 Besides the mothership and three sighting/sampling boats, a trawling
vessel with fish-finding device has been added to the research fleet
since the start of JARPN II to focus on the surveys of feed organisms.
Anchovy: feed species of a Bryde's whale.
Major findings of the offshore research were:
(1) Minke whales were found to be feeding mainly on 12cm large-size
anchovy in the offshore area. Combined with the findings of the coastal
survey in April-May that the minke mainly feed on krill and sand
lance in the coastal area, it showed that minkes use a variety of
fish species as food.
(2) Seasonal changes in feed species was clarified. It was found
that minke whales feed on anchovy in May-June and mainly Pacific
saury and other species in July-August.
(3)
It was confirmed that a substantial number of Bryde's whales were distributed
from coastal to offshore areas. Also seasonal changes in preference
of feed were observed, with mostly krill in May-June and anchovy in
July. |
A robust clubhook squid (body length: about 1m) found in
the stomach of a sperm whale.
This shows that sperm whales feed on surface and mid-layer squids. |
(4) It was confirmed that a large number of sei whales inhabit the
offshore area. The feed for this species ranged widely from zooplankton
to surface fishes such as anchovy.
| Anchovy found in a sei whale. This species was found to be consumed in largest quantities in the early part of the research. |
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