Leonardo Castro

• PhD
• University of Concepción

The effect of the combination of marine toxins produced by algal blooms, in conjunction with varying environmental characteristics on organisms in the water column, is a poorly explored research field. Pelagic fish species of commercial importance, such as anchoveta (Engraulis ringens) in central Chile, may be exposed to these combined factors in a...

El objetivo general del estudio fue evaluar el stock desovante de anchoveta (Engraulis ringens) y sardina común (Strangomera bentincki) durante el período de máxima actividad reproductiva, en el área comprendida entre las regiones de Valparaíso y de Los Lagos, al mismo tiempo evaluar las condiciones oceanográficas durante este proceso. El crucero d...

High-latitude marine environments, such as the Beagle Channel, are highly vulnerable to modifications related to climate change and anthropogenic impacts, which can rapidly affect the ecological attributes of plankton communities and thus alter ecosystem trophodynamics. This study compares the mesozooplankton community structure in the inner and ou...

Off the central-southern Chilean coast (35°–38°S), the Gulf of Arauco is one of Chile's largest semi-enclosed coastal areas. It hosts industrialized activities within a highly productive zone of the Southern Humboldt Current System. One of the principal hydrodynamical forcings of the region is the Biobio River, whose discharge significantly influen...

Se presentan resultados del proyecto “Evaluación del stock desovante de anchoveta y sardina común entre las regiones de Valparaíso y Los Lagos, año 2021”, cuyo objetivo general fue evaluar el stock desovante de los recursos anchoveta y sardina común durante el período de máxima actividad reproductiva. Además, se entregan resultados de las condicion...

Zooplankton is the primary production consumer in the aquatic food web in fjords and channels of western Patagonia. In this study, the role of vertically migrating and not-vertically migrating crustacean mesozooplankton (collected in a 300 μm mesh net) as potential consumers of spring phytoplankton was assessed in an inshore gulf of central Patagon...

Patagonian grenadier migrates from the southwest Atlantic and southeast Pacific to reproduce in the northern Chilean Patagonia. Spawning occurs mainly in winter at the continental shelf break (CSB), but eggs and larvae are also collected inshore of the Chilean Patagonian Estuarine System (PES) during winter and spring. In order to evaluate whether...

Forage fish play the crucial role of transferring energy from lower to upper trophic levels. These small pelagic fish feed on plankton and can compete with each other for food, leading to potentially complex interactions. Three forage fish species (Sprattus fuegensis, Strangomera bentincki, and Engraulis ringens) are commonly found in the inshore w...

Aplicar un enfoque holístico para evaluar los factores asociados a la sobrevivencia en los estadios tempranos de anchoveta y su relación con los forzantes ambientales en áreas recurrentes de crianza entre las regiones de Arica y Parinacota y Antofagasta, considerando la variabilidad espacio temporal de la zona. Objetivo específico 1: Caracterizar...

Obbjetivo General: Aplicar un enfoque holísico para evaluar los factores asociados a la sobrevivencia en los estadios tempranos de anchoveta y su relación con los forzantes ambientales en áreas recurrentes de crianza entre las regiones de Arica y Parinacota y Antofagasta, considerando la variabilidad espacio temporal de la zona.

Seasonal variation in the acoustic presence of blue whale calls has been widely reported for feeding grounds worldwide, however variation over the submonthly scale (several days to <1 month) has been examined to a much lesser extent. This study combines passive acoustic, hydroacoustic, and in situ oceanographic observations collected at a mooring i...

In southern Patagonia, the Beagle Channel shows very low production during winter but simultaneously sustains very dense aggregations of the pelagic stage of squat lobster (Munida gregaria), a benthic decapod whose pelagic juveniles have the largest body size within the chitinous pelagic community. To assess the coexistence of the mesozooplankton c...

In habitats impacted by bottom trawling that influences the resilience of few and widely distributed abundant species, it is relevant to analyze how populations are structured according to their niche and niche overlap, and hence contributing to the ecosystem-based management approach. We evaluated and compared the isotopic niche width and determin...

The Southern Ocean plays a major role in the Earth’s climate, provides fisheries products and help the maintenance of biodiversity. The degree of correspondence between physical and biogeochemical spatial variability and regionalization were investigated by calculating the main physical factors that statistically explained the biogeochemical variab...

The squat lobster Munida gregaria is considered a key species within food webs of sub-Antarctic ecosystems of South America, and represents a fundamental link between detritus and higher-level predators. Although ecological aspects of its lengthy pelagic phase have been well described, those of the benthic stage remain poorly understood, particular...

The southern hake, Merluccius australis , is one of the most important marine fishery resources in Chilean Patagonia. However, little is known about its early life history, especially the transport of eggs and larvae and the connectivity between spawning and nursery areas. An individual-based model (IBM) of the early life stages of M. australis, co...

The Inland Sea of Chiloé is a semi-enclosed sea of northern Patagonia characterized by freshwater inputs from a fjord in the north and high influence of offshore waters in its southern sub-basin. The zone has been referred to as an important fish nursery ground. In order to assess its relevance as a spawning ground and the strategies for temporal c...

The alternation of the classic and microbial food-webs in spring and winter, respectively, and the trespass towards higher trophic levels represented by fish early stages, are not well understood in Patagonia. These trophic routes were investigated in the inner Sea of Chiloe, an estuary of high ecological relevance in northern Patagonia. The isotop...

El objetivo general del estudio fue evaluar el stock desovante de anchoveta (Engraulis ringens) y sardina común (Strangomera bentincki) durante el período de máxima actividad reproductiva, en el área comprendida entre las regiones de Valparaíso y de Los Lagos, al mismo tiempo evaluar las condiciones oceanográficas imperantes durante este proceso. P...

We compared the isotopic (δ¹³C, δ¹⁵N) signals in particulate organic matter (POM), small sized copepods, exogenous feeding larvae, and anchoveta (Engraulis ringens) eggs and adults, in relation to oceanographic characteristics during this species’ reproductive season (late winter – spring, 2016 and 2017) in two spawning zones along the Humboldt Cur...

The daily egg mortality (Z) of small pelagic fish can be modulated by environmental variables as well as by population derived factors such as egg production and/or dispersion and aggregation processes. The anchovy daily egg mortality rate was compared across spawning areas distributed in the North (18∘25’S-26º03’S), Central (34º30’S-37º10’S), and...

As a result of climate change, the frequency of glacial lake outburst floods (GLOF) is increasing in Chilean Patagonia. Yet, the impacts of the flood events on the physics and biology of fjords is still unknown. Current velocities, density, in-situ zooplankton samples, and volume backscatter (S v) derived from an acoustic profiler were used to expl...

The Peruvian anchoveta Engraulis ringens is one of the most important commercial fishes along the Humboldt Current. Previous studies have shown that egg quality (volume, protein and lipid content) and hatching rates decrease during the spawning season, from the rainy winter to late spring. In this study, we assessed whether changes in atmospheric c...

The anchoveta (Engraulis ringens) is widely distributed throughout the Humboldt Current (4°30′-44°S). In recent years, its eggs and larvae have also been found inside fjords and channels of northern Patagonia, close to the southern limit of the central-south Chilean fishery zone. Currently, it is unclear whether these southern individuals constitut...

Evaluación del stock desovante de anchoveta y sardina común entre la V y X Regiones, año 2018 SUBSECRETARÍA DE ECONOMÍA Y EMT, Octubre 2019

We determined whether maternally influenced early life history traits varied for anchoveta eggs spawned in 2 contrasting environments: off northern (Iquique 23° S) and central (Talcahuano 36° S) Chile. Using eggs collected in the field, we showed that free amino acid contents, specific gravity, and vertical distributions of eggs in the water column...

Merluccius australis, known as southern hake, is a demersal fish that inhabits waters off the southern tip of South America. The main spawning area has historically been located in the Outer Sea off northern Chilean Patagonia, where these fish aggregate to reproduce during austral winter. An alternative spawning ground has been reported to occur wi...

It is relevant to understand the processes and factors that modulate the efficiency of the carbon pump throughout the ecosystem of Patagonian fjords. Spatial variability of primary productivity and bacteria-microplankton biomass was assessed in relation to inorganic nutrients and stratification across nearshore zones of southern Patagonia (50–53°S)...

The aggregation of plankton species along fjords can be linked to physical properties and processes such as stratification, turbulence and oxygen concentration. The goal of this study is to determine how water column properties and turbulent mixing affect the horizontal and vertical distributions of macrozooplankton along the only northern Patagoni...

The anchoveta (Engraulis ringens) and sardine (Strangomera bentincki) are coastal pelagic species with important spawning areas off the coast of Chile. The discharge of secondary-treated effluents from a kraft pulp plant near one of these spawning areas has raised environmental concerns. Therefore, effluent effects on the development of anchoveta a...

In recent decades, the distribution of the very abundant squat lobster, Munida gregaria, a key species in the Beagle Channel and southernmost Patagonian waters, has widened towards lower latitudes. The general objective of this study was to assess how early life stages of this species cope with changes in environmental conditions at sites within it...

Glacial lake outburst floods (GLOFs) in Northern Patagonian Ice Field affecting the Baker River basin have increased their frequency in recent years. To evaluate the impact of a GLOF in the hydrography and biological components of the plankton in the Baker Fjord, we assessed the relative contributions of terrigenous versus marine plankton carbon so...

The Puyuhuapi Fjord is an atypical fjord, with two mouths, located in northern Patagonia (44.7° S). One mouth lies to the south, close to the Pacific Ocean, whilst the second connects with the Jacaf Channel to the north where a shallow sill inhibits deep water ventilation contributing to the hypoxic conditions below ~ 100 m depth. Acoustic Doppler...

The southernmost Patagonian region constitutes a major glaciered area with a high freshwater input loaded with particulate and dissolved matter. We assessed the relevance of the terrestrial (allochthonous) and marine (autochthonous) matter that permeates into the fjord and channel system and their possible impact on the euphausiid-based food web. A...

Patagonian sprat (Sprattus fuegensis) is an important forage fish species along the southern tip of South America. We determined the isotopic composition (δ13C and δ15N) and trophic position of Patagonian sprat for two zones in the North Chilean Patagonia: the Inner Sea of Chiloé (42–45°S) and the Southern Channels (channels north of the Taitao Pen...

The finding of a late flexion cetomimid specimen of 24.6 mm body length (BL), plus a caudal streamer of 5.7 mm, collected in the southeastern Pacific near the Juan Fernandez seamounts (33.565°S; 77.710°W), is reported. The specimen was in good condition, almost fully pigmented, covered by small melanophores from the head to the caudal streamer, whe...

It has been proposed that current levels of ultraviolet B (UVB) radiation could cause lethal or sublethal effects on fish embryos located in the upper layers of the water column. Observed levels of UVB off central Chile (36°S, 73°W) indicate that planktonic fish embryos could be exposed to harmful UVB radiation. From July 2011 to January 2012 embry...

INFORME FINAL PROYECTO FIP 2005-13 EVALUACIÓN HIDROACÚSTICA y TS DE ALFONSINO y ORANGE ROUGHY

Informe Final Fondo de Investigacion Pesquera FIP 2006-09

Volume backscatter (Sv) derived from an acoustic profiler was used to explore the response of zooplankton abundance to a glacial lake outburst flood (GLOF) and to periodic deepening of the stratified layer in a Patagonia fjord. River discharge during the GLOF increased almost three-fold from 770 m3/s to 2200 m3/s. This pulse enhanced the gravitatio...

The study area encompasses the Puyuhuapi fjord (300 m depth) and Jacaf channel (200-400 m depth), located at ∼44° S in Patagonia. The Puyuhuapi fjord is connected to the open ocean by two mouths, where at one mouth, a shallow sill inhibits ventilation of deep fjord water. This study is aimed to improve our understanding of the zooplankton distribut...

The objective of this study was to estimate the surface flux of crustacean larvae at three points along the Baker/ Martinez fjord complex, Chilean Patagonia, during the season of maximum river discharge. Concurrent acoustic Doppler current profiler (ADCP) and zooplankton surveys were conducted along three across-channel transects spanning 58 km alo...

This study combined towed ADCP measurements with plankton and CTD profiling to evaluate residual circulation and plankton fluxes at 3 sections along the Baker/Martinez fjord complex in Chilean Patagonia, during the season of maximum river discharge (austral summer, February 2013). Although the Baker river is the largest in Chile, and its influence...

During 2010 several massive salp outbreaks of the Subantarctic species Ihlea magalhanica were recorded in the inner sea of Chiloé Island (ISCh, Southern Chile), affecting both phytoplankton abundance and salmon farmers by causing high fish mortality. First outbreaks were recorded during February 2010 when Ihlea magalhanica reached up to 654,000 ind...

During 2010 several massive salp outbreaks of the Subantarctic species Ihlea magalhanica were recorded in the inner sea of Chiloé Island (ISCh, Southern Chile), affecting both phytoplankton abundance and salmon farmers by causing high fish mortality. First outbreaks were recorded during February 2010 when Ihlea magalhanica reached up to 654,000 ind...

Freshwater inputs are major drivers of circulation, hydrographic structure, and productivity patterns along estuarine systems. We assessed the degree to which meroplankton community structure in the Baker/Martinez fjord complex (Chilean Patagonia, 47.5°S) responds to spatial and temporal changes in hydrographic conditions driven by seasonal changes...

The fjords and channels of the Chilean Patagonia are unique, and their high biological diversity is mainly associated with physicochemical characteristics of local water masses. The topography, depth, and extension of the Patagonian basins affect the extent to which water is exchanged between the inner and outer parts of the fjords, determining the...

Neuromast morphology and distribution are characterized during early ontogeny of anchoveta (Engraulis ringens) and common sardine (Strangomera bentincki). Although both species share morphological features, they show several differences during their early ontogeny, such as size at hatching and yolk absorption. Larvae were obtained from incubation o...

Neuromast morphology and distribution are characterized during early ontogeny of anchoveta (Engraulis ringens) and common sardine (Strangomera bentincki). Although both species share morphological features, they show several differences during their early ontogeny, such as size at hatching and yolk absorption. Larvae were obtained from incubation o...

Patagonian fjord systems, and in particular the fjords and channels associated with the Baker/Pascua Rivers, are currently under conspicuous natural and anthropogenic perturbations. These systems display very high variability, where limnetic and oceanic features overlap generating strong vertical and horizontal physicochemical gradients. The CIMAR...

Variations in the rate of embryonic malformations of the anchoveta Engraulis ringens in a spawning area off central–southern Chile were assessed. Eggs in stages of development subsequent to blastodisc formation were collected and preserved. Several severe malformations were identified and grouped by: (1) proliferation of disorganized tissue in earl...

Vertical distribution of microzooplankton and fish larvae was studied in a Patagonian fjord from Chile. Zooplankton collection, including larvae of the sprat Sprattus fuegensis (Clupeidae) and the lightfish Maurolicus parvipinnis (Sternoptychidae) were collected during a 25 h period inside Steffen fjord (47°S) during November 2008, using stratified...

Distribution of microplankton and fish larvae related to sharp clines in a Patagonian fjord Distribución del microplancton y larvas de peces relacionadas a clinas abruptas en un fiordo Patagónico Abstract.-Vertical distribution of microzooplankton and fish larvae was studied in a Patagonian fjord from Chile. Zooplankton collection, including larvae...

Zooplankton time series collected with different temporal resolution and coverage were examined to characterize seasonal and diel patterns in the abundance of Munida gregaria larvae and juveniles in the Baker river estuary. Zoeae were more abundant in late winter and spring, coinciding with the season of lower sediment transport and higher primary...

Pleuroncodes monodon is a conspicuous component of the Humboldt Current ecosystem. Benthic adults south of ∼22°S are associated with low temperature (T) ∼11°C and low dissolved oxygen (DO) (<0.5 mL L−1) waters during the hatching period. Because P. mondon inhabits an oxygen minimum zone and larval release is assumed to match most favorable environm...

Squat lobster populations found in the Humboldt Current System over the continental shelf from ~28 to 37°S release pelagic larvae in sub-surface cold (~11 °C) hypoxic waters. Larvae subsequently spread throughout the water column encountering both normoxic and hypoxic conditions. We analyzed some short- and long-term responses of Pleuroncodes monod...

This study reports changes in ascorbic acid (AA) in anchoveta eggs, copepods and zooplankton during the 2006, 2007 and 2009 main spawning seasons in the coastal area of the central Humboldt Current System, Chile. Anchoveta eggs, copepods and total zooplankton community shared a seasonal variation and an increasing trend in AA concentration from win...

Vertical distribution of fish larvae can be modified by a series of physical processes occurring in the water column at different time and spatial scales and also by biological processes occurring during larval development. To assess the factors affecting the vertical distribution of larval anchoveta Engraulis ringens during austral spring, meteoro...

Intense fishing mortality generates changes in marine populations and ecosystems, and an increase in the sensitivity to environmental changes. Fishery-induced demographic changes are the main mechanisms involved due to truncation of age structure of a population trough selective removal of larger and older fish from a population. As a consequence,...

Variability in Chilean hake reproductive tactics off central Chile was assessed by analyzing ichthyoplank-ton samples from nine oceanographic cruises (1996–2005) and through experimental trials with early life stages (eggs, yolk-sac larvae) during the main (austral spring) and secondary (late summer–early autumn) spawning seasons. Abundant eggs in...

Along the Humboldt Current System, the anchoveta (Engraulis ringens) is distributed between 4oS and 42oS. Environmental conditions differ markedly both between spawning areas and seasonally. Hence, different reproductive tactics are expected in response to the environment. Here we used information from Daily Egg Production Method surveys to study l...

In this study, we determined variations in ascorbic acid (AA) concentrations in the gonads and liver, and of the innate immune response (lysozyme activity and antiprotease) in the plasma of Engraulis ringens (anchoveta) and Strangomera bentincki (common sardine) during their reproductive seasons of 2007 and 2008 in the central area of the Humboldt...

In order to determine the changes in the relative importance of different kinds of preys as larval anchoveta Engralis ringens grows, the present study reports information about feeding incidence, type, size, and carbon content estimates of preys, at the beginning of the main spawning season in mid-winter off central Chile. Our results show a mixed...

The relationships between the distribution of different zooplankton and ichthyoplankton stages and physicalandchemicalvariableswerestudiedusingsamplesanddata(CTDprofiles,ADCPandcurrent meter measurements,nutrients,mesozooplankton,ichthyoplankton)obtainedfromdifferentstrata during two24-hcyclesattwooceanographicstationsinaChileanPatagoniangulfduring...

Two research cruises (CIMAR 13 Fiordos) were conducted in the N–S oriented macrobasin of the Moraleda Channel (42–47°S), which includes the E–W oriented Puyuhuapi Channel and Aysen Fjord, during two contrasting productive seasons: austral winter (27 July–7 August 2007) and spring (2–12 November 2007). These campaigns set out to assess the spatio-te...

To determine the beginning and end of the transition period from larvae to juveniles in anchoveta Engraulis ringens, seven morphometric measurements were carried out in 333 laboratory-reared and 324 field-caught larvae. Measurements of body morphometrics were employed to calculate the six body ratios selected to show transition changes described in...

Fatty acids • Anchovies • Fish eggs • Upwelling • Egg volume • Humboldt Current We assessed the fatty acid (FA) composition of anchoveta eggs collected from the plankton along with female anchoveta reproductive traits and environmental conditions during peak winter spawning in 2005 and 2007. Environmental conditions differed markedly between years...

This study assesses the spatial and temporal variations in eggs and larval distributions of Engraulis ringens and Strangomera bentincki during their peak and secondary spawning periods, in the zone adjacent to the Itata River mouth, Chile. The information on abundance and distribution of the early life stages of both fish species was obtained from...

The variability of spatial and temporal distribution of early stages of the mote sculpin Normanichthys crockeri from the upwelling ecosystem off central Chile was examined using a series of six oceanographic cruises, otolith-based larval growth, and experimental trials. Adults spawned year-round in surface waters near capes and inside bays along ce...

Se examinó la variabilidad en la distribución espacial y temporal de los estados tempranos del mote Normanichthys crockeri en el ecosistema de surgencias de Chile central, utilizando la información de una serie de seis cruceros oceanográficos, crecimiento larval basado en otolitos, y experimentos de desarrollo embrional. Los adultos desovan durante...

This study assesses the spatial and temporal variations in eggs and larval distributions of Engraulis ringens and Strangomera bentincki during their peak and secondary spawning periods, in the zone adjacent to the Itata River mouth, Chile. The information on abundance and distribution of the early life stages of both fish species was obtained from...

The distribution of gelatinous carnivorous zooplankton off central Chile (35-37°30′S) was assessed during upwelling conditions in spring 2001 using stratified zooplankton sampling. The hydromedusa Liriope tetraphylla (54.2 ind. m -2), siphonophore Sphaeronectes gracilis (16.5 ind. m -2) and ctenophore Pleurobrachia bachei (52.1 ind. m -2) were the...

To describe and quantify morphological abnormalities during the embryonic development of Strangomera bentincki an area nearby the Itata River mouth was sampled during the reproductive season 2007. Abnormality levels (3-13%) were coincident with reported levels for other Clupeids species inhabiting areas with similar environmental characteristics to...

We assessed the ontogenetic changes in protein content and free amino acids (FAA) in eggs and early larvae of Engraulis ringens (anchoveta) off central Chile on different dates during the spawning season. On all sampling dates, a reduction in embryonic yolk-sac volume, proteins and FAA concentrations occurred during development. Protein electrophor...