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El lobo marino común Otaria byronia se distribuye ampliamente en Sudamérica desde Perú pasando por Chile hasta Brasil en los océanos Pacífico y Atlántico, respectivamente. Es una especie abundante, muy vágil y sin problemas de conservación. Como todos los pinnípedos, exhibe una reproducción notablemente estacional y sincronizada con ligeras diferencias entre poblaciones, siendo una cópula atemporal el objetivo de esta nota. Durante septiembre de 2020 se realizó un censo de O. byronia en una lobera reproductiva de la costa de Chile central, cuyos individuos sobre una roca fueron observados con binoculares. Ocho individuos de Otaria byronia fueron registrados, de éstos, una pareja se cortejaba mutuamente moviendo sus cabezas, cuerpos y se desplazaban al unísono sobre la roca. Posteriormente el macho (un sub-adulto) montó a la hembra y copularon aproximadamente por 20 minutos tras lo cual, ella sin prisa salto al mar. Durante el cortejo, cópula e interacción, solo el macho emitió sonidos y no se observaron conductas agresivas mutuas, ni que la hembra se opusiera a ser copulada. Tampoco se observó que los otros individuos interactuaban con ellos. La reproducción de O. byronia ocurre durante el verano austral siendo esta cópula inusual para la temporada, sin precedentes en las poblaciones chilenas y en el subcontinente. Diversos aspectos como factores climáticos, fisiológicos o presión antropogénica se pueden sugerir como causas o detonantes de este evento. Lo anterior destaca la necesidad de ampliar los estudios en mamíferos marinos en la costa chilena, explorando el vínculo e impacto de los factores extrínsecos sobre las poblaciones.

An autonomous lander equipped with a video camera (dropcam) was used for in situ observations of the bento-demersal macrofauna on the upper continental slope off Punta Pichalo in northern Chile, an area of permanent coastal upwelling processes, located ~70 km north of Iquique. The lander was deployed at nine stations and between 227 and 798 m of depth. According to morphological characteristics, 34 operational taxonomic units (OTUs) were identified to the lowest taxonomic level; 24 belonged to macroinvertebrates and 10 to fishes. Macroinvertebrates comprised 9 OTUs of crustaceans, seven cnidarians, and six echinoderms. Fishes included 3 OTUs of the order Chondrichthyes, 3 belonging to macrourid. Perciformes, Anguilliformes, and Alepocephaliformes were represented by one OTU each. Also, we observed one species of lanternfish (Myctophidae). Apart from the brachyuran decapod Lophorochinia parabranchia Garth, 1969 and euphausiids, all species were observed at depths greater than 560 m. The presence of one individual identified as the granulate dogfish Centroscyllium granulatum Günther, 1887 extended the known distribution range of this species about 1000 km to the north. Images taken at 795 m showed Bathyraja peruana McEachran & Miyake, 1984. Our study suggests that the upper continental slope of northern Chile harbors nearly undiscovered biodiversity, worth to be studied more intensively to complete the comparable sparse knowledge about marine biodiversity and species distribution at the continental margin in front of Chile.

The South American fur seal (SAFS) is distributed from Peru (Pacific Ocean) to Uruguay (Atlantic Ocean). However, there is a section of coastline of about 2,300 km along the Chilean coast where no SAFS are recorded. Based on morphological comparisons 3 geographic forms have been reported (Peruvian, South Chilean, Atlantic), whereas preliminary genetic studies suggest the presence of 3 distinct genetic types (Peruvian, South Chile, Atlantic). However, both of these approaches are support only the existence of 2 independent evolutionary histories for SAFS (Peruvian, Atlantic), in which case, we would also expect to find some differences in the species' life histories among these locals populations (e.g., in the timing of the breeding season). In this study, we compare the breeding seasons of SAFS at Punta Pichalo (19°36'S-Chile), Isla Guafo (43°33'S-Chile), and Isla de Lobos (35°01'S-Uruguay) with data published for Punta San Juan (15°21'S-Peru). The periods for establishing territories, pupping, and mating took place on similar dates at Isla Guafo and Isla de Lobos, but occurred about a month earlier at Punta Pichalo and Punta San Juan. Pupping peaked at Isla Guafo on 15-December, at Isla de Lobos on 17-December, and at Punta Pichalo on 27-November. These differences in timing were not related to demographic, oceanographic or photoperiod conditions of the breeding sites under study, neither is related with the latitudinal effects on the breeding phenology. Based on results, we suggest that certain characteristics of life history can help identify species with independent evolutionary histories. El lobo fino Sudamericano (SAFS) se distribuye desde Perú hasta Uruguay. Sin embargo, existe un área de 2,300 km a lo largo de la costa de Chile donde no se registran ejemplares de SAFS. A partir de comparaciones morfológicas se ha identificado la presencia de 3 formas geográficas (Peruana, Chilena austral y Atlántica), a la vez que estudios moleculares preliminares sugieren la presencia de 3 tipos genéticos distintivos (Peruana, Chilena austral y Atlántico). Sin embargo, ambas aproximaciones apoyan la existencia de 2 historias evolutivas independientes para los SAFS (Peruana, Atlántica), en cuyo caso, se podría esperar encontrar similares diferencias también en aspectos de la historias de vida de la especie entre estas poblaciones locales (e.g., en el tiempo de la estación reproductiva). En este estudio, se comparó la estación reproductiva de ejemplares del SAFS establecidas en Punta Pichalo (19°36’S-Chile), Isla Guafo (43°33’S-Chile), e Isla de Lobos (35°01’S-Uruguay) con otros datos publicados para Punta San Juan (15°21’S-Perú). El periodo de formación de los harenes, el periodo de pariciones y el de cópulas ocurrieron en fechas semejantes en Punta Pichalo y Punta San Juan y aproximadamente un mes más tarde en Isla Guafo e Isla de Lobos. El máximo de pariciones se registró en Isla Guafo el 15 de diciembre, en Isla de Lobos el 17 de diciembre, y en Punta Pichalo el 27 de noviembre. Estas diferencias no estuvieron relacionadas con las características demográficas, ni con las condiciones oceanográficas o con el fotoperiodo de las colonias bajo estudio, ni tampoco estaría relacionado con el efecto latitudinal sobre la fenología reproductiva. En base a los resultados, se sugiere que ciertas características de las historias de vidas pueden también ayudar a identificar especies con historias evolutivas independientes. Fil: Pavés, Héctor J.. Universidad Santo Tomas, Santiago; Chile. Universidad Austral de Chile; Chile Fil: Schlatter, Roberto P.. Universidad Austral de Chile; Chile Fil: Franco-Trecu, Valentina. Universidad de la República; Uruguay Fil: Paez, Enrique. Ministerio de Ganadería Agricultura y Pesca; Uruguay Fil: Sielfeld, Walter. Universidad Arturo Prat; Chile Fil: Araos, Viviana. Universidad Arturo Prat; Chile Fil: Giesecke, Ricardo. Universidad Austral de Chile; Chile. Centro Fondap de Investigación En Dinámica de Ecosistemas Marinos de Altas Latitudes; Chile Fil: Batallés, Luis Mario. Ministerio de Medio Ambiente; Uruguay Fil: Cappozzo, Humberto Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina

Macrocystis pyrifera kelp beds play a significant ecological role along the coast of Chile. Besides their importance as food, protection structures, substrata, microhabitats and nurseries, regularly occurring natural disturbances (e.g. extremes of the climate variability El Nino–Southern Oscillation) and increased kelp exploitation affect these habitats. The present study aimed to test the dependence of reef fishes on Macrocystis pyrifera and to evaluate the effect of an enhanced habitat structure (experimental M. pyrifera bed) on the abundance, composition and spatial distribution on rock, on macroalgae, in the water column and on sand of the reef fish community. Boulders colonised by M. pyrifera were transported into three replicated experimental areas (9 m2 each) located in a barren ground area. Three barren ground areas (9 m2 each) without manipulation were selected as controls. The fish abundance, composition and spatial distribution on rock, on macroalgae, in the water column and on sand were recorded weekly by scuba diving over a period of 3 months, between 15 February 2007 and 13 June 2007 (4 months). Results indicate significantly higher abundances (mean = 225%) of fishes in the forested areas compared to the barren ground controls (mean = 3.71 fishes/9 m2 and 1.14 fishes/9 m2, respectively). Scartichthys gigas/viridis, Chromis crusma, Cheilodactylus variegatus and Isacia conceptionis numerically dominated the fish assemblages of the experimental kelp patches. Each fish species revealed different distributions in the forested areas: Scartichthys gigas/viridis was more abundant on rocks and C. variegatus in the macroalgae, whereas C. crusma and I. conceptionis preferred the water column above the experimental kelp bed. During the experimental time, the kelp lost some blades and some plants became detached. The overall number of fishes correlated with the declining kelp abundance (r = 0.964, p

Population characteristics and carapace growth rates were estimated for green turtles (Chelonia mydas) foraging in Arica Bay, northern Chile, from 2012 to 2016. Within the main foraging area of La Puntilla, an open population of up to 514 individuals was estimated by mark and recapture (Jolly-Seber method), with densities of 20–225 individuals/km2. Captured individuals (n = 159) ranged from 44.6 to 98.6 cm straight carapace length (SCL) with a mean SCL of 64.9 cm (SD 10.8); most turtles were juveniles; however, 10 were adults with SCL > 80 cm (three of these being males). A mean body condition index (BCI) of 1.64 (range 0.34–3.63) indicated healthy population conditions, with mean annual growth rates (AGR) of 4.6 cm/year (SD 2.97). The consistent presence of turtles between 2012 and 2016 and the relatively high abundance compared to the general situation reported for the species in Chile makes Arica Bay the most important feeding congregation of green turtles in the country. The population's healthy state and size, its location within an urban radius, and the multiple human uses of this site represent aspects that must be considered in protection and development plans for the city's coastal border.

Se analizaron los pterópodos thecosomados colectados en una transecta oceanógrafica efectuada entre Caldera, Chile (~27°S) y los alrededores de Isla de Pascua e Isla Salas y Gómez, Pacífico suroriental. Se registró un total de 2021 individuos, agrupados en 18 especies, siendo Clio pyramidata y Styliola subula especies dominantes a lo largo del transecto, las más frecuentes y representadas en 18 de las 23 estaciones analizadas. Las especies más abundantes fueron S. subula (35%), C. pyramidata (28%) y Cavolinia inflexa (13%). Las siguientes especies constituyen nuevos registros para el Pacífico suroriental: Cavolinia labiata, Cavolinia uncinata, Cavolinia gibosa, Cuvierina columnella, Clio cuspidata, Clio chaptali, Diacria trispinosa, D. quadridentata, D. major, Cymbulia sp. y Peracle reticulata. La clasificación permite reconocer tres conjuntos de estaciones caracterizadas por sus especies, abundancia total, riqueza de especies y diversidad, que incluyen un conjunto nerítico (71-79°W), un conjunto oceánico (82-105°W) y un conjunto de estaciones talasoepipelágicas asociadas a las islas oceánicas.

Observations on Chelonia mydas agassizii have been carried out on a monthly basis for the last 2 years along the Chinchorro beach in Arica (northern Chile), with the aim of monitoring and describing genetic and population parameters in this group of turtles. Eighteen Ch. mydas agassizii individuals were captured and marked from December 2011, to July 2013. These individuals had long carapace of 47 to 75.7 cm, of which 11 were identified as females and the rest were of undetermined sex (individuals of smaller sizes). We were only able to recapture one of such individuals 6 months later in the same feeding area. Sequencing of the mtDNA Control Region showed 4 haplotypes: 3 that had never been described before and one observed in several regions of the Pacific (Japan, Mexico and Ecuador). This information suggests that Ch. mydas agassizii may stay in the same feeding zone for months. Nevertheless, the genetic information did not indicate any association between the individuals captured from the Chinchorro Beach and a nesting area in the Pacific.

The coastal wetlands of the northern zone, being the focus of water presence in an extremely arid area, are particular ecosystems that shelter and serve as a refuge for exclusive flora and fauna species, and at the same time have been strongly associated with the history of the population and use of the territory by humans. This chapter analyzes the composition, diversity and abundance of flora and avifauna species of the coastal wetlands associated with the mouths of the rivers and streams of the northern zone of Chile and discusses their conservation status. The vegetation associated with these ecosystems tends to follow an order in fringes, presenting itself from the littoral zone to the submerged, natants, emerged/surfaced, and free floating species, marshy ones and finally shrubs. In terms of species, a total of 69 species are recognized in 4 classes. Out of these species, 80% are native and 14% introduced, with only three species being endangered. In the case of birds, there is a presence of 194 species, and the Lluta wetland is the one with the greatest representation of this group (154 spp.). Most of these species are residents of wetlands (140 spp.), but there are also visiting species (26 spp.), as well as accidental ones (28 spp.). Out of all of the avifauna recorded in these wetlands, 32 species are endangered. In general terms, the development of mining and agricultural activities, urbanization and modification of the water flows associated with the coastal wetlands of northern Chile are the main threats to this type of ecosystems, and should be considered in the regional conservation strategies for avifauna, flora and biodiversity in general.

Mediante análisis de fecas se estudiaron los hábitos alimentarios del león marino sudamericano (Otaria byronia) (LMS) en Punta Patache, norte de Chile durante 2 periodos El Niño (1997/98 y 2009/10). Las muestras fecales (n= 183) fueron colectadas en la lobera de Punta Patache, sur de Iquique (20º48’63’’S). Se identificaron 10 especies de presas neríticas (incluyendo 4 peces, 2 cefalópodos y 3 crustáceos). Los más importantes para el conjunto de ambos períodos fueron en términos de abundancia la anchoveta (Engraulis ringens) (7,4%), el langostino (Pleuroncodes monodon) (83,0%) y el calamar (Loligo gahi) (6,9%). En términos de biomasa consumida destacaron el calamar (35,7%) y el langostino (21,9%). En términos de aportes energéticos a la dieta, los más importantes fueron el langostino (19,9-32,7%) y el calamar (24,9-40,5%), en lípidos la anchoveta (31,8-36,4%) y en proteína el calamar (20,9-41,0%) y el langostino (22,5-29,9%). La comparación con resultados de estudios anteriores bajo condiciones ENOS neutrales/frías (1996 y 2015) destaca mayor consumo de anchoveta (82,8% y 23,3-48,4%, respectivamente). Sobre esta base se concluye que frente a la falta de anchoveta durante el desarrollo de eventos ENOS, el LMS ajustaría su dieta a otros recursos, situación que determina un ‘estrés nutricional’ derivado de una nutrición inadecuada, cuyas consecuencias son reducción del crecimiento, bajas en la tasa de natalidad, enfermedades, desnutrición y en muchos casos muerte, tal como se ha reportado para los ENOS fuertes 1982/83 y 1997/98.

Se presentan los resultados de diversas prospecciones de arañas realizadas en el norte de Chile, sobre cuya base se amplía la lista de especies conocidas para el extremo norte de Chile a 56 especies, distribuidas en 45 géneros y 25 familias.Las familias con mayor diversidad son Theridiidae, Salticidae y Lycosidae. Las especies Hogna subaustralis, Frigga crocuta y Steatoda triangulosa son nuevos registros para Chile. Se presentan datos distribucionales y los principales hábitats y microhábitats de las especies encontradas.

Understanding diversity patterns along environmental gradients lies at the heart of community ecology and conservation. Previous studies have found variation in bird diversity and density along "natural" elevational gradients in the Tropical Andes Hotspot. However, there is still a lack of knowledge about how bird communities respond to traditional land-use patterns, in association with other multiple drivers, along elevations. In the present study, we investigated biotic, abiotic and anthropogenic sources of variation associated with bird species diversity, density and turnover along a 3000-m elevational gradient, in southern limit of the Tropical Andes Hotspot, northern Chile. Over four seasons, we conducted 472 bird point count surveys and established 118 plots distributed across the Desert, Pre-Puna, Puna and High-Andean belts, where biotic, abiotic and anthropogenic factors were measured. We used mixed-effects models to estimate alpha diversity and multinomial Poisson mixture models to estimate species density, accounting for detectability. Species diversity and density increased until 3300 masl and then declined. This type of elevational pattern is characteristic of dry-based mountains, where environmental conditions are suitable at mid-elevations. Habitats shaped by traditional Aymara indigenous agriculture, associated with relatively high vegetation heterogeneity, hosted the highest values of bird diversity and density. Species turnover was structured by habitat type, while elevational ranges of most species were restricted to three relatively discrete assemblages that replaced each other along the gradient. Our study revealed a hump-shaped relationship between elevation and bird diversity and density in the Dry Tropical Andes Biodiversity Hotspot, supporting a diversity pattern characteristic of dry-based mountains of the world. Traditional Aymara agriculture may have constructed ecological niches for biodiversity at mid-elevations, enhancing vegetation heterogeneity, thus providing resources for resident and rare species. Increasing loss of traditional land-use may present a threat to the bird community in the Tropical Andes Hotspot.

Se estimo la distribucion y la abundancia poblacional del lobo marino comun Otaria flavescens en la costa de Chile central durante los meses de enero y febrero de 2007. Adicionalmente, se analizaron los cambios en la abundancia de esta especie durante el periodo 1970-2007. Los censos poblacionales se basaron en fotografias tomadas desde embarcaciones menores o desde avionetas. Se contabilizaron un total de 16301 lobos marinos (IC = 16209-16375) en 33 colonias (6 reproductivas y 27 no reproductivas). Despues de corregir por la proporcion de animales en el agua y por crias no registradas al momento del censo, se estimo una abundancia promedio de 18179 (95 % CI = 17777-18851) lobos marinos en el area de estudio. El analisis de tendencia poblacional presento que desde 1970 a 1985 la abundancia-lobo marino com-mostro una tendencia positiva de aproximadamente 2.1 % ano-1. Sin embargo, entre 1985 a 1997, y entre 1997 a 2007, el numero de lobos marinos muestra una tendencia estable o ligeramente negativa de 0.4 ± 0.1 % ano-1 y 0.5 ± 0.1 % ano-1, respectivamente. Se sugiere que la sobreexplotacion y la declinacion de las principales pesquerias en la zona central de Chife podria haber impactado negativamente la distribucion y abundancia del lobo marino comun en el area de estudio.

Specimens of Antennarius avalonis captured in the north of Chile are described. The information is compared with the data presented by previous authors. The distribution of the southeast Pacific species and those known from the continental and insular coasts of Chile is compared.

Macrocystis integrifolia and Lessonia trabeculata form vast kelp beds providing a three-dimensional habitat for a diverse invertebrate and fish fauna off northern Chile. Habitat modifications caused by the El Nino Southern Oscillation (ENSO) are likely to alter the inhabiting communities. The aim of this study was to reveal relationships between distinct habitat structures of a M. integrifolia kelp bed, a dense L. trabeculata kelp bed and L. trabeculata patches colonizing a barren ground, and the associated dominant macrobenthic key species. Seasonally 15 sampling units (10 m2 each) of any of the three habitats were monitored by SCUBA divers, which counted sporophytes and macroinvertebrates living between the latter. Furthermore, samples of plants were analysed in the laboratory to measure the morphological variables: total plant length, maximal holdfast diameter, stipe number, number of dichotomies per stipe, frond width and total drained wet mass. Multivariate analysis showed that the L. trabeculata kelp bed is denser, with a higher number of dichotomies per stipe, whereas sporophytes of M. integrifolia are longer with more stipes and wider fronds. Sporophytes of L. trabeculata patchily present on barren ground are shorter and have more stipes compared with those in the dense L. trabeculata kelp bed. Thus, the habitats provide different three-dimensional structures. The associated macrobenthic communities show a variable degree of overlapping; however, key faunal assemblages were distinguished for each habitat. Our study provides evidence that habitat diversity drives species diversity, the more homogeneous, monospecifically composed kelp bed habitats show comparatively low diversity, mainly caused by the dominance of the ascidian P. chilensis and T. tridentata in the M. integrifolia bed, and the mussel A. ater only present in the L. trabeculata bed. Species richness and diversity is highest in the heterogeneous habitat where L. trabeculata patches interrupt the barren ground. Our study revealed morphological differences between M. integrifolia and L. trabeculata kelp beds reflected in stipe number, plant length, dichotomies per stipe, and wet mass, which influence the composition of the associated characteristic fauna and its functional relations i.e. T. niger and T. tridentata.

A longstanding competition for fishery resources has existed in Chile between the South American sea lion (Otaria flavescens) and artisanal (small-scale) fisheries. This competition is viewed as a conflict by the fishermen because sea lions prey on fish caught in their fishing gear, often causing its damage. The objective of the study was to describe the interaction between sea lions and fishermen, and to evaluate the effects of operational interference caused by sea lions on their artisanal fishery. Descriptions of the interactions cited were made during 69 observational trips on fishing vessels plus interviews of 384 fishermen. Evaluation of the interactions was based on minimum and maximum scenarios. Almost all the artisanal fishermen complained of frequent problems with sea lions, however, such interactions were observed in 14.5% of the observer trips on fishing vessels. The results showed that loss of catch due to sea lions, varied between 1.83 and 21.1% of the CPUE (under minimal) and from 1.98 to 33.8% (under maximal) interactive scenarios. Although proportions of interactive fishing events and number of sea lions were different between the locations studied, CPUE per fishing gear did not differ significantly between interactive and non-interactive fishing trips among the areas. Also, no significant relation was found between the numbers of sea lions interacting during the fishing trip and the CPUE. Our results suggest that sea lions do not produce a significant effect on variations in the CPUE obtained by artisanal fishermen. Nevertheless, these findings must be confirmed with more intensive monitoring. A cooperative design of a co-management plan, which considers biological, social, and economical features will contribute to make consensus within the stakeholders looking for management options with the aim of reducing the conflicts.

Los estudios de variaciones de abundancia de las poblaciones a distintas escalas temporales permiten comprender como dichas poblaciones fluctuan en el tiempo y cuales son los factores que influyen sobre dichas variaciones. Se analizaron los patrones de abundancia del lobo marino comun (SASL, Otaria flavescens) a escalas diaria, mensual y anual en 2 loberas reproductivas del norte de Chile. Adicionalmente, se evaluo el efecto de El Nino sobre los patrones anuales de la especie. La abundancia de lobos marinos en Punta Negra (PN) disminuyo desde 1994 a 2011, mientras que en Punta Patache (PP) aumento, aunque el numero de crias fue proporcionalmente bajo. Los resultados demuestran un efecto importante de El Nino sobre la abundancia de lobos marinos, especialmente para hembras + juveniles en PN. La abundancia mensual de hembras y juveniles fue mayor en invierno, mientras que para machos adultos y subadultos no se encontro ningun patron. Finalmente, durante el dia la abundancia incrementa hasta llegar a un maximo hacia fines de la tarde, especialmente en el caso de hembras y juveniles. No se encontraron diferencias en los patrones de abundancia entre las epocas reproductiva y no reproductiva para ninguna de las clases de sexo/edad. Este estudio muestra que la abundancia en PP y PN muestra periodicidades anuales, mensuales y diarias, y que dichas periodicidades estan condicionadas tanto por factores intrinsecos (e.g., epoca reproductiva) como extrinsecos (e.g., hora del dia, El Nino). A escala anual, los resultados indican que aun a una escala local, las tendencias de abundancia en 2 colonias pueden ser diferentes.

Description of a specimen of Nicholsina denticulata (Evermann & Radcliffe, 1917) (Scaridae, Labroidei) captured in the north of Chile. The information is com...

From bibliographical information on bathymetric and latitudinal distribution of 110 marine fish species of western Patagonia (42º-57ºS), the ichthyogeographic zonation of the area is discussed. The bathymetric distribution of the fish species shows a species association distributed at depths less than 100 m, a second association between 50 and 500 m, and a third association below 500 m depth. This third one is interpreted as a transitional situation of the second one, because of the scarcity of endemic species. These associations present similar latitudinal zonation patterns, including separation into a northern sector, characterized by species of lower latitudes, a southern sector with characteristic and endemic elements of that zone, and an intermediate transition sector considered as an independent association by its large extension and species composition. The Straits of Magellan represent an important faunistic exchange zone between the bottom fish communities of the Southwestern Atlantic and the Southeastern Pacific. A partir de la información, principalmente bibliográfica, sobre distribución batimétrica y latitudinal de 110 especies de peces marinos de la Patagonia occidental (42º-57ºS), se presenta un esquema de zonación ictiogeográfica para el área. La distribución batimétrica de las especies muestra la existencia de una asociación de peces distribuida entre 0 y 50 m de profundidad, una segunda asociación entre 50 y 500 m de profundidad y una tercera asociación a más de 500 m de profundidad. Esta tercera asociación es interpretada como situación de transición de la segunda asociación, a causa de la escasez de especies endémicas. Estas asociaciones presentan un patrón similar de distribución latitudinal, que incluye un sector norte, caracterizado por elementos de latitudes menores, un sector sur, con elementos característicos del área y un sector intermedio de transición considerado como una unidad independiente por su extensión y composición íctica, confirmando los resultados de revisiones biogeográficas anteriores. El Estrecho de Magallanes destaca como sector de intercambio faunístico entre el Atlántico suroccidental y el Pacífico suroriental.

Background A number of studies have described the extension of ice cover in western Patagonia during the Last Glacial Maximum, providing evidence of a complete cover of terrestrial habitat from 41°S to 56°S and two main refugia, one in south-eastern Tierra del Fuego and the other north of the Chiloé Island. However, recent evidence of high genetic diversity in Patagonian river species suggests the existence of aquatic refugia in this region. Here, we further test this hypothesis based on phylogeographic inferences from a semi-aquatic species that is a top predator of river and marine fauna, the huillín or Southern river otter (Lontra provocax). Results We examined mtDNA sequences of the control region, ND5 and Cytochrome-b (2151 bp in total) in 75 samples of L. provocax from 21 locations in river and marine habitats. Phylogenetic analysis illustrates two main divergent clades for L. provocax in continental freshwater habitat. A highly diverse clade was represented by haplotypes from the marine habitat of the Southern Fjords and Channels (SFC) region (43°38' to 53°08'S), whereas only one of these haplotypes was paraphyletic and associated with northern river haplotypes. Conclusions Our data support the hypothesis of the persistence of L. provocax in western Patagonia, south of the ice sheet limit, during last glacial maximum (41°S latitude). This limit also corresponds to a strong environmental change, which might have spurred L. provocax differentiation between the two environments.

The coastal fringe off northern Chile (18o-23oS) is inhabited by numerous neritic fish species of which 249 are commonly observed during normal and cold La Nina (LN) conditions. During El Nino (EN) the ichthyofauna of northern Chile changes significantly due to about 100 invading fish species normally inhabiting lower latitudes, named "septentrional invaders" and "tropic-equatorial fishes". This results in a composition including 15 fish families and 86 genera. Analyses showed that species affected by EN were not the same between the last three EN events revealing that only the epipelagic species Anchoa naso, Albula vulpes, Atherinella nocturna and Scomberesox saurus stolatus behaved consistently. Off northern Chile, EN 1982/83, 1986/87, 1991/92, 1997/98, 2002/2003 and the not clearly EN defined 2004/2005 period with their aligned thermal abnormalities of each particular event were directly related to the number of invading/affected species. Most of the alien species (>50%) were epipelagic, 25% were typical for sandy beaches and 14.6% for rocky shores. The shore fish community did not show major changes during and after EN events, as only a few invading species were recorded; just Umbrina xantii was found during all events considered. In order to understand the response of the fish community to ENSO events a biogeographical analyses of 721 fish species reported for neritic habitats (coastal epipelagic and benthic) distributed between 0°-57°S (Gulf of Guayaquil to Cape Horn) was made. Their distribution ranges for normal oceanic conditions were taken from the very numereous existing literature. It is concluded that the north/south migration of Panamic and Peruvian warm water fishes during EN/LN events along the north Chilean coast between 18o-23oS, indicates that it represents a wide transition zone between the Peruvian and the Chilean ichthyogeographic provinces.

This research analyzed the effect of fecal contamination caused by sewage, and its relationship with the presence of enteropathogenic strains of Escherichia coli in the feces of South American sea lions (Otaria flavescens) from Iquique Bay and surrounding waters. The E. coli strains isolated from the water column of the bay and sewage outlet, showed the presence of the gene eae. In the strains isolated from the feces of both sea lion colonies no presence of virulent diarrheagenic genes was detected. The genotyping of strains resulted in clusters according to their origin and showed separation of the samples of E. coli population of the colonies of sea lions and those of the strains isolated from the column water of Iquique Bay.

The Humboldt Current System is a highly productive ecosystem that is subject to the dynamics of the El Nino Southern Oscillation (ENSO). El Nino (EN, the warm phase of ENSO) causes vital changes in surface water temperature, oxygen levels, and salinity conditions, which arc reflected in various responses of coastal pelagic and benthic organisms. For very shallow habitats such as sandy beaches, temperature and salinity are considered the principal parameters changing during strong EN. However, the mechanisms by which these changes effect change on the structure of coastal populations remains largely unknown. The surf clam Donax ohesulus is dominant on large sandy beaches of the Humboldt Current System. Its biogeographical distribution is largely influenced by EN-induced environmental changes. Despite the species' key role in the beach ecosystem, the effects of modified abiotic conditions on the meroplanktonic larval stages and threshold temperatures involved have not yet been investigated. After EN episodes, meroplanktonic larval stages play a crucial role in the medium- and long-term stability of shallow-water species. Thus, this study makes a first attempt to describe the ontogeny of D. ohesulus and examines the effects on development of EN temperature conditions (ENTC) in comparison with normal temperature conditions (NTC). Results indicate that early life history follows a pattern previously described for other donacid bivalves. Development, growth, and mortality of larvae were assessed during a 3-wk in vitro experiment, indicating that larvae reared under ENTC grew and developed faster in comparison with those reared under NTC; mortality was slightly higher under ENTC. During a 2nd experiment, larvae were exposed for 48 h to a distinct range of different salinities (35, 25, 15, and 5 ± 1) at 2 different temperatures (NTC and ENTC). At both temperatures, larvae suffered no mortality at medium and low salinity (35, 25, and 15 ± 1) but showed 100% mortality at very low salinity (5 ± 1) after 16 h at NTC and 32 h at ENTC. Activity of larvae was highest at medium salinity (25 ± 1) and lowest at normal salinity (35 ± 1). The results of this study indicate that early larval stages of D. ohesulus can cope with temperature and salinity changes induced during EN. Only extremely low salinity (5 ± 1) such as that observed close to river mouths may cause high mortality rates in D. ohesulus offspring.

Se estudio la dieta de Orestias agassii en tres lagunas asociadas al Salar del Huasco en el altiplano de la I Region. El contenido estomacal presento; ostracodos, anfipodos, copepodos, moluscos, coleopteros, acaros y algas macrofitas. Los resultados permiten afirmar que O. agassii es un predador carnivoro, que consume una amplia variedad de microcrustaaeos que busca activamente entre la vegetacion.

RESUMEN. Se comunican los primeros registros de los Pleuronectiformes Achirus klunzingeri (Soleidae), Etropusectenes y Bothus constellatus (Bothidae) y Symphurus elongatus (Cynoglossidae) en aguas de chilenas. Las caracteris-ticas morfologicas de los especimenes estudiados se confrontan con descripciones previas. Se discute su distribucionen el Pacifico sur oriental y aquella del orden en aguas chilenas. Palabras claves: Pleuronectiformes, nuevos registros, Etropus ectenes , Bothus constellatus , Achirus klunzingeri , Symphurus elongatus , norte de Chile. First records of Etropus ectenes Jordan, 1889, Bothus constellatus Jordan & Goss,1889, Achirus klunzingeri (Steindachner, 1880) and Symphurus elongatus (Gunther,1868) (Pisces: Pleuronectiformes) in Chile, with comments on the distribution of theChilean flounders ABSTRACT. The first records of the Pleuronectiformes Achirus klunzingeri (Soleidae), Etropus ectenes and Bothusconstellatus (Bothidae), and Symphurus elongatus (Cynoglossidae) in chilean waters are reported. The morphologicalcharacteristics of the studied specimens are compared with previous descriptions. Their distribution in the SoutheasternPacific and that of the order in Chilean waters are discussed.

Se analiza la composicion y estructura de la ictiofauna demersal en la zona norte de Chile (18o24'-21o26'S). Se registraron 50 especies pertenecientes a 16 ordenes y 31 familias de peces. Se amplia el rango de distribucion sur para las siguientes especies: Dibranchus spinosa, Cherublemma emmelas, Pachycara suspectum; y el rango de distribucion norte para Centroscyllium granulatum. Las familias mejor representadas son Macrouridae, Ophidiidae y Zoarcidae (6, 5 y 4 especies, respectivamente). Por su abundancia destacan las familias Macrouridae y Ophidiidae (46% y 21%, respectivamente) y las especies Trachyrhynchus helolepis (33%), Cherublemma emmelas (21%) y Trachyrhynchus villegai (8%). Las especies mas frecuentes fueron Coryphaenoides ariommus (69%) y Trachyrhynchus helolepis (56%). El analisis batimetrico indica la existencia de un conjunto demersal somero (0-100 m) y un conjunto demersal profundo (100-1000 m). El estudio de la composicion especifica permite reconocer la existencia de tres niveles batimetricos en el segundo conjunto (200-500, 500-700 y 700-1000 m). La distribucion latitudinal indica que la comunidad representa un estado transicional entre las asociaciones de la plataforma continental y el talud del sector Panama-Peru y Chile central, dominando elementos del primero.

Se estudian los peces mesopelágicos capturados en la capa profunda de dispersión sónica (DSL), en cinco transectos ubicados entre los 18°25' y 21°47'S frente a las costas de la I Región de Chile. Los transectos se extendieron desde las 10 a las 100 millas de la costa y las capturas se realizaron mediante una red de ti po IKMT de 9,16 m² de boca, en septiembre de 1988. Conjuntamente se registró la DSL mediante un equipo SIMRAD (32 KHz de frecuencia) y las condiciones de temperatura y salinidad de cada: estación. En el área y período de estudio se detectaron 39 especies y 21 familias. En términos de biomasa la familia más importante fue Myctophidae (22%), mientras que en número de individuos destacó Gonostomatidae (67%). El 62% de la ictiocenosis correspondió a especies de aguas temperadas (tropicales y/o subtropicales) y un 7,7% a especies de aguas frías (antárticas y/o subantárticas), sin que se pierda el carácter transicional de la comunidad. El análisis de diversidad de Shannon- Wiener y de similitud de Winer mostró la existencia de 4 grupos discretos de estaciones, determinados por condiciones oceanográficas y masas de agua particulares. La DSL mostró un descenso hasta los 250 m de profundidad durante el día y la separación de una capa que asciende hasta la superficie durante la noche

Information is presented on the results of 16 bird censuses of the western inlet and saltmarsh of the Puerto Espora area (Tierra del Fuego) on the first narrows of the Straits of Magellan. This area was one of the most affected by the oil spilled from the VLCC Metula in august 1974. The censuses were carried out periodically between September 1976 and September 1979. A total of 36 species were recorded, of which one third is commonly found. Topics analyzed include: the presence of species by sectors within the study area; the general diversity for each census, its variation through time and cluster analysis.