Directed acyclic graph of an integrated population model (IPM) for American alligators in Georgetown County, SC, USA. Parameters for which we computed posterior distributions are represented by circles, whereas observed data and extrinsic variables (nonupdated; shaded gray) are rectangular, with indexing for size class (j), site (survey route; i), temporal survey replicate (k), and year (t). The growth formula represents an alligator growth dataset (g; Wilkinson et al., 2016) that was used to derive transition probabilities for sex‐specific growth (ψjSex) outside of the IPM framework (Appendix S3). The large, dashed box represents the multistate mark–recapture–recovery model that used a mark–recapture dataset with dead recoveries (m), ψjSex, and a capture effort covariate (CEj,t) to estimate probabilities of recovery (r), detection (p.mj,t), and apparent survival (φj)—a shared parameter within the integrated likelihood for the state‐space abundance model. Input to the fecundity formula included the proportion of females in each size class (FPj; Rhodes & Lang, 1996; Woodward, 1996), the proportion of breeding females (BR; Wilkinson, 1983), and nest success (NS) and average annual clutch size (CLt) at the Tom Yawkey Wildlife Center (Wilkinson, 1983). The bottom row of boxes within the state‐space model reflect different types of nightlight survey data: Sized (cj,i,k,t), Aged (immatures: age.imi,k,t, adults: age.adi,k,t), or Unknown age (unki,k,t). These data were used to estimate two latent quantities specific to size class, the number of individuals encountered of known or unknown size (Detections; dj,i,k,t) and those encountered with size determined to at least immature/adult specificity (Aggregated; aj,i,k,t), with their associated detection probabilities (p.dj,i,k,t) and (p.a). Detection probability p.c was conditioned on the size‐classified counts. We modeled the effects of water level (WLi,k,t) and temperature (WTi,k,t) as survey replicate‐level covariates on p.dj,i,k,t. The true number of individuals in each size class (Nj,i,t) was estimated in the process component of the state‐space model by fecundity (fj,i,t), ψjSex, and φj, as well as the previous year's true number of individuals (Nj,i,t−1) and harvest (hj,i,t−1). We note that the true number of individuals in the first timestep (Nj,i,1) is not part of the state‐space model, so the dashed arrow between Nj,i,1 and Nj,i,t−1 reflects these collapsed dynamics.