The treatments were conducted in seven 1.5 m
3
aquariums maintained at 21–23 °C and salinity at 31. For each treatment, three replicates were set, and 40 hatchlings were assigned to each replicate. The
hatchlings were fed in plastic cages (24 cm×18 cm for the upper surface, 20 cm×12 cm for the lower surface and 12 cm in height) covered with a 40-mesh nylon cloth and floated on the water. The
clams were unclenched using a knife, and whole tissueflesh was
taken out to feed to the whelks. The frozen oysters were also provided
in whole flesh. With regard to the shrimps and mackerels, only the
muscles were used. The compound eel feed was mixed with water
into small pellets. The post-hatchlings were provided each diet in excess throughout the 10-week growth experiment. All diets were
replaced twice a day (8:00 a.m. and 8:00 p.m.). To prevent biofouling,
the cages were replaced every week. The seawater in the aquarium
was aerated and half of it was changed daily. During the experiment,
the total shell length of whelks in each cage was measured every 10d
using a vernier caliper from the apex of the shell spire to the anterior
canal. The wet body weight was measured, and survival was counted;
dead individuals were removed to avoid cannibalism.
Based on the results of the food preference experiment, the diet that
the post-hatchlings preferred was continuously provided for 140d to
assess growth regularity and potential under optimal conditions.
Every 30d, the total shell length of 30 hatchlings were measured, and
the relationship between both parameters was investigated.