Michelle Ridgway’s blog

5 June 2007  Pribilof Canyon

"Sea Whips" are a member of the Pennatulacean corals.  At over 2 meters high, Halipteris willemoesei is the tallest coral recorded in Pribilof Canyon. We will refer to three sources of data on its distribution and ecology:  a trawl-ROV study by Brodeur (2001), the NOAA Groundfish Observer online database, and the Greenpeace Bering Sea Canyons Submarine Expedition (2007). 

In the Brodeur (2001) study, the author reports observing dense aggregations of  Pacific Ocean Perch (Sebastes alutus) (>30 fish per minute) occupying "forests" of Halipteris willemoesii colonies. Colonies were evenly spaced about 2 m apart. This study contrasted these findings with areas in which no sea whips were found ... Pacific Ocean Perch were also absent.

NOAA_seawhip

The NOAA Groundfish Observer database invertebrate bycatch maps (right)show that seawhip bycatch in the pelagic trawl fishery occurred in the head of the canyon as well as on the shallower shelf just above the canyon in 2006. 

Sea Whips & POP

Submarine pilots also observed dense aggregations of Halipterus willemoesii in upper Pribilof Canyon during dives in 2007 (left). Like Brodeur, many observations of these sea whips revealed a close association with Pacific Ocean Perch, especially when whip density was higher. 

We are looking forward to seeing whether the sonar backscatter data can detect seawhips on the flat, sedimentary seafloor terrain they occupy. 

Sonar Survey

4 June 2009  Pribilof Canyon

Based on previous surveys in this region, it appears as if

Dense_plumarella

typical seafloor type in the upper canyon is compacted sediment with some sand or silt over the top. In this canyon seafloor image, Plumarella seafan corals are densely distributed (right), with a few sponges among coral colonies. 

Fish_scleractiniacoral

Clean, current-swept gravel bottom is also common at two sub dive sites in the upper portion of Pribilof Canyon (left).  In this image, largemouth sculpin, seastars, brachiopods, brittle stars, small demosponges and possibly a conical scleractinian coral are among the invertebrates occupying one dive site in the upper canyon (depth approx 280 m).   

Bill teaching Candace about sonar data aquisition

Aleutian Sunset

3 JUNE 2009 

We left Captain's Bay, Unalaska Island in the wee hours of this morning, headed directly to Pribilof Canyon.  Seas were calm, with a lovely sunset.  We arrived at the canyon this afternoon.

Since most of the crew were both tired and about to split up into shifts to work through the 24-hour days, we gathered in the survey room for likely the last time during the voyage.

Michelle & Candace: BioGeo Team

Our destination is the mushroom-shaped canyon laying just south of the Pribilof Islands (right).  The canyon edge is about 25 km south of St. George Island.

Michelle  and Candace will be observing data returns from time to time to see whether backscatter is useful for interpreting the seafloor substrata or biotic features. 

Pribilof Domain

Weather has been picking up through the day, .

Meanwhile, BioGea Team is plotting submarine and ROV dive sites in a GIS database and reviewing underwater film footage of those sites.

02 JUNE 2008  DUTCH HARBOR, ALASKA

The 230' hydrographic survey ship, Mt. Mitchell arrived at Captain's Bay, Unalaska Harbor early this morning!

Mt. Mitchell Captain & B. Tellman

Captain and crew just spent a week crossing the Gulf of Alaska, then another week in the Bering Sea searching for oceanographic moorings along the ice edge and near the Pribilof Islands.   They are in great spirits and busy changing equipment, personnel and topping up supplies for the Pribilof Canyon seafloor mapping expedition.

The ship has served on many Alaskan voyages and has a "following" in nearly every port! Visitor Brenda Tellman is gracing the bow with Captain Lawrence.

NOAA PMEL Oceanographic Mooring Arrays

The Mt. Mitchell took PMEL field staff to service buoys at central and southern Bering Sea sites last week.  Here, they are demobilizing -- removing gear from the Mitchell to ship to Seattle for data retrieval.  The buoyed arrays are moored at traditional locations in the Bering Sea to collect oceanographic data on current speed, direction, temperature, salinity, and other parameters. 

Exploring Dutch Harbor-Unalaska!

Ship and survey crew spent much of the day tending to chores and taking in shoreside opportunities not available at sea.  Many explored the open terrain of the island on foot or by vehicle.  Intrepid runner, AB Linda Mancuso ran 18 miles over the Unalaska Pass, while others drove around sight seeing and savouring local restaurant fare. 

Catch de Jour

Personal use king crab fishing opened in Dutch Harbor at Midnight, so w

Candace and I worked this afternoon with ADF&G Observer Program staff Mary and Melissa, to review the diversity of

Coral Class

corals, sponges and bryozoans their field crew have collected in Aleutian and Bering Sea fisheries.  This huge collection is in excellent shape and a great resource for training observers in Melissa's "Living Laboratory".  We are trying to determine which species may have sufficiently dense skeletons and size to be detected by sonar backscatter returns.  Paul Wilkins of the NOAA Fisheries and Monitoring Division toured us around the online databases which archive information on coral, sponge and bryozoan bycatch in federal fisheries.  These data show some bycatch of corals and sponges in Pribilof Canyon -- especially in the non-pelagic trawl fisheries.

Ballyhoo View

Candace Stepetin on the traditional Mt. Ballyhoo hiking trail.  Many seafarers hike the mountain before setting out to sea, as it provides a phenomenal view and a stretch of the legs before long journeys at sea. The view shows Unalaska and Dutch Harbor, including the original village and tremendous commercial fishing infrastructure supporting fleets, processing and shipping products harvested from the Bering Sea grounds.

We wrapped up our shore excursions by 2230 hours and set sail northeastward toward Pribilof Canyon shortly after midnight.

01 June 2009 Anchorage to Dutch Harbor, Unalaska Island, Alaska

PRIBILOF CANYON SEAFLOOR MAPPING EXPEDITION 2009

During our submarine expedition to the Bering Sea Caynons in 2007, we conducted 14 dives in Pribilof Canyon and 4 ROV surveys.  We distributed our dive effort around the canyons at roughly equidistant intervals, to cover the depth ranges reachable in the deepworker submarines -- a maximum of 630 meters.  The ROV could reach 1,100 meters.  At that time, we navigated using the best available bathymetric (seafloor depth) information available. 

Most of that data was based on relatively crude surveys from the 1960's, making it difficult to plan dives to precisely hit our depth and seafloor feature targets.  OK, we were essentially "flying blind"!  Our current mission is to map the canyons for purposes of future submarine research navigation and for many other purposes.

Pribilof Canyon and the connected Pribilof Domain waters surrounding the Pribilof Island Archipelago are recognized for their unique, highly productive characteristics by scientists in many disciplines --- geologists, fisheries biologists, oceanographers, benthic ecologists, foodweb specialists -- concur that the region's physical and biotic attributes are outstanding relative to the shelf break and shelf regions nearby.  How unique and quantifying facets of the canyon geo-bio setting are challenges we continue to address. 

Since so many marine scientific disciplines rely intimately upon modelling, and modelling requires a fundamental understanding of the geomorphology of the canyons, Dr. Dave Scholl and I underscored the importance of obtaining fine scale bathymetric data for the canyon system during our address at the Marine Science Symposium (Anchorage, January 2008).  Dave, who first mapped the canyons with Dave Hopkins in the late 1950s, was startled to find that very little mapping effort has been conducted in that area in nearly 50 years!

Finally, a team with the right stuff has been assembled to map

the canyon. 

St. Paul Islander, Candace Stepetin and I are focusing on biogeographical exploration of Pribilof Canyon.  We will be examining areas already surveyed visually by submarine and ROV in previous years to observe the depth profiles, geomorphology of the area, and to ascertain whether the backscatter component of the sonar returns being used on this survey are capable of detecting seafloor features documented by sub.

The team is gathered in Anchorage on weather hold ... awaiting our flight to Cold Bay and westward to Dutch Harbor this afternoon. 

Many weeks have passed since I returned from the Bering Sea Canyon Expedition, but not one day has gone by that I haven't dealt with some facet of the cruise observations, data, or sharing information through discussions and presentations.  As promised, I will provide initial findings of the research on as information from our international team of ecologists, biologists, geologists, biogeographers and taxonomists becomes available. 

Here are a few links to articles and radio pieces about the expedition.

Anchorage Daily News  September 2007

http://www.adn.com/news/environment/story/9283284p-9197791c.html

Juneau Empire   September 2007

http://www.juneauempire.com/stories/091607/loc_20070916020.shtml

Anchorage Daily News:  Relevations from the Deep

http://www.adn.com/life/alaskana/story/9463582p-9374837c.html

SCIENCE magazine October 2007

http://www.sciencemag.org/cgi/content/full/318/5848/181a#AFF1

http://www.sciencemag.org/cgi/content/full/318/5848/181a/F1

University of Alaska Geophysical Institute Science Forum

Revelations from a deep sea canyon, by Ned Rozell Fairbanks, Alaska

http://www.gi.alaska.edu/ScienceForum/ASF18/1880.html

Dutch Harbor Fisherman

http://www.alaskanewspapers.com/content/pdf/DH_09-06-07.pdf

Dutch Harbor Fisherman:  Photo on page 6

http://www.alaskanewspapers.com/content/pdf/DH_09-13-07.pdf

Alaska Public Radio

http://aprn.org/2007/08/13/bering-sea-under-submarine-examination-for-first-time/

Alaska Public Radio 

http://media.aprn.org/2007/ann-20071005-05.mp3

Alaska Public Radio

http://aprn.org/2007/08/21/greenpeace-documents-wildlife-habitat-in-pribilof-undersea-canyons/

Alaska Public Radio:  Scott Burton’s Interview with Scholl and Ridgway about 14-15 minutes into radio piece called "In the Trenches" 

http://www.akradio.org/archive/AK%2011-10-2007.mp3

Diving in the submarines is limited by several factors.  Fog, rough water and high winds have singly or collectively curtailed diving several times already.  But re-powering requirements can also lead to "down time" for the subs.  Batteries must be recharged through the ship's power supply for 3 to 5 hours between dives.  During these intervals, we used the ROV to explore deeper habitats within the canyons. 

SeaView ROV

The hightech Remotely Operated Vehicle is owned and operated by Matthew Cook, President of SeaViewSystems.com.  In launching the equipment, ship's crew and ROV technical crew carefully synchronize cranes and cable reels to deploy and then monitor the vehicle from deck (for the entire dive!). 

Meanwhile, Matt and Nuytco's chief navigator drive and track the ROV's position from the bridge deck.  Ship's officers continuously adjust twin props and thrusters to manuever the 220 foot Esperanza  over the tethered vehicle and then gently tow the apparatus to each station along the survey route. 

A cadre of our scientific team and ship's crew then gather around the live video screen to discover, observe and record marine life along the survey routes.  NMFS's sponge expert, "SpongeBob" was keen to point out exotic to cryptic sponges observed, while Greenpeace's John Hocevar, Clive, Timo, Kenneth, David, myself and others maintained records on invertebrate, fish and coral sightings. 

Sponges

Tooled with four dynamic thrusters and a powerful vertical thruster, the "DR", or "deep-rated" SeaView Falcon ROV was able to navigate in even high current areas for this work.  Laser beams with a 20 cm spread were used to scale the underwater video images.  We used a custom manipulator arm to collect selected specimens for further taxonomic analysis when possible.  Once captured by video and deftly collected by manipulator arm, precious specimens were transported across the seafloor to a specimen bin attached to the ROV's undersea "garage".   

The SeaView Falcon DR ROV was an excellent tool for extending our probing into the depths of Alaska's Zhemchug and Pribilof Canyons!  When it was "down time" for the subs and pilots, it was "show time" for the ROV to explore these marine habitats in an intimate manner that allowed for everyone onboard to collaborate in the research program.

The field research phase of our Expedition to the Bering Sea Canyons is winding down, and the Esperanza is laying on anchor near Captain's Bay, Unalaska.  Several updates written at sea for this blog were never posted due to satellite signal strength for transmission issues, vessel orientation, or computer dedication to other work at hand. 

I will "post" post those blogs, as well as continue to provide updates on findings from the expedition as they emerge.  More coming very soon!

Thanks to friends, family, colleagues and others that wrote in during the voyage .... it was great to hear from you and I am touched by your level of interest, support and encouragement. 

Deepworker on transect

Here is our team of Bering Sea Canyon Expedition Submarine Pilots: 

Kenneth Lowyck (Belgium), Michelle Ridgway (Alaska), John Hocevar (Texas), Timothy Marshall (California) and David Guggenheim (Washington, DC).

Whether diving together or collaborating on surface, these guys are excellent pilots and great to work with!   

SUBMARINE PILOTS

 We have completed 25 dives in Pribilof and Zhemchug Canyons, down to a maximum depth of 1,950 feet (about 325 fathoms, or over 650 meters).  Some dives were in tandem ... with two subs deployed together, and other dives were conducted solo -- one sub in the water at a time.  Individual dives have lasted nearly five hours from "hatch to hatch"!