Early Juvenile Growth and Behavior of Laevistrombus turturella(Gastropoda: Strombidae) in a Laboratory Microcosm Experiment

Abstract

The dog conch, Laevistrombus turturella, is an important marine resource of ecological and economic importance in the Southeast Asian region. Natural populations of L. turturella are under threat due to development and overexploitation, so efforts should be taken in culturing this species for commercial and conservation purposes. This study aimed to fill the knowledge gap in the life-history characteristics of L. turturella by investigating the growth and behavior of early juvenile L. turturella under laboratory conditions. Egg masses of L. turturella were collected from conch natural-spawning habitat. Upon reaching the late veliger stage (stage IV), L. turturella larvae was chemically induced, and newly metamorphosed juveniles were reared in small-scale laboratory microcosms. The microcosms were placed in an incubator at 28 °C and under 12:12 h light-dark condition, with very minimal aeration. Specific behavioral characteristics were observed at the onset and during the metamorphosis, and these characteristics resulted in highly camouflaged juveniles covered by surrounding sediment and debris. Burrowing behavior was first observed at day 56 post settlement, but they were only partially buried. Generally, juvenile conch showed fast and continuous growth, which were best modelled by fitting linear equations. Thus, a minimum size of 10 mm-shell-length juveniles is recommended for restocking. All these results indicated the technical viability of producing hatchery-reared juveniles for commercial purposes and for enhancing natural-stock populations.