A short-term Jolly–Seber mark-recapture model experiment is described. This experiment was aimed at estimating the rate of catch per unit effort (CPUE) and the catchability coefficient (q) of the Atlantic blue crab (Callinectes sapidus) in the fishing port of Sisal, Yucatan, Mexico. To estimate the local population size, 52 traps were deployed along four transects located in a coastal capture area of 3600 m−2. The CPUE and q were compared between the daily mark-recapture Jolly–Seber experiment and the bi-monthly (carried out every 2 months) samplings. The average abundance was estimated at 3475 individuals. All three suggested scenarios, applied to estimate densities, gave similar estimates, i.e. 0.0386, 0.0350, 0.0365 crabs m−2 for the first (Previously Cited Attraction Radius), second (CPUE per transect) and third (Catchability-Density Relationship), respectively. Based on the latter scenario, densities ranged from 27,900 (annual average) to 36,500 (Spring) crabs km−2. The average CPUE of the daily mark-recapture experiment was estimated at 1.96 crabs trap−1, whereas the average bi-monthly CPUE was estimated at 1.13 crabs trap−1. The q (per trap) was estimated at 0.0186 for the daily mark-recapture experiment and at 0.0247 for the bi-monthly sampling. Both catchability and CPUE increased in individuals whose size ranged between 110 and 170 mm CW. However, no significant difference (ANCOVAs) was found between the daily and bi-monthly samplings neither in CPUE nor in catchability. The use of both mark-recapture data and the Jolly–Seber model proved to be a fast and reliable method for estimating the abundance and catchability of Atlantic blue crab.

The genetics and ecology of pumas are well documented in North America but there is a lack of studies in South America, especially in Brazil. By means of a noninvasive method, faecal DNA analysis, we estimated puma abundance in two protected areas embedded in a human-disturbed landscape in the north-east of São Paulo state, in south-east Brazil. In 8 months of mark–recapture faeces sampling, 15 individual pumas were identified using seven microsatellite loci. The estimated abundance of pumas with the Jolly–Seber open population model was 23.81 ± SE 6.22. This is the first estimate of the abundance of pumas in a human-dominated landscape in São Paulo state, the most populous, developed and industrialized state of Brazil. The absence of high-quality habitats in the north-east of the state, the absence of direct competitors and the high availability of prey in protected areas are probably contributing to the high number of pumas concentrated in a relatively small area (c. 260 km2). Our results will contribute to the long-term monitoring of this puma population and, combined with other ecological, behavioural and genetic data, will help guide conservation action to maintain a viable population of the puma in this region.