Macro
Nudibranchs on the rocks, seahorses and giant jawfish, blennies peering out of old barnacle shells, and sea fans in the current.
Background photo: Megan Applegate (Malpelo, Colombia)
Sea slugs
Bright colours on the rocks
Also listed as Flabellina iodinea.
Key marks: A purple body, orange cerata and scarlet rhinophores; its range includes the Gulf of California (Wikipedia).
At San Carlos: Photographed at San Carlos in July 2024 (photo on this page).
Key marks: A translucent reddish-pink aeolid with close-set opaque white spots on the head and back and cerata in groups on raised ridges; the rhinophores have white leaflets with a pink patch (Sea Slug Forum). Reported only on Eudendrium hydroids (Sea Slug Forum).
At San Carlos: Described from Bahía de los Ángeles, in the Gulf of California (Wikipedia); photographed at San Carlos in July 2024 (photo on this page).
Formerly Chromodoris norrisi and Glossodoris norrisi (Wikipedia).
Key marks: A small white dorid densely covered in purple or reddish spots mixed with yellow dots, with orange dashes around the mantle edge and orange-red tips on the rhinophores (NudiPixel); up to 60 mm (Wikipedia).
At San Carlos: Ranges from Baja California to Costa Rica (Wikipedia); photographed at San Carlos in July 2024 (photo on this page).
A sap-sucking sea slug, not a nudibranch: it keeps chloroplasts from the algae it eats and uses them to photosynthesise (Wikipedia).
Key marks: Up to about 50 mm, pale green with white lengthwise streaks, densely folded side flaps edged in orange and black, and yellow-and-black striped rhinophores (Wikipedia).
At San Carlos: Common in the Gulf of California, down to about 20 m and often in sunlit shallows (Wikipedia); photographed at San Carlos in July 2024 (photo on this page).
Formerly Hypselodoris agassizii.
Key marks: A black body with yellow flecks and a row of white spots, a green-yellow-green band along the mantle edge and black rhinophores (Wikipedia).
At San Carlos: Photographed in the San Carlos area (underwaterphotography.com), and listed among the sea slugs seen on trips to Mulegé and San Carlos (underwaterkwaj).
Key marks: Turquoise and yellow-ochre regions separated by black lines; gills and rhinophores translucent pinkish brown with black tips (Sea Slug Forum).
At San Carlos: Listed among the sea slugs seen on trips to Mulegé and San Carlos (underwaterkwaj); also recorded at La Paz (Sea Slug Forum).
Also listed as Chromolaichma sedna or Glossodoris sedna.
Key marks: A white body with a red inner and yellow outer band around the mantle edge, and red tips on the rhinophores and gills; ranges from the Gulf of California to the Galápagos (Wikipedia).
At San Carlos: Listed among the sea slugs seen on trips to Mulegé and San Carlos (underwaterkwaj).
Small fish
Look slowly, close to the bottom
Protected in Mexico (NOM-059, “subject to special protection”) (Wikipedia).
Key marks: The largest seahorse, up to about 30 cm; males have a prominent keel (Wikipedia).
At San Carlos: Divers on a 2015 trip were shown seahorses at the San Antonio and San Nicolás islets; the report doesn’t name the species (Undercurrent).
Key marks: Small dark spots on the head and back; juveniles have six dark bars (Smithsonian SFTEP). Grows to about 51 cm and lives on sand and rubble (FishBase).
At San Carlos: The Smithsonian’s SFTEP database has records near San Carlos (Smithsonian SFTEP). Look for a head poking out of a burrow in the sand.
Key marks: Up to 6 cm, with thick cirri over the eyes and a red-brown oval on the cheek outlined in black and ringed with white spots (Wikipedia).
At San Carlos: A Gulf of California fish (FishBase) that lives in old barnacle and clam holes, with only its head showing (Wikipedia).
Invertebrates
On rock and sand
At San Carlos: Muricea plantaginea and M. californica were collected at 5–25 m in San Carlos Bay (Breedy & Guzman 2016); Tres Marías is a current-swept site of boulders and sea fans (Scuba Diving).
Endangered on the IUCN Red List (Wikipedia).
Key marks: Dark brown with orange papillae, about 23 cm long (Wikipedia).
At San Carlos: Protected in Mexico (NOM-059) and fished only under permit, with quotas, a 20 cm minimum size and a season that normally runs from October to May, after a full ban from 1994 to 2002 (Reyes-Bonilla et al. 2016). Leave it where it lies.
Unconfirmed
Found in the Gulf, not yet reported at San Carlos
These animals live in the Gulf of California, but no record at San Carlos itself was found.
Hands off
Don’t touch, move or hold marine life, including to set up a photo.
Credits
Photographed at San Carlos, July 2024
The sea slug photos are Megan Applegate’s own, taken at San Carlos in July 2024, © Megan Applegate, all rights reserved. Species without a photo link to photos online.
| Species | Photographer | Licence | Source |
|---|---|---|---|
| Spanish shawl | Megan Applegate | © Megan Applegate, all rights reserved | Photographer's own photo, taken at San Carlos, July 2024 |
| Bajaeolis bertschi | Megan Applegate | © Megan Applegate, all rights reserved | Photographer's own photo, taken at San Carlos, July 2024 |
| Felimida norrisi | Megan Applegate | © Megan Applegate, all rights reserved | Photographer's own photo, taken at San Carlos, July 2024 |
| Elysia diomedea | Megan Applegate | © Megan Applegate, all rights reserved | Photographer's own photo, taken at San Carlos, July 2024 |