Eden'S Whale

Several differences in anatomy are found between Bryde's and Eden's whales; morphological similarities have caused confusions regarding species identification.

B. brydei occurs in the Atlantic, Pacific, and Indian Oceans between the 40th parallels of latitude, preferring highly productive, tropical, subtropical, and warm, temperate waters of 16–22 °C (61–72 °F). In the North Pacific, they occur as far north as Honshu to the west and southern California in the east, with vagrants reported as far north as Washington in the United States. They occur throughout the eastern tropical Pacific, including Peru and Ecuador, where they are absent from July to September. They have also been reported in an upwelling area off Chile between 35° and 37°S. In the southwestern Pacific, they occur as far south as the North Island of New Zealand.

Bryde's whales feed on a wide variety of fish, planktonic crustaceans, and cephalopods. In the western North Pacific, Bryde's whales caught by Japanese scientific whaling vessels (2000–2007) mainly fed on Japanese anchovy (Engraulis japonicus, 52%) and various species of euphausiid (36%, including Euphausia similis, E. gibboides, Thysanoessa gregaria, and Nematoscelis difficilis), as well as oceanic lightfish (Vinciguerria nimbaria, nearly 3%), and mackerels (Scomber spp., less than 2%). The prey differed by location and season. In coastal areas, euphausiids dominated the diet, comprising 89 and 75% of the diet in May and June, respectively. Further offshore, Japanese anchovy was the dominant species, accounting for nearly 100% of the diet in late summer.

Their blow is columnar or bushy, about 3.0–4.0 m (10–13 ft) high. Sometimes, they blow or exhale while under water. Bryde's whales display seemingly erratic behaviour compared to other baleen whales, because they surface at irregular intervals and can change directions for unknown reasons.

They usually appear individually or in pairs, and occasionally in loose aggregations up to 20 animals around feeding areas. They are more active on the water surface than sei whales, especially in coastal waters.

Bryde's whales breed in alternate years, apparently in any season, with an autumnal peak. Their gestation period is estimated at 12 months. Calves are about 3.4–4.0 m (11–13 ft) long at birth and weigh 1,000 kg (2,200 lb). They become sexually mature at 8–13 years of age, when females are 12 m (39 ft). The mother nurses for 6–12 months.

Balaenoptera edeni is listed as least concern by the International Union for the Conservation of Nature and Natural Resources.

It is listed in Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix I, which prohibits commercial international trade.

Balaenoptera brydei has yet to be evaluated.

Bryde's whale is listed on Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals. It is listed on Appendix II as it has an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements.

In addition, Bryde's whale is covered by the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MOU).