Immediately after collection, three incubation cores per station were immersed in a temperature-controlled recirculating water bath incubator adjusted to the recorded bottom water temperature.
temperature-controlled recirculating water bath incubator
We used four 1200L recirculating tanks representing the four temperature treatments (11, 14, 18, 23°C). Each tank housed 12 rearing containers that represented the 3 replicates for each of the 4 populations (4 temperatures × 4 populations × 3 replicates = 48 containers).
The container design was identical to previous silverside experiments (e.g., Baumann & Conover 2011, Murray et al. 2014), i.e., we used round, white 20L containers equipped with individual airlines and mesh-screened (150 µm) holes, which guaranteed ~100% oxygenation and water exchange with the surrounding tank while retaining food. Tank water of ~ 30 psu was drawn from Coliumo Bay, filtered/UV-sterilized, and controlled for temperature via thermostats connected to commercial aquarium heaters or chillers.