On a recent U.S. Navy-funded large whale survey, HDR biologists observed a humpback whale feeding approximately 25 miles east of the Virginia coast. During this encounter, the whale was engaged in a behavior known as “bubble-net feeding”, or “bubble-netting”. Bubble-netting is a learned, complex feeding behavior seen in humpback and, occasionally, fin whales. Whales dive and begin blowing bubbles in a tightening spiral underneath their prey (typically small forage fish or krill) creating a “net” that corrals the prey into a tight cylinder of rising bubbles. It is typically observed with multiple animals cooperating to make this unique strategy work, but in this case, it was just a single whale feeding on Atlantic Silverside (Menidia menidia).

The research team is permitted to fly a drone and used it to capture a few of the bubble-net feeding sequences. Named “Tobin” by other researchers, this is a known whale from the Gulf of Maine Humpback Whale Catalog, curated by Center for Coastal Studies, the North Atlantic Humpback Whale Catalog, curated by Allied Whale, and the Mid Atlantic Humpback Whale Catalog, curated by the Virginia Aquarium. This same whale was also seen by HDR on 21 December 2014, about 15 miles offshore (in the Navy’s Naval Mine Exercise [MINEX] Training Area) and bubble net feeding with one other individual. Bubble-netting off Virginia is not a commonly seen feeding strategy, and with over 6 years between sightings of this individual in Virginia waters, it is interesting to see this whale is still up to similar feeding habits.

This project is led by researchers at HDR, funded by U.S. Fleet Forces Command, and managed by Naval Facilities Engineering Command Atlantic as part of the U.S. Navy’s marine species monitoring program www.navymarinespeciesmonitoring.us

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