Understanding and predicting the onset of biofouling on cultivated kelp

Rebekka Uhl¹, Dan Smale¹

¹The Marine Biological Association of the UK, UK

Seaweed aquaculture is widespread in Asia and is now gaining popularity in Europe for its uses in the food, pharmaceutical and cosmetic industries. Limitations for its spread in the UK have in-part been due to high levels of biofouling on cultivated kelp from epibionts such as hydrozoans, bryozoans, crustaceans and epiphytic algae. Biofouling harms seaweed farms due to its detrimental impacts on kelp biomass and quality by tissue damage, increased production costs and possible allergen risks.
This project aims to examine the temporal and spatial variation of biofouling on cultivated kelp to help predict the onset of biofouling events and therefore appropriate harvesting times for seaweed farms. The project will determine the abundance and taxonomic composition of epibionts on farmed kelp, specifically Saccharina latissima, in seaweed farms across the UK, Norway and Sweden. This will be complimented with monitoring of abiotic variables (such as light and nutrient availability) and biotic variables (such as plankton eDNA analysis). Samples will be collected fortnightly over the growing season of kelp, from January to August, to monitor the emergence and succession of epibionts and any direct impact of biofouling on the kelp fronds.
These data will determine the composition and on-set of biofouling organisms at each seaweed farm and thereby enable informed decision-making on appropriate harvest times. The addition of abiotic and biotic variables will provide possible rationale for the patterns seen, which can also be used to determine site and species selection at other farms in the future. Research has shown that biofouling can vary greatly within short geographical ranges, therefore this study will provide interesting insights due to its wide spatial and temporal range.