Meeting Abstract

102.3  Tuesday, Jan. 7 08:30  Potential biological implications of rapid ocean warming in the Bay of Fundy, Canada KOOPMAN, HN*; WESTGATE, AJ; SIDERS, ZA; UNC Wilmington; UNC Wilmington; UNC Wilmington koopmanh@uncw.edu

Ocean temperatures have been increasing globally at rates of 0.05–0.5ºC per decade, but little is known about potential consequences to ecosystems. One aspect of marine invertebrate physiology that is very thermally sensitive is reproduction, particularly in the American lobster, Homarus americanus. Lobsters require cold (<5-8 ºC) winters for proper ovarian development. The Bay of Fundy (BoF), Canada, is known to be an important reproductive area for lobsters both locally and for the entire Gulf of Maine, but little is known about recent ocean temperature trends in these waters. We observed rapid increases in summertime ocean temperatures in the BoF over a four year period. We deployed temperature recorders on nine free-swimming basking sharks (Cetorhinus maximus) in the BoF between August and September of 2008-2012 and obtained 33 days of water temperature data. Temperatures increased at all depths (0-230 m) over the study period; below the thermocline this increase was >2ºC. The magnitude of the increase in sea surface temperatures over the same time period was similar (from 13.7ºC to 15.9ºC) to those found at depth (8.8ºC – 11.1ºC). We also documented a decrease in the fecundity of female American lobsters (n=764) by 8-10% each year over this period (overall decline 25%; P<0.001). We do not know the precise cause of these temperature increases, but no association with local meteorological trends or the North Atlantic Oscillation were observed. Increasing temperatures have been predicted to lead to higher lobster landings in the short term, since animals are more mobile when warmer. However in the long term, these increased temperatures may negatively impact recruitment into the fishery via decreased reproductive success.