ABSTRACT For a population of locate, Thaisella chocolata, in La Rinconada, Chile, on a grid of 39 stations distributed along three 910 m-long transects at depths of 5 to 18.5 m, Moran and Morisita indices were used to evaluate whether density variations along the depth distribution are related to the stratification of larger sizes at the beginning of their reproductive process. Results indicate that before, during, and after forming reproductive aggregations, there is a T. chocolata increase in density in the shallow stratum (5 to 13 m). This finding is corroborated by the Moran index, which showed a greater autocorrelation in January-May, September-October, and January 2010, and by the Morisita index; thus, it is validated as a potentially easy-to-use indicator for assessing the reproductive process of this species. This index could also alert fishermen to the prevalence of reproductive aggregations in an area and that these aggregations should not be exploited as is currently the case to ensure the reproductive success of this species.

Abstract: The Chilean jack mackerel Trachurus murphyi support an important fishery in the South-eastern Pacific Ocean and has declined considerably over time. T. murphyi have asynchronous ovarian development with an oceanic spawning (September to January). Despite the economic importance of this resource critical issue such as characteristics and dynamics of atresia, which affect the reproductive output, are unknown. Females of T. murphyi caught in different spawning seasons were analysed to describe patterns of prevalence and intensity of atresia. General linear models (GLM) were performed by using prevalence and intensity atresia as response variables and gonadosomatic index, condition factor, sea surface temperature, postovulatory follicles and month/year as explanatory variables. The batch fecundity and relative fecundity were compared between females showing atresia, postovulatory follicles and non-atretic females. The stages of atresia identified were alpha, beta and gamma. The GLM showed that variations in the prevalence and intensity of atresia were explained for all variables, except condition factor for prevalence, and gonadosomatic index for intensity of atresia. According to our results, the dynamic of alpha and beta atresia could be considered a potential proxy for any disruption of spawning season. The batch fecundity and relative fecundity were lowest compared with other Trachurus spp. This is the first assessment comparing fecundity between atretic and not atretic females for this species.

Resumen: El jurel, Trachurus murphyi sustenta una importante pesquería en el Pacífico sureste la que ha declinado considerablemente en el tiempo. T. murphyi tiene un desarrollo ovárico asincrónico con desoves oceánicos (septiembre a enero). A pesar de la importancia económica de este recurso, se desconocen aspectos críticos de su biología, como las características y la dinámica de la atresia, que pueden afectar el rendimiento reproductivo. Hembras de T. murphyi capturadas en distintas estaciones de desove fueron analizadas para describir los patrones de prevalencia e intensidad de atresia. Se realizaron modelos lineales generales (GLM) usando prevalencia e intensidad de atresia como variables de respuesta e índice gonadosomático, factor de condición, temperatura de la superficie del mar, folículos postovulatorios y mes/año como variables predictoras. La fecundidad parcial y la fecundidad relativa se compararon entre hembras con atresia, hembras con folículos postovulatorios y hembras no atrésicas. Las etapas de atresia identificadas fueron alfa, beta y gamma. El GLM mostró que las variaciones en la prevalencia e intensidad de la atresia fueron explicadas por todas las variables, excepto el factor de condición para la prevalencia y el índice gonadosomático para la intensidad de atresia. De acuerdo con estos resultados, la dinámica de alfa y beta atresia pueden considerarse un potencial proxy para cualquier interrupción de la temporada de desove. La fecundidad parcial y la fecundidad relativa fueron más bajas en comparación con otros Trachurus spp. En esta especie, se hace una primera evaluación que compara la fecundidad entre hembras con y sin atresia.

RESUMO: Espécies de Vibrio são ubiquitárias em ambientes aquáticos, incluindo habitats costeiros e marinhos. A espécie Vibrio alginolyticus é oportunista para peixes, crustáceos e moluscos e a sua identificação através de testes bioquímicos pode ter a qualidade prejudicada devido às suas exigências nutricionais. O presente estudo utilizou Espectrometria de Massa por Tempo de Vôo de Ionização/Desorção por Laser Assistida por Matriz (MALDI-TOF MS) para identificar diferentes espécies de Vibrio provenientes de mexilhões (Perna perna) coletados em diferentes locais ao longo da costa do Rio de Janeiro. O gene rpoA foi utilizado como um marcador gênero-específico de Vibrio spp. sendo positivo em todos os 209 isolados. MALDI-TOF MS confirmou 87,75% de V. alginolyticus quando comparados com os resultados dos testes bioquímicos. Quatro isolados foram identificados como Shewanella putrefaciens (8,16%), um como V. parahaemolyticus (2,0%) e apenas um (2,0%) não foi identificado pela técnica proteômica. E o sequenciamento do pyrH confirmou 75% dos resultados da técnica proteomica. MALDI-TOF MS tem sido considerada uma excelente opção para a caracterização bacteriana, por ser eficiente, rápida, de fácil aplicação e este estudo confirmou a sua elevada especificidade e sensibilidade na identificação de bactérias marinhas.

ABSTRACT: Vibrio species are ubiquitous in aquatic environments, including coastal and marine habitats. Vibrio alginolyticus is an opportunistic pathogen for fish, crustaceans and mussels and their identification by biochemical tests may be impaired due their nutritional requirements. The study used Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) to identify 49 Vibrio spp. isolates associated with mussels (Perna perna) from different locations along the Rio de Janeiro coast. The rpoA gene was used as a genus-specific marker of Vibrio spp. and was positive in all 209 isolates. MALDI-TOF MS confirmed 87.8% of V. alginolyticus when compared to the results of the biochemical tests. Four isolates were identified as Shewanella putrefaciens (8.16%) and one was identified as V. parahaemolyticus (2.0%). Just one isolate was not identified by this technique (2.0%). The pyrH sequencing confirmed 75% of the proteomic technique results. MALDI-TOF MS is an excellent option for characterization of bacterial species, as it is efficient, fast and easy to apply. In addition, our study confirms its high specificity and sensitivity in these marine bacteria identification.

O presente estudo avaliou o perfil fenogenotípico de resistência aos antimicrobianos em espécies de Staphylococcus coagulase-negativo (ECN) isoladas do leite de vacas com mastite, em especial considerando a oxacilina. Dos 100 isolados de ECN, S.xylosus foi a espécie predominante, seguida por S. cohnii, S. hominis, S. capitis and S. haemolyticus Apenas 6% dos isolados foram fenotipicamente suscetíveis aos agentes antimicrobianos testados no ensaio de difusão em disco. O percentual de resistência à penicilina e ampicilina foi significativamente maior que aos outros antimicrobianos. Quatro isolados foram positivos para o gene mecA (4%), sendo todos representados pela espécie S.xylosus. O gene blaZ foi detectado em 16% dos isolados (16/100), sendo todos mecA positivos e a presença de ambos os genes foi correlacionada com a resistência fenotípica aos beta-lactâmicos. Foi possível concluir que as espécies de ECN provenientes de leite bovino apresentaram distintos perfis de resistência antimicrobiana, avaliados por testes fenotípicos e genotípicos, podendo dificultar a adoção de medidas de tratamento e manejo dos animais.

The present study evaluated the pheno- and genotypical antimicrobial resistance profile of coagulase-negative Staphylococcus (CNS) species isolated from dairy cows milk, specially concerning to oxacillin. Of 100 CNS isolates, the S. xylosus was the prevalent species, followed by S. cohnii, S. hominis, S. capitis and S. haemolyticus. Only 6% were phenotypically susceptible to the antimicrobial agents tested in disk diffusion assay. Penicillin and ampicillin resistance rates were significantly higher than others antimicrobials. Four isolates were positive to mecA gene (4%), all represented by the S. xylosus species. The blaZ gene was detected in 16% of the isolates (16/100). It was noticed that all mecA + were also positive to this gene and the presence of both genes was correlated to phenotypic beta-lactamic resistance. We conclude that CNS species from bovine milk presented significantly distinct antimicrobial resistance profiles, evaluated by phenotypic and genotypic tests, which has implications for treatment and management decisions.

Limatula chilensis sp. nov. is described on the basis of shell morphology and soft tissue anatomy. Studied individuals were obtained periodically between June 2008 and January 2009 from sublittoral soft-sediments off Punta Coloso in northern Chile at depths of 22 to 33 m. Shell morphology of the new species differs from the 4 described species of Limatula from the Pacific coast of South America and Antarctic Peninsula (5°-65°S). Main characteristics of L. chilensis include an average height of 3.50 mm (range 2.36-4.42, SD ± 0.60, n = 34), number of radial ribs 16-21 (mode = 20, SD= 1.69, n = 8) and greater shell obliqueness. L. chilensis is the only known species of the genus found off northern Chile.

Limatula chilensis sp. nov. se describe en base a la morfología de la concha y tejidos blandos. Los especímenes estudiados se obtuvieron periódicamente entre junio de 2008 y enero de 2009 desde fondos blandos someros submareales en Punta Coloso, norte de Chile, a profundidades entre 22 y 33 m. La morfología de la concha es diferente a la de las 4 especies de Limatula descritas para las costas del Pacífico de Sudamerica y Península Antártica (5º-65ºS). Las características más evidentes de L. chilensis fueron el tamaño 3,50 mm (rango 2,36-4,42, DE ± 0,60, n = 34), número de costillas radiales 16-21 (moda = 20, DE = 1,69, n = 8) y una fuerte oblicuidad de la concha. L. chilensis es la única especie conocida del género, para las costas del norte de Chile.

Se registra Hyperia curticephala (Amphipoda) viviendo en asociación con Chrysaora plocamia (Scyphozoa). Cinco ejemplares de C. plocamia presentaron entre 39 y 328 especímenes de H. curticephala. No hay evidencia estadística de correlación entre diámetro de umbrela y número de anfípodos, gráficamente es evidente una tendencia positiva. H. curticephala debe considerarse microdepredador y no parasitoide como ha sido sugerido para asociaciones entre hypéridos y plancton gelatinoso. Este registro extiende la distribución del anfípodo en aproximadamente 18° de latitud hacia el sur y corresponde al primer registro de un anfípodo asociado con medusas en Chile.

The metazoan parasite fauna of Hippoglossina macrops (n = 123) from northern Chile (30°S) is quantitatively described for the first time, and the role of host age and sex was evaluated. Twelve parasite species were recovered, including 5 ectoparasites (2 Monogenea, 2 Copepoda and 1 Piscicolidae) and 7 endoparasites (1 Digenea, 3 Cestoda, 2 Acanthocephala, and 1 Nematoda). The copepod Holobomolochus chilensis, the monogenean Neoheterobothrium sp., the adult acanthocephalan Floridosentis sp. and the hirudinean, Gliptonobdella sp. are new geographical and host records. The most prevalent ectoparasitic species were the monogenean, Neoheterobothrium sp. and the copepod, H. chilensis. Among endoparasites, the acanthocephalans Floridosentis sp. and Corynosoma australe were most prevalent and abundant. Prevalence and mean intensity of infection for most parasitic species were not affected by host sex, however the prevalence of Floridosentis sp. was significantly greater in males. Intensity of infection was positively correlated with host age for Neoheterobothrium sp., and negatively correlated for Floridosentis sp. and H. chilensis. The helminth species richness of the host H. macrops was lower compared to related flatfishes from the Northern Hemisphere. The relationship of the helminth fauna of H. macrops, its feeding habits and ecological habitats are discussed.

Parasitological analysis of 237 Menticirrhus ophicephalus, 124 Paralonchurus peruanus, 249 Sciaena deliciosa, 50 Sciaena fasciata and 308 Stellifer minor from Callao (Perú) yielded 37 species of metazoan parasites (14 Monogenea, 11 Copepoda, 4 Nematoda, 3 Acanthocephala, 1 Digenea, 1 Aspidobothrea, 1 Eucestoda, 1 Isopoda and 1 Hirudinea). Only one species, the copepoda Bomolochus peruensis, was common to all five hosts. The majority of the components of the infracommunities analyzed are ectoparasites. The Brillouin index (H) and evenness (J´) were applied to the fully sampled metazoan parasite infracommunities. High values of prevalence and mean abundance of infection are associated to the polyonchoinean monogeneans; the low values of J' reinforce the strong dominance of this group in the studied communities. The paucity of the endoparasite fauna may be a consequence of the unstable environment due to an upwelling system, aperiodically affected by the El Niño Southern Oscillation phenomena.

The analysis of density, spatial distribution and gonadic histology of a Thais chocolata population in small bay Punta Arenas (21°38'S-70°09'W), has allowed define certain indicators, which show that the reproductive aggregations would take place in the shallow zone (13-15 m depth) at the same time reported for other populations of this species in northern Chile. The feature that evidence such an event are referred to the aggregated distribution of sexually mature adults in the 13 m and 15 m isobath, a distinct times of the year. Such times are different from these established for the legal veda. Thus, this legal reduction should be restudied in order to protect reproduction of this specie and hence to prevent a potential collapse of the stock in the Regions I and II (18°-26°S), taking into account that the previous fishery in Regions III and IV (26°-32°S) have already collapsed since 1988

El análisis de la densidad, distribución espacial e histología de gónadas de Thais chocolata en caleta Punta Arenas (21°38'S-70°09'W), permitió definir ciertos indicadores que señalan que las agregaciones reproductivas se constituirían en la zona somera (13-15 m de profundidad), en las mismas épocas que se han señalado para otras poblaciones de esta especie de la zona norte de Chile. Los indicadores que evidencian este acontecimiento se refieren a la distribución agregada de organismos adultos sexualmente maduros en los veriles de los 13 m y 15 m, en diferentes épocas del año. La constitución de estas agregaciones en períodos diferentes al de la veda establecida para este recurso obliga el reestudio de esta norma, con el objeto de proteger su reproducción e impedir un eventual agotamiento del stock en las Regiones I y II (18°-26°S), considerando que la pesquería que existía en las Regiones III y IV (26°-32°S) colapsó en 1988

Three species of protistan and 22 species of metazoan parasites were obtained from a sample of 179 flatfish, (Paralichthys adspersus) taken-off Antofagasta, northern Chile. Prevalence of infection of seven parasites (Protista: 1, Copepoda: 2, Digenea: 1, Acantocephala: 1, Nematoda: 2) was significantly and positively correlated with host size. Host's sex do not seem to affect prevalence of infection, except for Nybelinia surmenicola, Capillaria sp. and Anisakis sp. (prevalence of infection significantly greater in males than females) and Philometra sp. (prevalence higher in females). Mean abundance is correlated with size in nine species (Protista: 1, Copepoda: 2, Digenea: 3, Acantocephala: 1, Nematoda: 2). Host's sex do not affect mean abundance, except for Cainocreadium sp. and Philometra sp.(mean abundance higher in females) and Nybelinia surmenicola, Capillaria sp. and Anisakis sp. (mean abundance higher in males).