Video tracking of marine invertebrate larvae

The tropical barnacle, Balanus amphitrite, is an economically important fouling species (it settles on natural and artificial submerged surfaces) with a short generation time and larvae that are relatively easy to culture in the laboratory. These attributes have contributed to its acceptance as a model species for larval settlement studies. The settlement stage larva the cyprid (figure 1) measures approximately 0.5 mm in length and is capable of swimming at high speed. On encountering a surface, the cyprid typically displays searching behavior, in which the cyprid ‘walks’ over the surface using the attachment discs of its paired antennules. This behavior has proved difficult to measure in detail by conventional means. Knowledge of such behavior is nevertheless important to the development of methods to interfere with this process, i.e. antifouling. The present investigation aimed to determine whether the settlement behavior of such small organisms was amenable to analysis by EthoVision and if so, to see how to optimize its use.