Solving Impediments to the Co-Culture of Seaweeds and Shellfish

Mike Graham and Scott Hamilton received $132,000 of funding from NOAA Sea Grant to investigate how integrated multi-trophic aquaculture of seaweeds and shellfish (oysters and abalone) may potentially mitigate the negative effects of ocean acidification on shellfish growth. Changing ocean pH is having negative impacts on oyster growers in the Pacific Northwest, and potentially on any shellfish growers, especially at the hatchery/nursery scale. Seaweeds, however, thrive off increased carbon dioxide and can buffer ocean acidification. We have added 24 new 300-gallon tanks to create a replicated design to assess the effectiveness of various species of seaweed in mitigating different acidification scenarios on the growth and health of shellfish. We are partnering with Hog Island Oysters and Monterey Abalone Company in this project. We are measuring shellfish growth with and without the seaweed buffer and seaweed growth with and without the added shellfish nutrients. In addition to providing much needed experimental scientific information on the effects of ocean acidification on shellfish hatcheries/nurseries, this project may demonstrate the utility of land-based integrates seaweed-abalone farms for expansion of the shellfish industry in California. Monitor the aquarium oxygen levels here.

Click the images below to see real-time Aquarium Room Oxygen Levels & Temperature (Left) and the Intake Seawater Quality Conditions (Right):

Native Olympia Oyster Culturing at MLML Supplements Elkhorn Slough Population

With funding from Anthropocene Institute and a collaboration with Kerstin Wasson (Elkhorn Slough National Estuarine Research Reserve) we have started a hatchery for the native Olympia Oyster (Ostrea lurida) with the intent of restocking impacted populations of this oyster in Elkhorn Slough and possibly later in San Francisco Bay. This project also requires the culture of microalgae as a food source for the developing oysters. We also monitor the water quality where these oysters are kept and published data can be seen here.

White Abalone Restoration and Probiotics to Treat Withering Syndrome (Funder: NOAA, Amount: $52,609)

Luke Gardner received funding from NOAA to rear endangered white abalone (Haliotis sorenseni) in aquaculture before outplanting them into the wild to recover their dwindling populations. This project is partnering with the Bodega Marine Laboratories to restore the shrinking white abalone populations. Bodega Marine Laboratories is part of the White Abalone Restoration Consortium, working to improve culturing methods, captive breeding, and disease research. To reduce disease in cultured white abalone this research will investigate the use of probiotics to treat withering syndrome. Withering syndrome, caused by Candidatus Xenohaliotis californiensis Bacterium (Ca.Xc) is a bacterial infection, which reduces, growth, feeding rates, survivorship, and the tissues in the digestive tract, foot and mantle of infected abalone. The only treatment for this infection is an antibiotic, which can cause antibiotic resistance genes rendering the antibiotic ineffective. Effluents from antibiotic treated water could spread antibiotic resistance genes to wild species and to humans through the food web. Antibiotics can also kill the beneficial gut bacteria in treated organisms. Therefore, antibiotics are not a viable therapeutic or preventative treatment. Probiotics could be used instead to combat withering syndrome and improve the overall health of cultured white abalone. The use of probiotics in aquaculture could also improve immune health and growth whether or not bacterial infections are present.

Development of techniques for the cultivation of monkeyface pricklebacks (Cebidichthys violaceus) as a sustainable alternative to Unagi. (Funder CA Sea Grant, NOAA Salton-Kennedy, Amount $200,674).

As a first step in developing a new species for aquaculture, graduate student Matthew Hoehn is developing spawning techniques and maturation protocols for captive breeding Monkeyface pricklebacks. These fish are a potential candidate for sustainable aquaculture because they are naturally herbivorous, and as such not reliant on wild caught fish meal and fish oil (considered unsustainable ingredients in aquaculture diets in the long term) or equivalent alternatives.  Their herbivory also means they are candidates for integrated multi-tropic aquaculture (IMTA) in that they would be well suited to be cultured alongside seaweed. Wild Monkeyface pricklebacks are in increasing demand in high-end restaurant markets, with their flavor reportedly similar to Unagi. Unagi is considered an unsustainable product in seafood markets, but the development of farmed Monkeyface pricklebacks could be marketed as a sustainable alternative to Unagi.

Lots of research is necessary for developing new aquaculture species. For example, optimizing growth rates by determining nutrition needs or changing tank settings will give important production information. However, being able to reliably spawn and raise animals without drawing on wild populations regularly is crucial to the successful and sustainable development of a new aquaculture species. Being able to culture future generations of fish in a closed life-cycle operation creates a system that can then be independent from wild populations and means growing Monkeyface pricklebacks will not negatively impact wild populations. Successfully reproducing Monkeyface pricklebacks in captivity will be a major milestone for understanding their viability as a new species in sustainable aquaculture.

Purple Hinged Rock Scallops – development of hatchery technology (Funder: Pacific States Marine Fisheries Commission, Amount: $120,000; CA Sea Grant - $34,000)

The purple hinged rock scallop (Crassadoma gigantea) is a promising species for mariculture on the West Coast. The species has a broad range (Alaska to Mexico) and grows rapidly, reaching market size in 2-4 years, similar to red abalone. Live rock scallops also have high market value. There is no significant commercial fishery for the species, however, and little is known about how to culture these scallops in captivity. One recurring impediment to commercially viable rock scallop culture is poor larval survival. Our project aims to specifically address this impediment by testing larval tank designs to reduce kinetic stress and tank abrasion. We also will examine factors associated with feeding and diet to develop effective and efficient methods for maintaining healthy broodstock and achieving successful larval metamorphosis of rock scallops. In particular we will identify the size and type of particles comprising the diet of scallops in the field; determine key functional groups and species comprising scallop diet required for gametogenesis and metamorphosis; and evaluate the effect of water flow on gonad development, and settlement of larvae.