These tanks were made from 20 L heavy-walled plastic 
pans (U.S. Plastics Corp., Lima, Ohio) modified by covering the handles in a buoyant foam and removing four panels from the bottom and replacing them with nylon screening (240 m mesh). A central cross-shaped area was left 
intact to create an inlet for upward-directed water fl ow; 
then additional shear flow was added with four additional 
adjustable water inlets around the edges approximately 
16 cm above the bottom, yielding a final volume in the 
chambers of 23 L (see Figure 2). All flow was regulated 
by valves to optimize the slow tumbling movement of the 
larvae in the chamber. The fl oating chambers were immersed in large 2,400 L pools to stabilize their temperature 
(28°– 31°C) and mimic natural temperature cycles throughout a 24 h period. To maintain water quality close to that 
which the larvae would experience in open water, the chambers were attached to a filtered (1 m) flow-through system 
with seawater pumped from the reserve, so that water was 
completely exchanged in the chambers several times each 
day. Flow rates through the chambers were maintained 
at approximately 2 L/min, and the bath of fresh seawater 
surrounding the chambers was turned over about one to 
two times per hour. Salinity, temperature, and pH closely 
mimicked natural conditions without additional effort.