Reintroduction has been recognized as a powerful conservation tool, but in order to ensure its success, animal monitoring is highly recommended. One way to monitor released animals is to put radiotelemetry collars on them. These devices, however, can harm the subjects, causing serious wounds. Our objectives in this work were to describe the injuries caused by a radiotelemetry collar model on reintroduced agoutis and to propose modifications to it. We equipped agoutis with TXE-311C radio collars (Telenax Wildlife Telemetry) before releasing them in the wild. They acquired serious wounds and one animal died. We then modified the collar structure to reduce its width and retention of water. After these modifications, the injuries did not occur again. As reintroduction is an expensive conservation strategy, any improvement that maximize its probability of success is important. We believe that the improvements we propose here have the potential to enhance the success of reintroductions and to increase animal welfare. This recommendation is more important when captive animals are re-introduced, because they tend to have lower immunity, particularly when they are released in rainy habitats.

O ambiente físico dos rios apresenta diversos desafios para os organismos que vivem sob sua influência. A velocidade da água, um dos fatores mais importantes a atuar nesses ambientes, tem influência local no substrato, temperatura e oxigenação da água. A força da correnteza age determinando a distribuição das espécies e as adaptações morfológicas e comportamentais dos organismos. O objetivo desse estudo foi abordar o tamanho relativo das brânquias de Cloeodes jaragua em dois meso-habitats: um ambiente lêntico (represa) e um ambiente lótico (áreas de correnteza) no Parque Nacional da Serra dos Órgãos - RJ. Um total de 20 indivíduos foi coletado em cada tipo de ambiente e as larguras da cabeça e brânquias foram medidas. O ambiente lêntico apresentou ninfas com medidas mais largas e mais constantes que o ambiente lótico. Este último, apesar de ser composto por ninfas em diferentes estágios de desenvolvimento, apresentou indivíduos com menores larguras de brânquias. Ambos, largura da cabeça e tipo de ambiente, explicaram o tamanho das brânquias, mostrando as condições dos habitats dos rios como importantes modeladores da morfologia desses animais.

Physical environment of streams present many challenging factors to the organisms living under its influence. Water speed, one of the most important factors affecting such environments, has local influence on substrata, temperature, and oxygen levels. It acts determining species distributions and morphological and behavioral adaptations of organisms. The aim of this study was to assess the relative size of gills of Cloeodes jaragua on two mesohabitats: lentic environment (river dam) and lotic environment (fast flowing area of a stream) in Parque Nacional da Serra dos Órgãos (RJ, Brazil). Twenty individuals were collected on each environment and width of the head and gills were taken. Lentic environment showed nymphs with broader and more constant measurements than the lotic environment. The former, despite being composed of nymphs on different stages of development, presented individuals with narrower gills. Both, head width and environment type explained gills size, showing that streams habitat conditions are important in shaping the morphology of these animals.