ARKEVs – Arrays to Recovery Kelp Ecosystem Vegetation – are a novel technique in kelp forest restoration thought up and designed by researchers and scientists at Moss Landing Marine Labs (MLML) and The Nature Conservancy (TNC), as well as many others involved in that project, and were first tested in northern California near Mendocino. They are engineered to give young bull kelps a place to grow out of reach of hungry sea urchins, so that kelp can once again grow in areas where it used to provide abundant kelp forests, supporting an entire ecosystem. The idea of growing kelp in urchin barrens is not new, and other methods have been attempted to varying degrees of success. ARKEVs appear to be hitting the right combination; they elevate kelp off the sea floor to avoid urchins, they allow kelp to grow through its complete life cycle and rain down reproductive material in the area, they are temporary and can be removed before powerful storms batter them, and they are affordable and reproducible.
ORKA decided to pilot the use of ARKEVs in Nellies Cove after talking with the project team in Mendocino and hearing about the different trials and tribulations they experienced. But before that could happen, we had to figure out how to ‘permit’ them in Oregon. They needed to be temporary and removed before they could be damaged by the ocean, and they couldn’t impose any risk to boating navigation. Luckily, ORKA had previously worked with the Department of State Lands on a site registration for kelp restoration – different than a traditional permit, this framework allows ORKA to work at predetermined sites and use techniques to try to bring back kelp. Because of this agreement with DSL in place, ORKA was able to amend the registration to add the use of ARKEVs. Forms filled, it was time to get to work.
Science Coordinator Sara Hamilton and I went to the hardware store, then another hardware store, then an electrical supply store (aluminum unistrut isn’t a common material for kelp nerds…), and we had what we needed. Hardware acquired, we had to pick the appropriate line to hold the little kelplings – it had to be buoyant to keep things vertical in the water column, too stiff and it might crush them when we spliced them in, too loose and they might get pulled free from the coastal surge. Honestly, ARKEVs are pretty simple to build. Once we sat down on the back patio, it was a simple matter of cutting some PVC and unistrut, gluing a few caps in place, and securing everything together with mounts. Cutting the right lengths of rope and deciding how to connect and tie everything together took a bit of trial and error, but we had our first prototype assembled in a little over an hour.
We needed to find suitable kelps to splice into our new ARKEVs, and we knew from our partners to the south that it was better to start with fairly small juvenile kelps, around 6”. In April and May when we were preparing to deploy, juvenile kelps that are trying to grow are often ripped free, their little holdfasts unable to hold on in the powerful surf. ORKA to the rescue! We walked the beach collecting the little recruits, hoping to give them a second chance to grow big and strong. We brought them back to the Port of Port Orford, tucked them into a seawater tote overnight, and prepared for the next morning of field work.
As we boarded the Black Pearl, we were filled with nervous, excited energy. We were trying something never before done in Oregon, and we had no idea how it would go. Were the kelps ok after washing ashore and hanging out in a tote overnight? Were they exposed to air for too long as we spliced them into the line, careful to treat each one like the little treasure we wanted them to become? Were they ok after we dropped the ARKEV and 45lb kettlebell anchor, watching with terror as the heavy weight ripped the whole unit into the murky depths?! We wouldn’t find out for a few weeks until we scheduled our first survey.
My first monitoring dive on the ARKEVs is an experience I will never forget. We knew generally where the ARKEVs were; we had just put them there a few weeks ago. But as I entered the water of Nellies Cove, which I had only dove a handful of times, it became clear that finding the ARKEVs would not be easy. The murky waters only offered a few feet of visibility, my fins pretty much invisible on my feet, and within minutes, it was clear we needed to conduct an extensive search to find our quarry – 10 foot structures located somewhere nearby. After a bit of underwater communication and coordination, we had our search pattern and began the hunt. After a few uneasy minutes, thinking to myself ‘where the @#$% are these things?!’, we found one. And those little baby kelps we were so worried about? They were thriving! Nearly all of them had doubled in size, some tripled, and only 3 of the original 30 had been lost. It was one of the most beautiful and inspiring things I’ve ever seen underwater and gotten to be a part of. I am literally tearing up a little thinking about it 🥲
Since then, I’ve had the pleasure of taking part in each of our monitoring dives. We added a second batch of ARKEVs with kelp spliced in, as well as some naked ARKEVs to see how fish like them without kelp. We saw a record recruitment of juvenile fish in Nellies Cove, and they loved hanging out in our little kelp experiment. Each time, finding the ARKEVs got a little easier (but was still pretty hard!). When the first cohort of kelps reached the surface, it was a huge relief – not only were they thriving, but they could also wave to us and tell us right where they were. Soon after reaching the surface, they began growing sori, the reproductive parts of the blades that will help give rise to the future kelp forests of Nellies Cove, helping achieve part of ORKAs ultimate goal – restoring healthy kelp forests.
Now, with the field season wrapping up in a few weeks, we’re preparing to haul in the ARKEVs and do a full analysis of how things went. But from my experiences making the ARKEVs, deploying and monitoring them, and seeing their progression, I can confidently say they have been a huge success. ORKA will do a full breakdown of our first year piloting ARKEVs; how did it go building them, and can we do it again without the use of plastics? How will we source the kelps next time, and will we be able to grow them in tanks instead of collecting them washed up? Can we expand the deployment to add more kelp, and do it in more sites? The next field season for ORKA is already being planned, and I am beyond excited to expand our kelp restoration project to help bring healthy kelp forests back to parts of the Oregon coast where they have been lost.