The Stratified-Petersen Analysis System (SPAS) is designed to estimate abundance in two-sample capture-recapture experiments where the capture and recaptures are stratified. This is a generalization of the simple Lincoln-Petersen estimator. Strata may be defined in time or in space or both, and the s strata in which marking takes place may differ from the t strata in which recoveries take place. When s=t, SPAS reduces to the method described by Darroch (1961) <https://www.jstor.org/stable/2332748>. When s<t, SPAS implements the methods described in Plante, Rivest, and Tremblay (1988) <https://www.jstor.org/stable/2533994>. Schwarz and Taylor (1998) <doi:10.1139/f97-238> describe the use of SPAS in estimating return of salmon stratified by time and geography. A related package, BTSPAS, deals with temporal stratification where a spline is used to model the distribution of the population over time as it passes the second capture location. This is the R-version of the (now obsolete) standalone Windows program available at <http://www.cs.umanitoba.ca/~popan/spas/spas_home.html>.
|Author||Carl James Schwarz|
|Maintainer||Carl James Schwarz <[email protected]>|
|License||GPL (>= 2)|
|Package repository||View on CRAN|
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