In the present study, to evaluate the invasive potential of
Sargassum muticum in the Irish context, seasonal growth, size
distribution and reproductive phenology during an annual cycle
were monitored in different representative habitats, and compared
to growth of the native species Himanthalia elongata with which it
might compete for space. The ecology of S. muticum has not been
previously studied but the distribution of S. muticum in Ireland is
very patchy and no extensive populations, where habitat types
could be replicated, were available at the time of investigation.
Therefore, this study focused on site-specific differences to create
an insight into the species, ecology along a diverse coastline on the
Irish west coast. Three study sites were chosen: one exposed site,
one sheltered site and a tide pool, all situated in close proximity.
Amongst these sites was Cashel Bay where the species was first
recorded in 2001 (Loughnane and Stengel, 2002). The other two
sites, Letterard and a tide pool at Moyrus, were located within
a radius of 15 km of Cashel Bay and also hold healthy S. muticum
populations. It was hypothesised that the species’ ecological traits
would show significant variations amongst these habitats and that
the findings might help with assessing the potential future impact
of S. muticum on native marine biota on the Irish west coast.