Meeting Abstract

P3-135   -   Defining thermal tolerances of lab-reared and wild caught Homarus americanus post larvae Jane, A.*; Frederich, M.; Waller, J.; Rasher, D.; O'Loughlin, H.; Annis, E.; University of New England, Biddeford, ME; University of New England, Biddeford, ME; Department of Marine Resources, Boothbay, ME; Bigelow Laboratory for Ocean Sciences, Boothbay, ME; Vassar College, Poughkeepsie, NY; Hood College, Frederick, MD ajane@une.edu

The American lobster (Homarus americanus,) is an ecologically and economically important species in the Gulf of Maine. Climate change is reshaping its biogeography; therefore, understanding the physiology of this species is required to predict future range shifts. While the thermal tolerance of adult lobsters is well studied, thermal tolerances of the earliest developmental stages remain understudied, and previous research has used only lab-reared larvae. We used scope for activity, measured by respirometry, as well as expression of heat shock proteins (HSP70) and AMP-activated protein kinase (AMPK) as indicators of thermal stress. We defined thermal tolerance limits for wild caught planktonic stage IV lobster larvae as well as stage IV lobster larvae reared in a lab setting at ambient, 18⁰C, and 14⁰C. Critical temperatures, defined by a complete lack of scope for activity, were reached at 8 and 26°C in lab-reared larvae raised at 18⁰C. By contrast, wild caught larvae maintained positive scope for activity to 4°C and 30°C. Larvae reared in the lab at ambient temperature had a range of positive scope for activity similar to those reared at optimal temperatures, with no differences in critical temperatures. Larvae raised at 14⁰C had scope for activity that was closer to wild caught larvae at lower temperatures but similar to other lab reared larvae at warm temperatures. Our results suggest that wild caught stage IV lobster larvae are more tolerant of both hot and cold thermal stress than their lab-reared counterparts, and that rearing temperature plays an important role in defining thermal tolerance. Such results have important implications for modeling the impacts of climate change on lobster distribution in the future. Funded by NSF grant# 1948108.