First observations on Bryozoans and Entoprocts in the Ria de Aveiro (NW Portugal) including the first record of the Pacific invasive cheilostome Tricellaria inopinata

The results of a survey on bryozoans and entoprocts in the Ria de Aveiro (NW Portugal) are presented. The Ria de Aveiro is a coastal lagoon hosting large port facilities and several tourist marinas, thus presenting a wide variety of submerged structures and consequently a rich fouling community. In June and July 2004, 10 stations were selected and biological samples were collected from hard substrates such as wooden piles and floating pontoons. The identification to species level revealed the presence of 2 entoprocts and 16 bryozoans (5 ctenostomes and 11 cheilostomes). The most common species are Bowerbankia gracilis (found in all stations), Cryptosula pallasiana and Bugula neritina (found in 8 and 9 out of 10 stations, respectively). Noteworthy is the occurrence of Tricellaria inopinata; it is well established in several sites of the two investigated channels and even becomes dominant in the Canal de Ovar. This cheilostome bryozoan is an alien species of Pacific origin, first introduced to Europe in the lagoon of Venice (Italy); this record in the Ria de Aveiro is the first one for Portuguese coasts. The case of T. inopinata has been studied in the lagoon of Venice as a meaningful example of bryozoan biodiversity loss related to the spread of alien species due to aquaculture activity and/or shipping (commercial vessels). The Ria de Aveiro, with its important port and tourist marinas, constitutes an ideal site for the development of alien species' propagules and a source for secondary dispersal; thus, improved monitoring of its fouling community could be useful to control and prevent the dispersal of non-native biota.