Reply to Fundamental design questions on Fri, 30 Oct 2026 22:48:08 GMT

kendall_barbery — Fri, 30 Oct 2026 22:48:08 GMT

@jonathan_tasmania_australia You're correct that these systems are deployed with significant variation, depending on the site, scale, and specific culture requirements of a given farm.

The larger the farm site, the more likely it is that different culture methods and gear are on separate longlines rather than the same longline. At a smaller scale, we've stacked our production and observed a positive correlation between kelp and mussel growth in particular, with the caveat that colocation entails additional operational considerations––particularly during outplanting and harvest activities.

Per Bren saying that the mussels went in after the seaweed was harvested, he's referring to leaving the kelp holdfasts and stipes on our longlines after the kelp harvest––they're a great substrate for collecting mussel spat. The spat often settles amidst the stipes, like on a fuzzy rope spat collector. Once the spat are large enough, we'd strip them from the kelp line and transfer the spat to mussel socks, which we would then hang from the longlines. That method is more unpredictable than purchasing spat (which we have also done), but it's worked for our purposes. We've tied the mussel socks to the kelp longline, attached them to a separate longline below the kelp longlines, and suspended mussel socks on adjacent longlines. We've used a continuous loop and separate socks spaced 1-3 meters apart. Lacking mechanized mussel harvesting equipment, individual socks might be a better approach. Separate longlines may be more operationally efficient, but stacking is possible if you're working within a small footprint.

For oysters, we've attached our bottom cages to the kelp longlines, but for larger production volumes, we've kept the cages in a zone adjacent to the kelp longlines. Some farmers alternate kelp lines and bottom cages (in deeper water sites). On some shallow water sites using flip bags or other floating gear, farmers will move the oysters to deeper water in winter and add kelp longlines in place of the flip bags in winter.

There are really a mixture of approaches and farmers hone the methods that work best for their sites and operations.

Could you share some context about your site along with your proposed design and production goals? I can tag some other folks who may be able to share some tips and advice based on their experience and research.

Reply to Fundamental design questions on Fri, 30 Oct 2026 22:41:46 GMT

lindsay_olsen — Fri, 30 Oct 2026 22:41:46 GMT

@jonathan_tasmania_australia Hey Jonathan,
For the most part, folks are using separate lines to grow shellfish and seaweed. There are some exceptions, but most folks have found that at scale, it makes sense to separate lines by crop type to gain efficiency. To reap the most benefits from co-culture, you could think of it like "row cropping" with one line of shellfish, one line of seaweed alternating. However, for convenience and efficiency, many people have their kelp lines and gear set up on one portion of their lease, and their shellfish lines set up on another portion of the same lease, and work the gear separately. I would say this is the most common configuration of farms growing both shellfish and seaweed.