Marine Field Station

In November, 2023, we purchased a 40 ft shipping container outfitted with a land-based urchin aquaculture system and transported it from Moss Landing to Noyo Harbor. This is one of several projects funded by a grant through the Congressman Huffman Community Project (House appropriations fund) administered through NOAA. SeaGrant/Moss Landing Marine Lab built the system we purchased and will be a partner moving forward.

The installation of a low-tech, land-based urchin ranching system at our marine field station in Noyo Harbor will allow us to explore the possibility of large-scale production of purple urchin at Noyo Center’s future Ocean Science Center on the Fort Bragg Headlands, and elsewhere in the region. This preliminary effort could prove essential to restoring our kelp forests by transforming starving, worthless urchin removed from urchin barrens into a valued, restorative seafood product while creating a new regional aquaculture industry.

The red abalone is one of our region’s most iconic species. Native only to the west coast of North America, the species is the largest abalone in the world and considered to be a seafood delicacy with strong cultural and culinary connections to the identity of coastal Californians, including Indian Tribes. In 2013-2014, an outbreak of “sea star wasting disease,” driven by warm water conditions, contributed to mass mortalities of the west coast’s sea star populations and the local extinction of sunflower sea stars (Pycnopodia helianthoides). The absence of these sea stars, which prey on juvenile purple sea urchins (Strongylocentrotus purpuratus), coupled with a record-breaking marine heat wave, enabled a sea urchin population explosion. As sea urchin’s primary food source is kelp, the resulting dramatic increase in the abundance of the purple urchins led to a 93% reduction in the abundance of bull kelp (Nereocystis luetkeana) in Northern California. This reduction in bull kelp abundance has triggered starvation conditions for wild red abalone and reproduction impacts on the survivors.

Prior to 2018, North Coast red abalone populations supported the world’s largest

recreational abalone fishery, with over 31,000 free diver participants per year, generating an estimated $44 million dollars of annual revenue for north coast communities. Since 2014, Northern California’s red abalone population has declined by 70% and the Fish and Game Commission closed the highly popular fishery in 2018, prohibiting abalone fishing in all of California for the first time in history. The unprecedented and rapid decline of this species prompted a listing as “critically endangered” by the International Union for Conservation of Nature. Surveys indicate that North Coast abalone remain in a state of starvation, with zero successful reproduction observed in the population since the kelp forest collapse (2015-2019). Even when cold water conditions return to Northern California, continuing high abundances of sea urchins are preventing widespread kelp recovery, and by extension, the recovery of abalone populations. Given the precipitous decline of wild red abalone densities and the species’ slow time to reach reproductive maturity, significant concerns have been raised regarding red abalone populations’ ability to recover.

Two primary issues are being addressed by the Abalone Broodstock Program:

1. Abalone are starving and are therefore not reproductive. We will collect adult abalone in the wild, bring them into tanks at the Noyo Center Field Station and Bodega Marine Lab (BML), and feed them until they become reproductive again. This can take up to two years.

2. Abalone are broadcast spawners and the population decline has taken abalone below the minimum viable density thresholds for successful reproduction. Therefore, we need to get more abalone in the system. The program to help restore white abalone in Southern California has taken 10 years to produce enough juvenile abalone for stocking in the ocean, during which time remnant wild stocks have declined to near extinction. Using this science/methodology, we will work with BML, CDFW, and the Kashia Tribe to create a broodstock of red abalone to outplant back in the restoration zones. Once adults are spawned, juvenile abalone will be distributed to Noyo and others to grow them out to a size big enough to survive in the wild. This could take an additional 3-5 years. Key to this effort is having suitable habitat for out planting the abalone, and we are partnering on a variety of proposals to work on bull kelp recovery. In one proposal, Noyo Center is responsible for contracting with commercial urchin divers to remove urchin on the Sonoma coast, and coordinating disposal. We are also collaborating with other partners on conservation efforts in Mendocino for future reintroduction of abalone.

We will install a few large abalone holding tanks for adult abalone that will be repurposed for the juveniles once we successfully spawn the adults. These tanks may be located inside the Field Station building for safety and care. The tanks may require their own water system. Seaweed (see below) will be grown onsite to feed the abalone.

Caring for herbivorous invertebrates requires the cultivation of food if we are not going to further impact dwindling wild seaweed populations. In land-based seaweed tumble culture, a steady flow of air emerges from the bottom of an open air container, keeping the seaweeds “tumbling,” suspended between the tank bottom and the water surface.

Past work has shown that abalone grow out faster with a red seaweed called dulce, Palmaria palmata. This seaweed species has the ability to fragment and regenerate: break one piece of seaweed in two, and, under the right conditions, both will continue to grow. We will experiment with cultivation of various seaweeds. Other species might include sea lettuce, Ulva rigida, and even bull kelp, Nereocystis luetkeana.

We also plan to use our seaweed tanks in an “integrated multi-trophic aquaculture system,” where seaweed and aquaculture are conducted together. The nutrients from urchin and abalone can help fertilize the seaweed, which also cleans the water. The seaweed, in turn, can be harvested and used for feed for the animals and people. Recent research indicates that juvenile abalone grew significantly faster in weight (22% increase) and shell area (11% increase) in 6 months when integrated with seaweed tank circulation.

2 or 3 large tubs will be placed in the side yard and integrated into the larger seawater system, feeding the abalone and helping to clean the water. Pumps and aerators will be used to tumble the seaweed.

Expected Outcomes:

● Grow food for the abalone, test against other feed with urchin.

● Show the benefits of an integrated multi-trophic aquaculture system.

● Determine the potential for scaling up on the headlands. Economics.

● Determine if there is interest in fresh seaweed from local restaurants