A new record of the introduced seaweed Undaria pinnatifida ( Laminariales , Phaeophyceae ) from the Cantabrian Sea ( northern Spain ) with comments on its establishment

Undaria pinnatifida was recorded for the third time at the Cantabrian Sea, northern Spain. This record represents the easternmost occurrence of this non-indigenous seaweed along the Spanish coast. Information on the establishment of the species is also provided.

The Asian kelp Undaria pinnatifida (Harvey) Suringar, 1873 (Laminariales, Phaeophyceae) is a non-indigenous aquatic plant species (NIS) which has become established in Europe since 1971 (see review by Inger Wallentinus (ICES 2007) for details).In Spain, U. pinnatifida was recorded for the first time in the Atlantic coast of Galicia (northwestern Spain) at Ria de Arousa in 1988.The most likely vector was imported spat of oysters Crassostrea gigas (Thunberg, 1973) from France.Since then, it has spread throughout the western Galician coast mainly due to aquaculture activities.Subsequently, it has also been reported in the Cantabrian Sea (northern Spain).The first record was from Gijón harbour, Asturias in 1995, and the most likely vector was on the hulls of fouled pleasure craft from France.It was next found in Cudillero harbour, Asturias in 2001 presumably moved there by shipping (see Figure 1 and references in Annex).
In this paper, a new locality for Undaria pinnatifida is reported which represents its third record, extending its eastern distribution limit in the Cantabrian Sea, northern Spain (see Figure 1 and Annex 1).The species was found on 23th June 2007 in the marina located inside Lastres inlet, Colunga (Asturias).No further population was found outside the marina of Lastres during this period.The specimens were found just below the water line attached to floating marina piers, where they formed small and scattered populations.Populations were composed of adult individuals with an average length of 40 cm.Individuals showed blade deterioration and possessed well-developed mature sporophylls, indicating that they were in a senescent phase.
These observations agree with the seasonality observed in the Atlantic and Pacific populations where the macroscopic stage of U. pinnatifida appears during winter months, matures during spring and senesces during summer (e.g., see ICES 2007 and references therein).Voucher specimens were deposited in the herbarium MGC-Phyc of Universidad de Málaga (UMA).It is important to point out that U. pinnatifida was observed again in the marina of Lastres inlet on February 2008, showing the successful establishment of this species.
The occurrence of Undaria pinnatifida in the marina of Lastres cannot be considered as a natural expansion based upon small natural dispersal of this species (Forrest et al. 2000).Fouling of boasts hulls cannot be completely ruled out as the introduction vector, but it seems not to be a feasible source since the marina had only 60 boats with local traffic.Furthermore, Of interest is the fact that Undaria pinnatifida has also been cultured with success by IEO since the early 2000s in Santander (Cantabria).This culture farm is placed outside the Bay of Santander at a small inlet adjacent to Mataleñas beach (see Figure 1 and Annex 1).At the culture ground the sandy bottom does not allow a settlement of benthic algae, but there is a rocky shore with an abundant algal community just a few metres away from the farm.A survey on these benthic algae has been carried out to search for U. pinnatifida during 2007 and 2008.However, this species has not been found although it was especially searched from the low neap tide water line (1.5 m) down to at least −5 m below the lower water line of spring tides (3.5 m).These lower intertidal and upper subtidal zones are the usual habit for this species in the Atlantic coast of Galicia (northwestern Spain) (Cremades et al. 2006).Specific surveys should be conducted to explain why U. pinnatifida has not become introduced in the Mataleñas inlet, Santander (Cantabria), opposite to what has happened in the Lastres inlet, Colunga (Asturias).

Figure 1 .
Figure 1.Map of the distribution of Undaria pinnatifida in northern Spain (▲, • record; see Annex 1 for details).
Records of Undaria pinnatifida in the Atlantic Ocean and the Cantabrian Sea, northern Spain.Undaria was cultured in the inlet of Lastres, Colunga since 2003 ** Undaria has been cultured in the inlet of Mataleñas, Santander since early 2000s but it have not been found in nature