Abstract
US Wind, Inc. is developing the Maryland Offshore Wind Project, an offshore wind energy project of up to approximately two gigawatts (GW) of nameplate capacity within OCS-A 0490, a Lease area of approximately 80,000 acres located off the coast of Maryland on the Outer Continental Shelf. Offshore bat monitoring was opportunistically undertaken using vessels conducting other surveys for the Project to determine if bats and bat patterns occur in the Lease area. The Lease area is located on the OCS within the Atlantic Ocean, approximately 10.5 miles offshore Ocean City, Maryland. For the purposes of this document, all distances are referred to as statute miles, unless stated otherwise. Bat activity off the shores of the Delmarva Peninsula in the Atlantic Ocean was documented using ultrasonic detectors mounted on three offshore geophysical survey vessels between March and October 2021, April and November 2021, and December 2021 and April 2022. Individual bat echolocation detections totaled 148. Individual bats cannot be distinguished acoustically; therefore, the aggregate number of recorded bat detections do not necessarily indicate the true number of bats present. Although recorded bat detections do not indicate the number of bats present within a given period of time, the metric provides a useful measure of bat activity. The association between bat activity, observation of species, time of year, and proximity from shore was investigated. Maximum detection distance from shore was 26.26 miles (mi), and mean distance was 3.4 mi. The most frequently detected bat was identified as Eastern Red Bat (Lasiurus borealis; LABO), representing 51% of bats identified to species or species group. Calls categorized as no identification (NOID) are defined as distinct bat detections, although the recording was not clear enough to be identified to the species level. These NOID detections represented 34% of detections. The remaining 15% of detections comprise of 9% Mexican Free tailed Bat (Tadarida brasiliensis; TABR), 4% Silver-haired Bat (Lasionycteris noctivagans; LANO), and 2% Big Brown Bat (Eptesicus fuscus; EPFU). The results of this survey show that as distance from shore increases, number of bat species and bat detections decrease. Bat detections in the Lease area represented approximately 9% of all bat detections. The highest density of bat detections occurred in late summer, which coincides with seasonal migratory bat patterns.