Table 1. Equations for the Delta method and for the two closed-population models.

Delta Method	$Var(N_{tot})=N_{tot}^2(\frac{\text{var }N}{N^{{}^{{}_2}}}/+\frac{1-\theta }{n\theta })$
Schnabel’s Binomial	$N=\frac{{\Sigma }_{i=2}^t{C}_i{M}_i}{{\Sigma }_{i=2}^t{R}_i+1}$
Schumacher & Eschmeyer	$N=\frac{{\Sigma }_i^t{C}_i{M}_i^2}{{\Sigma }_{i=2}^t{R}_i{M}_i}$

N_tot = estimated total population present during the sample period (including grade C sharks), N = estimated recognisable population, θ = proportion of recognisable individuals in population, n = total number of individuals captured during the sample period, C_i = number of potentially recognisable individuals captured at occasion i, M_i = number of previously sighted, recognisable (‘marked’) individuals in the population immediately before sample i was taken, R_i = the number of re-sighted individuals in sample i, and t = the number of sample occasions in the sample period.