Toshio Kasuya
University of Science and Technology, Sana'a
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Publication
Featured researches published by Toshio Kasuya.
BioScience | 2003
Phillip J. Clapham; Per Berggren; Simon Childerhouse; Nancy A. Friday; Toshio Kasuya; Laurence Kell; Karl-Hermann Kock; Silvia Manzanilla-Naim; Giuseppe Notabartolo Di Sciara; William F. Perrin; Andrew J. Read; Randall R. Reeves; Emer Rogan; Lorenzo Rojas-Bracho; Tim D. Smith; Michael Stachowitsch; Barbara L. Taylor; Deborah Thiele; Paul R. Wade; Robert L. Brownell
In an open letter published last year in the New York Times, 21 distinguished scientists (including three Nobel laureates) criticized Japan’s program of scientific research whaling, noting its poor design and unjustified reliance upon lethal sampling. In a recent Forum article in BioScience, Aron, Burke, and Freeman (2002) castigate the letter’s signers and accuse them of meddling in political issues without sufficient knowledge of the science involved in those issues. As members of the Scientific Committee (SC) of the International Whaling Commission (IWC), we can attest that the signers of the open letter correctly summarized criticisms made by researchers very familiar with Japanese
Frontiers in Zoology | 2017
Theoni Photopoulou; Ines Maria Ferreira; Peter B. Best; Toshio Kasuya; Helene Marsh
BackgroundA substantial period of life after reproduction ends, known as postreproductive lifespan (PRLS), is at odds with classical life history theory and its causes and mechanisms have puzzled evolutionary biologists for decades. Prolonged PRLS has been confirmed in only two non-human mammals, both odontocete cetaceans in the family Delphinidae. We investigate the evidence for PRLS in a third species, the false killer whale, Pseudorca crassidens, using a quantitative measure of PRLS and morphological evidence from reproductive tissues.ResultsWe examined specimens from false killer whales from combined strandings (South Africa, 1981) and harvest (Japan 1979-80) and found morphological evidence of changes in the activity of the ovaries in relation to age. Ovulation had ceased in 50% of whales over 45 years, and all whales over 55 years old had ovaries classified as postreproductive. We also calculated a measure of PRLS, known as postreproductive representation (PrR) as an indication of the effect of inter-population demographic variability. PrR for the combined sample was 0.14, whereas the mean of the simulated distribution for PrR under the null hypothesis of no PRLS was 0.02. The 99th percentile of the simulated distribution was 0.08 and no simulated value exceeded 0.13. These results suggest that PrR was convincingly different from the measures simulated under the null hypothesis.ConclusionsWe found morphological and statistical evidence for PRLS in South African and Japanese pods of false killer whales, suggesting that this species is the third non-human mammal in which this phenomenon has been demonstrated in wild populations. Nonetheless, our estimate for PrR in false killer whales (0.14) is lower than the single values available for the short-finned pilot whale (0.28) and the killer whale (0.22) and is more similar to working Asian elephants (0.13).
Archive | 2001
Robert L. Brownell; Phillip J. Clapham; Toshio Kasuya
Nature | 2005
Nicholas J. Gales; Toshio Kasuya; Phillip J. Clapham; Robert L. Brownell
Archive | 2003
Helene Marsh; Peter Arnold; Milton Freeman; David Haynes; David W. Laist; Andrew J. Read; John H. Reynolds; Toshio Kasuya
Marine Mammal Science | 1991
Toshio Kasuya
Marine Mammal Science | 2014
Ines Maria Ferreira; Toshio Kasuya; Helene Marsh; Peter B. Best
Marine Mammal Science | 2007
Miki Shirakihara; Hideyoshi Yoshida; Hiroyuki Yokochi; Hisao Ogawa; Taro Hosokawa; Naoto Higashi; Toshio Kasuya
Archive | 2017
Toshio Kasuya; William F. Perrin
Marine Mammal Science | 2008
Toshio Kasuya