How much seaweed can small farms produce?

[emma_wagstaff]

Hey everyone,

I work in the energy industry but I am also a huge fan of seaweed farming - one day I plan to start my own farm. When I read "Eat Like a Fish" I really agreed with Bren's vision that a "reef model" network of small ocean farms would be better than huge industrialized farms. I agree that this is our chance to learn from our mistakes on land and avoid giant industrialized mono-crop plantations.

However, my colleagues at the DOE who want to use seaweed to produce biofuel and biomaterials think that small farms can't possibly scale enough to meet the world's materials demands.

My thought is that small farms provide much greater benefits: since workers have more equity in their business, the farms can grow crops best suited to that region and the farms are near shore so they can better uptake nitrogen runoff and buffer coastlines from swells.

I also think those large offshore automated farms are going to be really hard to engineer since building in the ocean is so complex and demanding.

Does anyone have anything else to add to this argument? Do people with ocean farming experience think there is any role for automated tools? Maybe it's possible that the macroalgae species we eat will be produced by small farmers while the species used for biofuels/bioplastics will be grown by bigger operations?

I want to see the kelp market takeoff so we can reap all the planet-friendly benefits of farming in harmony with nature - but I don't want to see us scale in a way that makes it inaccessible to small farmers.

I am really excited to play with the tools on the hub and to see if I can start modeling yield - I personally feel that small farms could meet global demand but I want the numbers to prove it!

Thanks,

Emma

P.s: I am so excited the hub exists so I have other ocean-farming nerds to chat with :)

[alf_pryor17]

@emma_wagstaff -

Hi Emma,

I think these are really good questions. I'm based in Alaska and I consider myself a small scale farmer, currently farming around 38k ft this season on a 17-acre lease. I've also been a part of a arpa-e funded project looking into scaling up kelp farming for bio fuels the past three seasons. From my perspective I think there is a place and need for both but it comes down to what kind of markets are available and at what price per pound. In Alaska we are not as limited in the space available but we are also a long ways away from markets. So I think you'll see a more wholesale approach which means a low price per pound and larger farms. I think the east coast is much better suited for smaller scale farms due to the close proximity to food markets. If your looking to make a real impact on climate change through kelp farming it will have to be done with large scale farming. That's not to say small scale farms won't have an impact but if your looking at making major reductions in carbon it's going to have to be done at a massive scale. Right now there is a lot of money being put into using fermented kelp for animal feed. It's a massive potential market and could have some real impacts on climate change but to meet the price per pound will only be realistic with large scale farming. The food and possibly nutraceutical markets are the only real chance for small scale farmers. So the trick if you want a large number of small scale coastal farmers is to convince more people to eat kelp. 

As far as large offshore automated farming I think your right, it's a very tough engineering challenge. From the work I've done the past three years I definitely think there are pathways for getting this to work. It's going to take a lot more investment though. 

What would you consider a large scale farm? 

[michael_doall]

@emma_wagstaff - Great post Emma! I share your thoughts and concerns regarding the future scaling of the kelp industry and the viability of small kelp farms. I think the reply by alf_pryor17 touches on a lot of great points regarding differences in scale and proximity to markets between east and west coast farms.

For the past four kelp seasons I’ve been researching the feasibility of integrating sugar kelp into small oyster farms on Long Island, NY. Over this time I’ve conducted kelp cultivation trials at 16 different locations in all the main estuarine systems surrounding the island. Here’s a couple points I can make about how much kelp can a small farm produce, at least in these near-shore environments around Long Island.

1) There is a lot of variability among sites, and also among years at the same site.

2) We’ve achieved yields ranging from 4 to 9 pounds per foot of kelp line, with blade lengths up to 12 feet at the highest yields. Extrapolated over an acre assuming 5-foot spacing between lines, the highest yields  can produce 72,000 pounds per acre.

3) Surprisingly, the highest yields we’ve obtained have been in shallow waters where low tide depths are about 2 feet. Yes, 12-foot kelp blades in 2-feet of water!

4) preliminary results indicate that growth is higher in areas of higher nutrient loading. We have kelp currently growing in the heavily impacted waters of the East River near NYC and it’s doing awesome!

5) The earlier you can seed lines in the waters off Long Island, the better the growth and higher the yields. Even just a few weeks (early December vs late December) makes a big difference.