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Shellfish Assessment Program - Habitat Research: Past Research - Submersibles

1999 Patton Seamount Expedition

Photo of Dr. Bradley Stevens with the DSV Alvin
Dr. Bradley Stevens with the DSV Alvin

In July 1999, Dr. Bradley Stevens (formerly with the Shellfish Assessment Program) explored the Patton Seamount in the Gulf of Alaska with a deep-submergence vehicle, the DSV Alvin.

The Alvin can hold three passengers, typically a pilot and two scientists, in its 23 feet, 4 inches; cruise at a maximum speed of 2 knots; operate to a depth of 14,764 feet; and support its passengers for 216 man-hours (72 hrs by 3 persons).

During this expedition, several crab species were observed:

Photo of a giant spider crab, Macroregonia 
			macrochira   Photo of a grooved Tanner crab, Chionoecetes 
			tanneri   Photo of a golden king crab, Lithodes aequispina
Giant spider crabs (Macroregonia macrochira) were observed from 1030 meters down to as deep as 3240 meters. They were the most abundant crab below 1000 meters, and virtually the only species of crab below 2000 meters.   Grooved Tanner crab, Chionoecetes tanneri, were captured from 620 to 850 meters and observed on sandy and sedimented substrates, occasionally seen on rocks.   Golden king crab, Lithodes aequispina, were captured from 29 to 1944 meters and observed on rocky subtrates. Grasping pairs were commonly seen.
Photo of a scarlet king crab, Lithodes couesi   Photo of a king crab, Paralomis verrilli   Photo of a king crab, Paralomis multispina
Scarlet king crabs (Lithodes couesi) were observed down to 950 meters (juveniles) and between 530 - 600 meters (adults).   A king crab, Paralomis verrilli, was captured at 1074 meters.   A king crab, Paralomis multispina, was captured at 915 meters.
Photo of a squat lobster, Munidopsis 
			albatrossae   Photo of a squat lobster of Chirostylidae

Like king crabs, the family Galatheidae are classified as Anomurans, or "asymmetrical tail" crabs. The family Chirostylidae are small red crabs with long chelipeds. These were abundant among the rocks and cobbles on the upper slope and flat top of Patton Seamount, and were commonly observed among the branchs of gorgonian soft corals.

Squat lobsters, Munidopsis albatrossae (Family Galatheidae) were usually seen below 1000 meters   Squat lobsters of the Family Chirostylidae, (Chirostylus sp.), were observed above 500 meters.

2002 Gulf of Alaska Seamount Cruise with DSV Alvin

Photo of DSV Alvin launching from R/V Atlantis
Launching DSV Alvin from R/V Atlantis

In June, 2002, Dr. Bradley Stevens sailed on the R/V Atlantis (operated by Woods Hole Oceanographic Institute) to explore the Gulf of Alaska waters using the DSV Alvin. They studied the geology, microbiology, and ecology of deepwater crabs, corals, and other life on undersea mountains called seamounts. They visited six seamounts, five of them previously unexplored. These seamounts are: Patton, Murray, Chirikof, Campbell, Marchand, Scott, and Warwick.

Other objectives of Alvin's research on the seamounts were to: define the distribution of crab species with depth, associate crab species and their life history stages with substrates, examine dispersion patterns of crab species, collect crabs for life history information and culture, collect basaltic rocks for aging seamounts, make opportunistic biological and geological observations, collect soft coral samples for genetic studies, and to collect water and sediment samples for the study of bacteria.

Photo of a seamount bathymetry map. 
			Click image to enlarge.  

Full-coverage bathymetry maps were made of all six seamounts visited by the R/V Atlantis. SeaBeam surveys of the seamount bathymetry were conducted at night, leaving the days for Alvin dives. Click image to enlarge.

Photo of submersible trap catching spider crabs  

Either with Alvin's manipulators or the baited trap on an elevator, 28 spider crabs (Macroregonia macrochira were captured and then placed in a tank of chilled seawater.

Photo of bamboo coral, an isisdid coral  

At 325 meters bamboo coral, an isidid coral and brittlestars (opiuroids) were seen. The Bamboo coral is made of both calcium carbonate (white "legs") connected by proteins (black "joints"). Yellow crinoids were abundant from 583 meters to the top of the seamount at about 300 meters.

Photo of bamboo coral and brittlestar skeletons  

One goal of the Gulf of Alaska Seamount study was to collect the different corals and invertebrates found on the different seamounts, and to document their depth distribution and community structure. Dr. Amy Baco-Taylor was collecting soft corals for her genetic research, and tells more in her Ocean Explorer web article, Dispersal and Reproductive Biology of Deep-Sea corals. The skeleton of "Bamboo coral" and ophiurids or brittlestars shown here were examined in the lab aboard the R/V Atlantis. These specimens were collected at the Murray Seamount.

Photo of submersible rock being collected with
			a grabber  

Rocks were collected on five dives for microbiological studies and for samples to determine their volcanic histories. The Alvin manipulator placed the rocks in an isolation box, designed to minimize contamination of the rocks with surface water and to hold the rocks in their ambient sea water until they were transferred to sterile containers on deck. Microbes in these deep sea rocky environments may be some of the most primitive on Earth because of their potential ability to survive on a diet of rocks and water. This large basket with plastic fingers worked well for holding large crabs on Alvin's science tray, although smaller specimens sometimes escaped or washed out, particularly at the surface.

Shellfish Assessment Program - Habitat Research PAST RESEARCH

Related Publications

  • HOFF, G. R., and B. STEVENS. 2005. Faunal assemblage structure on the Patton Seamount (Gulf of Alaska, USA). The Alaska Fisheries Research Bulletin 11:27-36. Online.

See the publications and poster databases for additional listings.

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