Comparative analysis of morphometric traits of farmed sugar kelp and skinny kelp, Saccharina spp., strains from the Northwest Atlantic

Authors: UMANZOR, SCHERY - University Of Alaska; LI, YAOGUANG - University Of Connecticut; BAILEY, DAVID - Woods Hole Oceanographic Institute (WHOI); AUGYTE, SIMONA - University Of Connecticut; HUANG, MAO - Cornell University; MARTY-RIVERA, MICHAEL - University Of Connecticut; Jannink, Jean-Luc; YARISH, CHARLES - University Of Connecticut; LINDELL, SCOTT - Woods Hole Oceanographic Institute (WHOI)

Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/19/2021
Publication Date: 3/23/2021
Citation: Umanzor, S., Li, Y., Bailey, D., Augyte, S., Huang, M., Marty-Rivera, M., Jannink, J., Yarish, C., Lindell, S. 2021. Comparative analysis of morphometric traits of farmed sugar kelp and skinny kelp, Saccharina spp., strains from the Northwest Atlantic. Journal of the World Aquaculture Society. 2021;1-10. https://doi.org/10.1111/jwas.12783.
DOI: https://doi.org/10.1111/jwas.12783

Interpretive Summary: Farmers typically grow the seaweed sugar kelp, Saccharina latissima, by harvesting its spores from wild populations and growing out resulting progeny. We have initiated breeding of sugar kelp to improve the competitiveness of kelp farming in the United States. There are two distinct morphologies of sugar kelp, standard wide-blade and narrow blade, a putative species designated Saccharina angustissima and locally referred to as skinny kelp. We crossed cultures derived from 37 wild-collected blades representing five sugar kelp strains and one skinny kelp strain to produce 104 unique crosses. Each cross was outplanted on a near-shore research farm located in the Gulf of Maine. Sugar kelp and skinny kelp were interfertile, and produced mature and reproductively viable individuals. Morphological traits of individual blades varied depending on the parental contribution (sugar vs. skinny), with significant differences found in progeny blade length, width, thickness, and in stipe length and diameter (the stipe connects the blade to the holdfast). Wet weight and blade density per plot showed no significant differences regardless of the cross. Given their published genetic similarity and their interfertility shown here, S. angustissima and S. latissima may not be different species, and may each contribute genetic diversity to breeding programs aimed at meeting ocean farming and market needs.

Technical Abstract: Our team has initiated a selective breeding program for regional strains of sugar kelp, Saccharina latissima, to improve the competitiveness of kelp farming in the United States. Within our breeding program, we also include an endemic putative species, Saccharina angustissima, locally referred to as skinny kelp. We crossed uniclonal gametophyte cultures derived from 37 wild-collected blades representing five sugar kelp strains and one skinny kelp strain to produce 104 unique crosses. Each cross was outplanted on a near-shore research farm located in the Gulf of Maine (GOM). After the first farming season, our results indicated that sugar kelp and skinny kelp were interfertile, and produced mature and reproductively viable sporophytes. Morphological traits of individual blades varied depending on the parental contribution (sugar vs. skinny), with significant differences found in progeny blade length, width, thickness, and in stipe length and diameter. Despite these differences, wet weight and blade density per plot showed no statistical differences regardless of the cross. Given their published genetic similarity and their interfertility shown here, S. angustissima and S. latissima may not be different species, and may each contribute genetic diversity to breeding programs aimed at meeting ocean farming and market needs.