Ulva Lactuca and other green algaes
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Hey all, I am a boat captain in South Carolina and looking at the viability of growing mainly ulva lactuca and ulva intestinalis. I had a few questions, mainly about harvesting reproductive samples and transfer to tanks to make seed lines. If there is anyone with experience in green algae's I would love to throw a few questions your way!
@dakota_staff I've moved your post to the kelp hatchery topic since you're asking about making seeded lines. Hoping to give you more visibility there!
Also @toby_sheppardbloch if you have any ulva resources to share
@dakota_staff I don't know much about Ulva propagation--I think most cultivation is happening in land based tumble culture (at least in the US) because it lends itself to vegetative propagation so operators don't need to control the entire lifecycle. I've also heard about land based systems in NZ using Ulva to clean/bioremediate wastewater.
@Steven_hermans did a good roundup of Ulva projects a couple years ago-- a good jumping off point.
https://phyconomy.substack.com/p/ulva-too-much-or-not-enough
@dakota_staff I will mirror what Toby said regarding propagation in tumble culture. Your yield per linear area on the farm is only going to be around a Kg/m wet weight so it's not terribly productive in longline culture. You would need to have a supporting market paying a fairly high price to support this cultivation method. Ulva reproduction is complex, you often will have difficulty, as you mentioned, finding reproductive individuals as many "adult" blades are actually haploid "gametophytes" and when you do find a reproductive diploid individual and induce them to release zoospores they produce either asexual, diploid zoospores with four flagella, or haploid gametes with two flagella. The haploid zoospores can settle and become haploid thallus direct, adding to the confusion. It's difficult to know exactly what are going to get. Here is a link to an article where they had some success inducing spore release and producing haploid gametophytes https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4019596/.
Also, given how unpredictable Ulva reproduction can be, growing Ulva in tumble culture through fragmentation makes the most sense. You can choose individuals that have the characteristics that your market wants, and then propagate those individuals. Tumble culture allows for the tight control of parameters leading to improved yields and multiple harvests per year. An expensive breeding program may eventually yield results, but utilization of wild genetics is much cheaper! You can induce parthenogenic propagation through fragmentation, a process mentioned here: https://www.frontiersin.org/articles/10.3389/fmars.2022.816890/full.