Chub mackerel larvae fed fish larvae can swim faster than those fed rotifers and Artemia nauplii

ABSTRACT: Developmental changes of swimming speed were analysed in the chub mackerel Scomber japonicus raised on two distinct dietary regimens. One group was fed only zooplankton such as rotifers and Artemia nauplii (R group) and the other group was fed rotifers plus red sea bream Pagrus major larvae (Pm group). Fish from the Pm group grew faster than those from the R group, and both the cruise and burst swimming speeds were faster for the Pm group even when match-sized comparisons were made. Fish in the Pm group attained a standard length (SL) of 17.5 mm by day 14 and their cruise and burst swimming speeds were 5.39 SL/s and 18.45 SL/s, whereas the R group attained 17.35 mm SL by day 17 and their cruise and burst swimming speeds were 4.28 SL/s and 13.98 SL/s. The results suggest that the swimming speed of chub mackerel in the wild would develop differently depending on the food resources they happen to encounter.