Abstract Background Taxon- and/or ecosystem-based definitions of management units typically focus on conspicuous species and physical habitat limits; these definitions implicitly assume that these classification systems are related to the mechanisms that determine biodiversity persistence. However, ecological theory shows that this assumption may not be supported. Herein, we introduce the use of modularity analysis for objectively identifying management units and topological roles that land cover type plays on species movement through the landscape. Methods As a case study, we used a coastal system in Uruguay, with 28 land cover types and five taxa (from plants to mammals). A modularity-based approach was used to identify subsets of habitats with biotic affinity, termed modules, across the different taxonomic groups. Modularity detects the tendency of some land cover types to have a higher probability of the mutual interchange of individuals than other land cover types. Based on this approach, pairs of habitats that co-occur in the same module across taxa were considered in the same biodiversity management units (BMU). In addition, the topological role of each habitat was determined based on the occurrence of species through the landscape. Results Our approach determined three management units that combine land cover types usually considered independent, but instead are interrelated by an occurrence-based ecological network as proxies of the potential flow of individual and land use. For each selected taxon, the specific topological role of each habitat was determined. Conclusions This approach provides an objective way of delineating spatial units for conservation assessment. We showed that land cover types within these spatial units could be identified as refuges for specific types of biodiversity, sources of propagules for neighboring or overall landscapes, or stepping-stones connecting sub-regions. The preservation of these topological roles might help maintain the mechanisms that drive biodiversity in the system. Interestingly, the role of land cover type was strongly contingent on the taxa being considered. The method is comprehensible, applicable to policy and decision-makers, and well-connected with ecological theory. Moreover, this approach complements existing methods, introduces novel quantitative uses of available information, determines criteria for land cover classification and identifies management units that are not evident through other approaches.

The Southwestern Atlantic margin is characterized by several canyon systems incised on a huge contourite depositional system associated with the interaction of strong Antarctic water masses with the seafloor. So far, however, only one mega slide canyon (Cabo Polonio) has been described in the Uruguayan continental slope. In this work, sedimentary processes dominating the head of this mega slide canyon are described and interpreted based on the analysis of the composition (texture and fossils) and distribution of widespread gravel along its head and thalweg. This information is integrated with acoustic (multibeam and seismic) and hydrological data. Results suggest that the evolution of the head of the canyon presents retrogressive erosion related to debris and turbidity flows. This erosion is ongoing and/or has been active during the recent past and contourite deposits are involved in headwall erosion. The pathway of gravel along the canyon and the thalweg was reconstructed. The strong flow of the South Atlantic Central Water, and its interaction with the Antarctic Intermediate Water, dominates the modern hydrology, promoting highly energetic conditions enhancing headwall erosion. This work contributes to a better understanding of the sedimentary processes connected to an mega slide canyon in the upper slope off Uruguay and located in the northernmost distribution of the South Atlantic Contourite Depositional System.

An important ark clam (Arca zebra) artisanal fishery takes place in the east region of Venezuela. Besides the target species, trawling extracts a significant bycatch of several mollusk species including the gastropod Voluta musica, a threatened species according to the Venezuelan Red List of Endangered Species. In this paper we evaluate: 1) the composition of mollusk species in the bycatch, 2) the number of individuals of V. musica caught as bycatch and, 3) the abundance and size structure of the exploited population. Each fishing night, about 27,830 m² are trawled by each boat extracting on the average 607 kg of A. zebra meat and 19 kg of V. musica (whole shelled animal). This fishery activity potentially captures ~30,000 kg of ark clam meat and 922 kg of V. musica in one week (~95 snails/fishing night/boat). The size structure of the V. musica population at the ark clam bed is significantly smaller than in other nearby sites not impacted by trawling fishing activities. Non-targeted species extracted in the bycatch but consumed by the local inhabitants include the gastropods Chicoreus brevifrons, Phyllonotus margaritensis, P. pomum, Fasciolaria tulipa, Strombus pugilis, a few Trochidae species, and the bivalves Pinctada imbricata, Spondylus americanus, Anadarafloridana, A. notabilis, and Trachicardium muricatum. Individuals of V. musica along with several invertebrates are discarded. We recommend that V. musica should not be neglected as a conservation target, and despite that A. zebra fisheries are considered "artisanal", that more strict regulations should be established on it.

La pesca artesanal de la almeja arca (Arca zebra) es una de las pesquerías de mayor importancia en el oriente de Venezuela. En esta pesquería se capturan incidentalmente varias especies de moluscos, incluyendo el gasterópodo Voluta musica, considerada amenazada según el Libro Rojo de la Fauna Venezolana. En este trabajo se evalúa: 1) la composición de especies de moluscos en la captura incidental, 2) el número de individuos de V. musica capturados como pesca incidental y 3) la estructura de tallas y abundancia de la población explotada. En cada faena de pesca se arrastran 27.830 m² por cada barco, extrayendo en promedio 607 kg de A. zebra (sin concha) y 19 kg de V. musica (con concha). La flota completa captura ~30.000 kg de A. zebra y 922 kg de V. musica en una semana (~95 caracoles/noche de pesca/barco). La estructura de tallas de la población de V. musica en el banco de A. zebra es significativamente menor comparada con sitios cercanos no afectados por la pesca de arrastre. Otras especies capturadas incidentalmente son consumidas por los habitantes locales e incluyen los gasterópodos Chicoreus brevifrons, Phyllonotus margaritensis, P pomum, Fasciolaria tulipa, Strombus pugilis, y unas pocas especies de Trochidae, bivalvos Pinctada imbricata, Spondylus americanus, Anadara floridana, A. notabilis, Trachicardium muricatum. Los individuos de V. musica y otros invertebrados son desechados completamente. V. musica debe ser considerada como objeto de conservación, y a pesar que la captura de A. zebra es considerada "artesanal", se deberían establecer regulaciones más estrictas sobre esta especie.

Produtos plásticos tem se tornado um componente indispensável na vida moderna, como conseqüência disso a quantidade de plásticos descartados tem dramaticamente aumentado. É esperado que com o aumento da população de seres humanos a prevalência de descartes plásticos também aumente, a menos que hábitos cotidianos sustentáveis sejam incorporados, e novos materiais alternativos sejam descobertos e popularizados. Até o momento, diversas pesquisas têm mostrado os efeitos negativos de descartes plásticos sobre a fauna marinha e dulcícola (p. ex.: invertebrados, aves, tartarugas e mamíferos marinhos). Em ambientes aquáticos, plásticos estão em toda parte: na coluna de água, depositados em sedimento fino e dentro de estômago, estruturas respiratórias e tecidos de diversas espécies aquáticas, e são incorporadas nas teias alimentares através da ingestão. Este problema global também afeta atividades realizadas na praia e próximas à costa (p. ex.: turismo, pesca, e aqüicultura) com conseqüências sociais e econômicas negativas. Pesquisas que abordem os efeitos de plásticos sobre ambientes aquáticos no Uruguai é ainda incipiente. Com o objetivo de contribuir para o conhecimento científico, a tomada de decisões e o manejo de descartes plásticos, revisou-se a informação disponível acerca de fontes de descartes plásticos, observando os impactos delas sobre a biodiversidade e sobre questões políticas em sistemas aquáticos uruguaios. Além disso, revisou-se e sistematizou-se o alcance de iniciativas da comunidade, e examinou-se a política nacional de iniciativas de manejo. Descobrimos que os sistemas aquáticos uruguaios (de água doce, costeiros e marinhos bentônicos) são afetados pela poluição de plástico, pelas atividades terrestres e pelas atividades ligadas ao mar, embora as políticas a nível nacional sejam modernas e bem adaptadas para minimizar os impactos dessa poluição. Revisamos as interações biota-detritos plásticos, e encontramos evidência de impactos sobre diversos taxa aquáticos, incluindo a ingestão de microplástico per peixes de água doce, e da associação que existe entre biota e os detritos plásticos bentônica, geralmente pouco relatados. As configurações hidrográficas globais e regionais (Estuário Rio de la Plata), bem como questões ecológicas idiossincráticas, sócio-econômico e culturais fazem do Uruguai um valioso lugar-teste para este tópico. O objetivo final dessa pesquisa é minimizar os efeitos deste amplamente difundido problema de saúde, ambiental, econômico e estético.

Synthetic plastics have become an indispensable component of modern life, and the amount of plastics disposal has increased dramatically as a result. With human population increasing, it is expected that the prevalence of plastic debris in the environment will also increase, unless sustainable daily habits are incorporated, waste management improved, and new alternative materials are discovered and popularized. To date, several reports show negative effects of plastic debris on marine and freshwater fauna (e.g. invertebrates, birds, turtles, marine mammals). Plastic are ubiquitous in the water column, deposited in fine sediments and enter the guts, respiratory structures and tissues of different aquatic species, and are incorporated into food webs via ingestion. This global problem also affects beach and near-shore activities (e.g. tourism, fisheries, and aquaculture) with negative social and economic consequences. The research of plastics effect on aquatic environments in Uruguay is only incipient. With the aim of contributing to scientific knowledge, decision-making and the management of plastic debris, here we reviewed the available information on plastic debris sources, their impacts on biodiversity, and policy issues in Uruguayan aquatic systems. Moreover, we reviewed and systematized community outreach initiatives, and examined national policies and management initiatives. We found that Uruguayan aquatic systems (freshwater, coastal marine and benthic) are affected by plastic pollution, both from land-based and sea-based activities, although national-level policies are modern and well suited for minimizing the impacts of plastic pollution. We reviewed biota-plastic debris interactions, and found evidence for impacts on a number of aquatic taxa, including the poorly reported ingestion of microplastics in freshwaters fishes and the association with plastic benthic debris. Global and regional hydrographic settings (Río de la Plata Estuary), as well as idiosyn-cratic ecological, socio-economic and cultural issues, make Uruguay a valuable test-site for this topic. Our ultimate goal is to minimize the effects of this widespread environmental, economic, health and aesthetic problem.

Artisanal fisheries in Uruguay involve directly or indirectly more than 5000 people and constitute the main source of income in several coastal communities. However, and despite its economic and environmental importance, this activity is poorly documented. As such, this scarcity of information constrains the understanding and effective management of artisanal fisheries. This study aims to characterize different strategies of marine artisanal fisheries on the Uruguayan Atlantic coast and describe the spatial distribution of fishing effort. Based on a Principal Components Analysis we identified four fishing strategies targeting different species (mainly whitemouth croaker Micropogonias furniert, narrownose smooth-hound shark Mustelus spp., angel shark Squatina spp. and Brazilian codling Urophycis brasiliensis), exhibiting different seasonal patterns and fishing gear usage. Finally, the above outlined strategies showed differences in spatial utilization of the fishing area. Our results provide a spatially explicit framework for the management of Uruguayan marine artisanal fisheries.

En Uruguay las pesquerías artesanales involucran, directa e indirectamente, a más de 5.000 personas, constituyendo la principal fuente de ingresos en varias comunidades costeras. Sin embargo, a pesar de su importancia económica y ambiental, dicha actividad está muy poco documentada. De esta forma, la falta de información restringe la comprensión y el manejo efectivo de las pesquerías artesanales en el país. Los objetivos de este trabajo son caracterizar las diferentes estrategias de la pesquería artesanal de la costa atlántica uruguaya y describir la distribución espacial de su esfuerzo pesquero. En base a un Análisis de Componentes Principales se identifican cuatro estrategias de pesca dirigidas a diferentes especies objetivo (principalmente corvina Micropogonias furnieri, gatuzo Mustelus spp., angelito Squatina spp. y brótola Urophycis brasiliensis), que presentan diferentes patrones estacionales y del tipo de arte utilizado. Finalmente, las estrategias anteriormente descritas muestran diferencias en el uso espacial de las áreas de pesca. Los resultados proporcionan un marco espacialmente explícito para el manejo de las pesquerías artesanales en la costa atlántica de Uruguay.

This study aims to advance knowledge on the effects of bottom trawling in the shelled megabenthic gastropods from Uruguayan continental shelf. Composition of by-catch, species distribution, direct shell damage and mortality, and frequency of repaired shell damage were analysed from data collected on board of the research vessel "Aldebaran". A total of 12 megabenthic gastropod species was registered from 35 stations surveyed, either as live specimens or empty shells. From these, the shelled gastropods Adelomelon beckii, Adelomelon ancilla, Odontocymbiola magellanica, Fusitriton magellanicus and Zidona dufresnei dominated numerically the by-catch. We observed a spatial segregation of the gastropod assemblages along a bathymetric and latitudinal gradient, with O. magellanica, F. magellanicus and A. ancilla occurring at the southern portion of the study area, whereas A. beckii and Z. dufresnei were restricted to the northern and shallower areas respectively. Direct mortality was barely observed, but shells of A. ancilla, O. magellanica and Z. dufresnei were frequently damaged during the fishing operation and capture handling. Accordingly, we found a high positive correlation between the observed frequency of recent shell damage and the presence of scars, suggestive but not conclusive evidence on the relationship between incidence of repaired shell damage and trawling disturbance

Este estudio tuvo como objetivo profundizar el conocimiento de los efectos de la pesca de arrastre en los gasterópodos megabentónicos con concha, de la plataforma continental uruguaya. La composición, distribución de las especies, daños directo en la concha y mortalidad directa, así como la frecuencia de cicatrices en la concha fueron analizadas a partir de datos recolectados a bordo del barco de investigación "Aldebaran". Un total de 12 especies de gasterópodos megabentónicos se registró en las 35 estaciones monitoreadas, tanto como especimenes vivos o como conchas vacías. De ellos, los gasterópodos con concha Adelomelon beckii, Adelomelon ancilla, Odontocymbiola magellanica, Fusitriton magellanicus y Zidona dufresnei dominaron numéricamente la captura incidental. Se observó una segregación espacial de las asociaciones de gasterópodos a lo largo de un gradiente batimétrico y latitudinal, con O. magellanica, F. magellanicus y A. ancilla ocurriendo en la porción sur del área de estudio, mientras que A. beckii y Z. dufresnei estuvieron restringidos a las áreas mas norteñas y someras, respectivamente. Raramente se observó mortalidad directa, pero las conchas de A. ancilla, O. magellanica y Z. dufresnei resultaron dañadas frecuentemente durante las operaciones de pesca y posterior procesamiento de la captura. De acuerdo con esto, se encontró una alta correlación positiva entre la frecuencia observada del daño reciente de la concha y la presencia de cicatrices, una evidencia sugerente pero no concluyente acerca de la relación entre la incidencia de cicatrices en la concha y la perturbación ocasionada por la pesca de arrastre

La Coronilla-Cerro verde has been proposed as the first marine protected area in Uruguay. As part of a detailed benthic biodiversity assessment at the reserve, we analyzed the ophiuroid fauna collected in the intertidal and shallow subtidal during 2005 and 2006. Three species of ophiuroids were identified: Amphioplus lucyae, Amphipholis squamata and Amphiodia sp. Only two species belonging to the genus Amphiodia (A. pulchella and A. planispina) have been previously mentioned for Uruguayan waters, indicating that the unidentified species found in this study constitutes a previously unreported species.

La Coronilla-Cerro Verde ha sido propuesta como la primera área marina protegida del Uruguay. Como parte de un detallado análisis de la biodiversidad bentónica dentro de la reserva, se analizó la fauna de ofiuroideos colectada en el intermareal y submareal somero durante 2005 y 2006. Se identificaron tres especies: Amphioplus lucyae, Amphipholis squamata y Amphiodia sp. Solo dos especies del género Amphiodia han sido previamente mencionadas para la costa uruguaya (A. pulchella, y A. planispina) indicando que la especie de este género encontrada en este estudio corresponde a una especie aun no reportada.