The global population of jaguars Panthera onca has decreased significantly since the beginning of the 20th century. Given the scarcity of demographic and biological information, estimating population parameters is critical for the design of conservation measures. The jaguar's elusive behaviour makes it impossible to estimate and monitor populations by direct observation. We propose a non-invasive genetic sampling approach and demonstrate its potential for large-scale monitoring. Sex identification was optimized for faecal samples of jaguars and other felids. We also optimized a set of 11 microsatellite markers for reliable identification of individuals. We estimated the effectiveness of faecal sample genotyping in two distinct Brazilian biomes: the Pantanal and the semi-arid Caatinga. Almost 90% of the samples that were molecularly identified as jaguar (n = 90) were successfully genotyped and were assigned to 30 individuals. Genetic diversity was generally high but was significantly lower in the Caatinga population. We show that non-invasive genetic sampling can be a reliable tool to study population parameters and to monitor the genetic status of jaguar populations in different habitats. It may also be useful for future surveys of jaguars that address ecological, behavioural and conservation issues, and could provide a baseline for non-invasive genetic studies of other wild felid populations.

Restoration of shellfish populations is becoming an increasingly common practice worldwide, as natural fisheries succumb to pressures of overharvesting, habitat loss or degradation, and challenges from invasive competitors and pathogens. Primary genetic concerns relevant to shellfish restoration projects are reviewed, using the cupped oysters Crassostrea gigas and Crassostrea virginica as case studies. Molecular genetic tools can be used to delineate the geographic distribution of germ plasm diversity at the species and intraspecific levels, enabling more informed selection of genetic material for hatchery breeding and production. Maintenance of genetic variability and prevention of excessive inbreeding in hatchery stocks may be facilitated by the use of genetic markers for regular pedigree monitoring. The effect of hatchery supplementation on the effective population size of a recipient wild population (Ryman-Laikre effect) is reviewed in light of the population biology of bivalve molluscs, and appears to be minimal. Deployment of selected enhancement stocks may be a valuable tool for improvement of degraded wild populations, reversing the negative effects of generations of selective harvesting. Molecular genetic tools can be used effectively to monitor restoration programs, when the discriminatory power of the marker(s) is high and high-throughput scoring methods currently available are used.