Search

Observations of deep-sea dogfishes (family Squalidae) were made opportunistically via a remotely operated vehicle at a large food fall, a recently dead Atlantic Swordfish, Xiphius gladius, on a topographic rise at 453 m depth off South Carolina, USA (NW Atlantic). Genie’s Dogfish, Squalus clarkae (formerly S. mitsukurii), and Roughskin Dogfish, Cirrhigaleus asper, were the principal scavengers. Additional scavengers included crabs (Callinectidae) and a cutthroat eel (Synaphobranchus sp.). At least two Wreckfish, Polyprion americanus, were attracted to the carcass, and one was observed to prey directly upon a small dogfish. The aggregation of highly vagile scavengers to food falls, sources of organic carbon transfer to the deep sea, is generally assumed to be based on odor plumes, but acoustic cues from large and active scavengers can also account for rapid attraction of other scavengers and predators.

EX-18-06

EX-17-08

From February 12 to February 15, 2016 the team conducted shakedown tests of these new systems, tested data work flow and integrations, and prepared for the rest of the field season. EX-16-02 operations consisted of three ROV test dives and three nights of mapping operations with a primary focus on completing engineering priorities and testing new systems. The shakedown cruise ended earlier than expected, on February 15, when the ship returned to port due to a mechanical problem with the ship's Dynamic Positioning system.

This document contains project instructions for EX-16-02, the first ROV cruise of the 2016 field season. Operations for this cruise will include ROV, CTD, and mapping system shakedowns and exploration throughout the main Hawaiian Islands as time allows. The expedition will be staged in and out of Honolulu, HI with operations beginning on February 12th and concluding on February 17th. Operations will use the ship's deep water mapping systems (Kongsberg EM302 multibeam sonar, EK60 split-beam fisheries sonars, Knudsen 3260 chirp subbottom profiler sonar, Teledyne RDIWorkhorse Mariner and Ocean Surveyor ADCPs), a new Underway CTD system to support mapping, NOAA's two-body 6,000 m remotely operated vehicle (ROVs Deep Discoverer and Seirios) system, and the ship’s high-bandwidth satellite connection for real-time ship to shore communications. ROV dives will mostly be conducted during the day, and multibeam, singlebeam, and sub-bottom acoustic mapping will occur when the ROV is on deck. Target areas for operations will be identified prior to the cruise. However, exact locations of discrete ROV dives and mapping activities will be determined during the cruise as results of engineering and shakedown tests are evaluated and once weather and operational constraints are factored in.