Phase II: Strain hybridisation field experiments and genetic fingerprinting of the edible brown seaweed Alaria esculenta

Abstract

Under phase II of the Marine Research Measure several field trials were performed with five biogeographical dispersed North Atlantic strains and their hybrids of the edible brown alga Alaria esculenta at Ard Bay, Carna, Co. Galway. The weight, length, width, biomass per meter rope, growth rate and protein level were measured. The fastest-growing crosses were produced with female Norway gametophytes together with male gametophytes of other strains. The Canadian selfcross produced most biomass of over 45 kg per meter rope. The female Iceland x male Ireland crossing produced the second highest biomass figure of 13.75 kg wet weight per meter rope, while the Irish self cross using a strain from the Aran Islands produced 7.4 kg wet weight per meter. The Canadian selfcross expressed the highest protein level followed by the female Newfoundland x male Norway hybrid. These strains and hybrids are well suited to be included in a protein rich macro-herbivore diet. The Irish native strain showed a lower protein level of 8% of the wet weight. Genetic fingerprinting using RFLPs did not show any genetic differences amongst the strains in respect of the DNA examined. A detailed sequencing study on the Rubisco spacer region showed a negligible 3 bp difference between the Irish and Canadian strains In conclusion, the Canadian strain or hybrids derived from female Canada gametophytes or female Iceland gametophytes produce more biomass per meter rope and grow larger and wider in size compared to the native Irish strain. They Canadian strain also showed the highest protein values in the field trials and hence are most suited to be applied in Irish aquaculture of the brown seaweed Alaria esculenta.