Common minke whale calls were recorded from October to May – peaking in March – and had a source level of about 150 decibels at a reference pressure of one micropascal at one metre. Their source remained a mystery for decades. By the early 1980s they were thought to come from whales, but it wasn't known what species. In the early 2000s, it was suggested these sounds might originate from minke whales, based on their similarities to vocalizations produced by Southern Hemisphere forms. Finally, during a 2002 HICEAS ("H"awaiian "I"slands "C"etacean and "E"cosystem "A"ssessment "S"urvey) survey, the R/V "David Starr Jordan", using a
Antarctic minke whale dark gray dorsally and clean white (occasionally light gray to gray) ventrally with a thin, dusky margin. Some small, dark gray "speckling" may be present on the body. Antarctic minkes lack the bright white, transverse "flipper band" of the common minke and the white "shoulder blaze" and bright white "flipper patch" (occupying the proximal two-thirds of the flipper) of the dwarf minke. Instead, their narrow, pointed flippers, about one-sixth to one-eighth of the total body length, are normally either a plain light gray with an almost white leading edge and a darker gray trailing edge or two-toned, with a thin