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16 pages, 9 figures, 3 atbles ; The objective of the present study was to describe histological development of the European long‐snouted seahorse Hippocampus guttulatus, to increase understanding of the biology and physiology of the species. Most vital organs were present in juveniles by the time of their release from the male's pouch. Digestive tract specialization occurred at 89 effective day‐degrees (D°eff), corresponding to 15 days post partum (dpp), with development of the first intestinal loop and mucosal folding. At 118 D°eff (20 dpp), lipids were being mobilized from the liver and oocytes attained the perinuclear stage. The fovea emerged at 177 D°eff (30 dpp), contemporaneous with the shift from pelagic to benthic behaviour in juveniles. At this stage, the most interesting feature was the formation of the second intestinal loop. Male gonads were never observed during the study (from 0 to 354 D°eff; 0–60 dpp), but the first oogonia were present at 30 D°eff (5 dpp). In 354 D°eff (60 dpp) juveniles, oocytes were observed in a cortical alveoli stage, indicating maturity. Low digestive efficiency was observed at early stages, which was due to a poorly developed gastrointestinal tract and an immature digestive tract prior to 89 D°eff. The present study demonstrates that approximately 89 and 177 D°eff represent two important transitional stages in the early development of H. guttulatus. At a temperature of approximately 19 ± 1°C and an age of 1 month (177 D°eff), main organs were fully functional, suggesting that the adult phenotype was largely established by that age, with females becoming mature at the age of 2 months (354 D°eff) ; This study was partially financed by the European Union (Erasmus traineeship) and by a grant awarded by the Spanish Ministry of Education, Culture and Sport within the Campus do Mar International program, University of Vigo ; Peer reviewed

14 pages, 4 figures, 1 table, supplementary data https://doi.org/10.1016/j.scitotenv.2021.151359 ; The metabolism of contemporary industrialized societies, that is their energy and material flows, leads to the overconsumption and waste of natural resources, two factors often disregarded in the global ecological equation. In this Discussion article, we examine the amount of natural resources that is increasingly being consumed and wasted by humanity, and propose solutions to reverse this pattern. Since the beginning of the 20th century, societies, especially from industrialized countries, have been wasting resources in different ways. On one hand, the metabolism of industrial societies relies on non-renewable resources. On the other hand, yearly, we directly waste or mismanage around 78% of the total water withdrawn, 49% of the food produced, 31% of the energy produced, 85% of ores and 26% of non-metallic minerals extracted, respectively. As a consequence, natural resources are getting depleted and ecosystems polluted, leading to irreversible environmental changes, biological loss and social conflicts. To reduce the anthropogenic footprint in the planet, and live in harmony with other species and ourselves, we suggest to shift the current economic model based on infinite growth and reduce inequality between and within countries, following a degrowth strategy in industrialized countries. Public education to reduce superfluous consumption is also necessary. In addition, we propose a set of technological strategies to improve the management of natural resources towards circular economies that, like ecosystems, rely only upon renewable resources ; This study received Portuguese national funds from FCT (Foundation for Science and Technology) through project UID/04326/2020 and the Stimulus of Scientific Employment, Individual Support Call, 2017 (CEECIND/03072/2017). It also received funds from the Centre d'Estudis Antoni de Capmany and the Spanish government through the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S). Federico Demaria is a Serra Hunter fellow and acknowledges support from the Maria de Maeztu Unit of Excellence ICTA UAB (CEX2019-0940-M), and the projects 'EnvJustice' (GA 695446) and PROSPERA (GA 947713), both funded by the European Research Council (ERC). Claudia Ofelio is Research Associate at Hamburg University within the framework of the project CUSCO (FKZ:03F0813B). The Thermal Engineering and Energy Systems (GITSE) research group T55_20R received funds from the Aragonese Government (Department of Science, University and Knowledge Society) ; Peer reviewed