APPEARANCE OF JUVENILE HUMPBACK WHALES FEEDING IN THE NEARSHORE WATERS OF VIRGINIA

In the western North Atlantic, humpback whales (Megaptera novaeangliae) migrate from summer feeding grounds off the coasts of the northeastern U.S., Canada, Greenland, and Iceland to winter breeding grounds in the Greater and Lesser Antilles (Leatherwood et al. 1976, Katona et al. 1983, Martin et al. 1984, NMFS 199 1). The end points of the breeding migration are well documented (Katona 1986, Mattila et al. 1989, Katona and Beard 1990); however, exact routes are not known. It is believed-that these humpback whales migrate well offshore in deep ocean waters (Winn and Reichley 1985, Stone et al. 1987, Clapham and Mattila 1990, NMFS 199 1). It has also been suggested that during the breeding migration and residency on the breeding grounds, humpback whales engage in little, if any, feeding activity (Dawbin 1966, Baraff et al. 1991). Previous research has indicated that the geographic and temporal distribution of juveniles (sexually immature) in the western North Atlantic is similar to that of other humpback whales (Goodale 1982, NMFS 1991). Most adult and newborn North Atlantic humpback whales are on breeding grounds between January and April; however, there are reported sightings in high latitude waters in these months (Williamson 1961, Katona 1986, Whitehead 1987). Little information, though, exists on the activities of juveniles during this time. Known juveniles have been reported on the outskirts of primarily adult “surface active groups” in breeding areas (Mattila et al. 1989). Segregation by age and reproductive class has been reported for migrating humpback whales in other geographically distinct areas (Nishiwaki 1959, Dawbin 1966). This segregation has not previously been documented for North Atlantic humpback whales during winter migrations (NMFS 199 1). We offer the first report of humpback whales in nearshore waters off the coast of Virginia during the months of January through March 199 1 and 1992. We observed juvenile humpback whales feeding near the mouth of Chesapeake Bay, within 4 km of shore. The appearance of the whales was correlated with large aggregations of feeding birds and the presence of large schools of fishes. Our observations support the hypothesis that some juvenile humpback whales do not migrate to breeding grounds but, instead, migrate to mid-Atlantic nearshore waters apparently to feed.