Cristina Porcu

• University of Cagliari

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...

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...

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...

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 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...

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...

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...

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...

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...

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,...

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...

The Muraenidae is one of the largest and most complex anguilliform families. Despite their abundance and important ecological roles, morays are little studied, especially cytogenetically, and both their phylogenetic relationships and the taxonomy of their genera are controversial. With the aim of extending the karyology of this fish group, the chro...

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...

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...

A new approach to recruitment overfishing diagnosis is presented. We hypothesize that condition of recruits should increase when recruitment failures are caused by fishing activity. This would be a consequence of the increase in trophic resource availability, because the population is smaller than that which the ecosystem could support. Temporal se...

The uncertainty in age estimation by otolith reading may be at the root of the large variability in red mullet (Mullus barbatus) growth models in the Mediterranean. In the MEDITS survey, red mullet age data are produced following the same sampling protocol and otolith reading methodology. However, ageing is assigned using different interpretation s...

The present study provides updated information on the occurrence, abundance and biomass distribution patterns and length frequencies of Merluccius merluccius in the Mediterranean Sea, by analysing a time series of data from the Mediterranean International Trawl Surveys (MEDITS) from 1994 to 2015. The highest values of abundance and biomass were obs...

Thanks to the availability of the MEDITS survey data, a standardized picture of the occurrence and abundance of demersal Chondrichthyes in the northern Mediterranean has been obtained. During the spring-summer period between 2012 and 2015, 41 Chondrichthyes, including 18 sharks (5 orders and 11 families), 22 batoids (3 orders and 4 families) and 1...

Genetic information is crucial for the conservation of Dipturus oxyrinchus (Linnaeus, 1758), a threatened large skate with declining populations over most of its geographical range. The main aim of the present study was to investigate the genetic structure, connectivity and demographic history of the longnosed skate in Sardinia (western Mediterrane...

Knowledge of the mechanisms that allow coexistence among sympatric species is fundamental to understand ecosystem functioning. Resource partitioning among seven elasmobranchs inhabiting the Sardinian continental shelf (40°07′N, 9°00′E): Dasyatis pastinaca; Raja asterias; R. brachyura; R. clavata; R. miraletus; R. polystigma and Scyliorhinus canicul...

Fully protected areas (FPAs) help preserving biodiversity and reversing the global decline of fishery resources. Stocks of the European spiny lobster Palinurus elephas (Fabr. 1787), among the most precious gourmet seafood worldwide, are currently facing a dramatic decline. Previous attempts of recovery based on fishery restrictions or active post-l...

The oocyte maturation and spawning pattern of European hake Merluccius merluccius, one of the most important species in the Mediterranean fishery, were investigated using data collected in a scientific trawl survey (Mediterranean International Trawl Survey, MEDITS) as well as commercial landing data collected in several geographical sub-areas (GSAs...

Postcopulatory sexual selection, and sperm competition in particular, is a powerful selective force shaping the evolution of sperm morphology. While mounting evidence suggests that postcopulatory sexual selection influences the evolution of sperm morphology among species, recent evidence also suggests that sperm competition influences variation in...

The Norwegian skate Dipturus nidarosiensis (Storm, 1881) has only recently been recorded in the western Mediterranean Sea along the coast of southern Sardinia, off Algeria and the Alboran Sea. The present study confirmed the presence of the species in the Central Mediterranean Sea by identifying morphometric, morphological features and molecular ma...

Maturity is one of the most relevant 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 (SSB). It is also useful for determining the spawning season of a species and for monitoring long-term changes in the...

The global plastic economy demands to reduce the flow of plastic into oceans and promote remedial actions for already accumulated seafloor litter. In this perspective, baseline levels of contamination and tools for dating litter items in order to assess the efficacy of those actions, are thus needed. In this note we discuss the utility of introduci...

Over the last decades, the global climate change caused increase in seawater temperature, which have shown to be detrimental for Mediterranean red coral populations (Corallium rubrum). Recent researches on C. rubrum described how in shallow water habitats (i.e., up to 50 m depth), thermo-tolerance is influenced by local temperature fluctuations. In...

In the Mediterranean Sea, in addition to the two historically known species belonging to the Squalus genus, a third species, Squalus megalops, has been reported. Considering the high level of morphologic similarity of this species with the native species S. blainville, this study aims to evaluate the Central-Western Mediterranean spurdog population...

Eggcases of eight rajiform skates (Dipturus nidarosiensis, D. oxyrinchus, Leucoraja melitensis, Raja asterias, R. brachyura, R. clavata, R. miraletus and R. polystigma) present in the central-western Mediterranean are described, based on specimens obtained from fishery surveys. Eggcase features such as dimensions, horns and apron lengths, and prese...

Occurrence, abundance and size trends of 25 demersal Chondrichthyes (10 Sharks: 3 Carcharhiniformes, 2 Hexanchiformes, 5 Squaliformes; 14 Batoids: 3 Myliobatiformes, 8 Rajiformes, 3 Torpediniformes and 1 Holocephalan: 1 Chimaeriformes) collected from 22 years (1994–2015) of Mediterranean International Trawl Surveys (MEDITS) around Sardinian seas, w...

This study quantifies the main reproductive features of the long-lived red coral Corallium rubrum, an octocoral endemic to the Mediterranean Sea and neighboring Atlantic areas and one of the most valuable of all marine species, at different depths (38-40 m versus 96-115 m) in north-western Sardinian waters (Central-Western Mediterranean Sea). Diffe...

This work investigates life-history traits of the long-nosed skate Dipturus oxyrinchus, which is a common by-catch in Sardinian waters. The reproductive variables were analysed from 979 specimens sampled during scientific and commercial hauls. Females (10·4–117·5 cm total length, LT) attained larger sizes than males (14·5–99·5 cm LT). To evaluate a...

The rapid expansion of fisheries and globalized trade are emerging as the principal drivers of coastal and ocean threat. Considering the important role of Chondrichthyes as predators at the top of food chain in marine ecosystems, knowledge on their biology remains scarce in the Mediterranean. In this regard, our objective is to give information on...

Skates are often considered vulnerable to overfishing because of their peculiar life cycle characteristics rendering them susceptible to overexploitation. In this regard, life-history traits of a by-catch species, the long-nosed skate Dipturus oxyrinchus (Linnaeus, 1758) from Sardinian waters, were investigated. The age, growth and reproduction wer...

In this paper, the reproductive biology of the velvet belly Etmopterus spinax was analyzed in Sardinian waters (central western Mediterranean). This species was sexually dimorphic with females growing to a larger size than males. Marked sexual dimorphism in size was also observed along the bathymetrical gradient. Histological analysis of gonads was...

We studied the morphology and histology of the oviducal gland (OG) in the brown ray (Raja miraletus) and the long-nosed skate (Dipturus oxyrinchus) to understand its functional role in the reproductive strategy of these species. The external morphology of the gland was similar in both species, with lateral extensions like those found in other membe...

A total of 255 longnosed skate Dipturus oxyrinchus caught in Sardinian waters (central-western Mediterranean Sea), was analysed with respect to fish total length (LT ), season and depth, in order to provide information on diet and feeding behaviour. Specimens ranging from 93 to 1153 mm LT , were collected at depths between 121 and 671 m, during exp...

In the present study the life history traits of Raja brachyura from Sardinian waters (central-western Mediterranean) were investigated and the results compared with previously published data. The age, growth and reproduction were studied using 1792 specimens. Females ranged from 13.1 to 105.5 cm in total length (TL) and males from 18 to 96.5 cm TL....

The homing and orientation skills of Palinurus elephas were investigated in three no-take areas of the central-western Mediterranean in order to inform future reserve design. In general, P. elephas did not show a particular ability to orient homeward. A considerable portion of tagged lobsters were recaptured in the same direction as the capture poi...

The reproductive cycle of the deep-sea eel Nettastoma melanurum was described based on 397 specimens (171 males and 226 females). Experimental trawl surveys between depths of 772 and 1598 m and commercial hauls (580–600 m) on compact mud bottoms off the south-eastern Sardinian waters (central-western Mediterranean) were carried out. The Sardinian c...

In this paper we report information about the sexual maturity process of 245 Octopus vulgaris specimens (75 females and 170 males) from the Mediterranean Sea. For both sexes, six stages of sexual maturity (immature, developing, maturing, mature, spawning, and spent) are identified on the basis of macroscopic and microscopic observations of the repr...

We report data regarding the gonad development in females of Acanthephyra eximia Smith, 1884. Specimens were caught during experimental surveys carried out in Sardinian waters between 500 and 1880 m. We employed for our analysis of the ovary development both macroscopic observation and histologic analysis. According to the macroscopic observations,...

Twenty-three Dipturus nidarosiensis (Collett, 1880) (Elasmobranchii: Rajidae) were collected off the coasts of Sardinia between 550 m and 1688 m of depth in 2005-2011. A first description of some biological aspects as the vertical distribution, the reproduction and the diet of the Norwegian skate from the Central Western Mediterranean is provided....

The reproductive biology of the bathyal viviparous fish Cataetyx alleni was described based on 34 specimens (17 females and 17 males) caught during experimental trawl surveys carried out between 800 and 1700 m depth in the southeastern Sardinian Sea (central-western Mediterranean). Males and females were present at similar size intervals. For the f...

1. An assessment is made of the reserve's benefits within the no-take area of Su Pallosu (Western Mediterranean) and in its neighbouring fishing ground in the 12 years since its establishment. 2. Using tag recapture data, Palinurus elephas were found up to 50 km from the centre of the reserve. 3. Experimental CPUE inside the no-take area indicated...

Six measurements of 109 beaks (59 males and 50 females) of Histioteuthis bonnellii (Cephalopoda: Histioteuthidae) caught in the south Sardinian waters were interrelated with the size (ML) of the specimens. In both sexes, respectively for upper and lower beaks, the lateral wall and the hood grew faster than other parts (e.g. the rostrum). The analys...

Background. The shortnose greeneye, Chlorophthalmus agassizi Bonaparte, 1840, is a species with a circumglobal distribution and is among the most abundant commercial fishes in some Mediterranean areas. The knowledge of the biology and ecology of this species is poor and geographically limited, then the aim of this study is to provide a contribution...

This paper explores structure and spatial distribution of fish assemblages in an area of the central-western Mediterranean Sea (south Sardinian deep-waters) at depths between 546 and 1598 m. A total of 67 species (12 chondrichthyes and 55 teleosteans) were sampled. Multivariate analysis showed a clear pattern of zonation. Three main assemblages wer...

Fourteen specimens of the Norwegian skate, Dipturus nidarosiensis (Rajiformes, Rajidae), were caught off the Sardinian coasts (Central Western Mediterranean Sea) in 2005-2008 between 600 and 1420 m of depth. Their identification has been confirmed by the sequencing of three regions of the mtDNA (16SrDNA, control region and cytochrome c oxidase subu...

The reproductive biology of the bathyal hermaphrodite Bathypterois mediterraneus is described based on 348 specimens caught during experimental trawl surveys carried out between 800 and 1600 m depth off the south-eastern Sardinian Sea (central-western Mediterranean). Based on macroscopic and histological gonad analysis and monthly variation of GSI,...

We present the first data on the population structure, reproduction, and feeding ecology of Polycheles sculptus S. I. Smith, 1880 from the Sardinian sea. Samples were collected during experimental trawl surveys carried out in 2006-2007 in Sardinian waters, at depths between 1037 and 1598 m. A total of 72 specimens of P. sculptus, 31 males, 40 femal...

The diet and inter‐ and intraspecific interactions of two shallow‐water skates, Raja brachyura and R. miraletus, caught at depths between 30 and 162 m during trawl surveys carried out in 2005 and 2006 in the seas surrounding Sardinia (central‐western Mediterranean), were analysed. The low values of Levin and Shannon indexes (Bi = 0.37 and 0.42, res...

Community structure and faunal composition of bathyal decapod crustaceans off South-Eastern Sardinian deep-waters (Central-Western Mediterranean) were investigated. Samples were collected during 32 hauls between 793 and 1598 m in depth over the 2003–2007 period. A total of 1900 decapod specimens belonging to 23 species were collected. Multivariate...

The spotfin burrfish Chilomycterus reticulatus (405 mm standard length) is recorded for the first time on the shoreline of the Mediterranean Sea. The adult specimen was found dried on a beach near the south Sardinian Sea (S. Antioco's Island). Photographs and morphometrics of the specimen are given.

In this paper, we report data related to the reproductive biology of a cosmopolitan mesobathyal lobster, Polycheles typhlops (Decapoda: Polychelidae), caught in the Sardinian waters between 400 and 1400 m of depth. Macroscopic and microscopic analyses were performed on 1104 females and 895 males. The observation on the gonads leads us to conclude t...

Data are provided on the reproductive biology of a bathypelagic species Alepocephalus rostratus Risso, 1820 caught in the Sardinian Channel between 800 and 1200 m depth. The macroscopic and microscopic description of the gonads was based on 223 females and 95 males. Unlike most other teleosts, the testis is generally formed of two distinct subcylin...