Changing phenology and larval transport drive benthic species' wrong-way migrations

Heidi L Fuchs, Rutgers University New Brunswick, New Brunswick, NJ, United States, Robert J Chant, Rutgers University, Department of Marine and Coastal Sciences, New Brunswick, United States, Elias J Hunter, Rutgers University, New Brunswick, United States, Enrique Curchitser, Rutgers University, Department of Environmental Sciences, New Brunswick, NJ, United States, Gregory P Gerbi, University of Maine, Orono, United States and Emily Chen, Rutgers, United States
Abstract:
Ocean warming has driven some marine species to migrate poleward or to deeper water, tracking the climate velocity to remain at tolerable temperatures. On the Northwest Atlantic continental shelf, however, many benthic invertebrates' ranges have instead shifted southward and into shallower, warmer water. We tested whether these "wrong-way" migrations could arise from warming-induced changes in timing of spawning (phenology) coupled with larval transport. Results showed that larvae spawned earlier in the year encounter more downwelling-favorable winds and river discharge that drive transport onshore and down-shelf. Phenology and transport explained most observed range shifts, whereas climate velocity was a poor predictor. This study reveals a physical mechanism that counterintuitively pushes benthic species, including commercial shellfish, into warmer regions with higher mortality.
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