Two purplish hand sized slugs

What’s in the Tidepools? – December 2021

Sun sets along rocky beach. Sky is reflected in the ocean water.

What’s In the Tidepools? – December 2021

(NPS Photo/T. Woods)

Our dedicated volunteers at Cabrillo National Monument take photos of the exciting flora and fauna down in the tidepools! We want to try and capture the wonderful photos that volunteers are taking in the tidepool area. This blog post is published on a monthly basis, but we need your help. We encourage you to contribute by submitting your memorable photos and/or short videos to These can be of tidepool critters, fauna, bluff collapses, sunsets or anything you consider special. Make sure you include who took the photo and the location, if possible. Will you help?

It’s tidepool season again! As we move into lower and lower tides, we will resume monthly posts with all the fun things our wonderful TPERPers spot out there.

Here are some highlights from this month!

TPERPer Patrick Raetzman notes that this was the “best looking blue knobby sea star that I’ve seen in about 5 years.” It was found near the Zone 2/3 boundary.

A animal shaped like a star with bumps on each arm
NPS Photo/P. Raetzman – Blue Knobby Sea Star

A Fragile Rainbow Star was spotted just below the entry point. It was about a foot across and was very exciting for visitors. The name comes from the brilliant colors of its spines and tube feet, which are normally orange and blue.

A animal shaped like a star with bumps on each arm
NPS Photo/S. Kristiansen

Globose Kelp Crabs are most easily identified by their large size and bright reddish-orange color. At Cabrillo, they are generally spotted beneath the surfgrass or under flat rocks.

A red crab among long blades of green grass in shallow water
NPS Photo/T. Woods
NPS Video/M. Rose – Globose Kelp Crabs

An approximately 7-inch, healthy green abalone (Haliotis fulgens) was spotted below a rock in Zone 2. If it weren’t for the extremely low tide, it might have gone unnoticed.

A large, limpet-like creature under a rock
NPS Photo/N. Cheng

TPERP Sue observed this Moray Eel in the tidepools.

NPS Video/S. Kristiansen
NPS Photo/C. Spence – Swell Shark egg

This is a live swell shark egg. Swell sharks got their name from their defensive ability to swallow sea water in order to approximately double in size. The wiry tendrils on the egg sac are used to anchor onto kelp and rocks, which normally keep them from washing upon the shore.

3 thoughts on “What’s in the Tidepools? – December 2021

  1. I love these “What’s in the Tidepools” posts. For those of us who can’t be there up close and personal, they let us continue to explore and experience. Thank you!

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