Impact Assessment of Non-Mechanical Harvesting of Ascophyllum nodosum on the Recovery of Vertebrata lanosa and its Associated Biodiversity

Student: 
Sherif Abdallah

Ascophyllum nodosum is a dominant fucoid seaweed and is regarded as a primary keystone producer that supports biodiversity. A. nodosum is commercially harvested along the west coast of Ireland, providing an essential source of income to local communities. Verteberata lanosa, an obligate epiphyte on A. nodosum, supports complex food webs as it is less persistent to grazers. The thesis aim is to assess the potential regeneration of V. lanosa and its associated biodiversity after hand-harvesting with knives and using cutter rakes from boats in Kinvara, Galway Bay, Ireland. Samples were randomly collected from unexploited controls, hand and boat plots during baseline and three post-harvest surveys. V. lanosa biomass, species richness, H’, and J’ did not show temporal significant differences between hand and boat harvested samples. The nMDS plot did not show a distinct pattern of assemblages. Peringia/ Pusillina spp. had a relative abundance of 53.11% and 22.82% after one month of hand and boat harvest, respectively. One-year post-harvest, Peringia/ Pusillina spp. still dominated the hand-harvest plot with a relative abundance of 35.15%, while grazers, including Hyale sp., Littorina sp., and Jaera sp. dominated the boat-harvest one, suggesting faster recovery.