Orange ripple bryozoan - Schizoporella japonica

Background:
Bryozoans are colony-dwelling organisms, forming structures out of many microscopic individuals knowns as zooids (Missouri Department of Conservation, 2024). They may live in fresh or salt water, attaching to substrates such as aquatic plants, other creature’s shells, rocks, and litter (Wood, 2010). 
Schizoporella japonica is a marine intertidal bryozoan species, often found on rocky substrate or human built structures. It is recognisable by its vibrant orange colour and leaf-like growth pattern (Loxton et al, 2017) (fig. 1). 

Native Range and Distribution:
Orange ripple bryozoans are native to the coastline between China and northern Japan, but are known to have been introduced to the Western USA, Australia, New Zealand, the UK (Smithsonian Environmental Research Centre, n.d.), Ireland, and Norway (Loxton et al, 2017). 
Its first appearance in the UK was in Wales in 2010, with its first appearance in Scotland not long after, near Orkney in 2011 (Ryland, Holt and Loxton, 2014.). As of today, the species has been observed multiple times in Scotland and Northern Ireland, and only once in both Wales and England respectively (fig. 2) (NBN Atlas, 2024). Notably, this is an unusual case for the British Isles in which the invasive species is spreading from the north downwards (Loxton et al, 2017). 
As with most invasive yet physically immobile marine species, orange ripple bryozoans likely made their way to the UK while attached to ships or in ballast water (NNSS, 2017). 

Risks and Control:
Schizoporella japonica poses a potential risk to the Scottish oyster and mussel industries. Its growth increases competition for these economically important species and can reduce their market value (NNSS, 2017). It may grow on top of native species, smothering them (Sewell, 2019), while also interfering with aquaculture equipment, reducing its functioning and efficiency (NNSS, 2017). 
While recommendations and laws are in place to prevent the spread of invasive aquatic species, there will always be some risk. Thus, introduction of orange ripple bryozoans will likely never be fully preventable. Additionally, the species is easily mistaken for various other species, so even early identification of new colonies is extremely difficult. (Sewell, 2019).