Shipworms

Abstract: Publisher Summary A ubiquitous pest of all manner of timber in the sea, teredo— the shipworm, causes damage worth millions of pounds every year all over the world. Hidden protectively within the “heart” of both fixed and floating timber, and hardly visible from the outside, these borers work silently and reduce to soft sawdust even if it is the most resistant timber. Rasping with their shells mechanically, these living drills draw a major part of their nourishment from the hard cellulose. Unseen even by experts, this exotic menace converted solid pillars and piers into weak and fragile “honeycombs.” Along the entire seafront, bridges collapsed, piers crashed and boat hulls and wharf-piling crumbled. Like an unseen typhoon, it swept up the coast leaving a trail of destruction along its path. Though present in all seas, shipworms are particularly destructive in the tropical waters where they eat in discriminately every material of plant origin.

Abstract: Background: Bivalve teredinids inflict great destruction to wooden maritime structures. Yet no comprehensive study was ever carried out on these organisms in European coastal waters. Thus, the aims of this study were to: investigate the diversity of teredinids in European coastal waters; map their past and recent distributions to detect range expansion or contraction; determine salinity-temperature (S-T) requirements of species; flag, for future monitoring, the species that pose the greatest hazard for wooden structures. Results: A total of nine teredinid species were found established in European coastal waters. Seven were considered cryptogenic, of unknown origin, and two were considered alien species. Teredo navalis and Nototeredo norvagica were the species with the widest distribution in European waters. Recently, T. navalis has been reported occurring further east in the Baltic Sea but it was not found at a number of sites on the Atlantic coast of southern Europe. The Atlantic lineage of Lyrodus pedicellatus was the dominant teredinid in the southern Atlantic coast of Europe. In the Mediterranean six teredinid species occurred in sympatry, whereas only three of these occurred in the Black Sea. The species that pose the greatest hazard to wooden maritime structures in European coastal areas are T. navalis and the two lineages of L. pedicellatus. Conclusions: Combined data from field surveys and from the literature made it possible to determine the diversity of established teredinid species and their past and recent distribution in Europe. The environmental requirements of species, determined using climatic envelopes, produced valuable information that assisted on the explanation of species distribution. In addition, the observed trends of species range extension or contraction in Teredo navalis and in the two lineages of Lyrodus pedicellatus seem to emphasise the importance of temperature and salinity as determinants of the distribution of teredinids, whereas their life history strategy seems to play an important role on competition. Teredo navalis and pedicellatus-like Lyrodus species should be monitored due to their destructive capability. The two alien species may expand further their distribution range in Europe, becoming invasive, and should also be monitored.

Abstract: . Experiments were conducted to determine the decomposition rate of mangrove wood in two areas of differing water nutrient concentrations. Stakes were prepared from prop roots of Rhizophora inangle and from branches of Avicennia. Conocarpus and Lagguncularia. and tied in the natural habitat at two sites—Man-of-war Cay (high nutrient concentrations) and Twin Cays (low nutrient concentrations) — off the Belize coast. The stakes were retrieved after 4–24 months and the vertical zonation and succession of higher marine fungi was recorded. Consumption of wood by shipworms (Teredo bartschi), the major decomposers, was measured by digital analysis of the area of wood consumed by these boring organisms. Summary A total of 20 species of marine Ascomycotina, 2Basidiomycotina, and 6 anamorphic fungi were identified from the experimental stakes. Differences in species composition between the two sites of Twin Cays and Man-of-war Cay (Belize) were observed, as well as a certain degree of patterning in the vertical distribution of fungi. Among Ascomycotina, members of Halosphaeriales show a definite tendency to thrive at greater depths than other species. Mangrove decomposition by shipworms was clearly higher in the nutrient-rich waters of Man-of-war, where the stakes were already heavily riddled after 8 months and had mostly disappeared after 2 years, while they were still intact at the other site. No significant difference in degradation of the 4 species of mangroves was noted.