Temperature , upwelling, and habitat shape fish chorusing in California National Marine Sanctuaries

Abstract

Fish chorusing is when many fish call at the same time, often for mating purposes. We can use passive acoustic monitoring to track when and where fish choruses occur, but the roles of oceanographic and habitat conditions in shaping chorusing and its intensity remain poorly resolved. Here we used ∼16 cumulative recording-years of passive acoustic data from 2018 to 2022 across seven recording sites in Monterey Bay and Channel Islands National Marine Sanctuaries to model environmental drivers of chorusing by plainfin midshipman, bocaccio rockfish, white seabass, and two unidentified fishes. We modeled fish chorus presence and narrowband sound pressure levels using generalized additive models and generalized additive mixed models with open-source environmental data. For most species, probability of chorus presence increased under warm conditions and during periods of moderate upwelling. When chorusing occurred, predicted narrowband sound pressure levels were seasonally driven by temperature, and within the warm-season chorusing period, narrowband sound pressure levels increased with relatively stronger upwelling and associated cooler conditions. Most species chorused more, and at higher narrowband sound pressure levels, near land, but with distinct species-specific habitat associations that align with their reproductive modes. Our findings indicate that warm conditions cue seasonal chorus timing while seasonality and upwelling modulate how intensely fish chorus, clarifying how essential reproductive behavior responds to dynamic coastal habitat conditions. More broadly, understanding the environmental drivers of chorusing is critical for interpreting soundscape shifts as oceans warm and upwelling patterns evolve with climate change.