Development of the Core Lit Apparatus for Seaweed Hatcheries (CLASH) bioreactor using a germplasm approach

Author

• Phillip O. TahimicFollow

Graduation Date

Spring 2026

Document Type

Thesis

Program

Master of Science degree with a major in Natural Resources, option Fisheries

Committee Chair Name

Rafael Cuevas Uribe

Committee Chair Affiliation

Cal Poly Humboldt Faculty or Staff

Second Committee Member Name

Rachael Wade

Second Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Third Committee Member Name

Eric Bjorkstedt

Third Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Keywords

Kelp, Bioreactor, Land-based, Aquaculture, Northern California, Seaweed, Macroalgae

Subject Categories

Fisheries

Abstract

In comparison to the Asian aquaculture industry, the United States has minimal seaweed production. There are several drivers of the limited industry in the US, such as regulatory constraints and limited market demand, but the ability to scale is a considerable barrier to commercialization. One possible solution is the development of land-based systems that integrate bioreactors, which utilize fewer resources and do not wholly rely on an oceanic flow-through system. This study assessed the application of a modular bioreactor, known as Core Lit Apparatus for Seaweed Hatcheries (CLASH), as a nursery system and open-source project designed to expand land-based seaweed aquaculture. Specifically, the goal of this project was to investigate the feasibility of producing juvenile kelp in CLASH when seeded with gametophytes from a germplasm bank, a reliable seed stock technique for kelp farmers. The objectives of this research were to 1) demonstrate production of juvenile Alaria marginata sporophytes in the CLASH system and 2) characterize spatial effects within the CLASH system on A. marginata sporophyte development, proxied by blade length (mm) and percent kelp cover. Stock cultures of A. marginata gametophytes were used to seed ceramic tiles (n=12 per system) placed within 10-liter CLASH bioreactors (n=3) at different depths and positions using two application methods (paintbrush or spray application). There were no significant effects of seeding method, tile position, or tile depth on blade length (mm) or kelp cover (%) (Linear mixed effects model and Kruskal-Wallis tests, p > 0.05). After a 50-day nursery period in CLASH, blade length on tiles was 4.15 ± 3.97 mm (n=50/tile, mean ± sd), kelp cover per tile was 89.01 ± 9.96%, wet biomass per tile was 9.97 ± 5.39 g, and total wet biomass from 36 tiles was 375.28 g. Juveniles of A. marginata survived an additional 21 days after transfer from the CLASH system into an indoor tumble culture tank, demonstrating the potential of using the CLASH system as an intermediate nursery for A. marginata and to support mature sporophyte production in larger, fully land-based aquaculture systems in California.

Citation Style

Elsevier

Recommended Citation

Tahimic, Phillip O., "Development of the Core Lit Apparatus for Seaweed Hatcheries (CLASH) bioreactor using a germplasm approach" (2026). Cal Poly Humboldt theses and projects. 2586.
https://digitalcommons.humboldt.edu/etd/2586