Resumen.-Los fiordos de la Patagonia chilena, se caracterizan por fuertes gradientes físico-químicos horizontales y verticales que ejercen consecuencias en la distribución y abundancia del ictioplancton. Se recolectaron muestras de plancton mediante arrastre oblicuo con una red bongo en 40 estaciones, a bordo de un crucero bio-oceanográfico en fiordos interiores de la XI región sur de Chile (47° a 51°S). Los datos ambientales de la columna de agua fueron obtenidos mediante un perfilador de conductividad-temperatura-profundidad (CTD), y la turbidez fue medida con un turbidímetro portátil entre 0 y 100 m de profundidad. Las estaciones se distribuyeron por zona oceánica, canales y área de influencia de agua dulce. Se recolectó un total de 1424 larvas, representando 21 familias y 41 taxa. Los taxa dominantes fueron Maurolicus parvipinnis (31%), Sebastes oculatus (12%), Merluccius australis (11%), Lampanyctodes hectoris (10%) y Bathylagichthys parini (8%). La mayor variabilidad ambiental fue dada por la salinidad, principalmente en la zona con descarga de agua dulce. La zona oceánica presento una columna de agua mezclada con la mayor presencia de mictófidos como L. hectoris y peces hacha M. parvipinnis. No hubo un efecto significativo de los gradientes de turbidez sobre los ensambles de larvas de peces durante primavera. La zona de los canales se aprecia una mayor estratificación de la salinidad, densidad y una disminución de la turbidez, donde se distribuyeron en general las especies con menores abundancias. Por lo tanto, es posible definir dos ensambles ictioplanctónicos, uno con influencia oceánica y el otro de canales y zonas interiores.Abstract.-Chilean Patagonian fjords are characterized by strong stratification and chemical gradients which influence the ichthyoplankton distribution and abundance. Plankton samples were collected through bongo net oblique tows in 40 stations from onboard a bio-oceanographic cruise took place in inner fjords of southern Chile (47° to 51°S). Water column physical data were obtained with a conductivity-temperature-depth profiler (CTD) and turbidity was measured with a portable turbidimeter from 0 to 100 m depth. Stations were distributed by three zones: oceanic, channels and continental waters. A total of 1424 larvae were collected, representing 21 families. Dominant taxa were Maurolicus parvipinnis (31%), Sebastes oculatus (12%), Merluccius australis (11%), Lampanyctodes hectoris (10%), and Bathylagichthys parini (8%). Most of the environmental variability was determined by salinity, mainly in the area where continental waters are discharged. The water column in the oceanic zone presented mixed waters dominated by the myctophid L. hectoris and the sternoptychid M. parvipinnis. No significant effect of turbidity gradients on larval fish assemblages was evident during spring. The channel zone was both more saline, and density stratified with less turbidity, and lower abundance of species. Two ichthyoplanktonic assemblages were evident, one living in oceanic waters, and the other from...

The interannual variation

Early life traits (ELT) of the sand-burrowing cryptic marine fishSindoscopus australis(family Dactyloscopidae) were compared between cohorts hatched during winter and spring 2013, in nearshore rocky reefs off central Chile. Pelagic larvae were similarly abundant during both periods, but larger larvae were collected during austral spring. The sagittal otolith microstructure and size analyses also indicated that size-at-hatch was larger (4.7 mm) for the winter cohort, but winter larvae experienced slower growth rates (0.145 mm day−1± 0.008). Conversely, larvae from the spring cohort hatched at smaller sizes (2.9 mm), but they grew faster (0.182 mm day−1± 0.008). Hatching periods were coupled with the lunar cycle; in winter, hatching events were related to neap tides (first and third quarter moon), increasing chances of self-recruitment. Meanwhile, during spring, hatching occurred during spring tides, particularly over the new moon, decreasing chances of larval mortality by predation. Otolith traits used to test asymmetry among cohorts showed inconsistent results. Only sagittal perimeter presented fluctuating asymmetry, showing higher variance for the winter cohort. We conclude that this burrowing species displays different reproductive tactics at a seasonal scale.

ABSTRACT. Austral hake Merluccius australis sustain an important demersal fishery in South Pacific and Atlantic oceans. The main spawning and nursery areas are in the Chilean Patagonia, which is characterized by large inputs of freshwater from rivers and ice melting. The spatial distribution of larval austral hake M. australis was studied during spring, and the potential effects of oceanographic conditions (temperature, salinity, vertical stability and turbidity) on early life traits, derived from sagitta otolith microstructure analysis, size-at-age (SAR), individual larval growth (IGR) and bilateral asymmetry (FA6). Larval abundance ranged between 0.86 and 41.55 ind 1000 m -3 (median: 4.08 ind 1000 m -3) and population larval growth estimated by micro-increment counts of sagitta otoliths was 0.129 ± 0.010 mm d -1 , with age varying from 4 to 24 days old. All three indicators derived from otolith analysis (SAR, IGR, and FA6) showed positive and significant correlations with vertical salinity gradients; IGR and FA6 were also positively correlated to Brunt-Väisälä frequency (vertical stability) and FA6 was correlated to turbidity. Therefore, larval M. australis were larger-at-age, grew faster and showed more asymmetry in areas with more influence of freshwater runoff in south Pacific Patagonia.