Echinoderms

The gonads of both male and female sea urchins, usually called sea urchin roe or corals, are culinary delicacies in many parts of the world, especially Japan. In Japan, sea urchin is known as uni (うに), and its roe can retail for as much as ¥40,000 ($360) per kilogram; it is served raw as sashimi or in sushi, with soy sauce and wasabi.

In Mediterranean cuisines, the sea urchin Paracentrotus lividus is often eaten raw, or with lemon, and known as ricci on Italian menus where it is sometimes used in pasta sauces. It can also flavour omelettes, scrambled eggs, fish soup, mayonnaise, béchamel sauce for tartlets, the boullie for a soufflé, Hollandaise or fish sauce.

Sea Urchin (Echinus esculentus / Paracentrotus lividus)

The European edible sea urchin or common sea urchin, is a species of marine invertebrate in the Echinidae family. It is found in coastal areas of western Europe and considered "Near threatened" in the IUCN Red List of Threatened Species.

Coastal waters were once inhabited by massive kelp forests, but many of them have disappeared due to the explosion of sea urchins (another human-induced problem... we’ll get to that in a minute). Sea urchins pose a major environmental problem as they graze on kelp beds, leaving an underwater desert in their wake. This is an example of an ecological regime shift.

One way to address this problem, as in the case of Californian kelp forests, was the introduction of a predator which eats sea urchins: sea otters. In the 19th century, cowboys and other fools decimated otter populations for their furs. Little did they know this deleterious side gig would set a dangerous chain of ecological trends in motion).

Another possible solution to the environmental problem posed by sea urchins is to remove the urchins from the seabed and enhance them in landbased or seabased ranches to commercial size and quality, using specially designed feeds (see Urchinomics). Sea urchin roe is one of the world’s most sought-after delicacies and is served as sashimi at exclusive restaurants all over the world.

Sea cucumber (Holothuria tubulosa)

Though perhaps not possessing the most appetising of appearances, the sea cucumber is a mysterious and ecologically important benthic species. Rumour has it that if threatened they can expel their internal organs, only to reconstitute itself and re-grow to live another day. Like some kind of marine Voldemort. More commonly, they expel a sticky white substance which confuddles would-be attackers, leaving them in a bind.

Sea cucumbers serve a useful role in the marine ecosystem as they recycle nutrients, breaking down detritus and other organic matter, after which bacteria can continue the decomposition process.

Their industriousness places them well as co-culture species in aquaculture systems to mop up uneaten food and small organic material from fish, bivalves or other species. Currently, sea cucumbers are harvested from the environment, both legally and illegally, but are increasingly farmed in aquaculture farms. The harvested animals are normally dried for resale. In 2016, prices on Alibaba ranged up to $1,000/kg.

The harvested product is variously referred to as trepang, namako, bêche-de-mer, or balate. There are many commercially important species of sea cucumber that are harvested and dried for export for use in Chinese cuisine as hoisam. Various pharmaceutical companies emphasize gamat, the traditional medicinal usage of this animal. Extracts are prepared and made into oil, cream or cosmetics. Holothuria tubulosa has been investigated as a new source for omega-3 and omega-6 fatty acids, and the production of bioactive peptides.