Leonardo Airton Ressel Simões

Background/Objectives: Tributyltin (TBT), a potent biocide used in antifouling paints, is highly toxic to aquatic environments, causing oxidative stress, endocrine dysfunction, and metabolic disorders in aquatic organisms, including crustaceans. The blue crab Callinectes sapidus is an economically and ecologically important species in several countries worldwide and is considered an invasive species in Europe. Methods: This study evaluated the effects of 7 days of exposure to environmentally relevant TBT concentrations (100 and 1000 ng.L⁻¹) on the intermediary metabolism and oxidative balance of the blue crab Callinectes sapidus. After exposure, hemolymph samples were analyzed to determine glucose, lactate, total protein, and cholesterol levels. In tissue samples, concentrations of triglycerides, glycogen, total glutathione (GSH), reactive oxygen species (ROS), sulfhydryls, lipid peroxidation (LPO), and glutathione S-transferase (GST) activity were assessed. Results: In the hemolymph, glucose and lactate levels increased, while the total cholesterol, triglycerides, and total proteins decreased in all exposed groups. The GST activity increased in exposed tissues, while the total GSH and sulfhydryl content decreased. The ROS concentration increased in response to higher TBT concentrations. Conclusions: These findings highlight the toxicity of TBT and show that 7 days of exposure to environmentally relevant concentrations disrupts the metabolic homeostasis and oxidative balance in C. sapidus. Additionally, this study demonstrates that C. sapidus is sensitive to TBT exposure and has potential as a model species for ecotoxicological studies.

Ocypode quadrata, a Ghost crab species found along the western Atlantic coast, is considered a bioindicator of anthropogenic impact on sandy beaches. Ghost Crabbing, a touristic activity in which ghost crabs are chased just for fun, is a potentially threatening activity for this crab. In crustaceans, metabolites such as glucose and lactate, and the gene expression of crustacean hyperglycemic hormone (CHH) and heat shock proteins (HSPs) increase when the animals are exposed to several types of stress, including alterations in temperature, salinity, or exposure to xenobiotics. This work was developed to identify if being chased by humans would affect these markers of stress in this species of crab. The effects of chasing stress on hemolymph and tissue metabolites and the gene expression levels of CHH and HSP70 were investigated. The levels of lactate in the hemolymph of stressed crabs were six times higher than those of control crabs immediately after chasing and decreased progressively during recovery, indicating an active anaerobic metabolism during the stress. On the contrary, glucose levels in the hemolymph of the stressed crabs increased progressively from 30 to 60 min after chasing, indicating an inverse correlation between glucose and lactate and the conversion of lactate to glucose by gluconeogenesis. In stressed crabs, the levels of triglycerides in the hemolymph decreased 30 min after chasing, while the opposite tended to occur in the hepatopancreas, indicating that during recovery, the crabs use triglycerides as energy source to sustain aerobic metabolism. Finally, this study demonstrates that ghost crabs are stressed by minimum human contact and that “ghost crabbing” must not be encouraged as a tourist activity.

Amphibians and reptiles play an important ecological role in ecosystems; however, the scarcity of information and superstitions make them ill-treated and at risk of extinction. In this perspective, ethnoherpetology can make contributions, since it is a science that is dedicated to study the interactions between human beings and amphibians and reptiles. In view of this scenario, the objective of this research was to analyze the students' knowledge and perceptions about the herpetofauna. Thus, data were collected through the Free Evocation Test (EVOC), in the month of august 2017. The participating public was composed by 42 students, 21 from the 7th and 21 st 8th years of Elementary School of a public school, located in the municipality of Taquara, RS. Through the EVOC it was possible to observe well defined associations for the animals representative of the herpetofauna, predominating a feeling of fear and danger associated with the reptiles and of repulsion to the amphibians. Therefore, it is possible to conclude that there is still a need to promote studies on the native herpetofauna, in the scope of Basic Education, so that it can be respected and valued.

The Sinos River basin is impacted by industrial and agricultural activities, as well as by low rates of urban wastewater treatment. The purpose of this study was to monitor de Sinos River water quality using the micronucleus test in fish and the analysis of water physicochemical parameters. Bryconamericus iheringii specimens were captured in December 2013 (summer) and July 2014 (winter) at two sites located in the Sinos River: Caraá, in the upper section of the basin, and Parobé, in the middle section. After capture, animals were immediately killed and blood samples were collected for the micronucleus test. No significant differences were observed in micronucleus frequencies between sites and sampling periods. However, in the summer, nuclear abnormalities frequencies observed in Parobé were significantly higher than in Caraá. A higher frequency of nuclear abnormalities was also found in fish captured in Caraá during winter, in comparison with frequencies found in the summer. The results for the water physicochemical analysis showed values of total phosphorous, aluminum, lead, copper and iron above the allowed limits established by the Brazilian legislation. The nuclear abnormalities induction found in the present study may be associated to the presence of cytogenotoxic substances in the water.