1) Determine the role of kelp cultivation facilities as ‘artificial forests’.
2) Estimate the role of cultivated kelp as medium for distribution of unwanted species.
3) Evaluate the role of cultivated kelp on natural kelp communities.
Natural kelp forests are efficiently colonized by a wide variety of associated species. In addition, they form important nursing, feeding and hiding areas for fish, crabs and other commercial important species. Artificial reefs have attracted fish few days after being submerged. Kelp cultivation might form substitutes for natural kelp forests; however their role in providing substrate and shelter is obstructed as the production period is lasting only from Jan/Feb to May/June, depending on species and region, while the installations are more permanent. Remaining fertile kelps at the farm may release spores that can disperse to the adjacent rocky coastline and influence the natural kelp beds. If commercial production selects breeds with strong geno- and phenotypical properties, it is possible that these will have the ability to outcompete natural strains and species of kelp in the local environment.
T4.1. Abundance, species composition and function of kelp associated algae and invertebrates will be assessed at two different kelp cultivation facilities (SES and Hortimare) in May (prior to harvesting) and August (after harvest). Sampling will be performed by collecting kelp from the facilities, using fauna traps and through quantitative sampling on ropes using SCUBA. Abundance, species composition and functional traits will be compared with adjacent natural kelp forests and with published data on kelp forest flora and fauna. Quantification of fish species will be evaluated using Nordic gill nets (different mesh sizes).
T4.2. Distribution of unwanted and red-listed species will be assessed specifically during the quantification (T4.1) and the role of kelp cultivation as a medium for distribution of invasive, black-listed (unwanted) and red-listed (wanted) species will be assessed.
T4.3. Genetic diversity in natural kelp and the likelihood that mono-cultured cultivated kelp species will out-compete natural kelp will be assessed by the use of existing knowledge, literature surveys and models on spreading and suitable areas for kelp growth.
• Paper on abundance, biodiversity and function of species associated with kelp cultivation facilities compared to natural kelp forests; incl. the potential of kelp farms as nesting ground for unwanted and red-listed species.
• Report on up-to-date knowledge of genetic variation in kelp and assessment of potential risks of natural kelp populations.
• A baseline description of the current knowledge and gaps with a perspective for future studies.