Sugar Kelp Hatchery guidance - what went wrong?

Hi,
We have
successfully grown sugar kelp all the way from spores to maturity (10’ long
blades) but this year we failed 4 times to grow any seeds, and we are stumped
as to what the problem(s) are thus we’re reaching out to the community for
advice and guidance.
We followed the "Ocean Approved: Kelp Manual" as best we could. I've attached a word document with details and pictures of the process that we went through. I realize that this isn't a quick and dirty request but if anyone had time to read through this and offer suggestions or guidance I'd very much appreciate it.
Comments could be left here on the GW "community" or feel free to email or call me
Tks,
Mike
mike@pacificseafarms.com
206-491-0936
PSF Hatchery Process

kendall_barbery

Thanks for sharing this @mike_spranger. I converted your Word doc to a Google doc and have opened it up for comment access. That should help others to weigh in and collaborate to help troubleshoot. Find that doc here @toby_sheppardbloch @margaret_aydlett @david_bailey @lindsay_olsen Could you all take a look at Mike's description and comment as relevant? Please feel free to tag others who you think may have insights.

margaret_aydlett

@mike_spranger Hi Mike, thanks for sharing such a thorough write up! Here are some of my thoughts:

Salinity of 1.017 (sg) (~22 ppt) is a little low for what we normally use but if it matches the local water conditions for where the sorus collected it should not be any issue.
If you saw motile spores during the spore release, we can rule out that the issue was with the sorus preparation or release process.
The sodium thiosulfate in water conditioner you used would neutralize the residual bleach. The other components should not have any toxic effects on the kelp.
The seeding density should be 7500 spores per mL of water, not per spool as you said in #14. Maybe that was a typo?
20 mL of F/2 each week is low compared to our dosing, but if it worked in the past season this is probably not the issue.
Your inclination that the original growth was diatoms sounds correct based on the timeline you shared. We dose with GeO2 at a density of 0.11 mL of stock per 1 L of water in the tanks (stock solution is 0.1 g of GeO2 powder per 200 mL of water)
The first macro photo looks to me like there may be some spotty kelp growth, some diatoms, and some small specks of green micro algae.
The second photo shows definite spots of diatoms (the dark brown spots that sort of scatter outwards from a center).
The third photo seems completely blank. In our experience, this is usually a results of the water conditions in the tank. I would expect to see some contamination at the very least if the tank conditions were right.
The microscope photos of the seedstring are difficult to see, but it does look like there is a blade drooping down the side in one of them.
In the slide smear photos I see a lot of diatoms but also some juvenile kelp blades that seem to have been smothered. In cases like this in the past, we have rinsed spools under a steady, gently stream of clean saltwater to dislodge the diatoms and keep them from smothering the blades too much. The sporophytes stay attached by their holdfasts.
In the very last microscope photo, I see only diatoms. The blurrier stuff in the center of the photo could be bacteria or blades but it is too unclear to tell.
Using a 20-35 micron filter to filter you spore solution will help to avoid some contamination and is worth it in our opinion, but diatoms and other micro algae can still make it through the filters so it will not completely fix the issue.
We recommend weekly water changes at the very least, especially if you ar seeing contamination. The water change can decrease the density of diatoms, or other contamination, and prevent them from smothering the kelp before the blades are big enough.

Overall, there are a lot of factors that could have caused the issues. To narrow it down, I think you can start by assuming that everything that worked well for your good nursery season was not the issue this season (ie. water temp, using instant ocean, pH, salinity, stocking density, nutrient dosing, etc). If I’m understanding everything correctly, that leaves the water conditioner as the only variable, but I think it is unlikely that the conditioner caused the issues. I see sporophytes in some of the photos you shared, so it does not seem like the season was a complete bust, but the sporophytes were definitely smothered by contaminants. I would suggest using a filter for the spore solution and doing more frequent water changes in the upcoming season to help keeps contamination down.

Did you outplant any of the seed even though you weren’t happy with it? The photos of your lines look great!

mike_spranger

@margaret_aydlett Holy Cow, Margaret. Thank you for such a thorough response. I did make an error on the spore count I added per spool. I multiplied the amount of spores by the volume of my holding tubes to get the right volume of solution per holding tube/spool such that I was at 7500 spores
I’m glad that that dechlorination solution wasn’t a seaweed killer but I kind of wish it was so that I could ID that as my issue.
I need to get better educated on identifying what I’m looking at under the microscope plus I will pay more attention to the cleanliness of the water (change weekly) and your other suggestions
Do you have thoughts on the quality of the spores as the season progresses? In other words, my first attempt was with sorus collected in late November whereas the 2nd attempt was collected in January In both cases, to me the sorus was good and unfouled and the spores were highly mobile. As the season goes on do the spores “get tired” or otherwise degrade such that the likelihood of them producing seed goes down?
finally, I was going to out plant the seed string on my lines anyway but the wild set was so thick that I didn’t want to disturb or otherwise damage that so my crop this year will be entirely wild set

kendall_barbery

Thanks @Jamie_lee for adding comments to the doc as well!

mike_spranger

@margaret_aydlett hi Maggie, do you have any thoughts on this item? It may have gotten lost in all the details…

Do you have thoughts on the quality of the spores as the season progresses? In other words, my first attempt was with sorus collected in late November whereas the 2nd attempt was collected in January In both cases, to me the sorus was good and unfouled and the spores were highly mobile. As the season goes on do the spores “get tired” or otherwise degrade such that the likelihood of them producing seed goes down?

margaret_aydlett

@mike_spranger Hi Mike, our rule of thumb is that motile spores are motile spores. In southern New England, we certainly see sorus collected later in the season having more biofouling on it, but otherwise haven't noticed many differences.

tristan_s

@mike_spranger Hi Mike! I know diatoms can be a real threat to growing spores. I recommend to try to remove the silicate from the water that you are using. There are various methods that you can find online (E.g. filtering, RO, Calciumhydroxide). Because the diatoms are using the silicate to grow and reproduce, taking it away should significantly reduce the potential growth. Germanium dioxide would be a nice addition, but you mentioned it's very difficult to obtain for you.
My recommendations:

Make sure the salt that you are using has no silicate in it
Using a filter (5 - 35 µm, as mentioned by Margaret) to filter the spore solution helps a lot
Increase the amount of nutrients (also check if there is any silicate in it)

All the best,

Tristan

mike_spranger

@tristan_s hi Tristan. I’m using Instant Ocean. Can you advise if this has silicates that should be avoided?

tristan_s

@mike_spranger The report that you provided states that the second sample has 1.8 mg/l of silicate in it. The recommended amount should be below 1.0 mg/l to combat diatom growth. It's interesting to see that there are almost no trace minerals in the first sample. Just out of curiosity, what is the difference between the two samples?

mike_spranger

@tristan_s hey Tristan, I may have posted a chart that confused matters… I googled instant ocean ingredients/specifications and that’s what I got. I’m not setup to use actual ocean water and I believe instant ocean is the best and most widely used alternative for this purpose so I’m not sure what other choices I have…

tristan_s

@mike_spranger Hey mike, I think all the marine salt may contain traces of silicate. If would recommend treating the the marine salt before using it for hatchery purposes.
I would do the following:

Dissolve the needed salt in the minimum required amount of water (full saturation of regular salt is around 360 g/L)
Treat the solution with either calcium hydroxide (caustic soda) or use a RO-filtering system (reverse osmosis)
Dilute the filtered/treated salt solution to the final needed volume

The caustic soda will form white flakes that you can fish out with a fine mesh simply pass the solution over a cloth.
The caustic soda treatment can influence the pH (>9) so double check the pH once you have the final volume.
I hope this helps! Cheers!

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