Sea urchins
Sea urchins are echinoderms, a large phylum of marine animals that also includes starfish, sea cucumbers, and sand dollars. In culinary terms, they are grouped with shellfish, but are actually not closely related to most shellfish.
The name “sea urchin” comes from the spiny appearance of the sea creatures. “Urchin” is an old English word, originally from French, for “hedgehog”. The word is still in use in some parts of England today.
Sea urchins are round, spiny animals with a shell. They have a mouth, known as an ”Aristotle's lantern”, surrounded by five teeth on their underside, and they move with the use of hundreds of small tube feet.
Three species of sea urchin are commercially harvested in the Pacific Northwest: the red sea urchin (Mesocentrotus franciscanus), the green sea urchin (Strongylocentrotus droebachiensis), and the purple sea urchin (Strongylocentrotus purpuratus).
Sea urchins are collected by divers along the West Coast. In California, the fishery started in 1970, driven by demand from Japan, and took off quickly in the 1980s. It was soon found that sea urchin fishing was not sustainable. California, Oregon, and Washington put in regulations to protect the fishery soon after and it is still considered sustainable and stable today.
The sea urchin fishery in Oregon is mostly centered around southern Oregon, from Port Orford down to Brookings. Sea urchins are also harvested near Charleston and Depoe Bay. In Washington, sea urchins are harvested primarily around the San Juan Islands.
Sea urchin farming
Urchin populations have increased drastically along the West Coast in recent years. It is thought that climate change and changes to the food chain are the main contributing factors. Warm ocean temperatures have negative impacts on kelp forests, which prefer colder water.
Sea otter populations in the Pacific Northwest declined drastically in the early 1900s due to overhunting. Sea otters are a major predator of sea urchins and it is thought by some scientists that the lack of predation has contributed to rising sea urchin populations. Another theory is that a severe die-off of sunflower starfish in the mid-2010s may be causing the spike in sea urchins. Sunflower starfish were one of the top sea urchin predators but have nearly disappeared entirely from their habitats in California, Oregon, and Washington. Without sufficient predation, sea urchins have in turn overgrazed kelp forests and replaced large sections with urchin barrens, areas dominated by sea urchins. The exact mechanics which lead to the creation of barrens are not yet fully understood, but there is cause for concern amongst researchers as kelp forests represent a major habitat for many sea animals. Kelp forests harbor a far greater diversity of sea life than urchin barrens.
In the Pacific Northwest, from northern California to Washington, the main species creating urchin barrens is the purple sea urchin. The spread of urchin barrens leads to the question: why not eat them?
The issue is that the quality of the roe of sea urchins in the barrens is low. High-quality feed is scarce in barrens. With high numbers of sea urchins and no kelp to eat, the sea urchins survive on poor-quality food. Sea urchin gonads are also used to store nutrients, so without food, gonad production decreases.
A potential solution has been tapped into by some newer companies, such as Oo-nee Sea Urchin Ranch out of Newport, Oregon. Purple sea urchins are collected from barrens in southern Oregon, then placed in tanks where they are fed algae until they reach market size.
Cooking with sea urchins
Sea urchins are harvested for what is known as their “roe”. This “roe” is not actually eggs but is instead the reproductive organs of the sea urchin. The five gonads contained inside the urchin can be found by cracking open the shell.
Sea urchin roe is often marketed under its Japanese name, “uni”. The overwhelming majority of the world’s production of sea urchin roe is consumed in Japan, but it is also traditionally eaten in the Mediterranean and southern Pacific, and is an indigenous food along the West Coast of the United States and Canada.
Sea urchin roe has a strong “ocean” flavor, but without the brininess of other shellfish and a distinctly rich flavor. The roe is commonly eaten raw, but can also be cooked into sauces. Lower-grade roe is best used in such applications. The commercial harvest season in the Pacific Northwest runs year-round, but most of the harvest takes place in winter and spring. The quality of the roe peaks in the cold months and declines in early spring when sea urchins start spawning.
Species
Sea urchins
Harvested species
Red sea urchin (Mesocentrotus franciscanus)
Green sea urchin (Strongylocentrotus droebachiensis)
Purple sea urchin (Strongylocentrotus purpuratus)
Other species
Pale sea urchin (Strongylocentrotus pallidus)
Orange-pink sea urchin (Strongylocentrotus fragilis)
Harvested species
Red sea urchin: Mesocentrotus franciscanus, the red sea urchin, is found from Alaska to Baja California, in rocky habitats up to 300 feet deep. The red sea urchin is the main species targeted by dive fisheries, and an important fishery in both Oregon and Washington (and the rest of the West Coast). Red sea urchins are the largest native species and can reach sizes up to nearly 7 inches across. Typical commercially harvested urchins must are about 3.5 inches in size.
The green sea urchin, Strongylocentrotus droebachiensis, is the second-most targeted species in the Pacific Northwest. The species is found around the world in northern waters. In North America, it’s found from Alaska down to Washington’s Puget Sound. Like other urchins, they are mostly found in shallow waters, but have been found in deeper waters up to 3,200 feet. Green sea urchins reach about 2 inches across on average but can grow up to about 3 inches in size.
Strongylocentrotus purpuratus, the purple sea urchin, is found from Baja California to British Columbia, from the low-tide line to depths up to 500 ft deep. They grow at most to about 3 to 4 inches in size. They are sometimes commercially targeted, but are not a significant portion of landings. For example, they make up only 1% of the total number of sea urchins harvested in Oregon since the fishery began in 1986.
Other species
Two other sea urchins are found in our waters, both in deep waters. Neither has been targeted commercially in the Pacific Northwest. The pale sea urchin may have been targeted in Russia, but I haven’t been able to confirm this. Both are caught as bycatch from deep sea trap fisheries.
The pale sea urchin (Strongylocentrotus pallidus) is similar in size to the green sea urchin, with a similar habitat range in northern waters. It is found only in subtidal areas, from 100 feet to about 650 feet in depth.
The orange-pink sea urchin (Strongylocentrotus fragilis) grows up to 4 inches across and is found most frequently from about 650 feet to 1,000 feet deep along the West Coast of North America.
