Anesthesia of Epinephelus marginatus with essential oil of Aloysia polystachya: an approach on blood parameters

This study investigated the anesthetic potential of the essential oil (EO) of Aloysia polystachya in juveniles of dusky grouper (Epinephelus marginatus). Fish were exposed to different concentrations of EO of A. polystachya to evaluate time of induction and recovery from anesthesia. In the second experiment, fish were divided into four groups: control, ethanol and 50 or 300 mu L L-1 EO of A. polystachya, and each group was submitted to induction for 3.5 min and recovery for 5 or 10 min. The blood gases and glucose levels showed alterations as a function of the recovery times, but Na+ and K+ levels did not show any alteration. In conclusion, the EO from leaves of A. polystachya is an effective anesthetic for dusky grouper, because anesthesia was reached within the recommended time at EO concentrations of 300 and 400 mu L L-1. However, most evaluated blood parameters showed compensatory responses due to EO exposure.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul/Programa de Apoio a Nucleos de Excelencia (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior, Brazil (CAPES)info:eu-repo/semantics/publishedVersio

Multidecadal fishers’ knowledge reveals overexploitation of sharks in southeastern Brazil

Abstract Assessing the impacts caused by fisheries requires long-term data series and continuous landing monitoring, which are still scarce in several low and middle-income countries. Alternative approaches, such as fishers’ local ecological knowledge (LEK) have been employed to assess the history of marine resources and overcome the challenges of missing data. We documented temporal changes over the last 60 years in small-scale fisheries in Arraial do Cabo, Brazil. Interviews with 155 fishers revealed the capture of six shark species (one genus), all under extinction risk according to the global and the national Red Lists. Among these, Carcharhinus brevipinna, Carcharhinus plumbeus, and Isurus oxyrinchus are commercially important. While LEK suggests an increase in fishing efforts, with new fishing grounds emerging after 2006, the number of individuals caught has decreased over time. Historical shark exploitation has led to substantial declines in the catches of C. plumbeus and C. brevipinna, which have rare occurrences in the region. Although landing data are critical information for building local fisheries management plans and setting conservation strategies, monitoring in the region is discontinuous and should be prioritized by public policies