Background information and definitions
While aquaculture facilities can be partly located on land (hatcheries), most of it occurs at sea, in cages, pens, bags, or ropes exposed to the marine environment. They represent hard structures onto which organisms can attach and grow – known as the biofouling community. Non-native, invasive and other problematic species can be part of this biofouling community (Fitridge et al. 2012) and use aquaculture structures as “stepping stones” to spread and reach new areas to colonize (Ruiz et al. 1997). Non-native, invasive and problematic species can impact on native subtidal benthic invertebrate species through predation, competition for resources (food & space), contamination (for pathogens and diseases), or hybridization (through reproduction) (Bishop et al. 2010). Regularly removing biofouling organisms can potentially help reduce the risks that invasive, non-native and other problematic biofouling species pose to subtidal benthic invertebrates. Biofouling species can be manually or mechanically removed by introducing biological agents (such as a predatory species), or by undertaking regular cleaning of infrastructures (Fitridge et al. 2012). When removing biofouling care must be taken to ensure that biofouled marine debris is not created, as these can float to new destinations where these biofouling species can spread (Campbell et al. 2017).
Evidence for other interventions related to biofouling are summarised under “Threat: Invasive and other problematic species, genes and diseases – Prevent the attachment of biofouling organisms/species in aquaculture”, “Clean anthropogenic platforms, structures or equipment”, “Use antifouling coatings on the surfaces of vessels and anthropogenic structures”, “Use non-toxic antifouling coatings on surfaces” and “Restrict the use of tributyltin or other toxic antifouling coatings”.
Bishop M.J., Krassoi F.R., McPherson R.G., Brown K.R., Summerhayes S.A., Wilkie E.M. & O’Connor W.A. (2010) Change in wild-oyster assemblages of Port Stephens, NSW, Australia, since commencement of non-native Pacific oyster (Crassostrea gigas) aquaculture. Marine and Freshwater Research, 61, 714–723.
Campbell M.L., King S., Heppenstall L.D., van Gool E., Martin R. & Hewitt C.L. (2017) Aquaculture and urban marine structures facilitate native and non-indigenous species transfer through generation and accumulation of marine debris. Marine Pollution Bulletin, 123, 304–312.
Fitridge I., Dempster T., Guenther J. & de Nys R., (2012) The impact and control of biofouling in marine aquaculture: a review. Biofouling, 28, 649–669.
Ruiz G.M., Carlton J.T., Grosholz E.D. & Hines A.H. (1997) Global invasions of marine and estuarine habitats by non-indigenous species: mechanisms, extent, and consequences. American Zoologist, 37, 621–632.