What do these two whales have in common? They (#875, left and #879, right) have often been sighted group -feeding on herring where the “feeding call” is used, and have also been observed using the feeding call while feeding alone. Photos taken under authority of scientific research permits issued by the National Marine Fisheries Service.
Researchers have known for many years that Southeast Alaska humpback whales use a specialized trumpeting call when group-feeding on herring. The “core group” of whales that used to spend summers sub-surface feeding on herring in Icy Strait used this call routinely (listen to recording here ), and so do lunge-feeding groups in Chatham Strait and Frederick Sound who use bubble-nets to capture herring (listen to recording here).
The loud, intense feeding call is thought to function in group coordination, (“Ready, set, GO!”) or in startling the herring into a tighter school, potentially increasing the amount of herring the whales can capture per gulp. The call may also serve the purpose of recruiting new whales to join a feeding group. If lone whales produce feeding calls, it suggests that the call functions primarily in manipulating the herring. Hakai Magazine picked up the story and interviewed the study's lead author Michelle Fournet (read more here).
Fournet, M.E., Gabriele, C.M., Sharpe, F., Straley, J.M. and Szabo, A., 2018. Feeding calls produced by solitary humpback whales. Marine Mammal Science.
Contact Chris_Gabriele@nps.gov if you would like a copy of the Marine Mammal Science article.