Reef building worms in Iberian Mediterranean Coasts  <B>Reef building worms in Iberian Mediterranean Coasts</B><P>R. Porras1, J.V. Bataller1, E. Murgui1 and M.T. Torregrosa2<P> 1 Departamento de Ingenieria Hidraulica y Medio Ambiente, Universidad Politecnica de Valencia, Valencia, Spain <BR> 2 Instituto de Bachillerato Quart de Poblet, Senda Senent S/N, Quart de Poblet, Valencia, Spain<P> Abstract<P> During 1994 summer, a survey was conducted along Valencia Gulf coasts to determine the extension and abundance of Sabellaria alveolate reefs. A comparison of actual results with those obtained by the authors from previous surveys shows a reduction in the number of localities in which reefs were present, at least one time since 1989. Of a total of 23 stations, actually only persists in 13. Among these, in three of them, they show no changes; other four show evident regression signals and only three exhibit a considerable enlargement. Among destruction causes observed, the most frequent is sand level rise as a consequence of manmade actuations such as seawalls and sportive harbors construction, and beach nourishment projects. Al though reef destruction may be also due to natural causes as river floods or natural sand accumulation, in these cases, recovery after perturbation events have been recorded in many occasions between 1989 and 1994.<P>