Generalized Additive Models for Categorical Count Data: An exploration of the decline of queen triggerfish Balistes vetula in the Bahamas and Turks and Caicos

Citizen science is growing increasingly important for managers and conservation science. The REEF Volunteer Fish Survey Project provides an accessible and flexible way for divers to contribute observations to a large database. This flexibility comes with challenges for analysis, but these challenges can be addressed with analytical models that account for variation in survey effort in time and space. For this study, the authors used simulations as well as data collected in The Bahamas and Turks and Caicos from 1994–2020 to identify model approaches that were able to predict trends in both observation frequency and abundance at the survey level as a function of dive duration, location, and other covariates. The models identified a significant decline in Queen Triggerfish, which was used as a model organism for this study. This research opens the door for more in depth study of other understudied reef dwelling species, allows for higher resolution modeling of predictors of presence and abundance, and expands the set of tools available for researchers using REEF data.