Maria Cristina Follesa

• Full Professor
• University of Cagliari

The Mediterranean Sea, a biodiversity hotspot classified by the IUCN as critically threatened for sharks and rays, faces significant conservation challenges because of geopolitical complexities. Traditional, top‐down management strategies often fail, thus calling for alternative conservation approaches. This study documents the first recorded catch...

Humans have transformed ecosystems through habitat modification, harvesting, species introduction, and climate change. Changes in species distribution and composition are often thought to induce biotic homogenization, defined as a decline in spatial beta diversity through time. However, it is unclear whether homogenization is common in ocean ecosys...

Intra- and interspecific relationships among marine taxa, like invertebrates, fishes and marine mammals, are well known. However, relationships between bony fishes and cartilaginous fishes, mainly for trophic reasons, are rarely described and only in tropical environments. Here, we present the first documentation of associations between a stingray...

Microplastic (MP) pollution is a widespread and concerning environmental issue. The benthic layer is known as one of the major accumulation sinks, yet knowledge gaps still remain in describing the interactions of its biota with MPs. This work represents a comprehensive comparative analysis of MP ingestion in the four deep-sea crustacean decapods Ar...

Humans have transformed ecosystems through habitat modification, harvesting, species introduction, and climate change. Changes in species distribution and composition are often thought to induce biotic homogenization, defined as a decline in spatial beta diversity through time. However, it is unclear whether homogenization is common in ocean ecosys...

The precious red coral Corallium rubrum (Linnaeus, 1758) is a charismatic species living in the Mediterranean Sea and its Atlanticsurroundings, known for its slow growth and long lifespan. The development of a reliable method for assessing colony age hasenabled the comparison of average annual growth rates, minimising age-related variability. This...

The report of a capture of an “unusual” small skate from crew members involved in fishing activities in the Sentinelle bank (Central Mediterranean Sea), along with the description provided, led us to hypothesise that it could be Leucoraja melitensis, whose geographical range does not cover this area. For this reason, considering the alarming conser...

Mortality resulting from interactions with fishing gears represent an important threat to sensitive species globally. In this study, we address this issue by defining five species groups of marine megafauna (marine mammals, seabirds, demersal and pelagic elasmobranchs, and sea turtles), and conducting a productivity-susceptibility analysis (PSA) wi...

The number of threatened cartilaginous fishes has grown at an alarming rate in the last decades. Accurate identification of species becomes a critical aspect to assess and plan accurate conservation and management measures for this important group. In the past, the identification was based on morphological methods that have been progressively integ...

The white skate Rostroraja alba has exhibited a declining trend similar to that of several large-bodied batoids in recent years. Consequently, it has been classified as Critically Endangered in European waters by the International Union for the Conservation of Nature. The presence of this species in Sardinian seas (central-western Mediterranean Sea...

Marine biodiversity monitoring in the Mediterranean’s increasingly threatened ecosystems is crucial for effective ecosystem conservation and management. Here, we leveraged the Mediterranean International Trawl Survey program (MEDITS) to implement eDNA sampling through the recently tested ‘metaprobe’ procedure and characterize fish assemblages in th...

This study provides new insights onto spatial and temporal trends of seafloor macro-litter in the abyssal seafloor of Sardinian channel, in central western Mediterranean (Italy). Trawl surveys were conducted at depths between 884 and 1528 m, thus focusing on one of the least investigated marine environments. None of the considered sites was litter...

The bamboo-coral Isidella elongata is a key habitat-forming species in the deep Mediterranean Sea. This alcyonacean is listed as an indicator of Vulnerable Marine Ecosystems (VMEs) and as Critically Endangered due to bottom trawling impacts. In this work, a modeling approach was used to predict and map the habitat suitability of I. elongata in the...

The sustainable management and conservation of deep-sea species may be hampered by the paucity of data on their population structure and connectivity, in the face of ever-increasing fisheries pressure and other forms of impacts on deep-sea ecosystems. The rabbit fish, Chimaera monstrosa, is a deep-sea cartilaginous fish, reported worldwide in the p...

We evaluated the feasibility of classifying ommastrephid and loliginid squid species by statolith shape analysis into fisheries management units, or stocks. Statoliths of Illex coindetii (Verany, 1839) and Loligo forbesii (Steenstrup, 1856) were studied from multiple areas of the North East Atlantic and Northern Mediterranean Sea during 2021-2022....

The main objective of the Working Group on Biological Parameters (WGBIOP) is to review the status, issues, developments, and quality assurance of biological parameters used in stock assessment.

Introduction: The catecholaminergic component of the brain-pituitary-gonadal axis, which mediates the influence of external and internal stimuli on the central nervous system and gonad development in vertebrates, is largely unexplored in Chondrichthyes. We considered Scyliorhinus canicula (L., 1758) females as a model for this vertebrate's class, t...

Simple Summary Poor quality of biological information, such as age and growth parameters, could be a source of variability with a significant impact on stock assessment results. Concerning the ageing process, variability is frequently linked to differences in the interpretation of calcified structures. The evaluation of precision and accuracy there...

The progressive increase of marine macro-litter on the bottom of the Mediterranean Sea is an urgent problem that needs accurate information and guidance to identify those areas most at risk of accumulation. In the absence of dedicated monitoring programs, an important source of opportunistic data is fishery-independent monitoring campaigns of demer...

Despite the very scarce commercial interest, electric rays are frequently caught as bycatch in the Mediterranean area. The correct identification of specimens is needed to assess the impact of fisheries on populations. Unfortunately, torpedoes share high morphological similarities boosting episodes of morphological misidentification. Three electric...

The Brain-Pituitary-Gonadal (BPG) axis is an important anatomical interface coveying the environmental cues, the central nervous system and the reproduction. Lack of Knowledge exists about Cartilaginous Fish’ BPG axis. Do changes in activation of Catecholaminergic (CA) neurons in the oviparous Scyliorhinus canicula (Linnaeus, 1758) females’ brain...

Simple Summary Electric rays are currently poorly investigated; therefore, their biological status, species identification and distribution are often hard to assess. The present work, using mitochondrial sequence data, aimed to investigate (1) the genetic diversity of the three species of electric rays reported in the Mediterranean Sea (Torpedo tor...

Simple Summary The present study intended to investigate possible variations in body proportions during the growth of five different shark species that inhabit the Sardinian coastal waters (Central-Western Mediterranean Sea). Our results indicate that all of the evaluated species, while not presenting differences between sexes, seemed to show a gen...

Due to their late maturation, extreme longevity, low fecundity and slow growth rates, deep-sea Chondrichthyes are extremely vulnerable to human impacts. Moreover, assessing the impact of deep-sea fisheries is difficult, as many species (including sharks) are part of the bycatch and are often discarded at sea, and/or landed under generic commercial-...

The validation of growth of the European Anchovy (Engraulis encrasicolus Linnaeus, 1758) presents several gaps in the Mediterranean Sea, despite its growth has been widely studied using different methods. The uncertainty in estimating the European Anchovy age by otolith interpretation is linked to (i) the identification of the first growth ring; (i...

The present work compares microplastics (MPs) contamination in two charismatic crustaceans: European spiny lobster Palinurus elephas and langoustine Nephrops norvegicus. Samples (P. elephas n = 14; N. norvegicus n = 15) were collected between 76 and 592 m depth, from four sites in west Sardinia, Italy. An extraction protocol was applied on stomachs...

The thornback ray ( Raja clavata ) is the most important chondrichthyan in terms of landings in the Mediterranean Sea. Intense harvesting may induce negative genetic effects reducing the resilience of overfished species. For this reason, genetic diversity information should be considered in fisheries management and conservation policies. Microsatel...

A misalignment between the legislation and the effectiveness of Mediterranean fisheries management has emerged due to the status of the stocks (still largely in overfishing) and the discontent of stakeholders regarding management plans and tools that are not always recognized as appropriate to the characteristics of the concerned fisheries. Stakeho...

The present study, based on microsatellite markers, describes a population genetic analysis of the small-spotted catshark Scyliorhinus canicula (Linnaeus, 1758), representing one of the most abundant and commonly caught cartilaginous fishes in the Mediterranean Sea and adjacent areas. The analyses were performed to unravel the genetic features (var...

Spatangoids are probably the least resolved group within echinoids, with known topological incongruencies between phylogenies derived from molecular (very scarce) and morphological data. The present work, based on the analysis of 270 specimens of Spatangidae (Echinoidea, Spatangoida) trawled in the Sardinian seas (Western Mediterranean), allowed us...

By evaluating genetic variation across the entire genome, one can address existing questions in a novel way while raising new ones. The latter include how different local environments influence adaptive and neutral genomic variation within and among populations, providing insights into local adaptation of natural populations and their responses to...

Examination of the life-history traits variability along geographic patterns represents an important issue for elucidating intra-specific biological features in populations geographically separated and representing useful data to better ascertain potential stock boundaries. In this study, some biological and reproducitve traits of three Rajids Raja...

Holothuria tubulosa is one of the most common sea cucumber species inhabiting the Mediterranean Sea. Due to its commercial interest for the international market, it has been harvested without proper management causing the overexploitation of its stocks. Inadequate management is also caused by lack of information on basic biology and ecology not all...

Effectiveness of restocking programs in Marine Fully Protected Areas' (FPAs) can be highly affected by the movement behavior of the species to protect. We analyzed the data of 744 Palinurus elephas specimens tagged, relocated inside 12 FPAs, established in the seas surrounding Sardinia (central-western Mediterranean), and then recaptured. The overa...

The bamboo coral Isidella elongata is a forest-forming alcyonacean that dwells on deep-sea soft bottoms and is presently found in the Otranto Channel (Southern Adriatic Sea). In this study, we explored the spatial distribution and the demographic structure of the I. elongata facies (IF) over time, along with the diversity of IF-associated fauna in...

The analysis of 879 ROV dives carried out along the Italian coasts on hard substrata at mesophotic and upper bathyal depths (40-775 m) allowed us to evaluate the current basin-scale presence, relative abundance, bathymetric limits, and habitat preferences of one of the most charismatic Mediterranean habitat-former anthozoan species, Corallium rubru...

Simple Summary The European spiny lobster Palinurus elephas is a species with a high commercial value that inhabits the Mediterranean Sea and the adjacent Atlantic waters and is classified by IUCN as vulnerable due to its continuous overfishing. In this study, we analyse the reproductive parameters of P. elephas populations in two different fully p...

Simple Summary The diversity of reproductive mechanism in bony fishes is greater than in any other group of vertebrates. It ranges from oviparous, to several stages of viviparous forms. In this context, scorpaenoid fishes belonging to the families Scorpaenidae and Sebastidae are of particular interest, since they show extremely varied reproductive...

The veined squid, Loligo forbesii Steenstrup, 1856, occurs at the European Shelf areas including the Azores and represents a valuable resource for the European commercial fishery in the North East Atlantic. However, very little is known about its population structure and phylogeography. This lack of knowledge also impedes the development of sustain...

Simple Summary Black coral forests are three-dimensional components of the marine mesophotic benthic community that play a crucial role in the benthic–pelagic processes, enhancing substrate complexity and creating numerous ecological niches and biodiversity hotspots. The increase of natural and human pressures on these forests is decimating their s...

Vitellogenin is an essential protein involved in ovary maturation in many animals. Detection of this protein correlated with reproductive capacity may be important if carried out on marine organisms such as the red spiny lobster Palinurus elephas, a crustacean economically important crop from wild fish catches. Moreover, in recent years, vitellogen...

Simple Summary Octocorals are marine ecosystem engineers that can form dense patches on rocky substrates. These organisms enhance the three-dimensional complexity of the habitat and provide several ecological services within and around their canopy. Mapping their distribution and understanding the intra- and inter-specific processes that drive popu...

The current shift of fishery efforts towards the deep sea is raising concern about the vulnerability of deep-water sharks, which are often poorly studied and characterized by problematic taxonomy. For instance, in the Mediterranean Sea the taxonomy of genus Centrophorus has not been clearly unravelled yet. Since proper identification of the species...

The main objective of the Working Group on Biological Parameters (WGBIOP) is to review the status, issues, developments, and quality assurance of biological parameters used in assessment and management.

The Norwegian skate Dipturus nidarosiensis (Storm, 1881) has only recently been recorded in the western-central Mediterranean Sea. It was hypothesized a more ancient presence of the species, which has not been detected due to a misidentification with other species of the same genus. This situation could lead to underestimate the risk of a dramatic...

The lack of information on age validation often affects ageing studies in cartilaginous fish, even in the most common species. Recently, the annual growth band deposition pattern has been directly validated for thornback ray in the Mediterranean Basin, thus providing a highly reliable protocol for age reading. In this regard, taking advantage of th...

The Mediterranean Sea has a long-lasting history of fishery exploitation that, together with other anthropogenic impacts, has led to declines in several marine organisms. In particular, elasmobranch populations have been severely impacted, with drastic decreases in abundance and species diversity. Based on their experience, fishers can provide info...

Marine litter is an ever-increasing problem that demands immediate reduction plans and mitigation actions that should act synergically to efficiently meet ambitious goals. Since the seafloor has been recognized as the major sink for marine debris, the study of litter accumulation dynamics represent a fundamental tool to evaluate possible removal ac...

Galeus melastomus is an oviparous species showing a multiple oviparity with the production of 12–18 vitellogenic yolky oocytes. Fertilization takes place in the oviducal gland which produces a structurally complex capsule known as the egg capsule that supports and protects first the fertilized egg and then the embryo development. The egg capsule ha...

Female and male gametes of Galeus melastomus are described. Ovarian follicles are located under the germinal epithelium supported by a basement membrane. All the oogenesis phases from primordial follicles to vitellogenic ones were observed through the entire maturity development. Males have a cystic mode of spermatogenesis during which the germ cel...

The integument of Galeus melastomus consists of the epidermis and a thick dermis in which the microscopic features do not change during the ontogenetic development. The epidermis consists of a monolayered stratum basale and a multilayered stratum spinosum. The dermis is represented by a layer system, which consists of the subepidermal stratum laxum...

Galeus melastomus females, following the typical elasmobranch pattern, have a reproductive system composed of ovary, anterior and posterior oviducts, oviducal glands, and uteri. However, this species has only a functional right ovary associated with the epigonal organ, a lymphomyeloid tissue, producing different types of blood cells. Information ab...

Simple Summary The oviducal gland (OG) is a specialized region of the reproductive female system in cartilaginous fish located in the anterior oviduct. Its biological importance is closely related to the reproductive modalities of these species, and its basic function is the production of the egg jellies, the tertiary envelope formation (egg case i...

Galeus melastomus liver, like in all Elasmobranchs, is less definitively organized into lobules than in higher vertebrates. It is divided into two lobes, and its functions are assimilation of nutrients, production of bile, detoxification, and maintenance of the body metabolic homeostasis. The hepatic parenchyma, delimited by a simple cuboidal epith...

The blackmouth catshark, Galeus melastomus, is a small bottom‐dwelling shark distributed in the eastern Atlantic Ocean and in the Mediterranean Sea. It belongs to the Pentanchidae, a family of small slender deep‐water sharks which was previously included as a subfamily in the Scyliorhinidae. Taxonomically important features of this species are the...

Vitellogenin is an essential protein involved in ovary maturation in many animals. Detection of this protein correlated with reproductive capacity may be important if carried out on marine organisms such as the red spiny lobster Palinurus elephas, a crustacean economically important crop from wild fish catches. Moreover, in recent years, vitellogen...

Cartilaginous fish are commonly recognized as key species in marine ecosystems for their fundamental ecological role as top predators. Nevertheless, effective management plans for cartilaginous fish are still missing, due to the lack of knowledge on their abundance, distribution or even life-history. In this regard, this paper aims at providing new...

By evaluating genetic variation across the entire genome, one can address existing questions in a novel way while new can be asked. Such questions include how different local environments influence both adaptive and neutral genomic variation within and among populations, providing insights not only into local adaptation of natural populations, but...

Plastic waste dumped in the marine environment has severe ecological, social and economic impacts. In recent years, a series of scientific studies documented the contamination by macroplastic and its impact on marine organisms through the accidental ingestion of microplastics, which also originate from the degradation of macroplastic. However, the...

Skates are characterised by conservative body morphology which hampers identification and leads to frequent taxonomic confusion and market mislabelling. Accurate specimen classification is crucial for reliable stock assessments and effective conservation plans, otherwise the risk of extinction could be unnoticed. The misclassification issue is evid...

Seafloor macrolitter is ubiquitous in world's oceans; still, huge knowledge gaps exist on its interactions with benthic biota. We report here the colonization of plastic substrates by the Mediterranean red coral Corallium rubrum (L. 1758), occurring both in controlled conditions and in the wild at ca. 85 m depth in the Western Mediterranean Sea. Ju...

Despite being commonly recognized by the general public, knowledge about the biology and life-history of electric rays is still scarce. Globally, according to the International Union for Conservation of Nature, more of the 80% of the species belonging to the Torpedinidae family are, indeed, classified as Data Deficient, so as, in most of the cases,...

Whole-genome sequencing data were produced from a single flathead grey mullet female and assembled into a draft genome sequence, whereas publicly available sequence data were used to obtain a male draft sequence. Two pools, each consisting of 60 unrelated individuals, respectively, of male and female fish were analyzed using Pool-Sequencing. Mappin...

The white skate Rostroraja alba is assessed by the International Union for Conservation of Nature as Endangered globally and is now considered rare in the Mediterranean. This species has never been recorded in Sardinian seas (central western Mediterranean), but an empty eggcase was collected on a sandy bottom off the western Sardinia coasts during...

Raja clavata is the most widespread and landed skate species in the Mediterranean Basin. Despite its diffusion and economic importance, several aspects of its life history, such as age and growth, are poorly understood. This study evaluated the species’ growth in the South Adriatic Sea (Central Mediterranean Sea) and for the first time attempted an...

Submarine canyons are peculiar habitats of the continental margin due to their hydrodynamic and geomorphological features. Coral assemblages forming marine animal forests (MAFs) are one of the key benthic components dwelling in these habitats, where they enhance the substrate's heterogeneity and provide shelter, feeding and spawning habitats for a...

The bamboo coral Isidella elongata is a key structuring species on deep muddy bottoms, which has suffered severe consequences from bottom-fishing activities, as it often co-occurs with precious fishery resources such as red shrimps. A five-year series of data collected during a scientific trawl survey was used to localize the presence and to charac...

This study compiles information on the size distribution and reproductive patterns of five chondrichthyans and 10 bony species dwelling on the continental slope of the Central-Western Mediterranean (south-eastern Sardinian waters, depth 720-1890 m). The abundance of the relatively less numerous chondrichthyans was found to decrease with depth. Almo...

As far as is known, in this paper the first case of lacking of skin‐related structures (epidermis, stratum laxum, dermal denticles and teeth) in a free‐swimming elasmobranch, the blackmouth catshark, Galeus melastomus, is reported. The individual was caught by trawl in Sardinian waters (central‐western Mediterranean) in July 2019 at a depth of 500...

Mediterranean red coral Corallium rubrum is considered the most precious coral worldwide. Harvesting activities are performed by licensed scuba divers and managed through the recent pan-Mediterranean management plan issued by General Fisheries Commission for the Mediterranean (GFCM) along with measures locally enacted, imposing limits on licenses,...

Data-Deficient (DD) species are currently under threat because of the paucity of information regarding their abundance, distribution and biological traits. In this study we analysed temporal trends and bioecological features of the DD shark, Squalus blainville. Biological and fishery data were collected through two different scientific surveys span...

The Mediterranean Large Elasmobranchs Monitoring (MEDLEM) database contains over 3000 records (more than 4000 individuals) of large elasmobranch species from 20 different countries around the Mediterranean and Black seas, observed from 1666 to 2017. The main species included in the archive are the devil fish (1 813 individuals), the basking shark (...

Microplastics (MPs) are ubiquitous contaminants of the marine environment and the deep seafloor is its ultimate sink compartment. Manipulative and field experiments provided evidence of the ingestion of MPs by deep-sea fauna, but knowledge of MPs’ fate once ingested remains still scant. We provide evidence of MPs partial retention and fragmentation...

Rare and poorly studied species, like the endemic skates of the Mediterranean Sea, are considered prone to high rates of extinction and threat because of non-optimal reporting and sampling, which reduce the power of analyses. In this regard, the goal of this study was to establish some basic life-history parameters, unknown to date, of one of these...

Maturity is one of the most important biological parameters used in stock assessment programmes. Indeed, the macroscopic stage of gonadal development is an essential feature in estimating the maturity ogive and spawning stock biomass. It is also useful for determining the spawning season of a species and for monitoring long-term changes in the spaw...

The main objective of the Working Group on Biological Parameters (WGBIOP) is to review the status, issues, developments, and quality assurance of biological parameters for use in assess-ments and management that are in line with the requirements of end-users. In this final year of the three-year term, WGBIOP operated under challenging circumstances...

The main characteristics concerning the distribution of two of the most important decapod crustaceans of commercial interest in the Mediterranean Sea, the deep-water rose shrimp, Parapenaeus longirostris, and the Norway lobster, Nephrops norvegicus, are studied in the European Mediterranean waters. The study is based on data collected under the MED...

The high species richness, coupled with high proportion of endemism, makes the Mediterranean one of the world's 'biodiversity hotspots'. However, the continuous increase in fisheries in the last few decades has led to the overex-ploitation of their main commercial stocks. Using fishery-independent data collected under the framework of the MEDITS tr...

Summary: Marine litter is one of the main sources of anthropogenic pollution in the marine ecosystem, with plastic representing a global threat. This paper aims to assess the spatial distribution of plastic macro-litter on the seafloor, identifying accumulation hotspots at a northern Mediterranean scale. Density indices (items km–2) from the MEDITS...