Each individual squid or cuttlefish was reared in a 2.6-l plastic container (18 cm long,
13 cm wide and 11 cm high) with mesh bottom and lid, floating within a 300-l tank,
attached to a 12 000-l recirculating, natural seawater system. Individuals were held
separately so that food intake could be monitored, but also to prevent competition and
cannibalism. At the start of each experiment 10–12 hatchlings were allocated to each
treatment and placed randomly within four (1996 experiment) or three (1997 experiment)
300-l tanks. All tanks were located inside with a 12:12 h light–dark cycle and
with air conditioning to assist in controlling water temperature. Water temperature was
recorded daily (60.058C) with maximum–minimum thermometers. Temperatures
ranged from 24.5 to 27.58C in 1996 and from 26.5 to 28.08C in 1997.