Rapid expansion and potential range of the invasive kelp Undaria pinnatifida in the southwestern Atlantic

Coastal Patagonia, often regarded as a pristine confine of the world ocean, has been invaded by non-indigenous species that are rapidly modifying local ecosystems. One of the most conspicuous invaders is the kelp Undaria pinnatifida. First recorded near the city of Puerto Madryn (Argentina, 42.75°S) in 1992, during the last 15 years its range spread more than five degrees of latitude to the south. By 2007 it was first detected north of Valdes Península (a natural barrier), beginning its northward expansion, and between 2007 and 2011 spread along the coasts of San José and San Matías gulfs at an average rate of ~50 km yr-1. A small population was detected in Mar del Plata (Argentina, 38.04°S) in 2011, more than three degrees of latitude to the north, suggesting a new human-mediated inoculation. Based on experimental information and remotely sensed sea-surface temperature (SST) at the latitudinal range limits of U. pinnatifida populations worldwide, we hypothesize a thermal tolerance window between -0.6 °C and 16.8 °C average SST in the coldest month, and between 20 °C and 28 °C in the warmest month. Using climatologic satellite SST from several locations, we predict a potential latitudinal thermal range extending between Puerto Deseado (Argentina, 47.75°S) and Torres (Brazil; 29.35°S). Salinity and substrate quality however constrain suitable habitat in the southwestern Atlantic to discrete stretches of coastline, suggesting that the northern potential boundary would be around La Coronilla (33.90°S), on the Uruguayan littoral.Fil: Dellatorre, Fernando Gaspar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Amoroso, Ricardo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. University of Washington; Estados UnidosFil: Saravia, José. Provincia del Chubut. Ministerio de Desarrollo Territorial y Sectores Productivos; ArgentinaFil: Orensanz, Jose Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

Biological observations of the tope shark, Galeorhinus galeus , in the northern Patagonian gulfs of Argentina

During 1994–96, an experimental longline fishery for tope shark (Galeorhinus galeus) was carried out in the Nuevo Gulf of northern Patagonia and, in the summers of 2000–2001 and 2002, three boats conducted an exploratory commercial fishery for this species, accompanied by a scientific monitoring program. This paper summarizes the results of these fishing trials, and provides information on the biology of tope shark. Catches were highest from February to April, when tope shark represented 36% of the total fish caught, and elephant fish (Callorhynchus callorhynchus) and argentine hake (Merluccius hubbsi) accounted for 33% and 23%, respectively. Tope shark arriving in northern Patagonian waters during the summer are primarily mature males, immature and maturing females in their first and second non-gravid year. No gravid females were caught. These fish are part of the South-western Atlantic stock, which shows signs of over-exploitation, so we suggest that any longline fishery in Patagonia should remain on a small scale. We also recommend that an effective management plan is needed for the whole tope stock, establishing agreements on effort control and co-ordinated research between Brazil, Uruguay and Argentina.Fil: Elias, Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Rodriguez, A. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Hasan, E.. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Reyna, M. V.. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Amoroso, Ricardo Oscar. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentin

Effective fisheries management instrumental in improving fish stock status

Marine fish stocks are an important part of the world food system and are particularly important for many of the poorest people of the world. Most existing analyses suggest overfishing is increasing, and there is widespread concern that fish stocks are decreasing throughout most of the world. We assembled trends in abundance and harvest rate of stocks that are scientifically assessed, constituting half of the reported globalmarine fish catch. For these stocks, on average, abundance is increasing and is at proposed target levels. Compared with regions that are intensively managed, regions with less-developed fisheries management have, on average, 3-fold greater harvest rates and half the abundance as assessed stocks. Available evidence suggests that the regions without assessments of abundance have little fisheries management, and stocks are in poor shape. Increased application of area-appropriate fisheries science recommendations and management tools are still needed for sustaining fisheries in places where they are lacking.Fil: Hilborn, Ray. University of Washington; Estados UnidosFil: Amoroso, Ricardo Oscar. University of Washington; Estados UnidosFil: Anderson, Christopher M.. University of Washington; Estados UnidosFil: Baum, Julia K.. University of Victoria; CanadáFil: Branch, Trevor A.. University of Washington; Estados UnidosFil: Costello, Christopher. University of California at Santa Barbara; Estados UnidosFil: de Moor, Carryn L.. University of Cape Town; SudáfricaFil: Faraj, Abdelmalek. Einstitut National de Recherche Halieutique; MarruecosFil: Hively, Daniel. University of Washington; Estados UnidosFil: Jensen, Olaf P.. Rutgers University; Estados UnidosFil: Kurota, Hiroyuki. Japan Fisheries Research and Education Agency; JapónFil: Little, L. Richard. Csiro Oceans and Atmosphere; AustraliaFil: Mace, Pamela. Ministry for Primary Industries; Nueva ZelandaFil: McClanahan, Tim. Wildlife Conservation Society; Estados UnidosFil: Melnychuk, Michael C.. University of Washington; Estados UnidosFil: Minto, Cóilín. Galway-Mayo Institute of Technology; IrlandaFil: Osio, Giacomo Chato. Joint Research Centre (JRC); Italia. DG Maritime Affairs and Fisheries, European Commission; BélgicaFil: Pons, Maite. University of Washington; Estados UnidosFil: Parma, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Segurado, Susana. Sustainable Fisheries Partnership; Estados UnidosFil: Szuwalski, Cody S.. University of California at Santa Barbara; Estados UnidosFil: Wilson, Jono R.. University of California at Santa Barbara; Estados Unidos. The Nature Conservancy; Estados UnidosFil: Ye, Yimin. Food and Agriculture Organization of the United Nations; Itali

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Shell morphology changes in the scallop Aequipecten tehuelchus during its life span: A geometric morphometric approach

Shell morphology is a central feature of bivalve biology in fields such as taxonomy, evolution, and functional anatomy. When allometric shell growth occurs, traditional morphometric methods usually fail to provide robust, size-free shape variables. We used a more integrative approach, geometric morphometrics, to examine ontogenetic changes in the shell of the scallop Aequipecten tehuelchus. A single cohort that settled early in 2004 at a site in San José Gulf in northern Patagonia, Argentina, was sampled at irregular intervals over 5 yr. Different developmental stages had significant differences in shell shape. There was significant ontogenetic allometry, mainly reflected in the shape of the shell disc and the symmetry of the auricles. The most noticeable morphological changes in shell shape and size took place within the first 2 yr of life. Three different shell ecophenotypes were discriminated: spat, juveniles, and adults. Spat had a relatively large anterior auricle and a circular disc; auricles in juveniles were more symmetrical and the shell disc more elongated; and during the adult stage the auricles were small and asymmetrical and the disc elliptical. These 3 phenotypes may reflect changes in the scallop's life habits, as individuals develop from attached spat to actively swimming juveniles to more sedentary adults.Fil: Marquez, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Amoroso, Ricardo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Sainz Gowland, María Florencia. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Van Der Molen, Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

El alga exótica Undaria pinnatifida en Argentina : Biología, distribución y potenciales impactos

El alga exótica Undaria pinnatifida en Argentina Undaria pinnatifida es una macroalga parda originaria del este de China, Corea, Japón y sureste de Rusia, que fue detectada en Puerto Madryn en 1992; actualmente ocupa más de 1000km de costas Patagónicas y continúa dispersándose. Undaria desarrolla anualmente una fase esporofítica que crece durante el invierno y muere en verano, y una fase gametofítica microscópica muy resistente que puede funcionar como un banco de semillas. Las densas praderas que forma la especie, y su arribazón a la costa en épocas estivales impacta fuertemente sobre los usos turísticos de las playas y los arrecifes submarinos. Recientes estudios han identificado impactos negativos sobre el ensamble de macroalgas autóctonas y sobre los peces de arrecife. Sus rangos térmicos de supervivencia son amplios aunque la esporulación sólo ocurre después de períodos con temperaturas superiores a 14ºC y la maduración de los gametofitos solo ocurre por debajo de los 20ºC. El análisis de la temperatura de la superficie del mar en las diferentes zonas portuarias de la región, y su comparación con otras regiones habitadas por Undaria sugiere que la misma podría colonizar el norte del litoral de Argentina y Uruguay.Fil: Dellatorre, Fernando Gaspar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Amoroso, Ricardo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Baron, Pedro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin