Feeding preferences of the sea cucumber Apostichopus japonicus (Selenka) on various seaweed diets

Food choice experiments were conducted to study the preferred seaweed diet of the sea cucumber Apostichopus japonicus (Selenka). Six diets containing Sargassum thunbergii, Sargassum polycystum, Zostera marina, Ulva lactuca, fresh Laminaria japonica and boiled L. japonica were offered separately in a mixture with sea mud and rare earth oxides (as inert markers). A feeding preference model was constructed to calculate the feeding preference index of sea cucumbers on the seaweed diets above. Sea cucumbers showed clear preferences for the L. japonica diets over the other diets. Fresh and boiled L. japonica diets made up about 54.73% of the entire intake. The sea cucumber preference indices changed with time. The preference for S. thunbergii rose significantly, changing from being rejection to somewhat preferred over a 30 day period. Our study suggests that a diet containing about 50% L. japonica of the total algal is very suitable for sea cucumber culture.

► It is the first time that a generally applicable feeding preference model has been constructed.
► This model can calculate the feeding preference indices and the apparent digestibility coefficient.
► This is the first study about feeding preferences of A. japonicas on different seaweed diets.
► This research showed that L. japonica diet is the favorite food of A. japonicas.
► These results suggest optimum algal diets for formulated feed for A. japonicas.