Interazioni trofiche tra Condroitti in Mediterraneo

Chondrichthyans play an important ecological role, they tend to be high in the food web being very often predators at the top of marine food webs (Cortés, 1999; Ebert e Bizzarro, 2007). Sharks and rays appear to be particularly vulnerable to over-exploitation because of their K-selected life-history strategy (Cailliet et al., 2005). Therefore, given that the consequences of their intense exploitation could be very dangerous, many authors have stressed their vulnerability (Bonfil, 1994; Cahmi et al., 1998; Stevens et al., 2000; Fowler & Cavanagh, 2005) and the importance of their protection (Fowler & Cavanagh, 2005), unfortunately not so effective (Cavanagh e Gibson, 2004). Currently, many efforts are made in order to clarify and to better understand the functioning of marine ecosystems, for the purpose of an enhanced management. An exhaustive study of feeding habits and trophic interactions between species is required to obtain this information (Stevens et al., 2005), nevertheless data from literature regard a limited number of species. All that has provided the opportunity to undertake the analysis of feeding habits and trophic relationships between all the Chondrichthyans caught in Sardinian waters by trawler, in order to provide an overall view about the interactions that rule the funtcioning of marine ecosystems and energetic exchanges. Moreover, for the purpose of a better management, we have assessed the fishing impact on this important taxonomic group. All of these aims were obtained through stomach content analysis of all the species caught in the course of three years of study, taking into account some important factors as sex, size and depth that could influence the diet. Intraspecific and interspecific niche overlap, Trophic index and its trend were also determined in order to assess state of exploitation of Chondrichthyans. We analyzed the diet of 27 species M. punctulatus and D. nidarosiensis are new records for Sardinian waters and Mediterranean Sea respectively.,Among these, 14 species were caught occasionally or presented a high percentage of empty stomachs, so it was possible to provide only a preys list. Generally, some similarities could be noticed between all the species. The niche breadth was larger in the specimens caught at the deepest strata, likely due to their adaptation to oligotrophic conditions, characteristic of the deepest habitats. With variable proportions species prey on Crustaceans, Teleosts and Cephalopods, and minorly on Chondrichthyans too. Two distinct way of feeding, deeply influenced by body morphology. Batoids prey mainly on benthopelagic and benthic organisms, while shark-like species prefer nectonic preys or organisms more swimming prone. A few number of preys, characterized by a great abundance in the habitats that inhabit, represent the core of the diet of all the analyzed species. Mysids, like Gastrosaccus sanctus and Lophogaster typicus, Brachyurans of the genus Liocarcinus sp, Natantians as Solenocera membranacea, Pasiphaea multidentata and P. sivado, the euphausiid Meganyctiphanes norvegica and the Cefalopods belonging to the family Sepiolidae (mainly Heteroteuthis dispar) are the most representative. Moreover, teleostes like Gymnammodytes cicerelus and Glossanodon leioglossus are exploited by some species. Ontogenetic variation in feeding habits were noticed: in general small specimens eat small preys, especially benthic ones (crustaceans, small teleosts and sepiolids). With the growth preys bigger and more swimming prone become more important in the diet of all the species. Similarly, trophic index values increase with the growth, maintaining low levels of competition between species and improving survival rate of juveniles. Speaking generally, trophic level increase for species that prefer pelagic preys. No differences in trophic spectrum were observed among sexes that, in fact, are characterized by a high value of niche overlap. The analysis of the diet in function of depth does not show any significant difference, except for species that present a different bathymetric segregation. Niche overlaps analysis points out a greater interspecific competition between specimens of the deepest strata. These environments are characterized by oligotrophic conditions that lead to an intensive exploitation of a limited number of preys, thus maximizing the overlap between diets. Marine trophic index, estimated for MEDITS target species from 1994 to 2010, showed an increasing trend, probably related to the change in the Sardinian fishing fleet occurred at the beginning of the nineties. Marine trophic index for Chondrichthyans remained stable until 2001, then oscillated and, finally, tended do decrease slightly. The study allowed to discover a complex web of trophic interactions. Some results disagree with those reported in literature, indicating the existence of a big variety, also within the same species, related to geographical differences. More studies would be necessary to extend knowledge about the interactions that control the functioning of the ecosystems and to prevent the decline of this taxon, avoiding the negative effects of its loss. The final aim will be to provide appropriate management measures very soon, in order to ensure the protection of Chondrichthyans

Características reproductivas de un pez vivíparo de la zona batial Cataetyx alleni (Osteichthyes, Bythitidae) en el sureste del mar de Cerdeña (Mediterráneo centro-occidental)

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 first time, the internal fertilization was demonstrated by the finding of free spermatozoa scattered in the ovarian cavity. Based on macroscopic and histological gonad analysis, mature females were found in summer, autumn and winter, suggesting a long reproductive period. Inseminated females were observed only in November and January, in correspondence with the higher maturity of the males. These results suggest a probable reproductive peak with copulation in autumn-winter. Moreover, histological examination demonstrated that the ovaries of this member of the family Bythitidae had a ‘group-synchronous’ pattern. No spermatophores in males and embryos in females were observed in the histological sections analysed.La biología reproductiva de Cataetyx alleni, un pez vivíparo batial, fue descrita basándose en el examen de 34 especímenes (17 hembras y 17 machos) capturados durante las campañas experimentales de pesca de arrastre conducidas entre 800 y 1700 metros de profundidad en el sureste del mar de Cerdeña (Mediterráneo centro-occidental). Hembras y machos presentaron tallas similares. Por primera vez, la fecundación interna fue demostrada gracias al descubrimiento de espermatozoos libres dispersos en la cavidad del ovario. Basándose en análisis macroscópicos e histológicos, las hembras maduras fueron encontradas en verano, otoño e invierno, sugiriendo un periodo reproductivo muy largo. Las hembras fecundadas fueron observadas sólo durante el mes de Noviembre y Enero, conjuntamente con los machos de madurez máxima. Estos datos podrían suponer un posible máximo reproductivo con cópula durante el otoño y el invierno. Además, los exámenes histológicos demostraron que los ovarios de este Bythitidae presentan un modelo de sincronización de grupo. Ningún espermatóforo ni embriones fueron observados en las secciones histológicas analizadas

Reproductive characteristics of the bathyal viviparous fish <i>Cataetyx alleni</i> (Osteichthyes: Bythitidae) from the southeastern Sardinian Sea (central-western Mediterranean) MARIA

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 first time, the internal fertilization was demonstrated by the finding of free spermatozoa scattered in the ovarian cavity. Based on macroscopic and histological gonad analysis, mature females were found in summer, autumn and winter, suggesting a long reproductive period. Inseminated females were observed only in November and January, in correspondence with the higher maturity of the males. These results suggest a probable reproductive peak with copulation in autumn-winter. Moreover, histological examination demonstrated that the ovaries of this member of the family Bythitidae had a 'group-synchronous' pattern. No spermatophores in males and embryos in females were observed in the histological sections analysed

Genetic variation of goat Y chromosome in the Sardinian population

Sardinian goat population is commonly considered a crossbred of autochthonous animals with improved Mediterranean breeds, mainly the Maltese. It has been demonstrated by using autosomal microsatellites that the Sardinian goats can be divided into three subpopulations: Sardinian, crossbred with Maltese, and Maltese. The aim of this study was to evaluate sequence variation at Y chromosome in Sardinian bucks and to integrate autosomal microsatellites data. Blood from 190 bucks from 68 farms spread in the main Sardinian goat farming areas was sampled. Three ECONOGENE project primer pairs plus an additional one corresponding to a total of 7 SNPs were used. For all common SNPs, the most frequent allele corresponded to the ECONOGENE one. The additional analysed SNP showed allelic frequencies similar to the other markers. The comparison with haplotypes based on the 6 common SNPs showed that the Sardinian most frequent haplotype corresponded to the predominant one in Central Europe. Results of this study showed that the Sardinian goat population has 8 haplotypes resulting in a large diversity of paternal lineages. The next step will be linking autosomal information to Y chromosome data. In fact, up to date, it seems unfeasible to detect recent upgrading breeds by using Y chromosome variation only

Bio-Ecological Features Update on Eleven Rare Cartilaginous Fish in the Central-Western Mediterranean Sea as a Contribution for Their Conservation

Cartilaginous fish are commonly recognized as key species in marine ecosystems for their fundamental ecological role as top predators. Nevertheless, effective management plans for cartilagi- nous 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 information on the life-history traits, such as age, maturity, reproductive period, in addition to diet characteristics of eleven rare cartilagi- nous fish inhabiting the Central-Western Mediterranean Sea belonging to the orders Chimaeriformes (Chimaera monstrosa), Hexanchiformes (Heptranchias perlo and Hexanchus griseus), Myliobatiformes (Aetomylaeus bovinus and Myliobatis aquila), Rajiformes (Dipturus nidarosiensis and Leucoraja circu- laris), Squaliformes (Centrophorus uyato, Dalatias licha and Oxynotus centrina) and Torpediniformes (Tetronarce nobiliana), useful for their assessment and for future management actions. Particularly, the present paper provides for the first time the age estimation of D. nidarosienis and L. circularis which were both found capable of becoming older than ten years. In addition, the present study updates the sizes of first maturity of C. uyato and D. licha, which appeared to be capable of reproducing earlier than what was previously hypothesized, representing very valuable information for a better understanding of these rare species populations status and, eventually, their conservation. On the basis of the stomach content analysis, it was possible to identify five different predator groups

New insights on the systematics of echinoids belonging to the family Spatangidae Gray 1825 using a combined approach based on morphology, morphometry, and genetics.

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 to verify the constancy of some characters that we consider to be diagnostic at the genus level —such as the path of the subanal fasciole and the relationship between labrum and adjacent ambulacral plates —and to distinguish two distinct forms within the studied material. Based on morphological characters, morphometrics, and molecular analyses (sequencing of two mitochondrial markers: cytochrome c oxidase subunit1 (COI) and 16S), most of the individuals were classified as morphotype A and attributed to the species Spatangus purpureus, the most common spatangoid in the Mediterranean Sea, while a few corresponded to a different morphotype (B), genetically close to the species Spatangus raschi. Preliminary morphological analyses seemed to indicate that morphotype B specimens from Sardinia are slightly different from S. raschi and from Spatangus subinermis individuals, the second species of the family known to occur in the Mediterranean Sea. On the basis of morpho-structural observations and molecular analyses, comparing Mediterranean living forms with species from other areas (Central Eastern Atlantic, North Sea and neighboring basins, South African Sea, Philippines and Indonesian Archipelago, New Zealand, and Hawaiian Islands), the clear distinction of S. purpureus from several other species classified as Spatangus was confirmed. Based on the morphological and genetic differences, we propose to maintain the genus Spatangus including in it only the type species S. purpureus among the living species and to establish the new genus Propespatagus nov. gen. to include several other species previously classified as Spatangus. The clear distinction among different genera was also detected in fossil forms of Spatangus, Propespatagus nov. gen., and Sardospatangus (†) from the European Oligo-Miocene sedimentary rocks of Germany; the Miocene of Ukraine, Italy, and 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 to verify the constancy of some characters that we consider to be diagnostic at the genus level —such as the path of the subanal fasciole and the relationship between labrum and adjacent ambulacral plates —and to distinguish two distinct forms within the studied material. Based on morphological characters, morphometrics, and molecular analyses (sequencing of two mitochondrial markers: cytochrome c oxidase subunit1 (COI) and 16S), most of the individuals were classified as morphotype A and attributed to the species Spatangus purpureus, the most common spatangoid in the Mediterranean Sea, while a few corresponded to a different morphotype (B), genetically close to the species Spatangus raschi. Preliminary morphological analyses seemed to indicate that morphotype B specimens from Sardinia are slightly different from S. raschi and from Spatangus subinermis individuals, the second species of the family known to occur in the Mediterranean Sea. On the basis of morpho-structural observations and molecular analyses, comparing Mediterranean living forms with species from other areas (Central Eastern Atlantic, North Sea and neighboring basins, South African Sea, Philippines and Indonesian Archipelago, New Zealand, and Hawaiian Islands), the clear distinction of S. purpureus from several other species classified as Spatangus was confirmed. Based on the morphological and genetic differences, we propose to maintain the genus Spatangus including in it only the type species S. purpureus among the living species and to establish the new genus Propespatagus nov. gen. to include several other species previously classified as Spatangus. The clear distinction among different genera was also detected in fossil forms of Spatangus, Propespatagus nov. gen., and Sardospatangus (†) from the European Oligo-Miocene sedimentary rocks of Germany; the Miocene of Ukraine, Italy, and 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 to verify the constancy of some characters that we consider to be diagnostic at the genus level —such as the path of the subanal fasciole and the relationship between labrum and adjacent ambulacral plates —and to distinguish two distinct forms within the studied material. Based on morphological characters, morphometrics, and molecular analyses (sequencing of two mitochondrial markers: cytochrome c oxidase subunit1 (COI) and 16S), most of the individuals were classified as morphotype A and attributed to the species Spatangus purpureus, the most common spatangoid in the Mediterranean Sea, while a few corresponded to a different morphotype (B), genetically close to the species Spatangus raschi. Preliminary morphological analyses seemed to indicate that morphotype B specimens from Sardinia are slightly different from S. raschi and from Spatangus subinermis individuals, the second species of the family known to occur in the Mediterranean Sea. On the basis of morpho-structural observations and molecular analyses, comparing Mediterranean living forms with species from other areas (Central Eastern Atlantic, North Sea and neighboring basins, South African Sea, Philippines and Indonesian Archipelago, New Zealand, and Hawaiian Islands), the clear distinction of S. purpureus from several other species classified as Spatangus was confirmed. Based on the morphological and genetic differences, we propose to maintain the genus Spatangus including in it only the type species S. purpureus among the living species and to establish the new genus Propespatagus nov. gen. to include several other species previously classified as Spatangus. The clear distinction among different genera was also detected in fossil forms of Spatangus, Propespatagus nov. gen., and Sardospatangus (†) from the European Oligo-Miocene sedimentary rocks of Germany; the Miocene of Ukraine, Italy, and North Africa; the Plio-Pleistocene of Italy; and the Mio-Pliocene of Florida (USA). The new data can help in addressing taxonomic ambiguities within echinoids, as well as in improving species identification, and hence biodiversity assessments in the Mediterranean region

On the presence of the Endangered white skate Rostroraja alba in Sardinian waters

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 the MEDiterranean International Trawl Survey (MEDITS) program in 2019. A morphometric and morphological description of the Sardinian eggcase, after a comparison with measurements from other Mediterranean and Atlantic specimens, showed it to be clearly ascribable to Rostroraja alba

Detection on OAR7 of QTL affecting fat and protein yields in dairy sheep

The objective of this paper was identifying QTL that affect fat and protein yields in dairy sheep independently of milk yield. Data were collected in an experimental flock of 887 ewes organized in a daughter design. QTL detection focused on OAR7 where 13 microsatellites were available. The genetic abilities to produce fat and protein independently from the ability to produce milk were estimated as the residuals of the regression of EBV for fat and protein yields on EBV for milk yield. One QTL affecting fat yield (CWP=0.00009) and one QTL affecting protein yield (CWP=0.006) were detected. The most probable QTL location was 115.3 cM in the Sheep Best Position Linkage Map Version 4.7 for both traits. No QTL affecting milk yield was detected. The analysis of fat and protein yields independently of milk yield is an effective strategy to identify chromosomal regions affecting milk composition with no detrimental effect on milk yield

Patrones de distribución espacio temporal de las especies de macrúridos en el Mediterráneo norte

The present study describes for the first time the spatial distribution of five macrourid species throughout the Mediterranean Sea and analyses depth, geographical and time-related trends regarding their abundance, biomass and mean fish weight. The data were collected as part of the MEDITS annual bottom trawl survey carried out by several European Mediterranean countries from 1994 to 2015, using the same standardized gear and sampling protocol. The most represented species in terms of abundance and biomass was Coelorinchus caelorhincus. The bathymetric trend was different for each species. The shallowest occurring species was C. caelorhincus, followed by Hymenocephalus italicus and Nezumia sclerorhynchus, while Nezumia aequalis and Trachyrincus scabrus were the deepest. Overall, the mean weight of all the species increased with depth. C. caelorhincus and H. italicus occurred in the entire study area: the first species showed relatively high catches in most areas, while the second was more abundant in the central and easternmost areas. N. aequalis and T. scabrus were mainly reported in the western basin, and N. sclerorhynchus in the central-eastern areas of the Mediterranean. An increasing inter-annual trend in abundance was only detected for C. caelorhincus and N. sclerorhynchus, while variable fluctuations were observed in the other species.El presente estudio describe por primera vez la distribución espacial de cinco especies de macrúridos a lo largo del Mediterráneo en su vertiente europea, analizando las tendencias batimétricas, geográficas y temporales de la abundancia, la biomasa y el peso medio de las especies. Los datos utilizados provienen de las campañas de arrastre de fondo anuales, MEDITS, desde 1994 a 2015, llevadas a cabo por los países mediterráneos europeos utilizando un arte de arrastre y un protocolo de muestreo estandarizado. La especie más representativa en términos de abundancia y biomasa fue Coelorinchus caelorhincus. Las tendencias batimétricas fueron variables según la especie. La más costera fue C. caelorhincus seguida de Hymenocephalus italicus y Nezumia sclerorhynchus mientras que Nezumia aequalis y Trachyrincus scabrus son las que se localizaron a mayor profundidad. En general, el peso medio de las especies se incrementó con la profundidad. Geográficamente, C. caelorhincus e H. italicus se encontraron distribuidas a lo largo de toda el área de estudio: la primera mostró capturas relativamente elevadas en la mayoría de las áreas mientras que la segunda fue más abundante en las zonas central y oriental. N. aequalis y T. scabrus se capturaron fundamentalmente en la cuenca occidental mientras que N. sclerorhychus en las áreas centro-este del Mediterráneo. Únicamente se detectó incremento interanual en C. caelorhincus y N. sclerorhynchus, mientras que en el resto de las especies no se registó incremento ni descenso sino fluctuaciones interanuales

The Use of Reproductive Indicators for Conservation Purposes: The Case Study of Palinurus elephas in Two Fully Protected Areas and Their Surrounding Zones (Central-Western Mediterranean)

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 protected areas, including their surrounding commercial zones, in Sardinia (Italy, central-western Mediterranean), where a restocking programme was carried out. Here, data on fecundity, size at maturity, vitellogenin concentration and temporal trends of egg production of P. elephas was provided, and the relevance of this information for fisheries management and conservation planning is discussed. In 1990s, the European spiny lobster Palinurus elephas, one of the most commercially important species in the Mediterranean, exhibited a population decline. For this reason, fully protected areas (FPAs) appeared effective in re-establishing natural populations and supporting fishery-management objectives. Here, the reproductive parameters of P. elephas populations in two different FPAs (Su Pallosu and Buggerru, central-western Mediterranean), where a restocking programme was carried out, and in their surrounding commercial zones, were investigated from quantitative and qualitative perspectives. The comparison of fecundity between females collected inside and outside FPAs did not show statistical differences as well as the vitellogenin concentration, which did not vary among eggs of different size classes of females caught inside and outside the FPAs, indicating the same reproductive potential. The study demonstrated a benefit of overexploited populations in terms of enhancement of egg production overtime (15 years for Su Pallosu and 6 years for Buggerru) with a mean egg production 4.25-5.5 times higher at the end of the study than that observed at the beginning of the study. The main driver of eggs production appeared to be size, with larger lobsters more present inside the FPAs than outside. Given these results, the dominant contribution of the two studied FPAs to the regional lobster reproduction is remarkable