of distribution, especially in high sea areas, are still poorly understood. 2. This study contributes to improving knowledge about cetacean occurrence in largely unexplored areas of medium‐latitudes in the western Mediterranean Sea. Systematic surveys were conducted along a trans‐regional transect over 3 years (October 2012 to September 2015) allowing consistent data collection over almost 60 000 km of effort through all seasons. 3. Seasonal cetacean diversity wasinvestigated using a25km2 grid cell as a statistical unit to explore patterns of abundance, distribution, and habitat use in three marine sectors (Sardinian–Balearic, Bonifacio Strait, Tyrrhenian). All cetacean species regularly present in the Mediterranean basin were detected, with highest occurrence in fin whale and striped dolphin, followed by bottlenose dolphin and sperm whale. 4. The Sardinian–Balearic sector generally showed higher species richness and diversity than the Tyrrhenian, where seasonal variations were more pronounced. The study suggested seasonal movements, especially for fin whale and striped dolphin, in the Sardinian–Balearic sector with peaks of occurrence during spring/summer and lower numbers during winter/autumn, and also delivered interesting insights to rarer pelagic species. 5. The study identified areas/seasons in which the combined effect of high species diversity, abundance, significance of hot spots and presence of juveniles require increasing conservation effort. Results underline the important contribution of continuous monitoring in high sea areas to the implementation of adaptive protection measures.

15 páginas, 5 figuras, 2 tablas.-- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited, Spatially explicit risk assessment is an essential component of Marine Spatial Planning (MSP), which provides a comprehensive framework for managing multiple uses of the marine environment, minimizing environmental impacts and conflicts among users. In this study, we assessed the risk of the exposure to high intensity vessel traffic areas for the three most abundant cetacean species (Stenella coeruleoalba, Tursiops truncatus and Balaenoptera physalus) in the southern area of the Pelagos Sanctuary, which is the only pelagic Marine Protected Area (MPA) for marine mammals in the Mediterranean Sea. In particular, we modeled the occurrence of the three cetacean species as a function of habitat variables in June by using hierarchical Bayesian spatial-temporal models. Similarly, we modelled the marine traffic intensity in order to find high risk areas and estimated the potential conflict due to the overlap with the cetacean home ranges. Results identified two main hot-spots of high intensity marine traffic in the area, which partially overlap with the area of presence of the studied species. Our findings emphasize the need for nationally relevant and transboundary planning and management measures for these marine species, This work was supported by the “Banco di Sardegna” Foundation (BAN6077)

In the 1990s, the central Tyrrhenian Sea was regarded as a transit region for fin whales’ (Balaenoptera physalus) summer migration. In recent years, a much higher presence of fin whales during the entire summer season was reported in the region. The hypothesis that the central Tyrrhenian Sea may have become a summer feeding ground was tested gathering data from summer presence of whales in the region (40–42.5°N; 9–13°E) and investigating whether it might be related to sea surface temperature and chlorophyll-a concentration, considered as proxies of food availability. Results showed that whales always aggregate in the more productive portions of the investigated area; the general productivity of the area, however, did not directly influence the frequency of occurrence of whales. We concluded that the complex dynamics of the balance between feeding activities and avoiding pressures may have led fin whales to use the region as an opportunistic feeding ground.

Seasonal maritime traffic was investigated in relation to cetaceans, through direct observations (July 2013–June 2015) along three fixed transects in Western Mediterranean. Visually obtained vessel abundance was compared with Automatic Identification System data to explore if the two methods provided different results. Traffic intensity and composition were characterised by seasons and vessel categories. Finally, cetacean presence was investigated in relation to traffic by measuring the difference of vessel abundance in the presence and absence of animal sightings. Results showed that visual sampling was consistent with AIS data, providing more information on small-medium vessels. Traffic was more intense and diverse in Spring/Summer, and the highest vessel abundance and seasonal variations in composition emerged for inshore subareas. The difference of traffic in the presence and absence of cetaceans was higher in most offshore subareas in Spring/Summer, verified for B . physalus and S . coeruleoalba ; in inshore waters, mostly occupied by T . truncatus , no significant differences emerged.

From 1989 to 1992, systematic cetacean surveys were carried out twice weekly along a trans-regional fixed transect in the Central Tyrrhenian Sea, utilising passenger ferries as research platforms. Using the same protocol and supervised by the same investigators, the research restarted in 2007, providing the opportunity to compare consistent data over a long 20-year period. The monitored transect (Civitavecchia-Golfo Aranci) runs along a strategic area just outside the southeastern border of the Pelagos Sanctuary. Over the last two decades, an increasing trend of temperature and salinity, in the deep and intermediate layers, has been documented in the region, as well as general changes over the Mediterranean basin. These changes, together with the increasing impact of some pressures (e.g. maritime traffic) may have led to changes in oceanographic and anthropogenic features and, subsequently, in cetacean presence and distribution. The research aimed to verify whether any changes occurred in the pattern of cetacean occurrence over the 20-year period along the representative transect in the Central Tyrrhenian Sea. Data from 90 summer weekly runs undertaken in the 1990s were compared with data obtained from 95 runs undertaken in the 2000s. Each ferry run was considered an independent statistical unit: the encounter rate (ER = number of sightings per hour spent on effort) was calculated to compare relative abundance between periods, years and months. Spatial analysis was performed on geographical data using Kernel analysis to map the distribution of sightings. Logistic regression (GLM) was performed to compare habitat preference. Total encounter rate in the 1990s (ER = 0.59 ± CI 0.08) was significantly lower (P

The distribution and migration patterns of the fin whale (Balaenoptera physalus) in the Mediterranean Sea are largely unknown. This species is mostly at risk of ship strike, it is therefore essential to develop synoptic tools to derive its habitat at large scale. We describe a foraging habitat model for fin whales in the western Mediterranean Sea relying on species ecology for the choice of predictors. The selected environmental variables are direct and resource predictors available at daily and large scales. The feeding habitat was mainly processed from the simultaneous occurrence of large oceanic fronts of satellite-derived sea surface chlorophyll content (CHL) and temperature (SST). A specific range of surface chlorophyll content (0.11-0.39 mg m-3) and a minimum water depth (93 m) were also identified to be important regional criteria. Daily maps were calibrated and evaluated against independent sets of geo-located fin whale presence data. The main predictor of feeding environment was specific CHL fronts, therefore the derived habitat is potential and functionally-linked. The model performs well with 80% of presence data closer than 8.8 km of the predicted potential habitat. The computed monthly, seasonal and annual maps of potential feeding habitat from 2000 to 2010 generally correlate with current knowledge on fin whale ecology. Overall, the size of potential habitat of fin whales is ca. 11% of the western Mediterranean Sea surface and seasonal recurrent areas were clearly shown. The results also displayed a strong seasonality in habitat size and locations as well as high year-to-year variations (40% to 50%), which is essential to assess migration patterns and suggest sound protection measures., JRC.G.4-Maritime affairs

In summer 2010 and summer 2011, weekly cetacean surveys were undertaken in “passing mode”, using ferries as platform of opportunity, along the “fixed line transect” between Catania and Civitavecchia (Southern Italy). Of the 20 species of cetaceans confirmed for the Mediterranean sea, 8 were sighted within the survey period: 7 species represented by Mediterranean subpopulations ( Balaenoptera physalus, Physeter macrocephalus, Stenella coeruleoalba, Delphinus delphis, Grampus griseus, Tursiops truncatus and Ziphius cavirostris ) and one considered visitor ( Steno bredanensis ). We had a total of 220 sightings during the 2010 and a total of 240 sightings in the 2011. The most frequent species was S. coeruleoalba. By the comparison of the data from the two sampling seasons, a significant increase of D. delphis sightings and a decrease of sightings of B. physalus and P. macrocephalus was observed from 2010 to 2011. While all the other species were observed in both sampling seasons, Z. cavirostris and Steno bredanensis were observed only during 2011. The presence of mixed groups of odontocetes was documented too: we sighted groups composed by S. coeruleoalba and D. delphis , by S. coeruleoalba and T. truncatus , and by S. coeruleoalba and G. griseus . The results of this research add useful information on cetacean species in a very poorly known area and highlight the need to standardize large scale and long term monitoring programs in order to detect variation in presence, abundance and distribution of cetaceans populations and understand the effect of anthropogenic factors.