Gustavo Chiang

Biochemical and behavioral responses in the estuarine polychaete Perinereis gualpensis (Nereididae) after in situ exposure to polluted sediments.

In situ translocation experiments are advantageous relative to traditional laboratory experiments, particularly for understanding the bioavailability of trace metals like mercury (Hg). Individuals of the polychaete Perinereis gualpensis were translocated from a reference site (Raqui estuary, Chile) to an estuarine site with significant sediment Hg concentrations (Lenga estuary: 1.78-9.89 mg/kg). Individuals were exposed in polluted and non-polluted sediments for 21 days and sampled every 7 days with cages deployed at three different depths. Tissue Hg concentrations were measured in conjunction with oxidative stress responses. Translocated polychaetes rapidly accumulated Hg. Glutathione S-transferase (GST) activities measured from posterior body regions were 2-fold higher than control activities after 21 days of exposure. Other antioxidant measures were idiosyncratic. Distinct burrowing behavior differences were observed; control polychaetes exhibited more homogenous vertical distributions, whereas in Lenga, worms tended to remain in upper layers. These studies demonstrate that under natural conditions, Hg is highly bioavailable to polychaetes affecting both biochemical and behavioral responses after relatively short-term exposure.

Estrogenicity and intersex in juvenile rainbow trout (Oncorhynchus mykiss) exposed to Pine/Eucalyptus pulp and paper production effluent in Chile

Pulp and paper mill effluents (PPMEs) have been shown to increase gonad size, cause early maturation, and disrupt hormone functions in native and non-native Chilean fish. In this study, we assessed reproductive (plasma vitellogenin; VTG, gonad development) and metabolic (ethoxyresorufin-O-deethylase activity; EROD) end points, relative liver size (LSI) and condition factor (K) of juvenile female and male rainbow trout exposed to effluents. Unlike previous studies, which have focus either on the specific effects of effluent on fish in laboratory exposures or biotic population statuses downstream of discharge sites, we simultaneously assessed the impacts of PPMES on trout using two approaches: (1) laboratory exposures of tertiary treated PPME produced from processing Eucalyptus globulus or Pinus radiata; and (2) in situ bioassay downstream of the combined discharge of the same pulp mill. Despite an increase in the average gonadosomatic index (GSI) in exposed fish, no statistical differences in gonad size between exposed and unexposed individuals was detected. However, both female and male fish exposed to effluents showed significantly higher concentrations of plasma VTG, so more in fish exposed to Eucalyptus-based effluent when compared to Pinus PPME. In addition, male fish showed intersex characteristics in all exposure assays (Eucaliptus and Pinus) and, despite the low concentration of effluent in the river (<1% [v/v]), similar responses were observed in the caged fish. Finally, EROD activity was induced in both in situ exposures and laboratory assays at the higher PPME concentration (60-85% PPME). This study confirms estrogenic effects in Chilean fish exposed to PPME and the necessity for biological effects monitoring in addition to the assessment of physical-chemical endpoints as required in current government regulations.

Liver ethoxyresorufin-O-deethylase and brain acetylcholinesterase in two freshwater fish species of South America; the effects of seasonal variability on study design for biomonitoring

Responses at low levels of biological organization to evaluate environmental changes and water quality have been used for many years. South America is no different, and recently biochemical endpoints in fish have been used to assess the impacts of industrial and sewage effluents on wild fish populations. For Chilean native freshwater fish, basic biological data is scarce and data on 7-ethoxyresorufin-O-deethylase (EROD) and Acetylcholinesterase (AChE) activity is practically absent. Moreover, extensive variation in these two biochemical endpoints exists among species and seasons. In this article we evaluate seasonal variation in liver EROD and brain AChE activities in Trichomycterus areolatus and Percilia gillissi, two widely distributed native freshwater fish species in central Chile. We observed a marked seasonality in hepatic EROD activity in both species, with maximums for P. gillissi during winter months and sex differences in February, July, August and December. T. areolatus showed no sex differences, and peaks in EROD activity in the middle of summer, winter and late spring. Species differences in EROD activity were observed with activity being 1-2 orders of magnitude higher in P. gillissi compared to T. areolatus. Scarce seasonal variation and no sex related differences in brain AChE for both species were observed. Multivariate analysis (PCA) indicated that physical water quality parameters had some degree of responsibility for the seasonal responses found. The seasonal variability data of these biochemical endpoints were used to optimize study design for future monitoring programs, planning timing of sampling, increasing statistical power by collecting specific sample sizes required.

Persistent organic pollutants and porphyrin levels in excreta of penguin colonies from the Antarctic Peninsula area

Persistent organic pollutants (POPs) and their effects on Antarctic seabirds by using excreta as a non-destructive biomonitoring tool have received little consideration. Here we determine the levels of polychlorinated biphenyls (PCBs) and some organochlorine pesticides such as dichlorodiphenyltrichloroethanes (DDTs), hexachlorobencene (HCB), heptachlor, and endrin aldehyde in penguin excreta. Animal exposure to these environmental contaminants was determined through porphyrins in penguin droppings. Stool samples of Adélie penguin (Pygoscelis adeliae), chinstrap penguin (Pygoscelis antarctica) and gentoo penguin (Pygoscelis papua) were collected on two locations of the Antarctic Peninsula area: Base OH́iggins (Antarctic Peninsula) and Ardley Island (King George Island). Despite POPs have been banned more than three decades ago, the levels (ng g−1 ww) of PCBs (1.45-2.35), DDTs (1.33-1.76), HCB (0.51-1.70), endrin (0.48-0.71) and heptachlor (0.97-2.40) showed that these pollutants are still present in Antarctica. Porphyrin levels in excreta (4.6-6.7 nmol g−1 dw) were significantly correlated to POPs, indicating certain chemical exposure on penguin colonies that inhabit the Antarctic Peninsula area. The levels of heptachlor found in penguin guano may be affecting some biota in terrestrial sites next to nesting places. Further studies and better understanding of POPs impact on animal performance in Antarctic biota are recommended.

Characterizing Chilean blue whale vocalizations with DTAGs: a test of using tag accelerometers for caller identification

ABSTRACT Vocal behavior of blue whales (Balaenoptera musculus) in the Gulf of Corcovado, Chile, was analysed using both audio and accelerometer data from digital acoustic recording tags (DTAGs). Over the course of three austral summers (2014, 2015 and 2016), seventeen tags were deployed, yielding 124 h of data. We report the occurrence of Southeast Pacific type 2 (SEP2) calls, which exhibit peak frequencies, durations and timing consistent with previous recordings made using towed and moored hydrophones. We also describe tonal downswept (D) calls, which have not been previously described for this population. As being able to accurately assign vocalizations to individual whales is fundamental for studying communication and for estimating population densities from call rates, we further examine the feasibility of using high-resolution DTAG accelerometers to identify low-frequency calls produced by tagged blue whales. We cross-correlated acoustic signals with simultaneous tri-axial accelerometer readings in order to analyse the phase match as well as the amplitude of accelerometer signals associated with low-frequency calls, which provides a quantitative method of determining if a call is associated with a detectable acceleration signal. Our results suggest that vocalizations from nearby individuals are also capable of registering accelerometer signals in the tagged whales DTAG record. We cross-correlate acceleration vectors between calls to explore the possibility of using signature acceleration patterns associated with sounds produced within the tagged whale as a new method of identifying which accelerometer-detectable calls originate from the tagged animal. Summary: Characterization of the Chilean blue whale vocal repertoire and a modified method of using DTAG accelerometers to identify calling blue whales.

Persistent organic pollutants and porphyrins biomarkers in penguin faeces from Kopaitic Island and Antarctic Peninsula

Polychlorinated biphenyl (PCB) levels were determined in the faeces of three Antarctic Peninsula penguin species to assess viability as a non-invasive approach for sampling PCBs in Antarctic biota. These determinations were complemented with stable isotope and porphyrins assessments, and together this methodology determined the role of diet and metabolic disruption in penguins. Up to 60% of the collected faecal samples evidenced low molecular weight PCBs, of which, the more volatile compounds were predominant, in agreement with previous results. The highest PCB levels were reported in the gentoo penguin (Pygoscelis papua; 35.3ngg-1 wet weight average), followed by the chinstrap (Pygoscelis antarctica; 6.4ngg-1 wet weight average) and Adélie penguins (Pygoscelis adeliae; 12.9ngg-1 wet weight average). Stable isotope analyses (δ15N and δ13C) demonstrated that gentoo feeding and foraging habits differed from those of Adélie and chinstrap penguins. A strong positive correlation was found between PCB concentrations and δ15N, indicating the role of diet on the observed pollutant levels. Porphyrins metabolite levels were also directly correlated with PCB concentrations. These results suggest that PCB levels impair the health of Antarctic penguins.

Blue whales of the Chiloé-Corcovado region, Chile: Potential for anthropogenic noise impacts

Blue whales (Balaenoptera musculus spp.) were once abundant in the Southern Hemisphere, but commercial whaling hunted them to near extinction in the previous century. The species is currently listed as endangered on the IUCN Red List of Threatened Species. The Chiloe-Corcovado region in Chile is one of the most important areas in the Southern Hemisphere for blue whales since it functions as a feeding and nursing ground. In recent years, ship traffic has increased considerably in the area and noise pollution is a major concern. We review what is known about blue whales in this area, and also about potential effects of noise on their communication and behavior. Since we still know so little about the functions of blue whale vocalizations, and since reactions to various kinds of anthropogenic noise can be so variable, further research is required to understand the biological implications of the effects of ship noise on blue whale communication and overall fitness in the Chiloe-Corcovado region.

Regional Cumulative Effects Monitoring Framework: Gaps and Challenges for the Biobío River Basin in South Central Chile

La gestion sustentable de las cuencas hidrograficas en el mundo es problema que ha tomado una gran relevancia y atencion, en terminos de calidad y disponibilidad de agua para todos los usuarios de las cuencas. El crecimiento economico experimentado por Chile en los ultimos anos ha llevado a un aumento en el estres a los sistemas acuaticos continentales, especialmente la cuenca del rio Biobio. La cuenca del rio Biobio ha enfrentado un gran aumento en el desarrollo de hidroelectrico, y al mismo tiempo ha tenido que proveer los recursos para demandas hidricos que compiten entre si, como son la urbanizacion, agricultura e riego, forestal, acuicultura, turismo, recreacion, asi como ser parte del territorio de los pueblos originarios. Existe una creciente inquietud sobre el proceso actual de gestion de proyectos individuales con procesos individuales de Evaluacion de Impactos Ambientales (EIA). La evaluacion de los impactos de todas estas amenazas a los ecosistemas dulceacuicolas es un reto no menor. El rio Biobio ofrece una oportunidad para avanzar en una serie de areas importantes para la gestion regional de cuencas, incluyendo los requisitos nacionales de normalizacion para la vigilancia de los efectos y para el desarrollo de una base de datos regional. Para la cuenca del rio Biobio, el desarrollo de un marco conceptual como este requiere de varios pasos que incluyen la identificacion de: el alcance (cuenca y / o subcuenca) y el area de gobernanza (fisiograficas / geopolitica de gobierno); las amenazas al sistema (pasado, presente y futuro); los usuarios regionales de recursos, asi como los servicios publicos involucrados; la variacion natural y gradientes dentro del sistema. En esta revision planteamos los estudios piloto y criterios clave necesarios para ayudar a disenar un Marco Regional de Monitoreo de Efectos Acumulativos, incluyendo la seleccion de especies (sensibilidad diferencial de especies), los parametros a evaluar (nivel de organizacion), la magnitud del cambio que deseamos para detectar, asi como la frecuencia de monitoreo necesario para garantizar la gestion sustentable de la cuenca del rio Biobio.

DTAG studies of blue whales (Balaenoptera musculus) in the Gulf of Corcovado, Chile

This investigation set out to obtain data on the ecology, foraging and acoustic behavior of Chilean blue whales (Balaenoptera musculus) in the Gulf of Corcovado, which is an important feeding ground. We deployed 17 suction cup attached sound and orientation recording tags (DTAGs) on blue whales in 2014-16, for a total duration of 124h 08 min. Acoustic data on the tags revealed a variety of different calls. These included SEP2 (Southeast Pacific) song, previously described in this area, as well as other call types not previously described for Chilean blue whales. Downsweep calls similar to those described for other blue whale populations were observed on several tags, as were various other less stereotyped calls. We are currently working on characterizing these call types and also on using the accelerometers to identify calls from the tagged animal. Tag data will prove useful for interpretation of data collected in this area from passive acoustic monitors (PAM), both for species identification and possibly...

Seasonal changes in oocyte development, growth and population size distribution of Percilia gillissiand Trichomycterus areolatus in the Itata basin, Chile

Existen escasos datos de biologia basica sobre las especies de peces nativas chilenas de agua dulce y casi ninguno en sobre el crecimiento, el desarrollo gonadal y reproduccion, que son fundamentales para los propositos de la conservacion de sus poblaciones naturales. El analisis estacional de los parametros sub-individuales (desarrollo de oocitos) y poblacionales (frecuencia de tallas y tasa de crecimiento) en Trichomycterus areolatus y Percilia gillissi fueron evaluados entre febrero de 2007 y enero de 2008.El desarrollo de los oocitos posee una marcada estacionalidad en P. gillissi con oocitos maduros en octubre y una disminucion de estos estados maduros hacia enero. En T. areolatus encontramos oocitos maduros en Julio, pero con una mayor abundancia durante octubre, coincidente con datos previos de maximo desarrollo de la gonada. Ambas especies mostraron una estrategia reproductiva de desoves multiples, con una temporada de desove que comienza en primavera hasta principios de verano. Ambas especies evidencian un mayor numero de juveniles durante mediados de la estacion estival (P. gillissi), finales de la estacion estival (T areolatus) y principios de otono, con un numero decreciente hacia primavera. Los juveniles tienen un coeficiente de crecimiento (K) mayor (0.56-0.38 mm mes-1) comparados con los adultos (0.29-0.15 mm mes-1), y antes de primavera practicamente todos los individuos en la poblacion alcanzan la madurez (>50 mm for T areolatus and >40 mm for P. gillissi) y los juveniles son incorporados a la poblacion en una nueva fase de reclutamiento. El conocimiento de la variabilidad estacional de estas respuestas individuales (desarrollo de oocitos) y poblacionales (frecuencia de tallas, tasas de crecimiento) puede ayudarnos a un mejor entendimiento de la biologia de las especies, y simultaneamente mejorar el manejo y conservacion de la biota dulceacuicola.