Untitled

Abstract

Stomach contents analysis showed that the three whale species are highly dependent on small pelagic fish, i.e. Japanese anchovy, Pacific saury and mackerels in addition to copepods and euphausiids. Pianka's niche overlap index showed high diet overlap among whale species that occur in some areas where they feed on pelagic fish. Canonical correspondence analysis (CCA) indicated environmental and biological factors significantly contribute to the diet composition of whales. CCA also explained the distribution patterns of whales in relation to SST, chlorophyll a concentration and geographical variation. These analyses demonstrated that the diet composition of the baleen whales is determined by spatio-temporal environmental factors and the amount of small pelagic fish carried by the Kuroshio Current. The total seasonal prey consumption by whales in the study area was estimated to be 774 000 t of Japanese anchovy (16% of the consumed biomass), 44 000 t of Pacific saury (1% of the consumed biomass), and 140 000 t of mackerels (14% of the consumed biomass), indicating these baleen whales are important components in the ecosystem, and warrant inclusion in fisheries assessments.

Occurrence of Sei Whales (Balaenoptera borealis) in the Magellan Strait from 2004-2015, Chile

“…In this sense, sei whale have been reported to feed on a variety of prey species. In the Northern Hemisphere, food species include copepods, euphausiids, amphipods, decapods, cephalopods, and fish (Nemoto, 1959(Nemoto, , 1962Kawamura, 1973;Konishi et al, 2009). Even though the prey species are highly dependent on an ocean basin, swarming characteristics of the prey, availability, and seasonal conditions (Rice, 1977;Budylenko, 1978;Horwood, 1987;Flinn et al, 2002;Konishi et al, 2009), sei whales demonstrate a preference for zooplankton (Kawamura, 1973;Watkins & Schevill, 1979).…”

Morphological differences in skulls and feeding apparatuses between Antarctic (Balaenoptera bonaerensis) and common (Balaenoptera acutorostrata) minke whales, and the implication for their feeding ecology

“…In contrast, common minke whales are opportunistic D r a f t 27 feeders known to feed on a variety of prey species. They feed on schooling small pelagic fishes such as the Japanese anchovy (Engraulis japonicus Temminck and Schlegel, 1846), Pacific saury (Cololabis saira Brevoort, 1856), and krill in the western North Pacific (Tamura and Fujise 2002;Murase et al 2007;Konishi et al 2009). Notably, krill fed on by common minke whales in the western North Pacific is smaller than Antarctic krill in terms of body size.…”

Developmental Changes in the Morphology of Western North Pacific Bryde’s Whales (<i>Balaenoptera edeni</i>)

“…These studies have shown species-specific growth patterns, such as an increase in the length of the head region associated with a decrease in the length of the tail region in blue and fin whales [15] but no obvious trend in sei whales [16]. The prey species of Balaenoptera species range from planktonic crustaceans (copepods and krill) to schooling fishes, depending on the species [18] [19] [20] [21]. They feed using a unique system called "lung feeding" in which they engulf a large mass of water with prey and extrude only the water by filtering the prey items using their baleen plates [22].…”