Species profile
Devil weed
Sargassum horneri
Identify Devil weed (Sargassum horneri) from a photo: try it free in your browser, or get unlimited IDs, no sign-up, with the CatchRules app. Plus current fishing rules across 1 jurisdiction.
At a glance
Devil weed (Sargassum horneri) is a marine alga with specific harvest rules tracked in 1 of 66 jurisdictions covered by CatchRules.
Confirmed by 450 research-grade iNaturalist observations, concentrated in California.
Notable details
- Native to Japan and China, it was first recorded in Southern California around 2003.
- It can grow several meters tall, rapidly smothering native kelp and algae.
- Unlike most seaweeds, it completes its entire life cycle in under one year.
- Dense stands degrade habitat for native invertebrates and fish that depend on kelp forests.
Where Devil weed are seen
Jurisdictions with rules for Devil weed
Background
Sargassum horneri is a species of brown macroalgae that is common along the coast of Japan and Korea. It is an annual algae which has a varying fertile season along the coast. In Wakasa Bay, Japan it begins to grow in early autumn through winter and matures in spring, when the sea water temperature is around 11.6–15.2 °C (53–59 °F). Also called "devil weed", S. horneri has invaded the Eastern…
Background excerpt adapted from Wikipedia's Devil weed article (CC BY-SA). Visit Wikipedia for the full entry.
Other brown algae/kelps on CatchRules
Frequently asked questions
What is Devil weed?
Devil weed (Sargassum horneri) is a marine alga with specific harvest rules tracked in 1 of 66 jurisdictions covered by CatchRules.
What is the scientific name for Devil weed?
Devil weed is Sargassum horneri.
Is Devil weed regulated for fishing?
Yes — Devil weed has fishing regulations in 1 U.S. state and/or Canadian province tracked by CatchRules. See the "Jurisdictions with rules" section above for the binding-source links.
How can I identify Devil weed?
Take a photo with the free CatchRules app for iPhone or Android — on-device identification recognizes Devil weed along with ~1,500 other species. No sign-up, unlimited use.
Photo credit: iNaturalist / Wikipedia. Identification reference only — verify regulations with the issuing wildlife agency before retaining a catch.