Multidisciplinary estimates of connectivity and population structure suggest the use of multiple units for the conservation and management of meagre, Argyrosomus regius.

Information on population structure and connectivity of targeted species is key for proper implementation of spatial conservation measures. We used a combination of genomics, biophysical modelling, and biotelemetry to infer the population structure and connectivity of Atlantic meagre, an important fisheries resource throughout its distribution. Genetic samples from previously identified Atlantic spawning locations (Gironde, Tejo, Guadalquivir, Banc d'Arguin) and two additional regions (Algarve and Senegal) were analysed using genome-wide SNP-genotyping and mitochondrial DNA analyses. Biophysical models were conducted to investigate larval dispersal and connectivity from the known Atlantic spawning locations. Additionally, thirteen fish were double-tagged with biotelemetry transmitters off the Algarve (Portugal) to assess movement patterns and connectivity of adult individuals. This multidisciplinary approach provided a robust overview of meagre population structure and connectivity in the Atlantic. Nuclear SNP-genotyping showed a clear differentiation between the European and African populations, with significant isolation of the few known Atlantic spawning sites. The limited level of connectivity between these subpopulations is potentially driven by adults, capable of wide-ranging movements and connecting sites 500 km apart, as evidenced by tagging studies, whilst larval dispersal inferred by modelling is much more limited (average of 52 km; 95% of connectivity events up to 174 km). Our results show sufficient evidence of population structure, particularly between Africa and Europe but also within Europe, for the meagre to be managed as separate stocks. Additionally, considering the low degree of larvae connectivity, the implementation of marine protected areas in key spawning sites could be crucial towards species sustainability.

Residency and space use estimation methods based on passive acoustic telemetry data.

Acoustic telemetry has helped overcome many of the challenges faced when studying the movement ecology of aquatic species, allowing to obtain unprecedented amounts of data. This has made it into one of the most widely used methods nowadays. Many ways to analyse acoustic telemetry data have been made available and deciding on how to analyse the data requires considering the type of research objectives, relevant properties of the data (e.g., resolution, study design, equipment), habits of the study species, researcher experience, among others. To ease this decision process, here we showcase (1) some of the methods used to estimate pseudo-positions and positions from raw acoustic telemetry data, (2) methods to estimate residency and (3) methods to estimate two-dimensional home and occurrence range using geometric or hull-based methods and density-distribution methods, a network-based approach, and three-dimensional methods. We provide examples of some of these were tested using a sample of real data. With this we intend to provide the necessary background for the selection of the method(s) that better fit specific research objectives when using acoustic telemetry.

Weak biodiversity connectivity in the European network of no-take marine protected areas.

The need for international cooperation in marine resource management and conservation has been reflected in the increasing number of agreements aiming for effective and well-connected networks of Marine Protected Areas (MPAs). However, the extent to which individual MPAs are connected remains mostly unknown. Here, we use a biophysical model tuned with empirical data on species dispersal ecology to predict connectivity of a vast spectrum of biodiversity in the European network of marine reserves (i.e., no-take MPAs). Our results highlight the correlation between empirical propagule duration data and connectivity potential and show weak network connectivity and strong isolation for major ecological groups, resulting from the lack of direct connectivity corridors between reserves over vast regions. The particularly high isolation predicted for ecosystem structuring species (e.g., corals, sponges, macroalgae and seagrass) might potentially undermine biodiversity conservation efforts if local retention is insufficient and unmanaged populations are at risk. Isolation might also be problematic for populations' persistence in the light of climate change and expected species range shifts. Our findings provide novel insights for management directives, highlighting the location of regions requiring additional marine reserves to function as stepping-stone connectivity corridors.

Effects of dredged sediment disposal on the coastal marine macrobenthic assemblage in Southern Brazil.

The aim of this study was to evaluate the deposition impact of dredged material from Patos lagoon estuary on a benthic macroinvertebrate assemblage structure in an adjacent coastal marine area. Nine sampling stations were chosen at random in the disposal area, and nine others in the same way in an adjacent control area. Samples were collected at a 19 m depth before sediment disposal (11 July 2000), during dredging and disposal operations (25 Oct. 2000), and three months thereafter (24 Aug. 2001). Statistical analysis indicated that sampling periods presented similar characteristics in both the control and disposal sites. Disposal of dredged sediment from Patos lagoon had no detectable detrimental effects upon macrobenthic faunal assemblage at the dumping site. This result is attributed both to adaptation of resident biota to dynamic sedimentary conditions and to the fine estuarine sediment dredged, the dispersion of which in the water column might have minimized sediment deposition and consequent damage to the benthic fauna.

Effects of dredged sediment disposal on the coastal marine macrobenthic assemblage in Southern Brazil

Objetivou-se avaliar o impacto da deposição de material dragado proveniente da região estuarina da lagoa dos Patos sobre a estrutura da associação macrobentônica no sítio de deposição, situado no ambiente marinho costeiro adjacente à desembocadura da laguna. Nove estações de coleta foram sorteadas, tanto no sítio de deposição quanto na área controle adjacente. As amostras, a 19 m de profundidade, foram coletadas antes do início de deposição do sedimento (11/07/2000), durante as operações de dragagem e deposição (25/10/2000) e três meses após o encerramento das atividades de deposição do material dragado (24/08/2001). Análises estatísticas indicaram que áreas controle e sítio de deposição apresentaram características faunísticas similares dentro dos períodos amostrais. Não foram detectados efeitos prejudiciais da deposição do sedimento sobre a associação de macroinvertebrados bentônicos na área de depósito. Este resultado pode ser atribuído às características da biota residente que está, provavelmente, adaptada às condições da dinâmica sedimentar do local e também às características predominantemente finas do sedimento dragado que, ao dispersar-se na coluna d'água, minimizaram a deposição das frações mais finas e um eventual dano ao macrozoobentos.

Effects of dredged sediment disposal on the coastal marine macrobenthic assemblage in Southern Brazil

The aim of this study was to evaluate the deposition impact of dredged material from Patos lagoon estuary on a benthic macroinvertebrate assemblage structure in an adjacent coastal marine area. Nine sampling stations were chosen at random in the disposal area, and nine others in the same way in an adjacent control area. Samples were collected at a 19 m depth before sediment disposal (11 July 2000), during dredging and disposal operations (25 Oct. 2000), and three months thereafter (24 Aug. 2001). Statistical analysis indicated that sampling periods presented similar characteristics in both the control and disposal sites. Disposal of dredged sediment from Patos lagoon had no detectable detrimental effects upon macrobenthic faunal assemblage at the dumping site. This result is attributed both to adaptation of resident biota to dynamic sedimentary conditions and to the fine estuarine sediment dredged, the dispersion of which in the water column might have minimized sediment deposition and consequent damage to the benthic fauna.

Objetivou-se avaliar o impacto da deposição de material dragado proveniente da região estuarina da lagoa dos Patos sobre a estrutura da associação macrobentônica no sítio de deposição, situado no ambiente marinho costeiro adjacente à desembocadura da laguna. Nove estações de coleta foram sorteadas, tanto no sítio de deposição quanto na área controle adjacente. As amostras, a 19 m de profundidade, foram coletadas antes do início de deposição do sedimento (11/07/2000), durante as operações de dragagem e deposição (25/10/2000) e três meses após o encerramento das atividades de deposição do material dragado (24/08/2001). Análises estatísticas indicaram que áreas controle e sítio de deposição apresentaram características faunísticas similares dentro dos períodos amostrais. Não foram detectados efeitos prejudiciais da deposição do sedimento sobre a associação de macroinvertebrados bentônicos na área de depósito. Este resultado pode ser atribuído às características da biota residente que está, provavelmente, adaptada às condições da dinâmica sedimentar do local e também às características predominantemente finas do sedimento dragado que, ao dispersar-se na coluna d'água, minimizaram a deposição das frações mais finas e um eventual dano ao macrozoobentos.

Effects of dredging operations on soft bottom macrofauna in a harbor in the Patos Lagoon estuarine region of southern Brazil

Objetiva-se avaliar a resposta da associação de macroinvertebrados bentônicos ao efeito de dragagens do canal de acesso ao Porto de Rio Grande, na região estuarina da Lagoa dos Patos, RS, Brasil. Foram tomadas 3 amostras em nove estações de coleta, durante quatro cruzeiros sazonais. Uma das estações foi posicionada a montante da área dragada. As coletas foram efetuadas com um pegador van Veen de 0,08 m2. A análise de classificação (Similaridade Bray-Curtis) agrupou as estações de verão e outono, realizadas antes do início das dragagens, as quais mostraram maiores valores do número de espécies (35-36 spp) e das densidades do macrozoobentos. A estação localizada a montante da área de dragagem esteve sempre incluída neste grupo, independente do período de amostragem ou das condições de salinidade na região estuarina. Um segundo grupo incluiu as estações realizadas na primavera e no inverno, que coincidiram com o período de dragagem. Estas estações apresentaram menor número de espécies (20-18 spp.) e densidades, mas com um aumento da variância. A eficiente estratégia de resiliência das espécies estuarinas dominantes pode minimizar o efeito da dragagem sobre a biota, através de uma rápida recolonização das áreas dragadas no canal de acesso ao Porto de Rio Grande.

Effects of dredging operations on soft bottom macrofauna in a harbor in the Patos Lagoon estuarine region of southern Brazil.

An evaluation was made of the effects of dredging on the soft bottom community in the channel of the Rio Grande harbor in the Patos Lagoon estuarine region of southern Brazil. During four seasonal cruises, samples were collected from nine biological stations, one of which was located outside the dredged area. Three macrobenthic samples were collected on each cruise from each station, using a 0.08 m2 van Veen grab. A cluster analysis was applied to group summer and autumn cruise stations before the dredging period, revealing larger numbers of species (35-36 spp.) and higher densities of organisms. The station located outside the dredging area was always included in this group, regardless of the sampling period or conditions of salinity. Another group comprised the winter and spring stations during the dredging period. This group was characterized by stations with the fewest species (20-18 spp.) and the lowest and most variable organism densities. The efficient strategies of resilience of the dominant estuarine species may minimize the effects of dredging on the biota through the rapid recolonization of the soft bottom of the harbor channel.

Expression and function of ganglioside 9-O-acetyl GD3 in postmitotic granule cell development.

We have shown previously that the Jones monoclonal antibody (Jones mAb) recognizes 9-O-acetyl GD3 expressed during periods of neuronal migration and neurite outgrowth in the developing rat nervous system. In the present study we investigated the expression of this ganglioside in the developing cerebellum and correlated this expression with granule cell migration. Electron microscopic immunocytochemistry revealed that around the peak of cerebellar neuronal migration (7-day-old rat), 9-O-acetyl GD3 was localized at the contact sites between migrating granule cells and radial glia in the external granular layer and prospective molecular layer. In addition, using microexplant and slice cultures of the postnatal rat cerebellum, we tested whether the ganglioside detected by our antibody contribute to the regulation of neuronal migration in the cerebellar cortex. We have shown that the Jones mAb blocks the migration of neurons in a dose-dependent manner. These findings suggest strongly that 9-O-acetyl GD3 is involved in granule cell migration in the developing cerebellum.

Anticoagulant sulfated glycosaminoglycans in the tissues of the primitive chordate Styela plicata (Tunicata).

We performed a biochemical and histochemical study of sulfated glycosaminoglycans in the tissues of the ascidian Styela plicata. A highly sulfated dermatan sulfate and a heparin-like polymer, identified by incubation with specific lyases, occur at different concentrations in intestine, heart, pharynx, and cloak. Dermatan sulfate prevails in the pharynx, whereas the heparin-like polymer abounds in the intestine. Staining of tissues sections with the cationic dye 1,9-dimethylmethylene blue before and after incubation with specific lyases revealed that the dermatan sulfate occurs in the extracellular matrix, while the heparin-like polymer is located within cytoplasmic granules of cells in the lumen of intestine and pharynx. The dermatan sulfate has a similar disaccharide composition in all tissues studied, whereas the heparin-like polymer differs in sulfate content. A direct relationship between sulfate content of the heparin-like polymer and antithrombin activity was observed. Analysis of the repeating disaccharide units of the heparin-like polymer indicates the presence of relatively high amounts of the disulfated disaccharide namely DeltaUA-1-->4-GlcN(SO(4))-(6SO(4)), which may suggest the occurrence in ascidians of regulatory biosynthetic mechanisms different from those observed for heparin in mammals.

Essential thrombocythemia--clinical features, therapy and follow-up of 12 cases.

The authors analyzed twelve patients with symptomatic essential throthrombocythemia (E.T.) diagnosed from 1983 to 1991. Haemorrhagic and thrombotic phenomena were the main presenting features. Treatment consisted mostly of alpha-interferon (IFN-alpha 2b) subcutaneously in dosage ranging from 3 to 5 MU/m2 and hydroxyurea (HU) in conventional dosage. A clinical response was seen in seven patients treated with IFN-alpha 2b (4 CR and 2 PR), and in four patients treated with HU (3 CR and 1 PR). No significant side effects were observed. Our findings indicate that IFN-alpha 2b offers a non-leukaemogenic and very promising therapeutic alternative for E.T.