Scientific Research Plan, Crew & Collaborators

Dr. William F. Gilly
Director, Sea of Cortez Expedition and Education Project
Hopkins Marine Station of Stanford University
Oceanview Boulevard
Pacific Grove, CA 93950-3094
phone: (831) 655-6219
send e-mail to Bill Gilly

Jon Christensen
Coordinator, Sea of Cortez Expedition and Education Project
Steinbeck Fellow, San Jose State University
265 Scripps Court Palo Alto, CA 94306-4540
phone: 650-320-9504
cell phone: 650-759-6534
contact Jon Christensen

Research plan:

The purpose of this research expedition is to retrace the expedition made by John Steinbeck and Edward F. Ricketts in 1940 and survey invertebrate fauna in the same intertidal sites, as well as some additional sites. By comparing common species in the intertidal sites surveyed in 1940 to those found there today, we will identify any discernible biogeographic or temporal patterns of change in faunal assemblages. We will also establish a contemporary baseline at those sites. And we will extend this research around to the Pacific Coast of Baja California Sur to investigate the biogeography of the intertidal transition from the Sea of Cortez to the Pacific.

There are three main goals of our research program. A brief description of methods for each goal is listed here.

1. Site evaluation of a diverse set of Pacific Coast and Sea of Cortez sites with the following attributes in mind: a) create an identified species list of most common intertidal invertebrates and algae (100-200 species); b) identify Sea of Cortez species that fill niches of Pacific Coast species in southern sites; c) simple mapping of sites with GPS polygons made for different faunal assemblages and habitat features, as well as notes of habitat characteristics. This will be accomplished by a simple methodical search through different habitats by all researchers. The familiarity with general natural history and intertidal systems in particular of several of the participants will facilitate a relatively thorough search in a limited time. Notes will be made and compared subsequently aboard the ship. Collections will be made of 1-5 individuals for a voucher collection to be housed at CIBNOR-Centro de Investigaciones Biológicas del Noroeste in La Paz. Photographs will be taken of all species. Additionally, collections of unidentified species will be made for later identification by taxonomic experts. Dimensions of rocky benches at each site will be measured using GPS data points to estimate total area available to intertidal invertebrates. At each site, the areas of high, middle, low, and exposed tidal zones will be measured with their boundaries delineated by their positions on shore and the taxa that are present. In addition, percent cover of the following habitat attributes for the entire site will be estimated visually by the investigators: cobble, flat bench area, large boulders (greater than 0.5 m3), massives (rock formations whose vertical surfaces were greater than their horizontal top surface areas), calm pools, surge channels (narrow inlets of approximately 2 m or less in width with moving water), surge pools (rock surfaces which experience high wave action, even at low tide), and overall algal and bare rock cover.

2. Obtain relative estimates of population abundance for 12-18 common species. These surveys will use target transects on known habitats of these target species. At each site, 2 to 8 transects ranging from 4 to 50 m in length will be established. Transect length and number of quadrats sampled will vary with site depending on the area of habitat available. At each site we will attempt to sample 6 zones: (1) the high zone characterized by long exposure times, (2) the rockweed zone, (3) the mid-intertidal zone (characterized by macroalgae, especially brown turf algae), (4) the low intertidal zone (characterized by short-term exposure to air at low tide and the appearance of fleshy red algae), (5) surge channels or boulder fields, and (6) the exposed zone (characterized by direct exposure to wave action). We will count target species in 0.25m2 quadrats spaced at every meter along transects. At sites where the target species are rare, and thus not found along transects, we will conduct intensive searches in appropriate habitat for the species. Search areas will be marked and measured, so that species abundances for rare taxa can be reported per m2. In addition, larger and less abundant forms such as anemones, urchins, sea stars, and molluscs will be counted along band transects where an observer walks an 8 to 25 m path through the low or exposed zones and counts every individual of the species within a meter on either side of the transect line. Some large form species will be counted in the intertidal zone and in the shallow subtidal by snorkel along band transects.

3. Obtain size structure of target species. Up to the first 50 individuals of each of the target species encountered along transects will be measured for maximum shell length or body size or shell aperture. If species are rare, up to 50 individuals will be measured as encountered in searches. Additionally, selected sessile species will be marked for future assessments of growth rates. We estimate that most of the species we encounter will be identifiable on the spot and we will not need to collect them. However, over the course of our research we estimate that we may need to collect 1-5 voucher specimens of approximately 100 species for identification purposes. The final destination of these specimens will be CIBNOR-Centro de Investigaciones Biológicas del Noroeste in La Paz. We may also collect 20-50 specimens of approximately 25 of the most common species in the biogeographic transition zone between the Sea of Cortez and the Pacific Coast in order to conduct population genetics studies at some time in the future.

This research will be a collaboration between the project's chief scientist, Dr. William F. Gilly, and Dr. Rafe Sagarin, Dr. Charles Baxter, Nancy Burnett, Jon Christensen, and colleagues in Mexico.

For additional information on abundance surveys and site evaluation methods, please see: Sagarin, R., and S. Gaines, 2002. Geographical abundance distributions of coastal invertebrates: using 1-dimensional ranges to test biogeographic hypotheses. Journal of Biogeography, 29: 985-998. The original expedition also set crab traps several times and in this manner collected a number of arthropods, gastropods and echinoderms that were not collected in the intertidal.We will also repeat those surveys.

During this expedition, additional research will be conducted by Dr. William F. Gilly on Dosidicus gigas (jumbo squid) in the Sea of Cortez.

1. Squid tagging and video observations: At points along the proposed transit where we encounter Dosidicus gigas (jumbo squid) we will carry out experiments involving several types of electronic tags. We will also utilize video methods in an attempt to visualize their natural behavior. We will also carry out conventional plankton tows in an effort to collect paralarvae of this species. Finally, if we catch small specimens, we will bring them on board for behavioral observations in a large aquarium. This work will be part of a collaboration between the chief scientist and Mexican colleagues, Dr. Unai Markaida (El Colegio de la Frontera Sur, Campeche) and Dr. Cesar Salinas (CIBNOR, La Paz).

2. Electronic tagging: Adult squid will be captured using standard 30-40 cm jigs on hand-lines or with rod and reel. They will be brought on deck and will be fitted with an electronic tag and immediately released.These devices detach from the squid at a programmed time and transmit collected data on depth, temperature and light level to a satellite system. We will also use radio-acoustic tags that measure depth and temperature and transmit an acoustic that is monitored on the boat with a suitable receiver.

3. Video observation: We will deploy a video camera capable of forming images under low-light conditions in order to visualize natural behavior without the use of artificial light or human divers. The camera will be mounted in an underwater housing and will be suspended on a cable with a heavy weight to reach the appropriate depth. The specific goal is to visualize behavior during the day at depths of approximately 300 m. We hypothesize that squid spend daylight hours at these great depths where the oxygen content is very low. We would like to determine whether the squid are actively feeding at these depths or whether they are in an inactive state.

4. Plankton tows: The location of spawning for jumbo squid is unknown, but preliminary observations indicate that mature females have mated in waters of the central Gulf. We therefore hypothesize that a spawning ground may exist in the Gulf, and would like to test this idea by collecting paralarvae.

Port calls and research sites with dates and geographic coordinates:

Date & Location Lat(N) Long(W)
Purpose: Transit, Port Call, Visit, or Research.
Numbers correspond to research sites on cruise chart.
Letter indicates visit without research survey or collecting.

3/25 Monterey Port of embarkation
3/26 Transit
3/27 San Diego Port of Exit
3/28 Transit
3/29 Is. Cedros, C. San Augustin 28 05 115 20 Port of Entry, Research, 1
3/30 Pt. Falsa/Pt. Eugenia 27 51 115 04 Research, 2
3/11 Bahia Tortugas/Pt. Sargazo 27 40 114 54 Research, 3
4/1 Bahia Asuncion/Pt. San Pablo 27 13 114 28 Research, 4
4/2 Pt. Santa Domingo 26 19 112 41 Research, 5
4/3 Pt. Pequena 26 14 112 30 Research, 6
4/4 Pt. San Lazaro 24 46 112 16 Research, 7
4/5 Pt. Tosca/Is. Margarita 24 18 114 02.5 Research, 8
4/6 Pt. Conejo 24 04 110 00 Research, 9
4/7 Cabo San Lucas 22 52.5 109 53.5 Port Call, Research, 10
4/8 Cabo Pulmo 23 27 109 25 Research, 11
4/9 Pt. Lobos/Is. Espirtu Santo 24 27.5 110 18 Research, 14

4/10 Pt. Roca Caimancito/La Paz 24 13 110 17.5 Port Call, Research, 12
4/11 La Paz
4/12 El Mogote/La Paz 24 10.5 110 20 Research, 13

4/13 B. Amortajada/Is. S. Jose 24 53 110 34 Research, 15
4/14 Pt. San Evaristo/ Nopolo 24 59 110 45 Research, 16
4/15 Pt. Los Burros/Los Dolores 25 03.5 110 49.5 Research, 17
4/16 Pt. Botella/Ens. Los Pargos 25 17.5 110 57 Research, 18
4/17 Pt. San Marcial 25 31 111 01 Research, 19
4/18 Puerto Escondido 25 49 111 18 Research, 20
4/19 Loreto, Isl. Coronado, SW point 26 06 111 17 Port Call, Research, 21
4/20 Bahia Concepcion, E shore 26 35 111 41 Research, 22
4/21 San Lucas Cove 27 12 112 12 Research, 23
4/22 Santa Rosalia Port Call
4/23 Pt.Prieta/C.Virgenes 27 31 112 20 Research, 24
4/24 Pt. Baja/Boca San Carlos 27 42.5 112 38 Research, 25
4/25 Pt. Trinidad (El Majon) 27 49 112 43 Research, 26
4/26 Cabo San Miguel 28 12 112 47 Research, 27
4/27 Bahia San Francisquito 28 25 112 51 Research, 28
4/28 Bahia las Animas 28 49 113 21 Research, 29
4/29 Bahia de los Angeles 28 55 113 33 Research, 30
4/30 Puerto Refugio 29 34 113 32 Research, 31
5/1 Transit
5/2 Puerto Penasco Port Call
5/3 Transit
5/4 Is. Rasa 28 48 113 01 Visit, A
5/5 Is. Tiburon SW Corner 28 50 112 36 Research, 32
5/6 Is. San Pedro Martir 28 23 112 22 Research, 33
5/7 Transit
5/8 San Carlos, Sonora 27 57 111 05 Research, 34
5/9 Guaymas Port Call
5/10 Guaymas
5/11 Delta of Yaqui River 28 37 110 38 Research, 35
5/12 Estero de la Luna 27 18 110 35 Research, 36
5/13 Agiabampo estuary 26 25 109 18 Research, 37
5/14 La Paz Port Call
5/15 Is. Espirtu Santo, B. S.Gabriel 24 26 110 22.5 Research, 38
5/16 La Paz
5/17 La Paz

5/18 Transit
5/19 Transit

5/20 San Quintin Port Call
5/21 San Quintin
5/22 San Diego Port of Entry
5/23 Transit
5/24 Monterey

Specimens to be collected:

Scientific name; Common name; Number of specimens to be collected; Locations

Anthopleura sola; Sea anemone; 1-5; various locations
Anthopleura xanthogrammica; Sea anemone; 1-5; various locations
Anthopleura dowii; Sea anemone; 20-50; various locations
Bunodactis mexicana; Sea anemone; 20-50; various locations

Fissurella volcano; Keyhole limpet; 1-5; various locations
Didora diguati; Keyhole limpet; 20-50; various locations
Didora inaequalis; Keyhole limpet; 20-50; various locations
Didora saturnalis; Keyhole limpet; 20-50; various locations

Lottia pelta; Limpet; 1-5; various locations
Lottia strigatella; Limpet; 20-50; various locations
Lottia argrantesti; Limpet; 20-50; various locations
Lottia acutiplex; Limpet; 20-50; various locations
Lottia atrata; Limpet; 20-50; various locations
Scurria mesoluca; Limpet; 20-50; various locations

Lepidochitona harttweggii; Chiton; 1-5; various locations
Chiton virgulatus; Chiton; 20-50; various locations
Lepidozona serrata; Chiton; 20-50; various locations

Tegula funebralis; Trochid; 1-5; various locations
Tegula rugosa; Trochid; 20-50; various locations

Serpulorbis squamigerous; Vermetid; 1-5; various locations
Serpulorbis margaritaceus; Vermetid; 20-50; various locations

Nucella emarginata; Predatory snail; 1-5; various locations
Acanthina tyrianthina; Predatory snail; 20-50; various locations
Purpura pansa; Predatory snail; 20-50; various locations
Thais biserialis; Predatory snail; 20-50; various locations

Mytilus californianus; Sessile pelycypod; 1-5; various locations
Brachiodontes; Sessile pelycypod; 20-50; various locations
Chama; Sessile pelycypod; 20-50; various locations
Cardita; Sessile pelycypod; 20-50; various locations

Pisaster ochraceous; Sea star; 1-5; various locations
Heliaster kubiniji; Sea star; 20-50; various locations
Astrometus sertulifera; Sea star; 20-50; various locations

Strongylocentrotus purpuratus; Sea urchin; 1-5; various locations
Diadema mexicanus; Sea urchin; 1-5; various locations
Echinometra vanbrunti; Sea urchin; 20-50; various locations

Tetraclita squamosa rubescens; Barnacle; 1-5; various locations
Tetraclita stalactifera; Barnacle; 20-50; various locations
Chthamalus sp.; Barnacle; 20-50; various locations

Other species of noncommercial intertidal invertebrates and algae, which are common and which we cannot identify to genus, will be collected for identification purposes; 1-5; various locations.

The original Steinbeck-Ricketts expedition set crab traps several times and in this manner surveyed common arthropods, gastropods and echinoderms that were not collected in the intertidal. Any which we cannot identify to genus, will be collected for identification purposes; 1-5; various locations.

Paralarvae or small juveniles of squid captured during plankton tows will be preserved, some in ethanol (for molecular identification) and some in formalin (for anatomical identification). A maximum of 200 juveniles and paralarvae would be preserved.


The Gus-D

Bill Gilly
Chief Scientist

Exequiel Ezcurra
President, Instituto Nacional de Ecologia

Frank Donahue

Chuck Baxter

Nancy Burnett
Marine Biologist & Photographer

Jon Christensen
Cruise Coordinator & Writer

Sue Malinowski

Rafe Sagarin

Meriah Arias
Marine Biologist

Cesar Salinas

Arminda Mejia Rebollo

Gaston Bazzino Ferreri

Raul Ramirez Rojo

Michael Beman
Stanford University

Unai Markaida
El Colegio de la Frontera Sur

Rafael Riosmena-Rodriguez

Photo Credits:
Bill Gilly
by L.A. Cicero
Stanford News Service;
Frank Donahue and Chuck Baxter
by Robert C. Bain
San Jose State University
Photographic Services