Mark-Recapture methodology has been one of the major experimental methods for gaining information on wildlife populations over the last 100 years. The standard methodology for assessing mortality rates in open populations (the Cormack-Jolly-Seber method and its expansions) has assumed that the recapture are done instantaneously, or at least during a very short interval. This is often not the case as the sampling is often done during a season or a long term field trip. This text presents methods for analysing capture- and mortality rates from mark-recapture data where the data are not collected instantaneously, but more or less continously. The metod is based on semi-parametric models often used in survival analysis, such as the Kaplan-Meier or Cox models. The methods are illustrated using real data on fish and bird poulations.