Modeling and Mapping to Assess Spatial Distributions and Population Numbers of Fish and Invertebrate Species in the Lower Peace River and Charlotte Harbor, Florida

Abstract

AbstractCatch per unit effort (CPUE) was computed from fisheries‐independent monitoring data collected from 1996 through 2013 in the lower Peace River and Charlotte Harbor, Florida. Seasonal habitat suitability modeling (HSM) based on delta‐gamma generalized additive models was prepared for eight fish and invertebrate species life stages with affinities for either low or moderate salinities. Using a geographic information system, habitat maps were created from monitoring data for temperature, salinity, dissolved oxygen, depth, and bottom type in the study area. Gear‐corrected CPUEs derived from HSM were applied to corresponding habitat grid cells. Seasonal HSM maps were then created, depicting the spatial distribution and relative abundance for early juvenile, juvenile, and adult life stages. By overlaying Optimum abundance zones from each HSM map onto corresponding salinity grids, the preferred ranges of salinity were found to be similar between seasons for each of six estuarine‐resident species life stages. This implies that each resident species occupies a unique salinity range in the river and estuary, which varies little between seasons. During the summer wet season, the geographic ranges occupied by each resident species life stage expanded in response to increased inflow, while the preferred salinity ranges occupied were similar between seasons. However, this was not the case for the two estuarine‐transient species (Red Drum Sciaenops ocellatus and Spot Leiostomus xanthurus), which tended to utilize different salinity ranges between seasons. Habitat‐based population estimates were prepared for each species life stage by using the predicted CPUE grids used to create the HSM maps. The demonstrated methods support ecosystem‐based fishery management and management of freshwater inflow to tidal rivers.