Snapshot Cal Coast Logo (outline of the state of CA with silhouette of animals and photo of intertidal seaweeds & a starfish.

Pisaster ochraceus and tidepool diversity. Pillar Point, San Mateo County, CA


Snapshot Cal Coast is an annual California statewide effort to document our coastal biodiversity! We lead a campaign that encourages people to make and share observations of plants, animals, and seaweeds along the California coast using the iNaturalist app and work with partners to hold a series of coastal bioblitzes over two weeks every summer.  We focus on intertidal zones in California State Marine Protected Areas (MPAs), but we are interested in data from any coastal influenced habitats along the California Coast, including sandy beaches, bays, wetlands, and docks.  Led by the California Academy of Sciences with support from the MPA Collaborative Network and many, many other partners, together we are creating a snapshot in time of where species are located along our coast. This work is supported by the California Ocean Protection Council

Check out what we have done together over the last four years here


For 2020 Snapshot Cal Coast will have two parts: Physically distant and hyper-local June 1st-November 16th and (hopefully) more traditional November 28th-December 16th.


What is Snapshot Cal Coast?

Sea amemones

SUMMER & FALL Snapshot Cal Coast 2020 will be June 1st-November 16th!

This summer, due to the Coronavirus, our summer Snapshot Cal Coast will be different than in years past and will extend into the Fall. From June 1st-November 16th, we will hold a 'physically distant and hyper-local' Snapshot Cal Coast. Please only go to beaches that you can get to safely and legally on your own or with your families and make observations as long as you are following local laws and respecting beach closures.  The Cal Academy will provide digital and online resources, including species to look for and tips on how to look for different species. We will also provide a list of beaches and places we most need data from! Stay tuned! We are hoping to the more traditional Snapshot Cal Coast November 28th-December 16th.

For 1-2 weeks every year, we mobilize and organize our amazing partners up and down the State of California to make and share observations of as many coastal species as possible.

From Del Norte to San Diego and everywhere in between, we work together to build an annual snapshot of biodiversity along the California coast that is useful for scientists at local, regional, and state levels. We are building our community of observers and recorders interested in documenting California coastal biodiversity and answer targeted research questions in support of California Marine Protected Areas.

Together, we are gathering the data needed to determine species ranges now against which we can measure and monitor changes in the future.


How to get involved

People in the tidepools observing seaweed and animals with lots of fog.

How to participate in Snapshot Cal Coast 2020 Summer & Fall:

  1. Follow all local laws and respect beach closures and physical distancing rules. Check out this regularly updated list of beach closures & rules.
  2. Download the iNaturalist app for iPhone or Android
  3. Create an account to start making observations.
  4. Follow the Snapshot Cal Coast Summer & Fall 2020 project.
  5. Find a beach the needs data and sign up here or choose a beach or coastal area you can visit regularly.
  6. Head to the coast on your own, with your family or with the people you live with between June 1st-November 16th! Make and share observations of plants and animals you see, especially species on our most-wanted list.
  7. Here is a list of dates with good low tides in California, but check out NOAA's tide table to find exact times for low tides near you.
  8. Spread the word! Use our hashtag on social media #SnapshotCalCoast




What are we looking for this year?

Juvenile starfish

Our goal is to document as many species as possible, from as many places as possible. We are, though, specifically interested in a handful of species and groups. These 'most wanted species' are introduced species, species for which we have limited data on their ranges, species whose ranges are affected by changing oceanic conditions and habitat modification, and species that are affected by emerging diseases,

Always remember to follow the tidepooling best practices for your safety and the protection of seaweeds and animals:

  • Never remove any animals or seaweeds.
  • Take care to step on bare rock wherever possible.
  • Never move animals from place to place.
  • Never 'roll' rocks. 

Snapshot Cal Coast 2020 Summer and Fall:

We have put together a "most wanted list" based on our own questions and in consultation with others in the scientific community, California Coastal Commission, and California Department of Fish and Wildlife.

Click on a species name to see the existing observations of each species in California on iNaturalist.

Most Wanted Species

1. Species of Puff Ball Alage Colpomenia spp.

2. The introduced red bryozoan, Watersipora spp.

3. The rockweed species, Hesperophycus californicus

4. European Green Crabs, Carcinus maenas

5. The Dark Unicorn Snail, Mexacanthina lugubris

Checklist groups

Look for and document as many species in each of these groups, especially the species listed, as you can, plus all the other species you can find!



Anthopluera artemisia

Anthopleura elegantissima

Anthopluera sola

Anthopluera xanthagrammica


Chthamalus/Balanus (Acorn Barnacles)

Pollicipes polymerus (Gooseneck Barnacle)

Semibalanus carniosus (Thatched Barnacle)

Tetraclita rubescens (Pink Volcano Barnacle)


Haliotis cracherodii (Black Abalone)

Haliotis rufescens (Red Abalone)

Katharina tunicata (Black Katy Chiton)

Lottia gigantea (Owl Limpet)

Mytilus californianus (California Mussel)



Leptasterias (Six-rayed Stars)

Pisaster ochraceus (Ochre Star)

Strongylocentrtus purpurartus (Purple Sea Urchin)

Seaweeds & sea grasses

Caulacanthus ustulatus

Egregia menziesii (Feather-Boa Kelp)

Endocladia muricata (Turfweed)

Fucus distichus (Northern Rockweed)

Hesperophycus californicus (Olive Rockweed)

Mastocarpus ssp (Turkish Washcloth)

Mazzaella ssp (Iridescent Weed)

Neorhodomela larix (Black Pine)

Pelvetiopsis limitata (Dwarf Rockweed)

Postelsia palmaeformis (Sea Palm)

Saccharina sessile (Sea Cabbage)

Silvetia compressa (Golden Rockweed)

Phyllospadix ssp (Surfgrass)

Zostera marina (Eelgrass)



How we are using these data?

Map of California with MPAs highlighted

Citizen science can generate biodiversity data at scales intractable for other approaches. We are building the capacity to use citizen science observations to monitor Marine Protected Areas across California.

Citizen science – the involvement of non-scientists in the production of scientific knowledge – can generate biodiversity data at spatial and temporal scales difficult to achieve by other approaches. Our team – a collaboration between the California Academy of Sciences, the California Ocean Protection Council (OPC), and the California Department of Fish and Wildlife (CDFW) – is building the capacity to use citizen science observations to understand and monitor biodiversity across California’s Marine Protected Area (MPA) network.

Over the last decade, the Citizen Science team at the Academy has been developing a community of naturalists – scientists and non-scientists alike – working together to document biodiversity, connecting people to their local nature and simultaneously collecting data critical to science and management. In particular, a number of ongoing Academy citizen science initiatives focus on California’s coastal ecosystems. These include Snapshot Cal Coast – an annual California statewide effort to document our coastal biodiversity – as well as more frequent but more spatially limited community bioblitzes and intertidal monitoring.

All these biodiversity observations are collected and aggregated using a common platform – iNaturalist. iNaturalist is a global network of naturalists, citizen scientists, and biologists contributing biodiversity observations over space and time. It achieves this via a set of technological tools, which facilitate the recording, sharing and visualization of detailed biodiversity information.

The newest member of the Academy Citizen Science Team, Giovanni Rappacuiolo,  is developing innovative approaches and tools (here is an example) to make use of the Academy’s citizen science efforts and iNaturalist community-contributed observations in support of the State of California’s long-term MPA Monitoring Action Plan. Our aims are twofold. First, to provide recommendations for increasing the usefulness of ongoing citizen science data collection and exploiting iNaturalist observations to understand and monitor MPA biodiversity and to inform MPA management. Second, to generate knowledge of California coastal ecology and understand the effects of changing ocean conditions, by examining spatial and temporal variation in community diversity and its drivers, and documenting and understanding species’ range shifts.


Join iNaturalist

Our bioblitzes are powered by iNaturalist, our in-house, citizen science platform. It's a community-powered website and app that makes it easy to upload and share your observations in the field and to get help from other users with flora and fauna IDs.