Date: August 31, 2019
Location: Lat: 42.68255°, Lon: -64.21957°
Dive Depth Range: 306 - 358 meters (1,004 - 1,175 feet)
Today’s dive, proposed by our partners at Fisheries and Oceans Canada (DFO), involved surveying a previously unexplored region of the Scotian Shelf. A habitat suitability model predicted high probabilities for Vazella sponges, commonly known as the Russian hat sponge, in this area. However, this area had not previously been explored using deepwater submersibles, and the purpose of the dive was therefore to ground truth the model predictions. As it turned out, we did not observe Vazella sponges on this dive, but the absence of the species still provides valuable information that will help refine future iterations of the habitat suitability model.
As the remotely operated vehicles (ROV) approached the seafloor, a school of shortfin squid surrounded the ROVs and remained closeby for the majority of the dive. ROV Deep Discoverer reached the seafloor at 358 meters (1,175 feet) depth on a soft substrate, which characterized most of the dive. The substrate was generally fine, with sparse dropstones encrusted with anemones. Along the ROV dive track, we documented a variety of different benthic organisms, with abundant sea pens, scorpionfish, polychaete worms, crabs, and anemones.
Several predation events were observed throughout the dive, including squid feeding on krill, squid, and various fish; an anemone feeding on a fish; and the lobster Homarus sp. feeding on a squid. The ROVs also documented two abandoned lobster traps, which were encrusted with hydrozoans and anemones. A single suction sample was taken of a suspected foraminifera at the request of DFO and a squid sample was unintentionally collected because it was attached to the ROV.