2 posts tagged “bering sea”
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.
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.
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.
Throughout our expedittion in the southern Bering Sea, we have been incredibly blessed with excellent weather and the constant company of marine mammals and birds. Last night we had lots of company! As yet another productive day of undersea exporation wound down, and the ship slowed for the evening, we were joined by hundreds of seabirds.
Light and dark-phase northern fulmars (hundreds), mottled petrels (dozens) and albatross (9 total) gathered around the Esperanza in a huge flock. Some aggregations of birds were clearly feeding. Among the smaller birds, we spotted first two blackfooted (middle photo) and then a short tailed abatross (bottom . Within half an hour, three more short tailed albatross glided in and joined the other three albatross about 100 meters off of our stern! Then a Laysan's albatross joined them, and yet two more short tailed. The gathering of six short tailed abatross in one small aggregation so close to the ship was fantastic to witness. With fewer than1,200 remaining on the planet, this was a significant portion of their population!
Mannes' engineer crew shut down Esperanza's main engines for an evening drifting over the Canyon.
As daylight began to fade to darkness at around 10 pm, dozens of distant exhalation plumes from unknown cetaceans toward Experanza from the distant fogbank. First a few dozen, then over a hundred Fin whales were in sight of Esperanza's bridge! The massive whales were rolling about on the surface within 25 meters of the vessel on all sides! I never observed the Fins breaching, but they seemed to be lunging near the surface ... either at one another, or perhaps in pursuit of food. One individual was characterized by Diek as the "big bull" lunged on the surface directly toward Esperanza's bow several times.
Whether he was defending his feeding territory, or perhaps mating territory, or simply lunging for other reasons, we cannot know. But when a whale one-third the size of the ship makes such assertive gestures, I do wonder whether there was a message he was trying to convey.
WHY WERE ARE THEY HERE? I am not so familiar with the ecology of fin whales, except to know that they are considered generalists with regards to food preferences. They apparently feed on fish and invertebrates in the water column. Although we have seen few fish or euphausiids during our descent in submarines, we are definitely in squid country. We also know that at least some cod and myctophids are in the vicinity. So, these may be among the species that support the great whale populations. And since several of these species migrate up the the sea surface at night, perhaps that explains this apparent feeding frenzy at the corpuscular hour.
Studies by Alan Springer and other ecologist indicated that the Bering Sea shelf break, called the "greenbelt", is among the most productive ecosystems in the world. From phytoplankton to top predators, the carbon produced and transferred from the deep basin waters up the slope and onto the shallow shelf rivals that of any such system on the planet.
Helena, Rao and I continued watching the enormous pod of whales until well past midnight, at which time I had to leave the bridge to them and prepare for another day of submarining.
