The geographical distribution and the growth of the wood-boring molluscsTeredo navalisL.,Psiloteredo megotara(Hanley) andXylophaga dorsalis(Turton) on the Swedish West Coast

Teredo navalis has been found along the west coast of Sweden from the Norwegian border to Klagsharnn in the Oresund, Psiloteredo megotara also occurs along the west coast to Molle, in the northern Öresund. Between 1971 and 1975, a study was conducted at the Kristineberg Marine Biology Station on the growth of T. navalis and P. megotara. A negative correlation was noted between the population density of T. navalis and the growth of both T. navalis and P. megotara during this period. At the lowest mean specimen density, 22 per dm2, 44 per cent of T. navalis were longer than 10 mm (November 1974) whereas only 5 per cent had reached this length (December 1971) at the highest density, 268 specimens per dm2. The mean lengths of P. megotara at the corresponding times were 112 nun and 74 rnm, respectively. Over a 10-month period at the Bornö Hydrographical Station Xylophaga dorsalis burrows reached a mean length of 21.1 nun and a mean diameter of 7.7 mm.