The life history characteristics of the wood-boring bivalve Teredo bartschi are suited to the elevated salinity, oligotrophic circulation in the Gulf of Aqaba, Red Sea

In the Gulf of Aqaba, the slow, unidirectional surface inflow of oligotrophic waters from the Red Sea may limit the dispersal of planktotrophic larvae, thus favouring brooded over planktonic development. A site at the northern end of the Gulf was used to examine recruitment by wood borers of the family Teredinidae (Bivalvia) with brooded or planktotrophic larvae. Wood panels exposed for 4 months at depths from 6 m to 36 m, became colonised by the brooding Teredo bartschi and a few individuals of the planktotrophic Bankia carinata. Driftwood at the site contained I bartschi and the brooding isopod wood-borer Limnoria tripunctata. No significant variation in intensity of recruitment with depth was detected. The size distributions of shells within the panels were unimodal, suggesting a single period of recruitment, but shell size was negatively correlated with the degree of crowding. For T bartschi, the length and width of pallets proved to be good predictors of shell diameter. Pallet width also defines the diameter of the siphonal opening. Across the range of animal sizes sampled, this opening tended to be larger in T bartschi than that calculated from reported widths of Teredo navalis, a species which grows in more plankton-rich waters. Groups of larval shells, which averaged 66 pm in width, were found on the inner surface of about 7% of all adult shells investigated. They had the characteristic D outline and pitted surface of a prodissoconch I shell with or without a small amount of prodissoconch 11 growth. These would have resulted from a single spawning event at about the time of year that nutrient-rich waters mix into the upper water column. At Aqaba, a sink population of T bartschi is likely to be maintained by adults rafting from the Red Sea. These observations build a picture of the life history strategy of T bartschi: brooding with maternal rather than egg-derived nutrition; release of a non-feeding pediveliger: limited larval dispersal; rapid development of a synchronous brooding capability; dispersal by rafting as adults. (C) 2009 Elsevier B.V. All rights reserved.