Population genetic analyses are consistent with the introduction of Ceramium secundatum (Ceramiaceae, Rhodophyta) to Narragansett Bay, Rhode Island, USA

Abstract

During ongoing DNA barcode (COI‐5P) surveys of the macroalgal flora along the northwest Atlantic coast, we discovered a population of Ceramium secundatum in Narragansett Bay, Rhode Island, USA. This species is regarded as common and widespread in the northeast Atlantic, ranging from Norway to Morocco, but until now has not been reported from the western Atlantic. Several lines of evidence suggest that C. secundatum may be introduced to Narragansett Bay: (1) despite extensive collecting, specimens have only been obtained from a limited geographic range in the northwest Atlantic; (2) three other nonindigenous seaweed species are reportedly introduced in this region, which is thought to be a consequence of shipping; and (3) this species is introduced to South Africa and New Zealand. To investigate this suspected introduction, we applied population genetic analyses (using the cox2‐3 spacer) to compare the Narragansett Bay C. secundatum population to native populations in the Republic of Ireland and the United Kingdom. Collectively, analyses of biogeographical and molecular data indicate that C. secundatum is likely introduced to Narragansett Bay. The implications of this discovery are discussed.

Phylogenetic Analysis of the Red Algal Tribe Ceramieae Reveals Multiple Morphological Homoplasies but Defines New Genera

“…The clade Ceramium includes the generitype species C. virgatum Roth. In this revised circumscription, Ceramium sensu stricto is a North Atlantic genus, with Mediterranean representatives, that has been introduced to New Zealand and probably elsewhere (Bruce & Saunders 2015). None of the numerous schemes used to subdivide the genus based on the degree of cortication or the position of tetrasporangia (e.g.…”

Evidence for the introduction of the Asian red alga Neosiphonia japonica and its introgression with Neosiphonia harveyi (Ceramiales, Rhodophyta) in the Northwest Atlantic

“…There are numerous algal species that have had significant negative impacts when they were introduced to a new area. Along the New England coast, there have been many non-native red algal species discovered in recent years including Grateloupia turuturu Yamada (Villalard-Bohnsack & Harlin 1997), Gracilaria vermiculophylla (Ohmi) Papenfuss (Nettleton et al 2013), Heterosiphonia japonica Yendo (Schneider 2010), and Ceramium secundatum (Lyngbye) C. Agardh (Bruce & Saunders 2015). Grateloupia turuturu, Gracilaria vermiculophylla and Heterosiphonia japonica are known to be invasive worldwide and have spread rapidly along the coast of New England since their respective introductions (Mathieson et al 2008a;Nettleton et al 2013;Newton et al 2013).…”