Filogeografia do tubarão martelo Sphyrna zygaena (Chondrichthyes, Sphyrnidae) do Atlântico utilizando marcadores moleculares

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Filogeografia do tubarão martelo Sphyrna zygaena (Chondrichthyes, Sphyrnidae) do Atlântico utilizando marcadores moleculares

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparative neurocranial morphology of angelsharks from the south-western Atlantic Ocean (Chondrichthyes, Elasmobranchii, Squatinidae): implications for taxonomy and phylogeny

Neurocrania of three species of angelsharks from the south-western Atlantic Ocean, occurring off south-eastern and southern Brazil, are described. A detailed morphological description is provided of the neurocranium of Squatina guggenheim and compared with S. argentina and S. occulta. Despite being generally conservative, the neurocranium of Squatina presents significant differences among these species which aid in their identification, which is otherwise problematical. The main distinctions were found in rostral projections, anterior fontanellae, supraorbital crests, upper and lower postorbital processes, otic capsules, suborbital crests, and pterotic processes. Squatina guggenheim and S. occulta share more neurocranial characters when compared to S. argentina. No basal angle was found, but we confirm the presence of a very much reduced and barely noticeable basioccipital fovea in Squatina; systematic implications within elasmobranchs of these and other features are discussed.

Morphological observations of ampullae of lorenzini in Squatina guggenheim and S. occulta (chondrichthyes, elasmobranchii, squatinidae)

We have conducted a morphological study of the ampullae of Lorenzini on two shark species from Squatina Genus. In both species, S. guggenheim and S. occulta, the ampullae were observed like small pores scattered in the head region similar to other species of the Chondrichthyes Class. However, differently of the other species a greatest density of ampullae of Lorenzini was observed along of the body surface. After fixation using 10% formaldehyde, the ampullae were removed and processed for light and scanning electron microscopy. Macroscopically, the two shark species differed by the presence of dorsal spines that appeared from the head to the first dorsal fin in S. guggenheim and were absent in S. occulta. Microscopically, there were no differences between the ampullae of Lorenzini channels in these two species. The wall of the ampulla was formed by a simple squamous epithelium. Bands of connective tissue, hyaline cartilage and collagen fibers were found between the ampulla and the skeletal striated muscle layer. Nerve branches responsible for conducting signal pulses to the central nervous system were visible between the muscle and connective tissue layers. Using scanning electron microscopy and histological analysis, we found that the channels were twisted and positioned parallel to the skin. The inside of the channels contained a large amount of a gelatinous secretion composed by polysaccharides. Therefore, we conclude that the morphological combination of extended distribution of the ampullae of Lorenzini and the body shape may represent an adaptation of these species to their way of life. Microsc. Res. Tech. 75:12131217, 2012. (C) 2012 Wiley Periodicals, Inc.

Ahamulina n. gen. (Cestoda: Diphyllidea) from the polkadot catshark, Scyliorhinus besnardi (Carcharhiniformes: Scyliorhinidae), off Brazil

A new genus and species of diphyllidean, Ahamulina catarina n. gen. n. sp., is described from the polkadot catshark, Scyliorhinus besnardi, from Santa Catarina, Brazil. The new genus exhibits apical organ armature that is unique among diphyllideans in the arrangement and shape of the apical hooks as well as in the lack of lateral hooklets. The taxon also exhibits a bipartite cirrus sac. This is the seventh diphyllidean reported from a shark, and the third reported from a catshark suggesting that the dearth of cestode data for these particular sharks belies the true extent of diphyllidean diversity they host.

Species identification, distributioin and reproductive interactions of common smoot-hound and blackspotted smooth-hound shark (Genus mustelus) in the Adriatic Sea

Longstanding taxonomic ambiguity and uncertainty exist in the identification of the common (M. mustelus) and blackspotted (M. punctulatus) smooth-hound in the Adriatic Sea. The lack of a clear and accurate method of morphological identification, leading to frequent misidentification, prevents the collation of species-specific landings and survey data for these fishes and hampers the delineation of the distribution ranges and stock boundaries of the species. In this context, adequate species-specific conservation and management strategies can not be applied without risks of population declining and local extinction. In this thesis work I investigated the molecular ecology of the two smooth-hound sharks which are abundant in the demersal trawl surveys carried out in the NC Adriatic Sea to monitor and assess the fishery resources. Ecological and evolutionary relationships were assessed by two molecular tests: a DNA barcoding analysis to improve species identification (and consequently the knowledge of their spatial ecology and taxonomy) and a hybridization assay based on the nuclear codominant marker ITS2 to evaluate reproductive interactions (hybridization or gene introgression). The smooth-hound sharks (N=208) were collected during the MEDITS 2008 and 2010 campaigns along the Italian and Croatian coasts of the Adriatic Sea, in the Sicilian Channel and in the Algerian fisheries. Since the identification based on morphological characters is not strongly reliable, I performed a molecular identification of the specimens producing for each one the cytochrome oxidase subunit 1 (COI) gene sequence (ca. 640 bp long) and compared them with reference sequences from different databases (GenBank and BOLD). From these molecular ID data I inferred the distribution of the two target species in the NC Adriatic Sea. In almost the totality of the MEDITS hauls I found no evidence of species sympatry. The data collected during the MEDITS survey showed an almost different distribution of M. mustelus (confined along the Italian coasts) and M. punctulatus (confined along the Croatian coasts); just one sample (Gulf of Venice, where probably the ranges of the species overlap) was found to have catches of both the species. Despite these data results suggested no interaction occurred between my two target species at least during the summertime (the period in which MEDITS survey is carried out), I still wanted to know if there were inter-species reproductive interactions so I developed a simple molecular genetic method to detect hybridization. This method is based on DNA sequence polymorphism among species in the nuclear ribosomal Internal Transcribed Spacer 2 locus (ITS2). Its application to the 208 specimens collected raised important questions regarding the ecology of this two species in the Adriatic Sea. In fact results showed signs of hybridization and/or gene introgression in two sharks collected during the trawl survey of 2008 and one collected during the 2010 one along the Italian and Croatian coasts. In the case that it will be confirmed the hybrid nature of these individuals, a spatiotemporal overlapping of the mating behaviour and ecology must occur. At the spatial level, the northern part of the Adriatic Sea (an area where the two species occur with high frequency of immature individuals) could likely play the role of a common nursery area for both species.

First assessment on genetic structure and phylogeography of Mediterranean blue shark (prionace glauca, L. 1758) population using mitochondrial gene variation: a comparison with the Atlantic.

The blue shark, Prionace glauca, is one of the most vagile shark species worldwide distributed. The particular body shape allows blue sharks make transoceanic movements, leading to a circumglobal distribution. Due to its reproductive cycle, an extraordinarily high number of specimens is globally registered but, even if it is still a major bycatch of longline fishery rather than a commercial target, it is characterized by a high vulnerability. In this perspective it is important to increase the amount of informations regarding its population extent in the different worldwide areas, evaluating the possible phylogeographic patterns between different locations. This study, included in the "MedBlueSGen" European project, aims exactly at filling a gap in knowledges regarding the genetic population structure of the Mediterranean blue sharks, which has never been investigated before, with a comparison with the North-Eastern Atlantic blue shark population. To reach this objective, we used a dataset of samples from different Mediterranean areas implementing it with some samples from North-Eastern Atlantic. Analyzing the variability of the two mitochondrial markers control region and cytochrome b, with the design of new species-specific primer pairs, we assessed the mitochondrial genetic structure of Mediterranean and North-Eastern Atlantic samples, focusing on the analysis of their possible connectivity, and we tried to reconstruct their demographic history and population size. Data analyses highlighted the absence of a genetic structuring within the Mediterranean and among it and North-Eastern Atlantic, suggesting that the Strait of Gibraltar doesn't represent a phylogeographic barrier. These results are coherent to what has been found in similar investigations on other worldwide blue shark populations. Analysis of the historical demographic trend revealed a general stable pattern for the cytochrome-b and a slightly population expansion for the control region marker.

The Impact of Whaling on the Ocean Carbon Cycle: Why Bigger Was Better

Background: Humans have reduced the abundance of many large marine vertebrates, including whales, large fish, and sharks, to only a small percentage of their pre-exploitation levels. Industrial fishing and whaling also tended to preferentially harvest the largest species and largest individuals within a population. We consider the consequences of removing these animals on the ocean's ability to store carbon. Methodology/Principal Findings: Because body size is critical to our arguments, our analysis focuses on populations of baleen whales. Using reconstructions of pre-whaling and modern abundances, we consider the impact of whaling on the amount of carbon stored in living whales and on the amount of carbon exported to the deep sea by sinking whale carcasses. Populations of large baleen whales now store 9.1 x 10(6) tons less carbon than before whaling. Some of the lost storage has been offset by increases in smaller competitors; however, due to the relative metabolic efficiency of larger organisms, a shift toward smaller animals could decrease the total community biomass by 30% or more. Because of their large size and few predators, whales and other large marine vertebrates can efficiently export carbon from the surface waters to the deep sea. We estimate that rebuilding whale populations would remove 1.6 x 10(5) tons of carbon each year through sinking whale carcasses. Conclusions/Significance: Even though fish and whales are only a small portion of the ocean's overall biomass, fishing and whaling have altered the ocean's ability to store and sequester carbon. Although these changes are small relative to the total ocean carbon sink, rebuilding populations of fish and whales would be comparable to other carbon management schemes, including ocean iron fertilization.

Compilation of scientific results of the OASIS project

Seamounts are of great interest to science, industry and conservation because of their potential role as 'stirring rods' of the oceans, their enhanced productivity, their high local biodiversity, and the growing exploitation of their natural resources. This is accompanied by rising concern about the threats to seamount ecosystems, e.g. through over-fishing and the impact of trawling. OASIS described the functioning characteristics of seamount ecosystems. OASIS' integrated hydrographic, biogeochemical and biological information. Based on two case studies. The scientific results, condensed in conceptual and mass balanced ecosystem models, were applied to outline a model management plan as well as site-specific management plans for the seamounts investigated. OASIS addressed five main objectives: Objective 1: To identify and describe the physical forcing mechanisms effecting seamount systems Objective 2: To assess the origin, quality and dynamics of particulate organic material within the water column and surface sediment at seamounts. Objective 3: To describe aspects of the biodiversity and the ecology of seamount biota, to assess their dynamics and the maintenance of their production. Objective 4: Modelling the trophic ecology of seamount ecosystems. Objective 5: Application of scientific knowledge to practical conservation.

Estrategias de la anchoíta en un mar de tiburones : Las pymes conserveras marplatenses durante la valoración financiera (1975-2006)

Desde los años 70' Argentina se consolidó como un país pesquero, siendo la merluza hubbsi la principal especie capturada y exportada. Desde fines de la década de 1990 pequeñas y medianas empresas supieron conciliar extracción, manufactura y mercados explotando especies costeras, entre las cuales se destaca la anchoíta. El presente trabajo se centra en las estrategias de gestión, organización e innovación de Coomarpes e Indupesa, empresas que han subsistido en un mercado dominado por un poderoso oligopolio interno y por capitales foráneos que depredan el mar argentino y exportan productos con escaso agregado de valor hacia mercados europeos y asiáticos

Estrategias de la anchoíta en un mar de tiburones : Las pymes conserveras marplatenses durante la valoración financiera (1975-2006)

Desde los años 70' Argentina se consolidó como un país pesquero, siendo la merluza hubbsi la principal especie capturada y exportada. Desde fines de la década de 1990 pequeñas y medianas empresas supieron conciliar extracción, manufactura y mercados explotando especies costeras, entre las cuales se destaca la anchoíta. El presente trabajo se centra en las estrategias de gestión, organización e innovación de Coomarpes e Indupesa, empresas que han subsistido en un mercado dominado por un poderoso oligopolio interno y por capitales foráneos que depredan el mar argentino y exportan productos con escaso agregado de valor hacia mercados europeos y asiáticos

Estrategias de la anchoíta en un mar de tiburones : Las pymes conserveras marplatenses durante la valoración financiera (1975-2006)

Desde los años 70' Argentina se consolidó como un país pesquero, siendo la merluza hubbsi la principal especie capturada y exportada. Desde fines de la década de 1990 pequeñas y medianas empresas supieron conciliar extracción, manufactura y mercados explotando especies costeras, entre las cuales se destaca la anchoíta. El presente trabajo se centra en las estrategias de gestión, organización e innovación de Coomarpes e Indupesa, empresas que han subsistido en un mercado dominado por un poderoso oligopolio interno y por capitales foráneos que depredan el mar argentino y exportan productos con escaso agregado de valor hacia mercados europeos y asiáticos

Foraging behaviour of the epaulette shark Hemiscyllium ocellatum is not affected by elevated CO2

Increased oceanic uptake of atmospheric carbon dioxide (CO2) is a threat to marine organisms and ecosystems. Among the most dramatic consequences predicted to date are behavioural impairments in marine fish which appear to be caused by the interference of elevated CO2 with a key neurotransmitter receptor in the brain. In this study, we tested the effects of elevated CO2 on the foraging and shelter-seeking behaviours of the reef-dwelling epaulette shark, Hemiscyllium ocellatum. Juvenile sharks were exposed for 30 d to control CO2 (400 µatm) and two elevated CO2 treatments (615 and 910 µatm), consistent with medium- and high-end projections for ocean pCO2 by 2100. Contrary to the effects observed in teleosts and in some other sharks, behaviour of the epaulette shark was unaffected by elevated CO2. A potential explanation is the remarkable adaptation of H. ocellatum to low environmental oxygen conditions (hypoxia) and diel fluctuations in CO2 encountered in their shallow reef habitat. This ability translates into behavioural tolerance of near-future ocean acidification, suggesting that behavioural tolerance and subsequent adaptation to projected future CO2 levels might be possible in some other fish, if adaptation can keep pace with the rate of rising CO2 levels.

Literature review of elasmobranch bycatch and retention rate

To address growing concern over the effects of fisheries non-target catch on elasmobranchs worldwide, the accurate reporting of elasmobranch catch is essential. This requires data on a combination of measures, including reported landings, retained and discarded non-target catch, and post-discard survival. Identification of the factors influencing discard vs. retention is needed to improve catch estimates and to determine wasteful fishing practices. To do this we compared retention rates of elasmobranch non-target catch in a broad subset of fisheries throughout the world by taxon, fishing country, and gear. A regression tree and random forest analysis indicated that taxon was the most important determinant of retention in this dataset, but all three factors together explained 59% of the variance. Estimates of total elasmobranch removals were calculated by dividing the FAO global elasmobranch landings by average retention rates and suggest that total elasmobranch removals may exceed FAO reported landings by as much as 400%. This analysis is the first effort to directly characterize global drivers of discards for elasmobranch non-target catch. Our results highlight the importance of accurate quantification of retention and discard rates to improve assessments of the potential impacts of fisheries on these species.