Effects of density-dependent mortality on the relationship between recruitment and larval settlement

Criteria for recruitment limitation or regulation of open populations suggest that such regulation can only occur when population age structure (or recruitment) directly reflects previous settlement events, i.e., when mortality of settlers is density-independent. A simple mathematical model is used to relate recruitment density to settlement density when mortality is density-dependent. The results indicate that recruitment may still reflect settlement despite density-dependent mortality of settlers, especially when settlement densities are low. The conditions under which recruitment reflects settlement, or populations are recruitment limited, are much broader than originally assumed, and can be calculated from field data.