BIOGEOGRAPHY AND DISPERSAL OF COASTAL MARINE ORGANISMS - EXPERIMENTALSTUDIES ON A REPLICA OF A 16TH-CENTURY SAILING VESSEL

Observational and experimental studies were conducted on the dispersal of fouling organisms on a replica of a 16th-century sailing vessel al ong an 800 km transect from Yaquina Bay, Oregon to San Francisco Bay, California. The vessel sailed between four bays at slow speeds (3.5 to 4 knots), resided in each bay for approximately 30 d, and spent 1 to 3 d in the open ocean travelling between ports. Natural hull fouling a nd experimental fouling panels placed on the vessel were sampled upon departure and arrival at each port. All common fouling species survive d the open sea voyages between the harbors, with largely no ecological ly significant changes in abundance nor significant losses in overall diversity detected. In one port the vessel settled upon the harbor flo or periodically; several entrained benthic organisms were then transpo rted 390 km to the next port. Slow-moving, fouled sailing vessels of r elatively long port residencies may have significantly altered the dis tributions of marine and estuarine organisms not only globally (leadin g to the invasions of non-native species) but also along continental m argins (leading to the alteration of aboriginal patterns of distributi on). Shipping traffic may further play an important role in gene flow between isolated populations of obligate estuarine organisms, particul arly those with non-planktonic larvae.