SEAFWA 2016

AUTHORS: Jason O'Connor, John Knight - Florida Fish and Wildlife Conservation Commission

ABSTRACT: Saltmarsh Topminnows Fundulus jenkinsi are listed as a species of special concern in Florida and are candidates for federal listing. They occur in estuarine marshes along the gulf coast from extreme northwest Florida to Galveston Bay, Texas. The Saltmarsh Topminnow Action Plan was created to guide conservation and research actions within Florida with the goal of improving the status of the species to the point that it can be delisted. We began implementing the plan in August 2014. Our initial research objective was to develop site occupancy models to create unbiased estimates of the current distribution of saltmarsh topminnows within Florida. We surveyed 28 randomly selected sites from all available saltmarsh habitat within Perdido, Escambia, Blackwater, and East Bays. Sites were surveyed 7 times each between Mar 2016 and Mar 2017. We used ranked an a priori set of occupancy models using AICc to select the best occupancy model. Assuming constant detection and occupancy across sites, we estimated that a given patch of saltmarsh habitat within the sampling area had a 70% chance of being occupied by Saltmarsh Topminnows and that using our methods we would expect to detect Saltmarsh Topminnows at sites of known occupancy on 67% of surveys. The top ranked occupancy model included a quadratic effect of site salinity on occupancy probability. Additional sampling will help improve the occupancy and detection estimates and allow for development of more complex occupancy models. Future research will explore methods for estimating density will be investigated.