Marine large animals, such as marine mammals and seabirds, have been attracting attention from many people. What are the animals eating when and where? How are the animals acting underwater? Pleasure of the animals? I have also interests in ecology of the marine large animals, especially marine mammals.

  I have studied about foraging behaviour of Antarctic fur seals Arctocephalus gazella with acceleration data loggers. This study showed that the fine-scale (per 1 second) prey-capture events of seals. To monitor time-series changes in the frequency of prey- capture events could be used to place the foraging behaviour of marine mammals in the context of marine habitat features.

Publications

Refereed publications

Iwata. T., K. Q. Sakamoto,  E. W. J. Edward, I. J. Staniland, P. N. Trathan, Y. Goto, K.Sato, Y. Naito and A. Takahashi (2015) The influence of preceding dive cycles on the foraging decisions of Antarctic fur seals.Biol. Lett. 11: 20150227

Iwata, T., S. Yonezaki, K. Kohyama and Y. Mitani (2013) Detection of grooming behaviours with an acceleration data logger in a captive northern fur seal (Callorhinus ursinus). Aquatic Mammals. 39 (4), 378–384

Iwata, T., T. Hayashi, N. Takasawa-Kasamatsu (2013) Report of seabird observations in the Indian sector of the Southern Ocean during the austral summers of 2005 - 2008. Czech Polar Reports 3 (2), 82-86

Sakamoto. Q. K., A. Takahashi., T. Iwata., T. Yamamoto., M. Yamamoto., P. N. Trathan (2013) Heart rate and estimated energy expenditure of flapping and gliding in black-browed albatrosses. The Journal of Experimental Bilogy 216, 3175-3182

Iwata. T., K. Q. Sakamoto., A. Takahashi., E. W. J. Edward., I. J. Staniland, P. N. Trathan and Y. Naito (2012) Using a mandible accelerometer to study fine-scale foraging behavior of free-ranging Antarctic fur seals. Marine Mammal Science. 28 (2), 345-357.

Watanabe. Y. Y., K. Sato., Y. Watanuki., A. Takahashi., Y. Mitani., M. Amano., K. Aoki., T. Narazaki., T. Iwata., S. Minamikawa and N. Miyazaki (2011) Scaling of swim speed in breath-hold divers. Journal of Animal Ecology. 80 (1), 57-68.

Sakamoto. K. Q., A. Takahashi., T. Iwata and P. N. Trathan (2009) From the eye of the albatrosses: A bird-borne camera shows an association between albatrosses and a killer whale in the Southern Ocean. PLoS ONE. 4 (10), e7322.

Iwata, T., Y. Mitani, S. Yonezaki, K. Kohyama and A. Takahashi (2009) Validation of acceleration records to monitor swimming and prey capture behavior in the captive northern fur seal. Nippon Suisan Gakkaishi 75:989–994 (in Japanese with English abstract).

Current Research

○Decision-making about foraging behaviour of Antarctic fur seals

○Swimming behaviour of Bryde’s whales

○Escaping strategy of Harbor seals for Killer whales

○Distribution of seabirds  association with oceanographic features

E-mail: : tiwata@aori.u-tokyo.ac.jp