The economic cost of seabird bycatch in Argentinean longline fisheries

Seabird mortality in longline fisheries is believed to be an important cause of the reductions in many seabird populations worldwide, and results in reduced fishing efficiency and economic losses for fishing companies. We estimated the economic cost of not using seabird bycatch deterrents in Argentinean longline fisheries, with the intention of encouraging adoption of mitigation measures in those fisheries. We conducted the study in the Argentine ling Genypterus blacodes and Patagonian toothfish Dissostichus eleginoides fisheries from 2001 to 2006 on three fishing vessels. Data on the incidence of seabird bycatch were collected by seabird observers specially trained in seabird identification and data on the catch rates of target species, cost of bait and fish were provided by the fishing company, supervised by Federal Inspectors from the Provincial Fisheries Agency. To estimate the bait loss, we set lines both with and without the use of deterrents (streamer lines, night setting and strategic discharge of offal) in both fisheries. Seabird bycatch varies temporally and geographically, so to estimate economic losses using deterrents in each fishery, we used different bycatch rates/1000 hooks registered for different periods and fishing areas. Bycatch rates in the absence of deterrents were two birds/1000 hooks and 1.53 birds/1000 hooks for the Patagonian toothfish and ling fisheries, respectively. These rates equate to the loss of more than 1.5 and 2 million dollars over a 10 year period for each fishery. When estimations are made with lower mortality rates, economic losses declined abruptly and were in the order of hundreds of dollars/fishing trip, for the same period of time. Results show that using deterrents, long term profits for the fishing company increase at a considerably high rate (the decrease in monetary loss is an order of magnitude), and the mortality of seabirds decreases by the same proportion (CPUE of seabirds decreases from tens of thousands to a few hundred). In these fisheries, the use of mitigation measures that reduce bait loss and seabird mortality represents a win-win situation with benefits to conservation and fishing companies.Fil: Gandini, Patricia Alejandra. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Frere, Esteban. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Patrón de nidificación en el pingüino de Magallanes (Spheniscus magellanicus) : efectos de la calidad de hábitat y calidad de nido sobre su éxito reproductivo

Este trabajo se realizó en la colonia de Cabo Virgenes, provincia de Santa Cruz 52° 24' S 68° 26" W. La misma alberga un 50% de losindividuos reproductivos de la provincia de Santa Cruz y un 18% deltotal de los individuos reproductivos de la República Argentina. La colonia fue dividida en seis zonas de muestreo que fueron seguidasdesde el comienzo (setiembre) hasta el fin de la temporada (momento deindependencia de los pichones), durante tres temporadas reproductivas. Para su identificación los nidos fueron marcados con cintas numeradasy los adultos anillados con bandas metálicas numeradas. Se recogió información del éxito reproductivo y sus distintoscomponentes como la supervivencia de adultos y pichones, la depredación,etc, y se midieron distintas variables de hábitat como la coberturavegetal, la densidad de follaje la altura de la vegetación etc. Se evaluó la calidad del sitio de nidificación a dos escalas 1) Parche 2) Nido. Se encontró que la heterogeneidad de hábitat (diferencias entre losdistintos parches) determinaron que tanto el éxito reproductivo como suscomponentes no fueran homogéneos dentro de la colonia. Estas diferenciasno estuvieron explicadas por una sola variable. Una combinanción devariables como un indice de calidad “H” permitieron predecir el éxitoreproductivo, independientemente de la temporada reproductiva. Deacuerdo con los resultados obtenidos de calidad de hábitat y éxitoreproductivo se sugieren medidas de manejo sencillas para ladiagramación de la Reserva Turistica de Cabo Virgenes. Al analizar la escala "nido" se encontró que las diferencias en laestructura general de las matas influyen sobre el éxito reproductivo ysus distintos componentes. Nidos protegidos por matas más altas y conmayor cobertura global ubicados en zonas de menor densidad tendrán mayoréxito reproductivo. Los nidos de mayor cobertura vegetal global estuvieron sometidos a unimpacto de depredación menor independientemente del área que seencuentren (central o periférica). Una vez identificadas las variables que afectaron la calidad del nidose encontró que los nidos de mayor calidad se usaron en mayor proporciónpara la reproducción y a su vez se ocuparon primero verificándose elpatrón de ocupación temporal propuesto por Orians y Wittemberg (1991). Los individuos reproductivos seleccionarán sus nidos de acuerdo aléxito reproductivo de la temporada anterior de manera de maximizar suéxito reproductivo.Fil: Gandini, Patricia Alejandra. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Cormorants of the patagonian coast: population status, ecology and conservation

lo largo de la costa de Argentina nidifican cinco especies de cormoranes: el Cormorán Imperial (<i>Phalacrocorax atriceps</i>), el Cormorán Cuello Negro (<i>Phalacrocorax magellanicus</i>), el Cormorán Gris (<i>Phalacrocorax gaimardi</i>), el Biguá (<i>Phalacrocorax olivaceus</i>) y el Guanay (<i>Phalacrocorax bougainvillii</i>). En este trabajo se resume el estado del conocimiento actual, incluyendo información inédita, sobre los principales aspectos de la biología, la ecología, la abundancia y la distribución de las poblaciones de cormoranes en la costa argentina. Además, se presenta un análisis sobre los efectos y conflictos que las principales actividades humanas (transporte de petróleo, explotación guanera, turismo e interacciones con pesquerías) tienen sobre este grupo de aves marinas en la Patagonia argentina. Una serie de recomendaciones sobre estudios futuros para mejorar el manejo y la conservación de estas especies es presentada como conclusión del trabajo.Five species of cormorants breed along the Argentinean coast: Imperial Shag (<i>Phalacrocorax atriceps</i>), Rock Shag (<i>Phalacrocorax magellanicus</i>), Red-legged Shag (<i>Phalacrocorax gaimardi</i>), Neotropic Cormorant (<i>Phalacrocorax olivaceus</i>) and Guanay Shag (<i>Phalacrocorax bougainvillii</i>). This study presents the state of nowadays knowledge, including unpublished information, on different aspects of biology, ecology, abundance and distribution of cormorants’ populations in the Argentinean coast. It also presents an analysis of the effects and conflicts that the main human activities (oil transportation, guano explo.tation, tourism and interaction with fisheries) have on cormorants’ populations in the Argentinean Patagonia. Recommendations for future scientific studies to improve cormorant management and conservation are presented as the final conclusion of this study

Landscape dynamics of Paspalum quadrifarium grasslands analyzed by Morphological Spatial Pattern Analysis (MSPA)

Background. Despite its wide distribution worldwide, only 4.6% of temperate grasslands are includedwithin systems of protected areas. In Argentina, this situation is even more alarming: only 1.05% isprotected. The study area (central area of the southern Salado River basin) has a large extent ofgrasslands of Paspalum quadrifarium (Pq) which has been target since the last century of a variety ofagricultural management practices including fire burning for cattle grazing.Methods. Were used as base data bynary images of presence-ausence data of Pq coming from a 42-year (1974-2016) land cover change study performed over Landsat Imagery (MSS, TM, ETM, and OLIsensors). MSPA (Morphological Spatial Pattern Analysis) and Network Analysis were performed to thedata using Guidos Toolbox for the estimation of habitat and connectivity dynamics of the Pq patches(fragments).Results. Was observed a loss of area and habitat nuclei of this grassland between the beginning and theend of the study period. A drastic reduction in connectivity was also evident in resulting maps. Thenumber of large Pq grassland fragments (> 50 ha) decreased during the study period, and fragmentationmeasured as number of components (patches) was higher at the end of study period. The Pq pajonalnuclei had their minimum representativeness in 2000, and recovered slightly in 2011, but with asignificant percentage increase of the small patches (=islets) and linear elements as bridges andbranches. Large corridors (mainly edge of roads) could be observed at the end of study period, while thetotal connectivity of the landscape pattern drops abruptly.Discussion. The habitat reduction could have an impact on the ecosystem functioning and the mobilityof some species of native fauna. The connecting elements of the landscape were maintained and/orrecovered in percentage in 2011 and 2016. This fact, although favoring the dispersion of the presentdiversity in the habitat nuclei could cause degradation by an edge effect. On the methodological side, theuse of a proved tool as Guidos Toolbox for evaluating forest fragmentation could also be useful formonitoring dynamics of a grassland-habitat fragmentation.Fil: Gandini, Marcelo Luciano. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Lara, Bruno Daniel. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: Moreno, Laura Beatriz. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Cañibano, María Alejandra. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Gandini, Patricia Alejandra. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Does National power trigger ocean conservation?

States are reacting to the global crises of biodiversity and the provision of ecosystem services mainly through the expansion of their networks of protected areas. This reaction would have been boosted by the commitments made between the parties of the Convention on Biological Diversity, and facilitated by the opportunities offered by isolated territories, where economic interests are minimal. However, few studies have discussed the importance of national power as conservation conditionings, particularly in the ocean. In this regard, here we evaluate whether the relative extent of marine protected areas (MPAs) is related to different elements of national power. Following a quantitative approach and incorporating into analyses 155 countries, our models suggest that an increasing power (in terms of country size –land and ocean– and military capacity) is related to greater marine protection. Although these patterns could be initially associated with the ample human and economic resources of most powerful countries and with the opportunities provided by their overseas territories, different arguments would support national power elements as conservation drivers. Specifically, the exertion of such power through conservation could be linked to geopolitical strategies such as the (re)validation of a country's sovereignty over its Exclusive Economic Zone (EEZ), the greater regulation of the circulation and use of this space, the greater influence in the regional context, and the assurance in the provision of future ecosystem goods and services. In this way, changes in geopolitical conditions could affect MPAs, compromising the effective conservation of biodiversity and ecosystem processes, as well as the sustainable management of assets.Fil: Baldi, Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Schauman, Santiago Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Gandini, Patricia Alejandra. Universidad Nacional de la Patagonia Austral. Unidad Academica Caleta Olivia. Instituto de Cultura, Identidad y Comunicacion.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentin

Plovers and Sandpipers Census in Bahia Nueva (Puerto Mdryn, Chbut)

Seasonal abundance and distribution of plovers and sandpipers on the shores of the Golfo Nuevo, in the vicinity of Puerto Madryn were analyzed. Weekly census were made from April 1984 to September 1986. Twelve species of plovers and sandpipers were identified. The seasonal abundance of the most common species (Charadrius falklandicus, Calidris alba, Calidris fuscicollis, Calidris bairdii and Pluvianellus socialis) was related with the mean weekly amplitude of the photoperiod for this latitude. Acording to the timing of arrival, departure and the length of time the species remained in the area. Three behavioural patters were identified. Shorebirds concentrated on the shores of Puerto Madryn whenever the photoperiod amplitude is between 14 hrs of dayligth at lhe earIy March and 13 hrs of dayligth at the end of September. When the photoperiod amplitude reaches maximum values (summer) these shorebirds were not present

The diet of adult and chick rock shags (Phalacrocorax magellanicus) inferred from combined pellet and stable isotope analyses

The current information about the diet composition of the rock shag (Phalacrocorax magellanicus) in the SW Atlantic coast comes mainly from conventional pellet or stomach content analysis from a few locations situated in northern Patagonia (Chubut Province, Argentina). In this work, we studied the diet of breeding rock shags over several years at a colony from southern Patagonia (Ría Deseado, Santa Cruz Province, Argentina) using a combined technique of conventional diet assessment (pellet analysis) and stable isotope analysis of carbon and nitrogen. Our results confirm the importance of benthic prey and the low inter-annual variability in the diet of the rock shag. These results coincide with previous research in relation to the exploitation of slow moving, predictable, but low-energy density prey. The stable isotope mixing models, which was informed with prior data obtained from pellet analysis, allowed for the detection of subtle differences between the diet of adults and chicks, consisting in the incorporation of higher proportions of cephalopods, an energy-rich prey, in the diet of chicks. By comparing our results with the diet of the red-legged cormorant, which breeds in sympatry in the Ría Deseado Estuary and whose diet composition is strongly pelagic, we suspect a certain level of trophic resource partitioning between these rock shag and red-legged cormorant.Fil: Morgenthaler, Annick. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; ArgentinaFil: Millones, Ana. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; ArgentinaFil: Gandini, Patricia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; ArgentinaFil: Frere, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentin

Kelp gull ( <i>Larus dominicanus</i> ) as a carrier of pathogens in the patagonian coast

En este trabajo se estudió el transporte de enterobacterias por parte de la gaviota cocinera (<i>Larus dominicanus</i>), en un sector de la costa patagónica. A lo largo de un año (1995-96), un total de 100 individuos de distinto sexo y clase de edad, fueron capturados en el basural pesquero de Puerto Deseado. A cada uno de ellos se le realizó un hisopado cloacal y el sexo fue determinado por disección en el laboratorio. El análisis bacteriológico fue realizado por medio de pruebas bioquímicas convencionales, determinándose la presencia de al menos 10 especies de enterobacterias pertenecientes a los géneros: <i>Escherichia, Proteus, Citrobacter, Salmonella, Hafnia, Shigella, Enterobacter y Yersinia</i>. No se hallaron diferencias en las tasas de prevalencia entre sexos y clases de edades. La presencia de patógenos, para el hombre ó el ganado, en el tracto intestinal de las gaviotas a lo largo del año no mostró grandes diferencias, salvo para Proteus, que tuvo un pico de presencia durante la primavera y el verano y Citrobacter, durante la primavera. Salmonella typhimurium representa la entero bacteria encontrada de mayor riesgo para el hombre y el ganado y fue registrada durante gran parte del año. Aunque en el presente estudio no se investigan las tasas de infección bacteriana en humanos o ganado, la abundancia de gaviotas cocineras, sus hábitos alimenticios y la ubicación relativa de la ciudad (entre las colonias y el basural), convierten a estas aves en un probable candidato como vector de patógenos. Palabras Claves: Gaviotas, Larus dominicanus, enterobacterias, basurales, residuos, PatagoniaIn this paper we analyzed the carriage of pathogens by Kelp gulls (Larus dominicanus) in a portion of the Patagonian coast. During one year (1995-96), 100 individual s of different sex and age class were caught at fisheries tip of Puerto Deseado. Faecal samples were obtained from individual birds by cloacal swab and sex was determined at laboratory by dissection. We registered at least ten species of bacteria of eight genus (Escherichia, Proteus, Citrobacter, Salmonella, Hafnia, Shigella, Enterobacter and Yersinia), using standard biochemical technics. There were no differences in carriage rates between sexes and age classes. Camage rates were similar over almost all year, but Citrobacter was more abundant during Spring and Proteus during Spring and Summer. Salmonella typhimurium represents the more risky species for cattle and humans and it was found during most of the year. Despite this study was not focused to investigate the infection rates in humans or cattle, the abundance of kelp gulls, its pattems of feeding and movements, the relative location of the city (between fisheries tip and breeding areas), makes the species a very likely candidate for a pathogens vector

Aplicaciones matemáticas sobre un implemento de uso agropecuario

A partir de una situación real y concreta con la cual puede enfrentarse un alumno de la carrera de ingeniería agronómica, tanto en la situación de estudiante como posteriormente de profesional, en este trabajo, se pretende hacer uso del tema áreas y volúmenes, un contenido incluido en el plan de estudios, con el objeto de poder resolver una problemática donde se integren los conocimientos matemáticos como prioridad en la solución del mismo

Dimensión fractal en la enseñanza secundaria

Los fractales son entes matemáticos de singular importancia y se caracterizan por ser estructuras en las que una propiedad se repite de forma infinita. Aparecen en la naturaleza a menudo y es importante que el alumno entienda algunos conceptos relacionados con el mundo de la fractalidad y sus aplicaciones. En este trabajo se introduce el concepto de dimensión fractal por medio del método box counting aplicado a un accidente fisiográfico, una laguna