ABSTRACT The inland waters in the Andes Mountains in the extreme north of Chile are in a zone with a marked arid climate in the called Atacama Desert (23° S, Antofagasta region, Chile) that has sporadic rains mainly in January or February (summer rains/Altiplano winter), many of these water bodies have high mineral contents due high mineral contents, and low species diversity (mainly crustacea and insecta). The present study aims to do a comparative analysis of inland water crustaceans in different kinds of water bodies in the surroundings of San Pedro de Atacama and Salar de Atacama in the north of Chile using co-occurrence null model analysis. The results revealed a scarce species richness and random species associations due to the lack of a structured pattern and many recurring species in the studied sites. Species reported, and species associations agree with literature descriptions. Nevertheless, more ecological studies would be necessary to understand the community patterns in these water bodies.

RESUMEN Los cuerpos de agua en la cordillera de los Andes del extremo norte de Chile están en una zona con un clima árido marcado en el denominado Desierto de Atacama (23° S, Región de Antofagasta, Chile), que tiene lluvias esporádicas en enero o febrero (lluvias estivales/invierno altiplánico), muchos de estos cuerpos de agua tienen alto contenido de minerales y baja riqueza de especies (principalmente crustáceos e insectos). El objetivo del presente estudio es realizar un análisis comparativo de los crustáceos de aguas continentales en diferentes tipos de cuerpos de agua en los alrededores de San Pedro de Atacama y del Salar de Atacama en el norte de Chile usando análisis de modelos nulos de co-ocurrencia de especies. Los resultados revelaron que hay baja riqueza de especies y que las asociaciones de estas son aleatorias, debido a la carencia de un patrón estructurado, por la presencia de muchas especies repetidas en los sitios estudiados. Las especies reportadas y las asociaciones de especies reportadas concuerdan con los antecedentes de la literatura. No obstante, serían necesario más estudios ecológicos para comprender los patrones comunitarios en estos cuerpos de agua.

Resumo A cultura da ostra tem como problema de produção o organismo incrustante, neste contexto, avaliou como controle biológico contra organismos incrustantes e sedimentos a introdução do gastrópode Tegula atra (Lesson, 1830) em culturas de ostras chilenas (Triostrea chilensis Phillippi, 1844) em condições de presença e ausência de fome, localizadas em gaiolas flutuantes e culturas de fundo. A predação e o efeito mecânico no pastejo de T. atra geraram uma diminuição em sete dias de 19,8% e 13,7% dos organismos incrustantes na cultura em gaiola e nos sedimentos de fundo, por efeito de gastrópodes sem fome, respectivamente. Considerando que houve decréscimo de 12,6% e 11,4% dos organismos incrustantes na cultura em gaiola e nos sedimentos de fundo pelos efeitos dos gastrópodes com fome respectivamente. Os organismos incrustantes removidos eram principalmente algas, ascídias coloniais, poliquetas, briozoários e pequenos crustáceos.

Abstract The oyster culture has the incrusting organism as problem for production, in this context, it evaluated as biological control against incrusting organism and sediments the introduction of gastropod Tegula atra (Lesson, 1830) in Chilean oysters (Triostrea chilensis Phillippi, 1844) cultures in conditions of starvation presence and absence located in floating cages and bottom cultures. The predation and mechanic effect on T. atra grazing generated a decreasing in seven days of 19.8% and 13.7% of incrusting organisms in cage culture and bottom sediments by effects of gastropods without starvation respectively. Whereas it had a decrease of 12.6% and 11.4% of incrusting organisms in cage culture and bottom sediments by effects of gastropods with starvation respectively. The incrusting organism removed were mainly algae, colonial ascidia, polychaeta, bryozoan and small crustaceans.

Abstract Temporary pools are freshwater bodies of significant interest due to their high species diversity, and the colonization and extinction processes observed at temporal scales. The aim of the present study was to perform a short-term ecological comparison in a group of shallow temporary pools in northern Chilean Patagonia in two periods, August and September 2018. The results revealed marked differences in terms of species richness in the study pools at different conductivities and chlorophyll a concentrations. The dominant species was the calanoid copepod Boeckella gracilis Daday, 1902, while the presence of the rare Anostracan Branchinecta rocaensis Cohen, 1982 was reported in conditions of low chlorophyll a and low conductivity. The community was studied using co-occurrence null models that revealed the absence of structured patterns in species associations, and the presence of niche overlap, with many repeated species that have a similar ecological niche. The present results are identical with observations from temporary pools in southern Chilean Patagonia.

RESUMO A fauna bentônica nos córregos do norte da Patagônia é caracterizada pela presença de espécies indicadoras de qualidade da água. O objetivo do presente estudo foi caracterizar as comunidades bentônicas em riachos associados a locais com presença de florestas de Nothofagus e com intervenção humana sem florestas de Nothofagus usando modelos nulos em ecologia, teoria unificada de biodiversidade unificada (UNTB) e método de grupo de par não ponderado com média aritmética (UPGMA). Os resultados do modelo nulo de co-ocorrência de espécies revelaram que as associações de espécies são aleatórias, enquanto os resultados de modelos nulos de sobreposição de nicho revelaram a presença de sobreposição de nicho. Os resultados do UNTB revelaram baixo número de espécies. Os resultados da UPGMA demonstraram que a composição de espécies é específica para cada local, existindo diferenças marcadas. Os resultados expostos concordam com os resultados observados para os rios chileno central e norte da Patagônia, onde a composição das espécies é variável de acordo com as propriedades da bacia circundante e às condições sazonais.

ABSTRACT The benthic fauna in northern Patagonian streams is characterized by presence of water quality indicator species. The aim of the present study was characterized the benthic communities in streams associated to sites with presence of Nothofagus forests and with human intervention without Nothofagus forests using null models in ecology, unified neutral theory of biodiversity (UNTB) and unweighted pair group method with arithmetic mean (UPGMA). The results of species co-occurrence null model revealed that species associations are random, whereas the results of niche overlap null models revealed the presence of niche overlap. The UNTB results revealed low species number. The results of UPGMA revealed that species composition is specific for each site existing marked differences. The exposed results agree with results observed for central and northern Patagonian Chilean rivers, where the species composition is variable in according to surrounding basin properties and seasonal conditions.

Este artigo descreve a frequência e o número de Sphyrion laevigatum da pele de Genypterus blacodes, o qual é um importante recurso econômico no Chile. A análise baseada em modelos de distribuição espacial, demonstrou que os parasitos tendem a ficar agrupados. A variação numérica de parasitas por hospedeiro pode ser descrita por distribuição binomial negativa. O número máximo observado de parasitas por hospedeiro foi dois.

This paper describes the frequency and number of Sphyrion laevigatum in the skin of Genypterus blacodes, an important economic resource in Chile. The analysis of a spatial distribution model indicated that the parasites tended to cluster. Variations in the number of parasites per host could be described by a negative binomial distribution. The maximum number of parasites observed per host was two.

Chilean intertidal copepods have been a littleies studied group, there are isolated reports for the central Chilean coast and island territories. The aim of this study was to analyze intertidal copepod assemblies on Chilean islands territories (Easter Island, San Felix, San Ambrosio, Alejandro Selkirk and Robinson Crusoe islands) and compare them with respect to an area of the continental coastal zone (Montemar, Valparaíso), through null model analysis of species co-occurrence and a cluster analysis. Null model results indicated. for a simulation, the existence of regulatory factors, while two simulations showed no regulatory factors, that would presumably due to the low number of species reported. Moreover, cluster analysis revealed the existence of a core group comprising the islands Alejandro Selkirk, San Felix, and Robinson Crusoe, followed later by Easter Island, and finally Montemar. Ecological topics were analyzed, mainly related with regulation patterns of species richness, as possible explanations for the observed results.

Los copépodos intermareales chilenos han sido un grupo poco estudiado, existiendo reportes aislados para el litoral de Chile central y para territorios insulares. El objetivo del presente estudio fue analizar los ensambles de especies de copépodos intermareales en territorios insulares chilenos (islas de Pascua, San Félix, Alejandro Selkirk y Robinson Crusoe) y compararlas respecto a una zona del continente (Montemar, Valparaíso), por medio de un análisis de modelo nulo de co-ocurrencia de especies y un análisis de conglomerados. Los resultados del modelo nulo indicaron, para una simulación, que hay factores reguladores, mientras que en dos simulaciones no hay factores reguladores, lo que se debería al bajo número de especies reportadas. Por otro lado, el análisis de conglomerados reportó la existencia de un grupo principal conformado por las islas Alejandro Selkirk, San Félix y Robinson Crusoe, seguido después por la isla de Pascua y finalmente por Montemar. Se analizaron tópicos ecológicos, principalmente relacionados con los patrones de regulación de la riqueza de especies, como posibles explicaciones de los resultados observados.

The increased activity of aquaculture in Chile involves cultivation of salmonids, oysters mussels and other species such, and to a lesser extent species such as red abalone (Haliotis rufescens) and Japanese abalone (Haliotis discus hannai). The aim of this study was to evaluate the growth rate of Haliotis rufescens and Haliotis discus hannai fed with different pellet based diets with Macrocystis sp. and Ulva sp., grown in ponds for 13 months. The results for both species denoted that there was an increase in length and biomass during experimental period, existing low growth rates during the austral winter (July-September) and increase during the austral summer (December-January). Results are consistent with descriptions of literature that there is high rate of growth during the summer and using diet of brown algae. From the economic standpoint abalone farming would be an economically viable activity for local aquaculture, considering the water quality and food requirements.

El incremento de las actividades de acuicultura en Chile involucra principalmente cultivo de salmónidos, ostiones, algas, mitílidos y otras especies, y en menor escala especies como los abalones rojo (Haliotis rufescens) y japonés (Haliotis discus hannai). El objetivo del presente estudio fue evaluar el crecimiento de Haliotis rufescens y Haliotis discus hannai alimentados con diferentes dietas a base de pellet Macrocystis sp. y Ulva sp., cultivados en estanques durante 13 meses. Los resultados para ambas especies denotaron que hubo incremento en longitud y biomasa durante el periodo experimental, existiendo bajas tasas de crecimiento durante invierno austral (julio-septiembre) e incremento durante el verano austral (diciembre-enero). Los resultados concuerdan con las descripciones de la literatura en que hay altas tasas de crecimiento durante el verano usando dieta a base de algas pardas. Desde el punto de vista económico el cultivo de abalones sería una actividad económicamente viable para la acuicultura local, si se considera los requerimientos de calidad de agua y alimentación.

The Chilean inland water crustaceans are characterized by a combination of endemic and cosmopolitan species: some occur throughout the territory of continental Chile, while others are restricted to specific latitudinal regions. This study examined the zoogeographical patterns exhibited by Chilean inland water crustaceans. We considered six regions: Northern Chile (18°-27°S), North-Central Chile (27°-30°S), Central Chile (30°-38°S), Northern Patagonia (38°-41°S), Central Patagonia (41°-51°S), and Southern Patagonia (51°-55°S), and these were identified based on literature records of inland water crustaceans. The classification analysis generated dendrograms for the following groups considered in this categories: all inland water crustaceans (Branchiopoda, Copepoda and Malacostraca), the zooplanktonic crustaceans (Branchiopoda and Copepoda), the Malacostraca alone, and each group separately. Analysis of total data and of the zooplankton group taxa alone revealed the existence of a main grouping consisting of the three Patagonian zones plus Central Chile, that is distinct from that of Northern Chile and North-Central Chile. Similarly, analysis of the malacostracan data revealed the existence of two main groups, one comprising the three Patagonian zones plus Central Chile, contrasted with a second group of Northern and North-Central Chile combined. Our results are in agreement with other panbiogeographical studies of South American crustaceans and insects. Possible factors responsible for generating this pattern are the dispersal and colonization potential of zooplanktonic crustaceans and the marked endemism of the malacostracans.

Los crustáceos de aguas continentales chilenas se caracterizan por una combinación de especies endémicas y cosmopolitas, algunas se encuentran a lo largo del territorio de Chile continental, mientras que otras están restringidas a regiones latitudinales específicas. El presente estudio examinó los patrones zoogeográficos exhibidos por crustáceos de aguas continentales chilenas. Se consideraron seis regiones: Norte de Chile (18°-27°S), Norte-Central de Chile (27°-30°S), Chile Central (30°-38°S), Norte de la Patagonia (38°-41°S), Patagonia Central (41°-51°S), y Sur de la Patagonia (51°-55°S), identificadas sobre la base de registros de la literatura de crustáceos de aguas continentales. Los análisis de clasificación generaron dendrogramas para las siguientes agrupaciones consideradas en estas categorías: todas las especies de crustáceos de aguas continentales (Branchiopoda, Copepoda y Malacostraca), crustáceos zooplanctónicos (Branchiopoda y Copepoda), sólo Malacostraca, y cada grupo por separado. El análisis de todos los grupos y de los grupos zooplanctónicos reveló la existencia de un gran grupo con las tres regiones de la Patagonia más Chile central, diferente al de la zona norte y norte-central de Chile. De manera similar el análisis de datos de malacostracos reveló la existencia de dos grandes grupos, uno con las tres zonas de la Patagonia y Chile central, contrastado con un segundo grupo conformado por la zona norte y norte-central. Estos resultados concuerdan con estudios panbiogeográficos de crustáceos e insectos sudamericanos. Como posibles factores responsables podrían ser la dispersión y potencial colonización de crustáceos zooplanctónicos y el marcado endemismo de los malacostracos.

Nematóides do gênero Anisakis têm nos peixes marinhos seus hospedeiros intermediários. Um desses hospedeiros é Thyrsites atun, um importante recurso pesqueiro no Chile entre 38 e 41° S. Este artigo descreve a freqüência e o número de nematóides Anisakis nos órgãos internos de Thyrsites atun. Uma análise baseada em modelos de distribuição espacial demonstrou que os parasitos tendem a ficar agrupados. A variação numérica de parasitas por hospedeiro pôde ser descrita por distribuição binomial negativa. O número máximo observado de parasitas por hospedeiro foi nove. Os aspectos ambientais e zoonóticos desse estudo também serão discutidos.

Nematodes of the genus Anisakis have marine fishes as intermediate hosts. One of these hosts is Thyrsites atun, an important fishery resource in Chile between 38 and 41° S. This paper describes the frequency and number of Anisakis nematodes in the internal organs of Thyrsites atun. An analysis based on spatial distribution models showed that the parasites tend to be clustered. The variation in the number of parasites per host could be described by the negative binomial distribution. The maximum observed number of parasites was nine parasites per host. The environmental and zoonotic aspects of the study are also discussed.