Sanctuary Integrated Monitoring Network
Monitoring Project

Detecting non-native species in kelp forests and on rocky shores

Principal Investigator(s)

  • Greg Ruiz
    Smithsonian Environmental Research Center
  • Jonathan Geller
    Moss Landing Marine Laboratories, California State University
  • Andy Chang
    Smithsonian Environmental Research Center
  • Chela Zabin
    Smithsonian Environmental Research Center
Start Date: October 01, 2014

As part of a larger research effort focused on detecting marine non-native species in California bays and estuaries, we last year began surveys for target non-native species along the outer coast. We surveyed 10 rocky intertidal sites from Marin County to Monterey County and 8 kelp forest sites from Monterey to Carmel. Our list of target species is comprised of non-native species previously reported from the open coast of California or established in protected bays and estuaries and deemed capable of colonizing the open coast.

Our goals were to: 1) document the presence of target non-native species along the coast; 2) quantify their current abundance and distribution at study locations.

Summary to Date

In October 2014 we surveyed eight kelp forests at popular dive sites from Breakwater Cove (San Carlos Beach) in Monterey to Pt. Lobos State Park in Carmel (see Figs. & Images tab above). We surveyed rocky intertidal sites over the course of two spring tide series (see Figs. & Images tab above).

Of our target species, the bryozoan Watersipora subtorquata, was the most widespread. We recorded W. subtorquata from four subtidal sites (Breakwater Cove, McAbee Beach, Hopkins Marine Station, and Lovers Point) and from four intertidal sites (Slide Ranch, Breakwater Cove, McAbee Beach, and Hopkins Marine Station). Watersipora colony sizes were typically small, representing between 0.1-2.5% cover across study transects, but were widely distributed within our transects in some locations (i.e., found in 23% of quadrats at Breakwater Cove and 10% of quadrats at McAbee Beach). The bryozoan was attached to a wide variety of substrates, including rock, barnacles, algae and crabs. Subtidally, it was found on both horizontal and vertical surfaces, but appears to be limited to vertical surfaces in the intertidal zone.

The red turf alga Caulacanthus ustulatus was found at Soquel Point in Santa Cruz in a single transect, growing on native mussels, below the zone of a similar native, Endocladia muricata.

We are awaiting confirmation of identifications for other species, but a species of Colpomenia was found at several sites, as were putative specimens of the sponge Hymeniacidon.

Undaria pinnatifida, which is abundant in Monterey Harbor, was not found in the kelp forests. Neither was Sargassum muticum, a non-native species widely distributed in California estuaries, nor was Sargassum horneri, which is found along the open coast in Southern California.

Monitoring Trends

  • The invasive bryozoan Watersipora subtorquata appears to be the most widespread of the targeted non-native species. Originally introduced into harbors and marinas, the deep red bryozoan is now in several areas along the open coast.


This project was funded by the California Department of Fish and Wildlife. As reports become available to the public, we will post them as PDFs.

Study Parameters

  • Dispersal & Recruitment
  • Non-indigenous species

Study Methods

Targeted non-native species

Our surveys focus on 16 conspicuous and morphological distinct organisms, listed below:

Colpomenia peregrina
Sargassum muticum
Sargassum filicinum=horneri
Undaria pinnatifida
Caulacanthus ustulatus
Grateloupia turuturu
Lomentaria hakodatensis

Watersipora spp.
Bugula “neritina”
Conopeum spp.
Schizoporella spp.

Botryllus spp. (tuberatus, schlosseri)
Botrylloides spp.
Styela clava

Hymeniacidon sinapium
Halichondria spp.

Within study transects for each of our target species, we recorded presence, % cover, number of individuals (when applicable), and the type and orientation of substrate to which they were attached.

Kelp forests

Eight subtidal sites were surveyed at the following locations:

1. Breakwater Cove, Monterey
2. McAbee Beach, Monterey
3. Hopkins Marine Station, Pacific Grove
4. Lovers Point, Pacific Grove
5. Coral Street, Pacific Grove
6. Copper Roof House, Carmel
7. Monastery Beach, Carmel
8. Pt. Lobos State Park, Carmel

At each location, we surveyed along 2-4 30 x 2 m transects, running perpendicular to shore. Survey depths were typically in the 7-10 m range and not deeper than 18 m. Diver teams swam the transect, surveying one m on each side. When target species were encountered, 0.5 m quadrats were placed to aid in quantitative measurements. We recorded the quadrat’s position within the transect. Voucher specimens were collected to confirm identifications using morphological and/or genetic methods.

Rocky intertidal

Ten rocky intertidal sites were surveyed at the following locations:

1. Duxbury Reef, Bolinas
2. Slide Ranch, Marin Headlands
3. Fitzgerald Marine Reserve, Moss Beach
4. Mavericks, Half Moon Bay
5. Davenport Landing Beach, Davenport
6. Soquel Point, Santa Cruz
7. Breakwater Cove, Monterey
8. McAbee Beach, Monterey
9. Hopkins Marine Station, Pacific Grove
10. Lovers Point, Pacific Grove

At intertidal sites, we combined transect surveys with 20-minute walking surveys to cover a broader area. At each site, we surveyed along a 30 x 2 m transect placed in the mid-intertidal; when possible we also placed transects in the low and/or high zones. Target species within transects were recorded as above.

Figures and Images

Figure 1. Location of subtidal survey sites sampled in the fall/winter of 2014.

Figure 2. Percentage of quadrats (1 by 1 m ) in which the invasive bryozoan Watersipora subtorquata was found. Note the decline as distance from the harbor increases.