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The occurrence and spatial distribution of copepods of the family Paracalanidae was analyzed at eight stations located ten miles from the coastal profile of the Ecuadorian coast from 2016 to 2022. Eight species were recorded in the study: Paracalanus parvus, Paracalanus campaneri, Bestiolina sp, Acrocalanus longicornis, Acrocalanus sp, Calocalanus pavo, Calocalanus pavoninus, and Calocalanus plumulosus. The first three species are common in coastal and shelf waters and the remaining five in oceanic waters. Paracalanus parvus was the most abundant and frequent in the study area ranging from a few individuals to thousands, while the remaining species ranged from a few individuals to hundreds. A high abundance of coastal species in the study area would indicate that there is a greater influence of coastal waters over oceanic waters. In addition, it was possible to note that the distribution of the Paracalanidae species group was significantly correlated with low temperature and salinity values. [ABSTRACT FROM AUTHOR]

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Copyright of Estudios Internacionales is the property of Instituto de Estudios Internacionales de la Universidad de Chile and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For a century, the Beagle Channel was a point of contention for Chile and Argentina concerning their borders in the southern zone. Its geographical location implied a dispute between both nations' opposing geopolitical interests. This article analyzes the dispute over the Beagle Channel through a qualitative methodology with an established timeline (1881-1984). To this end, it assumes a geopolitical approach, resourcing the treaties and agreements established during this time and Chilean and Argentine authors defending the interests of their respective countries. As a result, it establishes the implications in the Austral-Antarctic Sea and the consequences in the maritime and continental shelf domains, which persist to this day. [ABSTRACT FROM AUTHOR]

Background and aims: Planktonic dinoflagellates have a great ecological significance in marine environments. While some dinoflagellate species commonly reach bloom concentrations and are thus conspicuous components of marine phytoplankton, others occur in very low abundances which make them difficult to detect in field studies. Here we analyzed dinoflagellate composition and abundance in five oceanographic expeditions carried out in continental shelf and slope waters of the Argentine Sea. M&M: Plankton abundance was estimated by the Utermöhl method, using inverted microscopy, whereas further optical and scanning electron microscopy was applied for the identification of dinoflagellate species. Results: We focused on the occurrence of seven dinoflagellates that have been previously poorly documented or overlooked in marine environments worldwide: Dinophysis microstrigiliformis; Gyrodinium sp.; Karlodinium elegans; Oxytoxum laticeps; Peridiniella danica; Peridiniella globosa and Prorocentrum nux. The latest and K. elegans are observed for the first time in field conditions after their original descriptions based on cell cultures. While most species were detected in low or moderate abundances, P. nux, which is the smallest Prorocentrum species, reached 82,000 cells L-1 in slope waters. Very small Gyrodinium cells (11.5 μm long; 8.7 μm wide) with a distribution restricted to slope waters during spring, were not possible to be accurately assigned to a species. Conclusions: This study contributes to the understanding of dinoflagellate diversity in the Argentine Sea and the worldwide distribution of little known species. [ABSTRACT FROM AUTHOR]

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Anuario Español de Derecho Internacional is the property of Servicio de Publicaciones de la Universidad de Navarra, S.A. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de Estudios Internacionales Mediterraneos is the property of Taller de Estudios Internacionales Mediterraneos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de Ciencias is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Four hundred-thirty six polychaetes collected in soft bottoms from the Gulf of Venezuela were examined. Samples were taken from ninety stations, between 2008 and 2012. Thirhteen species were identified, belonging to four families from Eunicida: Eunicidae (6 spp.), Onuphidae (5 spp.), Lumbrineridae (1 sp.) and Oenonidae (1 sp.). Seven of these species are new records for Venezuela. These results increase the knowledge about marine biodiversity from the continental shelf in Venezuela and the southern Caribbean Sea. [ABSTRACT FROM AUTHOR]

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In this study, fifteen species of benthic polychaetes associated with soft bottoms of the Gulf of Venezuela are taxonomically analyzed. The material was collected in ninety stations between 2009-2012. A total of 421 specimens were examined, among which 13 species of wandering polychaetes belonging to eight families were identified. Among the species identified Paranaitis polynoides, Phyllodocidae, and Aglauphamus verrilli, Nephtyidae, constitute new records for Venezuela. These results increase knowledge about marine biodiversity in the Venezuelan continental shelf. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ars Boni et Aequi is the property of Universidad Bernardo O'Higgins, Facultad de Derecho y Comunicacion Social and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The distribution area of Halophila engelmanni is enlarged for Cuban shelf. 83 records of the presence of this species were found in 67 sites of the marine Cuban shelf. [ABSTRACT FROM AUTHOR]

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dado que los elasmobranquios son frecuentemente depredadores tope en los ecosistemas marinos, la información sobre su dieta es esencial para entender las relaciones tróficas en estos sistemas. La similitud trófica entre seis especies de batoideos (Rhinoptera steindachneri, Rhinobatos glaucostigma, Dasyatis dipterura, Urotrygon aspidura, U. nana y U. rogersi) fue examinada por medio del análisis de contenidos estomacales de 140 individuos. Los especímenes fueron capturados en la pesquería comercial de camarón en el Pacífico central mexicano. En total, el 88.6% de los estómagos analizados estaban parcial o completamente llenos, permitiendo la identificación de 77 tipos de presa. Los principales componentes en la dieta fueron los crustáceos, seguidos por anélidos y moluscos. Los valores de amplitud de dieta en las seis especies indicaron baja diversidad en los ítems presa. El análisis de similitud de dietas sugirió dos grupos funcionales: R. glaucostigma, U. nana y U. aspidura pertenecen al grupo "cancritrófico" (P < 0.05) y U. rogersi y D. dipterura al grupo de anélidos y crustáceos. Para R. steindachneri no hubo un patrón evidente de asociación (se alimenta principalmente de ofiuros). Con base en estos resultados, se argumenta que la distribución de recursos alimenticios (partición del nicho) entre las seis especies favorece su coexistencia. [ABSTRACT FROM AUTHOR]

Copyright of Nova Acta Científica Compostelana is the property of Universidad de Santiago de Compostela, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nova Acta Científica Compostelana is the property of Universidad de Santiago de Compostela, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rhodoliths are one of the most extensive benthic communities of the Brazilian continental shelf, but their structure is poorly known. The richest marine flora of Brazil's coastal zone is found in Espírito Santo State and its diversity has been partly associated with the presence of extensive areas of rhodoliths, extending from the intertidal zone to 120 m across the continental shelf. One species of kelp, Laminaria abyssalis, is endemic to this area and occurs between 45 and 120 m depth. Our objective was to determine the density and physical dimensions of the superficial rhodoliths between 4 and 55 m depth in the southern region of Espírito Santo State. The study area was 3 to 45 km offshore. Samples were obtained in 2004 and 2005 by Scuba diving in three depth zones: 4-18 m, 25-30 m and 50-55 m. Transect lines and video images were used to determine rhodolith density. The diameter and sphericity of at least 60 individuals from each zone were measured. Rhodolith size increased and density decreased from the shallow to the deeper zones. Spheroidal was the typical shape throughout the depth zones. Five rhodolith-forming genera were identified: Lithothamnion, Lithophyllum, Hydrolithon, Neogoniolithon and Sporolithon. Epibenthic biomass and species richness over the rhodolith bed in the shallow zone was lowest in winter, likely the result of disturbance caused by typical winter storms. Changes in light and temperature are probably the most important factors in the changes observed in the rhodolith beds from the deepest zones. [ABSTRACT FROM AUTHOR]

Catch data of the yellowfin tuna (YFT) fishery were used to study the relationship between the seasonal and spatial variations of YFT with or without the presence of mesoscale structures at the entrance to the Gulf of California (19°-24° N, 104°-112° W). The YFT catches were distributed mainly over the continental shelf and around islands and seamounts. High concentration sets of YFT occurred throughout the year around the Marías islands and Cabo Corrientes, particularly in March and June. A warm (>28°C) coastal jet with a width of 1.5 Rossby radius (∼20.6 km) was observed off Cabo Corrientes during February and April, covering all the continental shelf off Cabo Corrientes. The jet moved at an average speed of 0.31 m s-1 and extended northwards to the Roca Corbetera seamount. The interaction with cooler water generated a frontal zone around which the YFT catches were concentrated. In contrast, during March the wind field was more favorable for the development of coastal upwelling off Cabo Corrientes. We observed an upwelling region with sea surface temperature of 18°C and an offshore width of about a 3.7 Rossby radius of cold water that covered some 2600 km². The YFT catches occurred in warmer water north of the upwelling zone. [ABSTRACT FROM AUTHOR]

A method to filter fluctuations in the hydrophysical properties of the continental shelf, caused by intense internal tides, is proposed. The method is based on a smoothing. of the field of the properties analyzed with a filter, the parameters of which are determined by the shape of the spatial correlation function of the field pulsations. Thefiltering method was tested on data from a fast oceanographic survey, conducted in an area of the monitoring polygon of the waters aroundBarra de Navidad. The survey was conducted on 25 and 26 November 1995, with an undulating CTD. In one day, 86 vertical profiles of temperature and salinity were obtained from nine transects perpendicular tothe coast (survey area of 100 x 25 km) to a depth of 100 m. The filtering algorithm of the internal waves is studied in detail. The fieldmeasurements present an analytical shape obtained from an equation in which the elements describe the components: low frequency, pulsating and related to daily behavior. The results of the analysis of the initial temperature and salinity fields with respect to homogeneity and isotropy are discussed, as well as the structural peculiarities of the estimates of the spatial correlation functions. It is observed that the temperature and salinity fields along the shelf, within the limits of the polygon scale, are neither homogenous nor isotropic. The correlation functions of the field pulsations analyzed are more clearly observed in the thermocline. The characteristic scales perpendicular to the coast are smaller than along it. Examples of smoothing the temperature and salinity fields in the thermocline are given. [ABSTRACT FROM AUTHOR]

Three cruises (DEM I, 11 and 111) were conducted along the coast of Jalisco and Colima (Mexico) during three hydroclimatic seasons, defined by the pattern of the surface currents. Trawl samples were taken at seven sites along the coastline and four bathymetric levels (20, 40, 60 and 80 m). During the three cruises, 170 invertebrate species were identified. The crab Portunus xantusii afnis was the most abundantspecies: 62.6% during DEM 1, 26.8% during DEM 11 and 42% during DEM III. The diversity (H) estimated was moderate to low, of 1.93, 2.62 and 2.39 for the three cruises, respectively. No significant differences in diversity were observed among the three cruises and the differences in diversity among depths were only significant during DEM I. The minimum sample sizes for diversity and richness indicate that at least 20,422 organisms are needed to estimate diversity and 34,476 for richness. [ABSTRACT FROM AUTHOR]

Presents information on a study which investigated the abundance of the invertebrate communities in one sector of the soft-bottom continental shelf off Jalisco and Colima, Mexico. Materials and methods; Results; Discussion.

Mollusks collected from soft bottoms of the continental shelf off Jalisco and Colima were analyzed. Three cruises were made during one year (1995-1996) on board the ship BIP-V. The samples were taken duringhalf-hour trawls, in seven different localities at four different depths (20, 40, 60, 80 m). A checklist is presented that contains 92 species of mollusks, belonging to 3 classes (Gastropoda, Bivalvia and Cephalopoda) and 37 families. Five new records are obtained for Nassarius guaymasensis, Latirus mediamericanus, Chicoreus (Phyllonotus) peratus, Hexaplex nigritus and Polymesoda (Egela) infata, which are range extensions. [ABSTRACT FROM AUTHOR]

Presents a list of decapod and stomatopod crustaceans of the soft bottoms of the continental shelf off Jalisco and Colima, Mexico. Description of the topography of the coastal zone off Jalisco and Colima; Geographic position, mean bottom water temperature and salinity of the sites and the sampling depths of the continental shelf; Number of decapod and stomatopod crustaceans that were identified.