Chapter 18. Razorfish and scallops CHAPTER 18. RAZOR FISH AND SCALLOPS ALAN BUTLER CSIRO Marine and Atmospheric Research, Hobart, Tasmania 7001. Email:
[email protected] Figure 1. Razorfish Pinna bicolor near seagrass, Posidonia sp. The individual in foreground shows some recent, rapid growth at the posterior margin of the shell and an epifauna mainly of serpulids but with a gastropod, a few bryozoans, and a small colony of a didemnid ascidian beginning to overgrow the bryozoans. The shell in the background is dead, may have been there for a decade, and has a well-developed epifauna, mainly of bryozoans with a couple of sponge colonies. Introduction This chapter outlines some ecological studies of bivalve molluscs in Gulf St Vincent (GSV) waters. It is eclectic, not attempting to cover all studies of bivalves, but mainly those of several large species—the ‘razor fish’ Pinna bicolor, and the scallops Mimachlamys asperrima and Equichlamys bifrons—which are conspicuous, and have proven instructive not only for understanding the ecology of these sorts of animals (sessile filter-feeders, with broadcast spawning, external fertilisation and a long larval period), but of the dynamics of the Gulf ecosystem and of the relationships between species. A vast amount has been written about the ecology of bivalves worldwide (e.g. Wilbur & Yonge 1964- 1966; Bayne 1976; Yonge & Thompson 1976; Purchon 1977; Wilbur 1983-1988; Suchanek 1985; Ludbrook & Gowlett-Holmes 1989; Beesley et al. 1998), and no attempt is made to summarise it here. 238 Chapter 18. Razorfish and scallops Razor fish ‘Razor fish’ are bivalve molluscs, not fish.