Mysticetes. Six species of baleen or mysticete whales potentially occur in Fram Strait throughout the year (Table 2-1). All baleen whales that may be found in the ACOBAR Experiment area except the minke and humpback whales are considered to be endangered or critically endangered under the ESA and IUCN. The minke whale is the most common baleen whale in the region and is commercially hunted. Hearing and sound production is highly developed in all studied marine mammal species. Mysticetes, like other marine mammals, rely heavily on sound and hearing for communication and sensing their environment (Xxxxxx, 1969; Xxxxxxx and Xxxxxxx, 1985; Xxxxxxx, 2009). Cetaceans have the broadest acoustic range and the only fully specialized ears adapted for underwater hearing. Little information, however, is available on the individual hearing capabilities of many marine mammals; no direct measurements of mysticete hearing sensitivity have been conducted (Ketten, 1994 and 2000; Xxxxxxxxx, 2002). ] Blue Whale (Balaenoptera musculus) Blue whales are the largest living animal, growing to lengths of 27 m (Xxxxxx et al. 2002). Blue whales are classified as endangered under both the ESA and by the IUCN. In the northern hemisphere, the IWC recognizes two stocks of blue whales: the North Atlantic and the North Pacific. There are no current reliable abundance estimates for the North Atlantic stock (Waring et al. 2013), though it is believed blue whales number in the hundreds in the northeast Atlantic (Pike et al. 2009). Blue whales are primarily found in deeper, offshore waters and are rare in shallower, shelf waters (Xxxxxx et al. 1988). These large baleen whales are distributed from the ice edge to the subtropics in both hemispheres (Xxxxxx et al. 2002). Blue whales occur from Baffin Bay and the Greenland Sea to the waters of Northern Norway and Svalbard (Mizroch et al. 1984a). In two year-long, passive acoustic studies of Fram Strait, blue whale sounds were recorded June to November (Xxxxxx et al. 2012; Xxxxx et al. 2012) and not during the rest of the year. These long-term studies demonstrate that blue whales follow the traditional baleen pattern of summer residency at northern latitudes, migrating to southern latitudes for the winter (Xxxxxx et al. 2002). FINAL EAR-2 FOR THE ACOBAR ACOUSTIC TOMOGRAPHY EXPERIMENT IN FRAM STRAIT Table 2-1. Marine mammals potentially occurring in Fram Strait and their status under the ESA and IUCN as well as their densities. Common Name Scientific Name Statu...
