Meeting Abstract
Marine polychaetes in several genera, including Polydora, Pseudopolydora and Boccardia, are known to excavate burrows in the shells of bivalves and other mollusks. Species of shell-burrowing worms in the genus Polydora described from the Atlantic and Gulf coasts of the U.S. include P. websteri, P. concharum, , P. commensalis and P. neocaeca. While fascinating to natural historians because of their unique burrowing habits, worms that inhabit the shells of commercially important shellfish are considered pest species because their burrowing activity can negatively impact shellfish appearance, and severe infestations can lead to shellfish mortality. Using a combination of morphological analyses and sequencing of mitochondrial COX1 and nuclear 18S rRNA genes, we examined the taxonomic affinity of polydorids sampled from the shells of scallops and oysters cultured at five shellfish farms located from Alabama to Maine. We found that P. websteri, the most common polydorid in oysters from these five farms, was nearly identical at both genetic markers to P. websteri from Asia and Australia. We obtained samples of P. neocaeca from both scallops and oysters at one site in Massachusetts. Morphological and molecular analyses suggest that P. neoceaca from this site is identical to P. haswelli, a species previously described from Japan. These same analyses provide evidence that worms sampled from one farm in Maine are identical to P. onagawaensis, another species first described from northeastern Japan. Taken together, our results support the conclusions of Sato-Okoshi and others that shell-boring polychaetes in the genus Polydora have been inadvertently transported worldwide as a consequence of the movement of non-native commercially important shellfish.
