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A total of ten red seaweed species are recognized as introduced into the North Sea from other parts of the world. These are Asparagopsis armata and Bonnemaisonia hamifera (Bonnemaisoniales), Grateloupia doryphora (Halymeniales), Antithamnionella spirographidis, Antithamnionella ternifolia, Anotrichium furcellatum, Dasya baillouviana, ?Dasysiphonia sp., Polysiphonia harveyi and Polysiphonia senticulosa (Ceramiales). The oldest of these is B. hamifera, introduced prior to 1890, while the most recent, ?Dasysiphonia sp., was first found in 1994 and still requires taxonomic investigation. A variety of distribution patterns is seen, with geographical ranges varying from general within the North Sea to very restricted. The diversity of introduced red algae on eastern coasts of the North Sea is much greater than in the west. The most likely explanation for this pattern is that French coasts were the initial site of introduction for many of the seaweeds, which were then distributed northwards by the residual surface currents. Their increasing success in the Netherlands has probably been promoted by the drastically changed local hydrodynamic conditions which have also permitted the recent introduction of many native European species. Of the biological features of species that may favour their success as introductions, clonal vegetative propagation, often with specialized propagules or fragmentation mechanisms, is almost ubiquitous. Low-temperature tolerances can be inferred, but data are sparse. Many of the alien red algae in the North Sea contain anti-grazing compounds such as bromophenols, which may contribute to their invasive potential by deterring grazing sufficiently to permit establishment of an inoculum. I N T R O D U C T I O N T h e first i n t r o d u c t i o n s of exotic s e a w e e d s into n o r t h e r n E u r o p e w e r e r e c o g n i z e d in t h e late n i n e t e e n t h a n d early t w e n t i e t h c e n t u r i e s ( F a r n h a m , 1980). T h e s u b s e q u e n t s p r e a d of t h e s e s e a w e e d s w a s followed k e e n l y b y p h y c o l o g i s t s in t h e 1930s a n d 1940s. D u r i n g t h e 1970s t h e r e w a s a r e s u r g e n c e of i n t e r e s t in i n t r o d u c e d algae, p r o m p t e d by t h e r e c o g n i t i o n of s e v e r a l n e w aliens ( F a r n h a m , 1980), w h i c h c u l m i n a t e d in d e t e r m i n e d a t t e m p t s to e r a d i c a t e t h e f u c o i d b r o w n a l g a Sargassurn rnuticum from t h e s o u t h coast of E n g l a n d . T h e failure to e l i m i n a t e or e v e n slow t h e s p r e a d of S. rnuticum p r o b a b l y cont r i b u t e d to a d e c l i n e in t h e a t t e n t i o n p a i d to a l i e n s e a w e e d s . O v e r t h e last f e w y e a r s t h e r e h a s b e e n a r e n e w a l of i n t e r e s t in m a r i n e i n t r o d u c t i o n s ( S i n d e r m a n et al., 1992; B o u d o u r e s q u e et al., 1994; R i b e r a & B o u d o u r e s q u e , 1995). Ballast w a t e r h a s b e e n t h e m a i n focus, h o...

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Aim  To study the siting of marine protected areas (MPAs) with respect to the biogeographical distribution of seaweeds within the Agulhas Marine Province and to assess the effectiveness of current MPAs in including (conserving) seaweeds of the South African south coast. Location  South Africa – the south coast between Cape Agulhas and the Eastern Cape/Kwazulu‐Natal border, and eight MPAs within that area. Methods  We used interpolated seaweed distribution records from all available sources, in 50‐km coastal sections. Cluster analysis (Jaccard Average Linkage) of species presence/absence data provided measures of similarity between coastal sections and between MPAs. Complementarity analyses identified the sequence of ‘importance’ of sections/MPAs for conserving seaweed species. Results  Species presence/absence data indicated two main groups, representing western (cooler water) and eastern (warmer water) biogeographical divisions, as well as several biogeographical subdivisions within each of these groups. Complementarity analysis yielded a sequence of ‘importance’ of coastal sections (in terms of the highest number of species included) that began with a section just east of central in the Agulhas Marine Province, around Port Alfred, where there is no MPA. This was followed by the easternmost section (warmest water), which contains the Pondoland MPA, and then by the westernmost (coolest water) section, containing the De Hoop MPA. Similar analysis of the actual species collected in MPAs showed a generally similar pattern. Main conclusions  Seven current MPAs and one proposed coastal MPA in the Agulhas Marine Province appear to be well distributed and well sited to include (conserve) the full biogeographical range of seaweeds. However, if further MPAs are to be considered, the Port Alfred area is recommended for improved conservation. This study did not examine estuaries, which may require improved conservation efforts. Seaweed distribution data, which are often relatively complete, offer a good tool for planning the siting of coastal MPAs.

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We report the occurrence of four red macroalgae new to Europe. Two species were unambiguously determined to the species level with a DNA barcoding approach, while the remaining two species could only be assigned to a genus. Gelidium vagum was found in the Oosterschelde estuary the Netherlands). Gracilariopsis chorda, Chondracanthus sp. and Solieria sp. were found in the Gulf of Morbihan in Brittany (France); Solieria sp. was also subsequently observed in the Thau Lagoon (France). Gelidium vagum and Gracilariopsis chorda are species originating from the north-western Pacific, around the Japanese archipelago. Phylogenetic analyses also show a likely Pacific origin for Chondracanthus sp. and Solieria sp. Three of these species are likely to have been introduced after 2008, indicating some active transport pathways between the Pacific and the north-eastern Atlantic. These findings also underline the importance of consistent and continuous local expertise (versus rapid assessment) in early warning systems

Material of Rhodochorton purpureum (Lightf.) Rosenv. and R. floridulum (Dillw.) N~ig. from the European Atlantic coast was cultured in the laboratory and the life histories of these species were established. The life history of R. purpureum proved to agree in almost every aspect with earlier findings on this species; the life history of R. floridulum shows a resemblance to that of R. purpureum, in that no free carpospores are produced, but the pattern of post-fertilization development is simpler in R. floriduh~m: the tetrasporophyte develops directly from the fertilized carpogonium, and no morphologically distinct carposporophyte is present. The special pattern of life history in these Rhodochorton species is thought to warrant the maintenance of such species in a separate genus within the Acrochaetiaceae. 279