Purple Sea Urchin
Strongylocentrotus purpuratus
The Science
THE SCIENCE
Individuals in the intertidal decorate themselves with shells, rocks and pieces of algae as protection from sun and predators.

Taxonomic description
- Key identifying features for this sea urchin are purple spines that protrude from a round body. [3]
- Ranges in size from 5-10 cm (2-4 in) wide by 4 cm (1.6 in) tall. [3]
- Adolescents have mostly pale green spines that darken to purple as they mature. [3]
Distribution
- Found along the Eastern Pacific from Baja California, Mexico up the coast to Alaska. [3]
Life history
- Average lifespan of 20 years. [4]
- Is a seasonal breeder; January, February, and March are primary reproductive months. [4]
- Oviparous reproducer, where the development of the offspring occurs outside the mothers body. [4]
- Fertilized eggs settle on a substrate where it begins to develop. [3]
Habitat
- Rocky intertidal and kelp beds, founds in depths of up to 160 meters (525 ft). [4]
- Water temperatures in excess of 22.8°C (73° F) increase mortality. [3]
- Primarily eats algae including giant kelp; predators include starfish, otters, and humans. [4]
- One of the primary natural predators of urchin, the sea otter, is endangered which has allowed for a population boom and subsequent reduction in kelp in some areas. [3]
The Fishery
THE FISHERY
Harvested as food in the 1990s, this species is now mostly harvested for scientific research.

Seasonal availability
- Available year round. [3]
Regulatory and managing authority
- As established by the Marine Life Management Act, the California Fish and Game Commission regulates the fishery, and the California Department of Fish and Wildlife manages this fishery in state waters. [12]
- The California Sea Urchin Commission and the Pacific Urchin Harvesters Association combines input from the industry and government entities to inform regulatory and management measures for this fishery. [6,9]
Gear type
- Hand picked using SCUBA, and an urchin rake to collect urchin in mesh bags. [1,2]
Status of the fishery
- The California fishery was launched in the early 1990’s with export to Japan and the Mediterranean, where it is considered a delicacy [3,5], but shipping costs, and limited harvest areas and season (Sept-Oct) for high quality urchin made it not viable. [2,10]
- There are currently no major conservation efforts, with populations in some areas, such as Northern California, large enough to be suppressing kelp. [4,10]
- Fishery is small and predominantly in Southern California aimed at scientific research demand [2,3], although efforts to renew the fishery in northern California are being considered to relieve grazing pressure on kelp. [10]
Potential ecosystem impacts
- Harvesting has minimal environmental impacts due to hand harvesting methods.
- Local harvest may limit urchin population booms form sea urchin barrens. [8,10]
The Seafood
THE SEAFOOD
It is easy to spot sea otters that regularly eat purple sea urchin because their teeth turn purple!

Edible portions
- Gonads from females and males (that produce roe or milt). [6]
Description of meat
- Color of the roe ranges from yellow to orange. [7]
- Soft and buttery with a sweet and salty deep ocean flavor. [7]
Culinary uses
-
It can be eaten fresh or live from the shell. [6]
-
Prepared raw, baked, sautéed, or steamed. [6]
-
Commonly used in dishes such as sushi and pasta, but can be found in a variety of dishes and cuisines. [6]
-
For a tutorial on how to open a sea urchin at home, visit Youtube. [13]
Nutritional Information
- A 100 g (3.5 oz ) raw serving of roe is a good source of fatty acids, proteins, minerals, and vitamins. [6,11]
Toxicity report
- No known toxins. [4]
Seasonal availability
- Available year round in California. [4]
References
[1] Alaska Department of Fish and Game. Commercial Dive Fisheries Sea Urchin Information., Web. www.adfg.alaska.gov/index.cfm?adfg=CommercialByFisheryDive.seaurchin . Accessed 10 May 2017.
[2] Halmay, P. 2017. Interview: Purple Sea Urchin. San Diego Commercial Fisherman, F/V Erin B. San Diego, CA 13 May 2017.
[3] Parker, D., Thomas E. 2002. Chapter 10. Purple Sea Urchin. Pages 10-1 to 10-4 In C. Ryan, M. Patyten (eds.) Annual Status of the Fisheries Report through 2003. California Department of Fish and Wildlife, Belmont, CA. Web. nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=34393&inline. Accessed: 21 Apr. 2017.
[4] Monterey Bay Aquarium. Purple Sea Urchin. Web. www.montereybayaquarium.org/animal-guide/invertebrates/purple-sea-urchin. Accessed: 6 Apr. 2017.
[5] Arkive. Purple sea urchin (Strongylocentrotus purpuratus). Web. http://sarkive.com/invertebrates-marine/strongylocentrotus-purpuratus/. Accessed: 5 May 2017.
[6] Pacific Urchin Harvesters Association. Sea Urchin Nutritional Information. Web. http://puha.org/nutritional-information/. Accessed: 10 May 2017.
[7] McDonnell, J.J. 2017. Sea Urchin. Web. www.jjmcdonnell.com/products/sea-urchin. Accessed: 10 May 2017.
[8] Worley, A. 2001. Strongylocentrotus purpuratus. Animal Diversity Web. animaldiversity.org/accounts/Strongylocentrotus_purpuratus/. Accessed: 5 May 2017.
[9] California Sea Urchin Commission. n.d. Web. http://www.calurchin.org/about_us.html. Accessed 04 June 2017.
[10] Steele, B. 2017. Personal communication. California Commercial Fisherman. Santa Barbara, CA. 02 June 2017.
[11] Fresh Raw-Sea Urchin Uni. n.d. Myfitnesspal.com. Web. https://www.myfitnesspal.com/food/calories/sea-urchin-uni-199071965. Accessed 21 September 2017.
[12] Marine Life Management Act. n.d. California Department of Fish and Wildlife. Web. https://wildlife.ca.gov/Conservation/Marine/MLMA. Accessed 24 August 2020.
[13] Hawk, C. Youtube. 2015. 3 Ways to Crack an Urchin. Web. https://www.youtube.com/watch?v=_Au3Q-p7mfw. Accessed 2 Feburary 2021.
[14] meggle. flickr. 2010. Purple sea urchins. Digital image. Web. https://www.flickr.com/photos/sesen/4474833069. Accessed 23 February 2021.
[15] Wound, Adam C. Bad. iNaturalist. 2013. Pacific Purple Sea Urchin. Digital image. Web. https://www.inaturalist.org/photos/296022
[16] Martinez, Sarka. iNaturalist. 2016. Pacific Purple Sea Urchin. Digital image. Web. https://www.inaturalist.org/photos/4406035