Attachment of Larvae of the Olympia Oyster, Ostrea Lurida, to Plane Surfaces

Abstract

It is characteristic of oyster larvae, as well as the larval forms of a great many fixed marine invertebrates, that they are free-swimming for a considerable length of time before becoming attached and assuming the adult form. Prytherch ('31, '34) has recently made a study of the process of attachment, or setting, of larvae of the oyster (Ostrea virginica) native to the Atlantic and Gulf coasts, and has called attention to certain factors influencing the larvae in the attachment stage. This author's experiments dealt in detail with the nature of the setting process and the mode of metamorphosis, and took into account the chemical conditions of the water with respect to their effect in initiating the setting reaction. In the present experiments attempts were made to determine the abundance of larvae setting as influenced by certain physical factors, without considering the original cause of setting. Growers and observers of the native oyster of the Pacific coast have commonly noted that a large proportion of the small oysters, or spat, are found on the under surfaces of shells or other material to which the larvae become attached. The question therefore arose as to whether this was due to some specific reaction of the mature larvae or merely to the fact that sedimentation and growth of algae and other organisms on the upper surfaces prevented attachment of larvae.