Presence and development of populations of the introduced brown alga Sargassum muticum in the southwest Netherlands

Can Native Epiphytes affect Establishment Success of the Alien Seaweed <em>Sargassum Muticum</em> (Phaeophyceae)?

“…A previous study at Letterard and a nearby tidepool found the main onset of fragmentation for this species to occur in September (Baer and Stengel 2010), which is similar to observations at other locations in northern Europe (e.g. Fletcher and Fletcher 1975;Critchley et al 1987;Steen 2004;Thomsen et al 2006). Since trophic status, light penetration and temperature were similar at both Cashel and Letterard (Baer and Stengel 2010), it seemed that the level of wave exposure was the main factor that determined the degree of epiphyte coverage.…”

Canopy characteristics of the brown alga Sargassum muticum (Fucales, Phaeophyta) in Lake Grevelingen, southwest Netherlands

“…The introduction and establishment of the invasive brown alga Sargassum muticum (Yendo) Fensholt in the Netherlands has been documented extensively by Prud'homme van Reine (1977aReine ( , 1977b, Nienhuis (1982), Prud'homme van Reine & Nienhuis (1982) and Critchley et al . (1987).…”

“…The introduction of the alga was noted within a year of its entry (Nienhuis, 1982) ; population development and effect on indigenous macro algae were monitored subsequently (Critchley et al, 1987). The invasive alga has been very successful in establishing extensive populations within this favorable, non-tidal environment .…”

“…Plants as small as 0 .3 m can reach the water surface as early as mid-November, and with continuous and rapid growth , the dense canopy is present permanently until mid-August, when the primary laterals are cast off as part of their natural senescence cycle (Jephson & Gray, 1977 ;Critchley et al, 1987). The holdfast/main axis is persistent and remains in a reduced form until regrowth of the next season's primary laterals .…”

“…This period followed the exceptionally cold winter of 1980-81, when areas of Lake Grevelingen froze, resulting in ice-scouring of the algal communities attached to the lake's dykes (see Critchley et al, 1987 for illustrations) .…”