Title A note on differences of species composition between swimming larvae and post-larvae of abalone, Haliotidae, in the coast of Sagami Bay
Authers Toyomitsu HORII, Hiroaki KUROGI, Yoshikazu KAJIGAYA,Naoyuki TAKIGUCHI and Masami HAMAGUCHI
Keywords abalone, larva, spat, species composition
Citation Bull. Fish. Res. Agen. supplement No. 5, 85-89, 2006
Abstract
Four species of large-sized abalones inhabit Japan, and the three species of Haliotis discus discus, H. gigantea and H. madaka are distributed over the warm current region. The main distribution depths are different among these three species; H. discus discus is shallowest, and H. madaka is deepest. However, it is not clarified why habitation depth differs. We collected planktonic larvae and spat in different water depth, and the differences of the species composition were investigated. The floating larva was collected by plankton net (the caliber of 36cm, NXX13) from Dec. 2 to 8, 2003. The distribution depth of planktonic larvae changed with days, but the fixed tendency was not shown. The species composition of planktonic larva was 52% of H. gigantea , 38% of H. discus discus, 3 % of H. madaka and 4 % of hybrid of H. disucus discus and H. madaka. In two investigating sites (2m and 8m depth), the spat was collected by plastic plate collectors from Dec.3 to 9, 2003. The species composition was 14% of H. gigantea and 72% of H. discus discus in shallower site, and 64% and 21% in deeper site, respectively: there was significant difference between the two sites. These result suggested that the reason that H. discus discus inhabits in shallower area is because the larva selects shallower area as settlement place by certain behavior.
URI http://www.fra.affrc.go.jp/bulletin/bull/bull-b5/19.pdf