Cost-effective use of aerial imagery to quantify faunal-habitat associations across multiple spatial scales

Abstract

We investigated the utility of publicly available map products to identify faunal-habitat associations to inform fisheries management. The influence of structural and abiotic variables on the abundance of 4 focal species (red drum Sciaenops ocellatus, spotted seatrout Cynoscion nebulosus, blue crab Callinectes sapidus, and brown shrimp Farfantepenaeus aztecus) was examined at multiple spatial scales in the Mission-Aransas estuary, Texas, USA. Structural habitat data were derived from the 2004 Benthic Atlas of Texas and paired with species abundance and hydrographic data collected by the Texas Parks and Wildlife Department’s Fisheries Independent Monitoring program. Blue crab and brown shrimp distributions at the ecosystem scale were driven primarily by abiotic factors such as salinity and distance to inlet, but structural habitat became relatively more important at smaller spatial scales. Variation in spotted seatrout abundance was primarily driven by seagrass and saltmarsh extent at the ecosystem scale but was driven by abiotic factors at the sub-region scale. Red drum distribution was driven primarily by abiotic factors, and association with structural habitats was bay-specific; there was no clear pattern in the influence of spatial scale on the relative importance of structural versus abiotic habitat variables for red drum. Results demonstrate that leveraging existing mapping efforts can allow fisheries managers to incorporate habitat data into fisheries management when funding or logistical challenges may otherwise prevent habitat monitoring at management-relevant scales. More research is warranted to investigate the temporal limitations to this approach, such as identifying the ‘shelf life’ of historical mapping products for utility in fisheries management.