Noury's Argonaut
Also calledrough-keeled argonaut
Sources place it in the eastern Pacific, including all Mexican Pacific waters. None read for this page lists California or gives a northern limit.
Sightings
2026 season, numbered oldest first, every one sourced
Central California
- #2Oct 20, 20261 reportMonterey
- Source
- iNaturalist 409750801
Southern California
- #1Sept 19, 20261 reportSanta Cruz Channel, Channel Islands
- Source
- iNaturalist 402324473
About this fish
What it is, where it comes from, and whether it has been here before
How it lives
Noury's argonaut spends its whole life at or near the surface of the open sea. Large numbers of females have been seen at the surface in daylight, and they sometimes attach to each other in chains of up to 18. A female can carry eggs at up to 3 stages of development in a single shell.
Where it normally lives
Eastern Pacific, including all Mexican Pacific waters.
This argonaut lives in the eastern Pacific, including all of Mexico's Pacific waters. Its shells wash up most often in southern Baja California Sur from January to March. The sources read for this page do not list California.
Range source: SeaLifeBase · Mexican Shells
In California
iNaturalist holds 2 California records from 2026, both research grade, which means other users agreed with the ID. One is from the Santa Cruz Channel in the Channel Islands on September 19, and the other is from Monterey on October 20. The records do not say whether each was a live animal or a washed-up shell.
Photos
From California this season
No photos yet. If you photographed this animal in California this season, send it in.
Identification
How to tell it from the locals
Noury's argonaut is a small open-ocean octopus. Females make a thin, paper-like shell and carry it with them, which is why argonauts are also called paper nautiluses. The shell is cream with brown along the oldest part of its ridge, and it reaches about 2.3 inches long. Mexican Shells gives females about 4 inches and males about a third of that, while SeaLifeBase records females up to about 7 inches.
Details
Rarity in the compendium is Nautical Nick's call on how likely a diver is to run into the animal on the California coast this season, not how rare it is where it normally lives.