Fixed-station and glider-based passive acoustic monitoring reveals spatiotemporal spawning dynamics of Atlantic cod and their potential interaction with offshore wind energy

Abstract

Atlantic cod, which produce sounds associated with courtship behaviors and are overfished in the US, are potentially vulnerable to disturbance from offshore wind energy (OWE) construction and operation during their spawning period. We used a combination of fixed-station and glider-based passive acoustic monitoring methods to evaluate the spatiotemporal spawning dynamics of Atlantic cod and assess their potential interaction with OWE at the extreme southern extent of the species’ range in Southern New England waters of the Western North Atlantic Ocean. Generalized linear modeling of call presence and rates suggests that spawning was concentrated in November and December and was greatest near the new and full moons. The results from both fixed-station and glider-based methods suggest that spawning overlaps with planned OWE construction in time and space. Comparison of these temporal spawning dynamics in Southern New England to analogous PAM data from the geographically separated Massachusetts Bay winter-spawning Atlantic cod subpopulation revealed that the seasonality of inferred spawning was the same between the two regions. By leveraging multiple methods and datasets, this work demonstrates the effectiveness of PAM for understanding spawning phenology of and potential disturbance to an economically important fishery.