Juan José Alava

Habitat-based PCB environmental quality criteria for the protection of endangered killer whales (Orcinus orca).

The development of an area-based polychlorinated biphenyl (PCB) food-web bioaccumulation model enabled a critical evaluation of the efficacy of sediment quality criteria and prey tissue residue guidelines in protecting fish-eating resident killer whales of British Columbia and adjacent waters. Model-predicted and observed PCB concentrations in resident killer whales and Chinook salmon were in good agreement, supporting the models application for risk assessment and criteria development. Model application shows that PCB concentrations in the sediments from the resident killer whales Critical Habitats and entire foraging range leads to PCB concentrations in most killer whales that exceed PCB toxicity threshold concentrations reported for marine mammals. Results further indicate that current PCB sediment quality and prey tissue residue criteria for fish-eating wildlife are not protective of killer whales and are not appropriate for assessing risks of PCB-contaminated sediments to high trophic level biota. We present a novel methodology for deriving sediment quality criteria and tissue residue guidelines that protect biota of high trophic levels under various PCB management scenarios. PCB concentrations in sediments and in prey that are deemed protective of resident killer whale health are much lower than current criteria values, underscoring the extreme vulnerability of high trophic level marine mammals to persistent and bioaccumulative contaminants.

Polychlorinated Biphenyls and Polybrominated Diphenyl Ethers in Galapagos Sea Lions (Zalophus wollebaeki)

Concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) were measured in muscle-blubber biopsy samples from 21 Galapagos sea lion (Zalophus wollebaeki) pups that were live captured in the Galapagos Islands (Ecuador) using gas chromatography/high-resolution mass spectrometry. Only traces of PBDEs were detected in one male pup, whereas PCDDs and PCDFs were not detected in any sample. The total concentration of PCBs (ΣPCB) in the pups averaged 104 μg/kg lipid (range, 49-384 μg/kg). No statistically significant differences in ΣPCB were observed among the four study sites in the Galapagos Islands. Concentrations of PCB congeners in Galapagos sea lion pups were dominated by low-molecular-weight congeners. These results suggest that global transport is the main source for PCBs in Galapagos sea lions. The ΣPCB levels were below immunotoxic and endocrine-disruption thresholds in pinnipeds, suggesting a limited risk of adverse health effects. The present study indicates that Galapagos sea lions can serve as a useful sentinel of pollutants with a long-range transport capacity and that Galapagos Islands are not exempt from the threats of global pollutants despite its remote locale.

In hot soup: sharks captured in Ecuador's waters

Sharks never stop growing and neither does the Asian demand for sharkfin soup. Ecuador is one nation of many that feeds the demand for fins, and fishers there catch more than 40 different shark species. But shark catches have been considerably underreported worldwide. Until the 2005 update of fisheries data, the United Nations Food and Agriculture Organisation (FAO) did not report elasmobranches for Ecuador, indicating that the Ecuadorian government did not report on these species. This study reconstructs Ecuadors mainland shark landings from the bottom up from 1979 to 2004. Over this period, shark landings for the Ecuadorian mainland were an estimated 7000 tonnes per year, or nearly half a million sharks. Reconstructed shark landings were about 3.6 times greater than those retroactively reported by FAO from 1991 to 2004. The discrepancies in data require immediate implementation of the measures Ecuadorian law mandates: eliminating targeted shark captures, finning and transshipments, as well as adoption of measures to minimise incidental capture. Most of all, a serious shark landings monitoring system and effective chain of custody standards are needed.

PBDE flame retardants and PCBs in migrating Steller sea lions (Eumetopias jubatus) in the Strait of Georgia, British Columbia, Canada

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in blubber biopsy samples from 22 live-captured Steller sea lions (Eumetopias jubatus) that had just entered the Strait of Georgia, British Columbia, Canada, for their overwintering feeding season. ∑PBDE ranged from 50μgkg(-1) (lipid weight) in adult females to 3780μgkg(-1) in subadult individuals. ∑PCBs ranged from 272μgkg(-1) in adult females to 14280μgkg(-1) in subadult individuals. While most PBDE and PCB congeners were transferred through milk to pups, PCBs with logK(OW)>7.0 (PCBs 206, 207, 208 and 209) appeared constrained, resulting in a lighter mixture in pups compared to adult females. The ratio of individual PCB congeners by metabolic group (Groups I, II, III, IV and V) to PCB-153 regressed against length of males suggested poor biotransformation of these compounds (slopes did not differ from zero, p>0.05). PBDE congeners 49, 99, 153 and 183 appeared bioaccumulative (slopes of ratio BDE/PCB 153 versus length were higher than zero, p<0.05), but the dominance of the single congener, BDE-47 (64% of total PBDEs), likely due in part to debromination pathways, reduced our ability to explore congener-specific dynamics of PBDEs in these pinnipeds. With 80% of our Steller sea lions exceeding a recent toxicity reference value for PCBs, the fasting-associated mobilization of these contaminants raises concerns about a heightened vulnerability to adverse effects during annual migrations.

Climate change–contaminant interactions in marine food webs: Toward a conceptual framework

Climate change is reshaping the way in which contaminants move through the global environment, in large part by changing the chemistry of the oceans and affecting the physiology, health, and feeding ecology of marine biota. Climate change-associated impacts on structure and function of marine food webs, with consequent changes in contaminant transport, fate, and effects, are likely to have significant repercussions to those human populations that rely on fisheries resources for food, recreation, or culture. Published studies on climate change-contaminant interactions with a focus on food web bioaccumulation were systematically reviewed to explore how climate change and ocean acidification may impact contaminant levels in marine food webs. We propose here a conceptual framework to illustrate the impacts of climate change on contaminant accumulation in marine food webs, as well as the downstream consequences for ecosystem goods and services. The potential impacts on social and economic security for coastal communities that depend on fisheries for food are discussed. Climate change-contaminant interactions may alter the bioaccumulation of two priority contaminant classes: the fat-soluble persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), as well as the protein-binding methylmercury (MeHg). These interactions include phenomena deemed to be either climate change dominant (i.e., climate change leads to an increase in contaminant exposure) or contaminant dominant (i.e., contamination leads to an increase in climate change susceptibility). We illustrate the pathways of climate change-contaminant interactions using case studies in the Northeastern Pacific Ocean. The important role of ecological and food web modeling to inform decision-making in managing ecological and human health risks of chemical pollutants contamination under climate change is also highlighted. Finally, we identify the need to develop integrated policies that manage the ecological and socioeconomic risk of greenhouse gases and marine pollutants.

Mercury accumulation in sediments and seabird feathers from the Antarctic Peninsula

In an effort to assess the impact of mercury in the Antarctic Peninsula, we conducted ecotoxicological research in this region during the summer of 2012 and 2013. The objectives were to assess: (a) mercury levels in sediment samples; (b) mercury accumulation in Antarctic seabird feathers: Catharacta lonnbergi (brown skua), Pygoscelis papua (gentoo penguin) and Pygoscelis antarctica (chinstrap penguin); and (c) biomagnification (BMF predator/prey) and biota sediment accumulation (BSAF skuas/sediment) factors. Mercury concentrations in sediment were relatively low. Mercury concentrations were significantly higher in brown skuas and gentoo penguins than in chinstrap penguins (2012), and significantly higher in brown skuas than in both penguins (2013). BMF indicated 2-7.5 times greater mercury levels in brown skuas than in penguins. BSAF values suggested an apparent temporal decrease of 18.2% of this ratio from 2012 to 2013. Long-range environmental transport is the likely route of entry of mercury into the Antarctic Peninsula.

Ecología poblacional, distribución y estudio de hábitat de Crocodylus acutus (Cuvier, 1807) en la “Reserva de producción de fauna manglares El Salado” del estuario del Golfo de Guayaquil, Ecuador

An assessment on the population ecology, distribution and habitat of the American crocodile (Crocodylus acutus) was conducted within the recent protected area ?Reserva de produccion de fauna manglares El Salado?, Gulf of Guayaquil, Ecuador. The study was developed along 15 km of mangrove channels and tidal creeks, using nocturnal spotlight boat surveys during the dry season (September to December, 2004). About four crocodiles, with a relative abundance of 0.45 ind./km, ranging 0.27?0.63 ind./km, were detected. Crocodiles were aggregated in the final extreme of a tidal creek (Estero Plano Seco), where the water salinity ranged 10.0?28.0 psu and releasing of effluents (>32.0°C) from electric power plants and run-off from urbanized centers have been evidenced. Most of the crocodile sightings occurred during low tide. The population was represented only by adults (50%) and juveniles (50%); subadults and hatchlings were not observed during the study period. The population density found in this study is one of the lowest densities for American crocodile in the American regions. The euryhaline ability and tolerance to inhabit elevated surface water temperature (thermoconformer) confirm the physiological adaptation of this reptile species. More ecologic and population studies are needed to elucidate some gaps and the environmental factors influencing on the species conservation, as well as the establishment of management strategies to ensure its survival.

Modeling PCB-bioaccumulation in the Bottlenose Dolphin ( Tursiops truncatus ): estimating a dietary threshold concentration.

An individually based (IB) model to predict PCB concentrations in the bottlenose dolphin population of Charleston, SC, USA, was developed with the aim to gain a better understanding of the bioaccumulation behavior and health risk of dietary PCBs across the population and their prey. PCB concentrations predicted in male and female bottlenose dolphin were in good agreement with observed tissue concentrations corroborating the reliability of the model performance and its utility in gaining a more complete view of risk. The modeled cumulative distribution of ΣPCB concentrations for the population with a breakdown into juvenile, adult male, and female subclasses ranged from 3600 to 144,400 ng/g lipid with 66% to >80% of the population exceeding the established threshold for adverse health effects of 17,000 ng/g lipid. The model estimated that a dietary PCB concentration not exceeding 5.1 ng/g wet wt would be required to reach a condition where 95% of the population would have tissue levels below the health effect threshold. The IB model for PCBs in bottlenose dolphins provides a novel approach to estimating the maximum acceptable dietary concentration for PCBs, a central and important factor to protect these apex predators. The model also enables effective prediction of concentrations in dolphins from fish contaminant surveys which are logistically easier and less costly to collect.

Carbon productivity and flux in the marine ecosystems of the Galapagos Marine Reserve based on cetacean abundances and trophic indices

RESUMEN El rol de los cetaceos en la productividad y flujo de energia en los ecosistemas marinos es escasamente conocido en el Pacifico sureste. Este estudio propone estimar la produccion secundaria y terciaria de cinco especies de cetaceos representativos de diferentes ecosistemas marinos de las Galapagos usando calculos asociados de valores anuales de produccion primaria y flujo de carbono, estimaciones de abundancia relativa, biomasa, densidad absoluta y niveles troficos disponibles en la literatura. De acuerdo a las ecuaciones propuestas para el calculo de productividad, se obtuvo que el cachalote (Physeter macrocephalus) y la orca carnivora-generalista (Orcinus orca) tuvieron el valor mas bajo de produccion terciaria al nivel de depredador tope para regiones del oceano abierto sin afloramientos, mientras que las ballenas de Bryde (Balaenoptera edeni) y azul (B. musculus) alcanzaron los valores mas altos de produccion terciaria (13,7 y 35,4 gC m-2 yr-1, respectivamente) en zonas de afloramientos localizadas al oeste y suroeste de las Islas Galapagos. La produccion primaria anual se correlaciono significativamente con las producciones terciarias de ballenas barbadas y odontocetos, usando un nivel de transferencia de energia del 15%. Cuando se combino a las especies de cetaceos considerados en este estudio, se encontro una correlacion positiva, pero no significativa entre la produccion primaria anual y la produccion terciaria de cetaceos. Esta relacion fue influenciada por los diferentes niveles troficos en la cadena alimenticia y los valores anuales de productividad primaria de cada uno de los ecosistemas marinos seleccionados. Mas investigacion es requerida para determinar la abundancia, seleccion de presas, tasa alimenticias, y tasas de hundimiento de material fecal proveniente de mamiferos marinos en aguas marinas de las Galapagos, asi como su funcion en el flujo vertical de carbon.

First Documented Record of Nesting by the Olive Ridley Turtle (Lepidochelys olivacea) in Ecuador

ABSTRACT We report on the first confirmed occurrence of Lepidochelys olivacea nesting in Ecuador based on the presence of eggshells and the identification of a late-stage embryo at a beach located in Manta (lat 0.94°S, long 80.7°W), Manabí Province, Ecuador, in October 2004. This is the second-most-southerly record of olive ridley nesting on the Pacific coast of South America.