Davidson Seamount: 2002 Expedition
- Andrew DeVogelaere
Monterey Bay National Marine Sanctuary
- Gregor Cailliet
Moss Landing Marine Laboratories, California State University
- Mario Tamburri
University of Maryland
- Randall Kochevar
Monterey Bay Aquarium
- William Douros
Monterey Bay National Marine Sanctuary
End Date: May 24, 2002
The Davidson Seamount is an impressive geologic feature located 120 km southwest of Monterey, California. This inactive volcano is roughly 2,300 m tall and 40 km long, yet its summit is far below the ocean surface (1,250 m). In May 2002, a diverse group of scientists led by the Monterey Bay National Marine Sanctuary embarked on an exploration to more fully characterize the Davidson Seamount.
Using the research vessel Western Flyer and ROV Tiburon, we completed 6 full-day dives and recorded 90 hours of video from all depths of the seamount. Meanwhile, at the surface, a team counted seabirds and marine mammals. We collected 104 rock samples, 21 sediment cores, 123 biological samples, and 3 trash items. While detailed analyses are still in progress, it is clear that these assemblages of species are arranged in previously undiscovered large, contiguous patches, and are susceptible to physical disturbance.
The number of new species is unknown, but with the samples collected and associated digital video, there is a potential to describe several. At least 4 rare fishes were observed and many invertebrates have yet to be identified. Our work is helping resource managers make a decision regarding inclusion of the Davidson Seamount into the Monterey Bay National Marine Sanctuary boundary to conserve and protect the species and habitats there.
Summary to DateWe collected 104 rock samples, 21 sediment cores, 123 biological samples, and 3 trash items. The crest of Davidson Seamount had the highest diversity of species, including large gorgonian corals and sponges. While detailed analyses are still in progress, it is clear that these assemblages of species are arranged in previously undiscovered large, contiguous patches, and are susceptible to physical disturbance.
The number of new species is unknown, but with the samples collected and associated digital video, there is a potential to describe several. At least 4 rare fishes were observed and many invertebrates have yet to be identified.
To learn more about the Joint Management Plan Review process and Davidson Seamount protection, go to the Ecosystem Protection - Davidson Seamount website.
- Apparent species zonation patterns found along the seamount: crest, slope, base.
- Several rare and unique fish species observed. Rare sea toad (Bathychaunax coloratus) seen alive for the first time. Halosaur (Aldrovandia sp.) observation may be the first reported occurrence in the California Current.
- Species assemblages are arranged in previously undiscovered large, contiguous patches, and are susceptible to physical disturbance.
- Age & Growth
- Habitat association
- Geological characterization
Study MethodsHabitat and Species Analyses
To document habitat and species occurrence at the Davidson Seamount, digital video (Sony Digital Betacam™ format) was continuously recorded, as well as, intermittent high-quality digital camera (Nikon® Coolpix® 990) still images. During each ROV dive, video frame grabs were recorded and preliminarily annotated using MBARI’s computer video annotation program, VICKI (Video Information Capture with Knowledge Inferencing). Several video sampling methods were used to characterize the Seamount: 1) video transects; 2) video frame grabs; and 3) general observation video footage. Transect length and duration depended on dive objectives and suitable habitat for ROV operation. Video frame grabs were conducted at predetermined dive depths, and consisted of a series of six video frame grabs at depth: 1) pan left, distant; 2) pan left, close-up; 3) center, distant; 4) center, close-up; 5) pan right, distant; and 6) pan right, close-up. General observation video footage was used to explore the area, and recorded during collection of rocks, animals, and sediment cores. Transects and frame grabs will be used to quantify habitat and macrofauna.
After the cruise, preliminary frame grab annotations were edited at MBARI’s Video Lab. Species were identified to lowest possible taxa. In many instances, species names were not known and common names were assigned to animals. As a result, an Image Library has been created to identify known and unknown species. Images of unknown species will be discussed with taxonomic experts to assign species names, if available. In addition, biological tissues from select species collected during dives will aid in species identification. The Image Library will also help with species identification in the quantification analysis using video transects and still video frame grabs.
Marine Mammal and Seabird identification and quantification. Scan sampling was performed every 30 minutes for a duration of 10-15 minutes, searching behind the ship with the stern-mounted ‘bigeyes’ (25x150) and in other directions with the handheld binoculars (7x50). Prior to each scan sample, weather conditions were entered into a laptop computer that was linked to a global positioning system (GPS) to record time and position. Sighting effort was maintained throughout the duration of the expedition, regardless of sea state conditions.
Genetic sampling of sperm whales.
We attempted to obtain skin samples from a small pod of sperm whales sighted 22 May, approximately four miles from the R/V Western Flyer. A small boat was launched from the ship and approached within 30 meters of the whales before they dove beneath the surface. We were unable to relocate the whales and no skin samples were obtained.
Figures and Images
Map showing the location of the Davidson Seamount in relation to the Monterey Bay National Marine Sanctuary.
Close-up map of the Davidson Seamount.
Stalked white ruffle sponge on the Davidson Seamount (2563 meters).
Mystery mollusk (nudibranch) above the Davidson Seamount (1498 meters).