A model is presented for the estimation of population density using line-transect methods on clustered individuals. The model assumes independent sighting of clusters but does not require all individuals in a cluster to be sighted.

This article considers a new method of line transect density estimation wherein sampling is terminated as soon as either a fixed length L0 of the transect is transersed or a fixed number N0 ofjects are sighted. The case N0-->[infinity] corresponds to the method currently in use.