Prof. Peter Petraitis1, Prof. Steve Dudgeon2
1University of Pennsylvania, Philadelphia, USA, 2California State University, Northridge, USA
The Gulf of Maine on the east coast of North America is warming faster than more than 95% of the world’s oceans and from 2011 to 2021, the rate of warming has been 0.63°C per decade. In addition, abundances of intertidal gastropods and recruitment of mussels (Mytilus edulis) and barnacles (Semibalanus balanoides) have been declining at alarming rates. Published regressions based on our 1997-2018 data showed declines in abundances of three common gastropods averaged 3.1% per year (Testudinalia testudinalis, Littorina littorea, and Nucella lapillus), and declines in recruitment of 15.7% per year for mussels and 5.0% per year for barnacles. Our recent data (2019 to 2022) show accelerating declines with 60% of 198 observations below the 1997-2018 prediction interval of 1997-2018 regressions. From 2017 to 2022, declines in abundances of gastropods have averaged 8.5% per year, while the decline in mussel recruitment has remained nearly the same (14.6% per year). Barnacle recruitment has increased (19% per year). Based on data from the nearest offshore buoy, the declines are correlated with warming water temperatures. Gastropod abundances show lagged correlations with summer temperatures in the previous two years while recruitment of mussels is correlated with water temperatures when larvae are in the water column. The declines are sobering and suggest these species, which are iconic of intertidal shores in the Gulf of Maine, will be rare within the next two decades.
Biography:
Peter Petraitis was undergraduate at UCSB where he was influenced by Joe Connell. He completed his PhD at Stony Brook University with Jeff Levinton and was a postdoctoral fellow at Woods Hole Oceanographic Institution. He has been a visiting scholar at the University of Sydney and a Fulbright Scholar at Pontifica Universidad Católica de Chile. Petraitis has also worked on niche theory and multiple stable states, and conducted research on the effects of climate change on the plant communities in the semi-arid steppe of Mongolia. He is currently an Editor-in-Chief of the Journal of Experimental Marine Biology and Ecology.
