Long-term survival of an introduced red alga in adverse conditions

Abstract Marine macroalgae can expand their distribution ranges by different human-mediated vectors, and certain species traits such as survival time out of water and regrowth of fragments are important factors determining the probability of spread. We tested the survival and capacity of regrowth of the introduced Asian red alga, Gracilaria vermiculophylla, collected in the north-eastern Kattegat, on the west coast of Sweden. Gracilaria vermiculophylla was kept in darkness under moist conditions at 8°C forbetween 4 and 175 days. Following this storage, the shoots were placed in seawater medium (two salinities, 26 and 35) at a temperature of 11.5°C. Regardless of the salinity and the duration of the storage, all shoots grew. No correlation was seen between growth rate and storage time, but G. vermiculophylla grew faster in a salinity of 26 than 35. Between two and four weeks of growth, several of the shoots started to fragment. The new fragments continued to grow after detachment. This study showed that G....