Abstract The freshwater prawn Macrobrachium jelskii (Miers, 1877) is a species with wide geographical distribution. However, the biological and ecological aspects of this species are poorly studied. Thus, the present study was carried out in Batateiras River, at the municipality of Juazeiro do Norte, located in the south of Ceará, in the semiarid region of northeastern Brazil. Samples were carried out monthly between January and December 2013, along the river margins. A total of 628 M. jelskii specimens were collected, 347 males and 281 females. The overall sex ratio was 1:0.81 (M:F). In relation to the carapace length, males reached sexual maturity at 5.1 mm while females reached morphological sexual maturity at 7.1 mm. Females were morphometrically larger than males, with means of 7.04 mm (± 1.61) and 5.97 mm (± 0.78), respectively. The ovigerous females were more frequent in the rainy season. Female fecundity showed a positive correlation with growth. Thus, our results report previously unknown information about M. jelskii for a semiarid region of northeastern Brazil.

Abstract Freshwater crabs are important components of aquatic ecosystems; however, their distributions are restricted because of characteristics of their life history, which hinder conservation strategies. Fredius reflexifrons is a widely distributed freshwater crab of the Amazon basin with relictual occurrences in small wetlands on the Planalto da Ibiapaba in Northeastern Brazil. Habitat degradation, destruction of forest patches, channeling of water bodies, and the use of land for legume cropping can seriously impact the species by leading to the extinction of its relic populations, which have limited distributions in the Área de Proteção Ambiental (APA; Environmental Protection Area) Bica do Ipu of the Planalto da Ibiapaba. The objectives of this study were to assess the distribution of F. reflexifrons in APA Bica do Ipu, identify the main impacts from anthropic activities, suggest potential actions to mitigate these impacts, besides providing recommendations for the expansion of the APA. Fredius reflexifrons was recorded in eleven sites in the Planalto da Ibiapaba, of which nine are new records and five are not located within the APA. These findings evidence the need of expanding the APA to encompass the newly known distribution of F. reflexifrons in order to assure its protection.