Marine Algae & Forage Fish

Disclaimer: The following suggestions are presented for informational purposes only, and are not intended, nor should be taken, as medical advice. Please consult your doctor if you require advice on natural or supplemental forms of Omega-3 essential fatty acids (EFAs).

Fish are not the only source of Omega-3 EFAs. Plant-based, marine and non-marine sources of Omega-3 EFAs are available. Information on plant-based, non-marine sources of Omega-3 EFAs can be found in Plant-based Sources of Protein & Omega-3 EFAs under Solutions. This section outlines plant-based, marine sources of Omega-3 EFAs (algae).

Phytoplankton and the marine food chain

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are long-chain Omega-3 polyunsaturated fatty acids (PUFAs) found in marine animals (fatty fish) and marine plants (algae). Phytoplankton, including microalgae, diatoms and dinoflagellates, are the major primary producers of the EPA and DHA that provide the Omega-3 for all life in the ocean.

Phytoplankton are microscopic, single-celled plants, bacteria and algae that use chlorophyll to convert energy from sunlight via photosynthesis into chemical energy in the form of sugar to power their cellular activity. Phytoplankton are vital for the efficient functioning of marine food webs, directly feeding the tiniest zooplankton, herbivorous and omnivorous fish, but also indirectly feeding large carnivorous fish and cetaceans, including the great baleen whales.

Phytoplankton form the base of the marine food chain. Primary consumers of phytoplankton include zooplankton, small fish, and crustaceans. Fish cannot synthesize their own Omega-3 EFAs and must obtain it from their food. Forage fish, including herring, sardine, menhaden and anchovy, are small pelagic fish that feed near the bottom of the food chain on phytoplankton and zooplankton, and are preyed on by larger omnivorous and carnivorous predatory fish, seabirds and marine mammals.

Herbivorous fish obtain Omega-3 from consuming phytoplankton, naturally rich in EPA and DHA. Omnivorous fish obtain Omega-3 from consuming phytoplankton, or herbivorous fish that have consumed phytoplankton. Predatory, carnivorous fish obtain Omega-3 from their prey, including herbivorous fish, fish that consume zooplankton or other carnivorous fish.

Eating low on the marine food chain

Stocks of many large carnivorous fish species, including swordfish, tuna, salmon and mackerel, are overfished, and it has been suggested we consume more species lower on the marine food chain including sardines and herring, the plankton-eating forage fish.

But this solution is not a simple one. Marine food webs and the food chains they consist of are incredibly intricate and complex, unlike simpler terrestrial systems, where changes in one trophic level may have an immediately visible effect. Increased consumption of forage fish, or any fish species, may lead to the depletion of those fish stocks, which would affect those species that rely on them for their survival.

We cannot all begin to avoid larger carnivorous fish species or consume smaller, forage fish, nor can we all stop eating fish and start eating algae for our Omega-3 EFAs because those alternative choices may affect marine food chains and marine food webs in unforeseen ways.

Plant-based, marine sources of Omega-3 EFAs

If we are vegetarian, vegan, don’t eat a lot of fish, or choose not to eat fish at all, there are plant-based, marine sources of Omega-3 EFAs available as alternative sources of EPA and DHA, including many species of marine micro-algae (as well as chlorella and spirulina, a type of blue-green algae, or cyanobacteria) and species of marine macro-algae or seaweed (wakame and nori). 100g of seaweed provides about 100mg EPA, but little DHA.

Several micro-algae species are used in plant-based, marine Omega-3 EFA supplements, but the two most common species are Crypthecodinium cohnii, a dinoflagellate microalga high in DHA, and Schizochytrium sp., a unicellular protist with a 2:1 ratio of DHA (28%) to EPA (14%) (TGA 2018). Chlorella and spirulina don’t contain high levels of EPA or DHA.

Available consumer products

Nordic Naturals offer high quality, sustainably sourced, 100% vegetarian and non-GMO marine micro-algae supplements. Two Algae Omega soft gel capsules daily provides 195mg EPA and 390mg DHA, while two Algae DHA soft gel capsules daily provide 500mg DHA.

VegMarine by Pharma Marine is a premium quality plant-based marine algae product made from sustainable micro-algae grown in closed systems in Europe. GreenOMEGA 3 from Green Nutritionals is a 100% vegan marine algae supplement containing 850mg of marine micro-algae oil, with 255mg DHA and 127mg EPA in each capsule.

© 2016 – 2021 Seafood Free September


Green Nutritionals,

Nordic Naturals,

Therapeutic Goods Administration (TGA), (2018), Compositional guideline: DHA/EPA rich Schizochytrium algal oil,

VegMarine, Premium DHA from Algae,