Two species of clams, Mya arenaria (1) and Mya truncata (2), were hand collected from Métis-sur-Mer, Québec, Canada (48° 40' 4.6092" N, 68° 1' 5.9484" W) and by SCUBA diving (~ 10 m) at Godbout, Québec, Canada (49° 19' 25.626" N, 67° 35' 17.034" W) respectively. The clams were brought to the wet labs of the Maurice-Lamontagne Institute in Mont-Joli, Québec for acclimatization to experimental conditions. A clams' ability (1) or inability (0) to bury itself into the substrate (sand) was observed visually to control for it's possible relationship to clam performance variability, as well as their common garden tank (pre.acclim) to control for possible tank variability. After > 1 month in this pre-acclimatization phase, during the months of november and december 2020, clams were measured for morophometrics (length, width, and height) with a vernier caliper to control for the relationship between size and clam physiology, and transferred to the experimental system and subjected to a combination of two stressors: one of seven levels of heatwave (2, 7, 12, 17, 22, 27, or 32 °C) crossed with one of two levels of harvesting (with, without). The true temperature was recorded (truetemp) with HOBO 8K pendant data loggers to measure the variation in real temperature experienced by the clams in each tank. Four tank replicates were used for each of the fourteen (7 x 2) experimental treatments to account for possible tank effects. In each of these tanks (1-4), eight individuals of each species were placed together to increase replication. At the end of the experimental period, mortality was assessed by prodding clams in each tank for each species (mya_spp_heatwave_mortality_data) as a measure of response to the stressors. In surviving individuals, three tissues -- mantle (m), gills (g) and posterior adductor muscle (a) were dissected from each individual to asses inter organ differences and the tissues were flash freezed for metabolomics analysis. A targeted metabolomics analysis was run over the months of March to May 2021 at the Iso-BioKem laboratories in Rimouski, Québec, Canada to quantify 48 metabolites with an Agilent 1260 Infinity II high performance liquid chromatographer (mya_spp_heatwave_metabolomics_data) as a measure of response to the stressors.

This dataset includes information on individual clams and their survival assessed after 12 days in the experimental conditions (alive = 0, dead = 1) the targeted temperature (2 - 32 C) and the true temperature, the harvesting treatment (with = 1, without = 0), the species (mya arenaria = 1, mya truncata = 2), and the replicate tank (replicate). Based on the presence of fixed (temperature, harvesting, species) and random effects (replicate) in the experiment, a generalized linear binomial mixed effects model was selected to analyze the effects of our treatments. For these analyses, the true temperature (truetemp) was used as a continuous independant variable.*Some replicate tanks experienced technical problems which led to abnormal variation in temperature during the experiment, and must be removed for further analysis (see Code/Software section)