Determination of 17<i>α</i>-Methyltestosterone in Freshwater Samples of Tilapia Farming by High Performance Liquid Chromatography

17α-methyltestosterone is used to induce the sex reversal of Tilapia sp. to obtain cultures mono-sex to an economically viable. This practice may lead to environmental contamination and problems in human health. Therefore methods need to be developed to detect residues of 17α-methyltestosterone in aqueous matrices. A simple high-performance liquid chromatographic method using ultraviolet detection (245 nm) and testosterone as internal standard has been developed for the monitoring 17α-methyltestosterone in freshwater samples of tilapia aquaculture. The method described involves limited sample preparation as it includes a filtration followed by a single solid-phase extraction step using C18 cartridge. Validation data indicated that the HPLC-UV method for 17α-methyltestosterone determination in the concentration range of 50 - 2000 μg/L provided good linearity, sensitivity, accuracy and precision. Method performance was efficiently applied to monitoring the freshwater samples of fish ponds and the surrounding aquatic channels.

Sea Turtle Nesting: What Is Known and What Are the Challenges under a Changing Climate Scenario

The rate of climate change experienced globally in recent decades may compromise sea turtles’ survival;especially temperature increase, which is particularly fast, impacts life history characteristics, such as temperature-dependent sex determination (TSD), late maturity and sea turtles highly migratory nature. This review aims to identify and summarize the information that has been collected from 2009-2020 in order to aid future empirical studies that seek to fill these and other knowledge gaps, and subsequently assist conservationists in making multilevel decisions to protect sea turtle populations and species. In a summarized way the general knowledge acquired so far on the influence of environmental abiotic and biotic factors on nesting behaviour and hatching, emergence and survival successes of sea turtle hatchlings, was gathered. To accomplish this work, a search on Web of Science, Science Direct, NCBI/PubMed, and Google Scholar was carried out using the terms “sea turtles + climate change”. Published articles in the period 2009-2020 were selected, related to the nesting ecology of 5 species of sea turtles: Caretta caretta, Eretmochelys imbricata, Dermochelys coriacea, Chelonia mydas, Lepidochelys olivacea. Emphasis was also placed on geographical information and on population location (e.g. climatic conditions during the nesting season). These articles (N = 126) were analysed giving relevance to researcher’s data interpretations, comparisons with other researches, and the reached conclusions. An attempt was made to represent all 5 species of sea turtles when selecting articles on each of the environmental factors that influence sea turtle nesting: temperature, humidity, nesting substrate, gases, depth of the nest, sea surface temperature (SST), nest location on the beach, nesting phenology and geographic distribution of nesting habitats. The interaction between these parameters and their consequences on the terrestrial phase of reproduction are presented and discussed.

The Poorly Known Northeast Atlantic Regional Management Unit for Loggerhead (Caretta caretta)

Loggerheads are distributed by ten Regional Management Units (RMUs) worldwide. The Atlantic Ocean houses three of these: the Northwest, Southwest and Northeast RMUs. The most studied is, so far, the Northwest RMU, but the other two have focused attention of researchers. In contrast, marine turtles from the African Atlantic region (Southeast) belong to a complex but little-known region. What is their role in the Atlantic? Are these RMUs connected? To understand these questions, research was made of reports and publications concerning the Northeast Atlantic (NEA) RMU. The asymmetry in information and available knowledge about NEA is high when compared to other RMUs. This demonstrates that there is still a lack of conservation programs besides Cape Verde, and that there is difficulty in transforming data (nesting ecology, molecular, telemetry, etc.) into publications. However, this issue is evident for other marine turtle species of East African Atlantic. There is a need for better scientific support, to enable local conservation programs to deliver data in reports, and even scientific publications. There are so many aspects of loggerhead’s life cycle that will only be unravelled by more and better supported studies. This is a paper that, by analysing the available information of the NEA loggerhead RMU, reflects the following steps to address in loggerhead conservation for the African Atlantic coast.