Nitophyllum stellatocorticatum -

This red alga originally occurs in the northwest part of the Pacific Ocean (Japan, Korea) ^[2].

First observation in Belgium

On July 9, 2023, Nitophyllum stellatocorticatum was first discovered in the Sluice Dock in Ostend, forming large patches on the pontoons ^[3].

Distribution in Belgium

In Belgium, this red alga has so far only been found in the Sluice Dock in Ostend ^[3].

Distribution in neighbouring countries

Nitophyllum stellatocorticatum was first recorded in the Netherlands in 2006, in the Eastern Scheldt ^[4]. To date, its distribution appears to be mainly restricted to the Eastern Scheldt and the Grevelingenmeer, where this red alga has been increasingly observed since 2022 ^[3-5]. In the western Mediterranean, Nitophyllum stellatocorticatum was found in the Thau Lagoon near Montpellier, France, in the summer of 2003 ^[6,7], a lagoon where Japanese oysters were imported for aquaculture activities ^[6]. In the far western Mediterranean, the species is considered established ^[7].

This species was likely introduced to new areas (both primary and secondary) through the transport of shellfish for aquaculture purposes ^[3,6]. However, the possibility of introduction via biofouling on ship hulls cannot be ruled out ^[3].
 

Nitophyllum stellatocorticatum is found in stagnant water in the lower littoral and sublittoral zones ^[3,4]. There is limited information available on the species' tolerance limits to physicochemical variables.

No information available. 

There are no known effects or measures related to the presence of Nitophyllum stellatocorticatum.

Nitophyllum stellatocorticatum can grow up to 30 cm in length and feels thin and very soft. This red algae is transparent and light red to pink in color. The fronds are one cell layer thick, lack veins, and can be either relatively regularly dichotomous or irregularly branched. The reproductive organs are scattered on the fronds like little dots ^[2]. However, the specimens found in the Sluice Dock were lacking these dots ^[3]. As such, non-fertile specimens can be confused with other leaf-like red algae, making a microscope necessary for accurate identification ^[4].

[1]          World Register of Marine Species (WoRMS) (2024). Nitophyllum stellatocorticatum Okamura, 1932. https://marinespecies.org/aphia.php?p=taxdetails&id=652187 (2024-10-18).  

[2]           Van der Loos, L.; Karremans, M.; Perk, F. (2021). Veldgids Zeewieren. KNNV Uitgeverij: Zeist. ISBN 978 90 5011 8019. 302 pp. [https://www.vliz.be/nl/imis?module=ref&refid=336668]   

[3]           Jonckheere, I.; Kerckhof, F. (2024). Waarnemingen gedaan tijdens de SWG-excursie naar de Spuikom van Oostende op 9 juli 2023 met vondsten van verschillende nieuwe geïntroduceerde soorten voor de Belgische fauna. De Strandvlo 44(2): 33-41.  [https://www.vliz.be/nl/imis?module=ref&refid=394050]   

[4]           ANEMOON Verspreidingsatlas Wieren. Nitophyllum stellato-corticatum Okamura, 1932. https://www.verspreidingsatlas.nl/S372437 (2024-03-26).  

[5]           GBIF. Nitophyllum stellato-corticatum Okamura, 1932. https://www.gbif.org/occurrence/map?taxon_key=2662093 (2024-03-26).  

[6]           Mineur, F.; Belsher, Th.; Johnson, M.P.; Maggs, C.A.; Verlaque, M. (2007). Experimental assessment of oyster transfers as a vector for macroalgal introductions. Biol. Conserv. 137(2): 237-247. [https://www.vliz.be/en/imis?module=ref&refid=393682]   

[7]           Zenetos, A.; Gofas, S.; Verlaque, M.; Cinar, M.E.; García Raso, J.E.; Bianchi, C.N.; Morri, C.; Azzurro, E.; Bilecenoglu, M.; Froglia, C.; Siokou, I.; Violanti, D.; Sfriso, A.; San Martín, G.; Giangrande, A.; Katagan, T.; Ballesteros, E.; Ramos Esplá, A.A.; Mastrototaro, F.; Ocaña, O.; Zingone, A.; Gambi, M.C.; Streftaris, N. (2010). Alien species in the Mediterranean Sea by 2010. A contribution to the application of European Union’s Marine Strategy Framework Directive (MSFD). Part I. Spatial distribution. Mediterr. Mar. Sci. 11(2): 381-493. [https://www.vliz.be/nl/imis?module=ref&refid=287592]

VLIZ Alien Species Consortium (2024). Nitophyllum stellatocorticatum. Introduced alien species of the Belgian part of the North Sea and adjacent estuaries anno 2024. Flanders Marine Institute (VLIZ). 3 pp.