Can the Herbicide Dicamba Produce Oxidative Stress in the Native South American fish Jenynsia lineata at Environmentally Relevant Concentrations?

Dicamba (DIC) is one of the most applied auxin herbicides worldwide. Sublethal effects in the South American native fish Jenynsia lineata exposed to DIC concentrations close to environmental concentrations (0.03-30 µg/L) during 48 h were analysed thorough the evaluation of catalase (CAT), glutathione S-transferase (GST), superoxide dismutase (SOD) activities and malondialdehyde (MDA) and H2O2 levels for detecting potential oxidative stress. In gills MDA increased showing oxidative damage probably because of an inefficient antioxidant defense. This response evidenced the important role of gills as an organ of direct contact with waterborne contaminants. In addition, other changes in the biomarkers of oxidative stress were observed such as the inhibition of SOD activities in brain and the inhibition of GST in liver. These results show that short- term exposures to environmentally relevant concentrations of DIC could induce sublethal effects in native fish.

Alternative Conservation Paradigms and Ecological Knowledge of Small-Scale Artisanal Fishers in a Changing Marine Scenario in Argentina.

We studied conservation paradigms of small-scale artisanal fishers and other actors involved in the conservation of the Bahía Blanca Estuary (BBE)-a Southwestern Atlantic estuary under anthropogenic pressures (conservationists, NGOs, individuals in the private sector and the port consortium). We focused on the relationship between fishers and non-human entities (e.g., animals, tides, lunar cycles, etc.) from alternative conservation paradigms according to Pálsson's schema (orientalism, paternalism, communalism). We also explored the ecological knowledge of fisher communities to identify possible conservation strategies. Using an ethnographic approach, we identified communalism as the dominant paradigm within the fisher communities as opposed to the paternalistic and orientalist approaches of conservationists and industry employees in the BBE. Fishers demonstrated a broad knowledge on the effects of climate change on fish stocks and pollution on ocean environments and biota, which gillnets avoid catching juveniles and threatened species, and landscape changes over the long-term period, among others areas that could be useful for conservation of these changing coastal ecosystems. We conclude that understanding local perspectives and practices is essential for a democratic exchange among different bodies of knowledge to conserve marine ecosystems.

A baseline study of microplastics in the burrowing crab (Neohelice granulata) from a temperate southwestern Atlantic estuary.

Growing evidence has demonstrated that microplastics (MPs) are available for a wide range of marine organisms, with filter-feeding bivalves and crabs being especially vulnerable. The crab Neohelice granulata is considered a key and structuring species in the Bahía Blanca Estuary (BBE) (SW Atlantic) and its ecological role makes this species especially vulnerable to several pollutants. In this study, male specimens of N. granulata and water samples were collected at three sites in the BBE for the presence of MPs. Different types of MPs were found in all the crabs and the water column samples, although the most frequent were fibers <500-1500 µm, mainly blue. This is the first study to identify MPs in the gills and digestive tract of N. granulata. Moreover, gills presented higher total abundances of MPs than the digestive tract, which suggests that in this case the main uptake of MPs would be by adherence to the gills.