- 著者
- Hiroto Murase Koji Matsuoka Kazuyoshi Watanabe
- 出版者
- Publication Committee for Cetacean Population Studies
- 雑誌
- 鯨類資源研究 (ISSN:24345571)
- 巻号頁・発行日
- pp.2022F001, (Released:2022-10-25)
- 参考文献数
- 52
The relationships between oceanographic conditions and the distribution of common minke whales off southeastern Hokkaido was investigated in this study. Sighting surveys of common minke whales in this region were conducted in September, in 2002 and from 2004 to 2006. The density index (DI, the number of schools per 100 n.miles) of the whales decreased from 5.6 schools in 2002 to 1.2 schools in 2006. During the 4 years in which surveys were conducted, the monthly mean sea surface temperature (SST) in the survey area increased from 16.6°C in 2002 to 19.5°C in 2006, while the mean SST recorded at sighting locations was 15.5°C. The proportions of surveyed areas with a monthly mean SST ≤16°C in 2002 and 2004 were 46.5% and 17.0% respectively, whereas in 2005 and 2006, none of these areas had a monthly mean SST of less than 16°C. Pacific saury are among the major prey items of the minke whales in this region, and the number of the fishing boats was used as an indicator of the presence of the species in the surveyed area. The 4 year mean SST at the locations of the boats was 15.1°C. A reduction in the local abundance of the saury from 2002 to 2006 was inferred from the number of the boats operating in the region. These findings suggested that the apparent decline in the abundance of whales in the study area was associated with changes in SST and the availability of Pacific saury.
- 著者
- Mohammad Musharraf Uddin BHUIYAN Yo SUZUKI Hiroyuki WATANABE Eunsong LEE Hiroki HIRAYAMA Koji MATSUOKA Yoshihiro FUJISE Hajime ISHIKAWA Seiji OHSUMI Yutaka FUKUI
- 出版者
- 日本繁殖生物学会
- 雑誌
- Journal of Reproduction and Development (ISSN:09168818)
- 巻号頁・発行日
- vol.56, no.1, pp.131-139, 2010 (Released:2010-03-05)
- 参考文献数
- 40
- 被引用文献数
- 4 10
The objectives of this study were to choose an effective embryo reconstruction method and an effective post-activation agent for in vitro production of sei whale (Balaenoptera borealis) interspecies somatic cell nuclear transfer (iSCNT) embryos. Moreover, trichostatin A (TSA) treatment of whale iSCNT embryos was performed to improve the in vitro embryo development. In Experiment 1, the fusion rate was significantly higher (88.1%) in embryos reconstructed using the intracytoplasmic cell injection method (ICI) than that (48.7%) in the subzonal cell insertion (SUZI) counterpart. The rates of pseudopronucleus (PPN) formation (77.4 vs. 77.2%) and cleavage (24.5 vs. 37.0%) did not vary between ICI and SUZI. However, the PPN formation and cleavage rates were significantly (P<0.05) lower in the iSCNT embryos than in the parthenogenetic control (95.7% and 64.4%, respectively). Although 21.5% of the bovine parthenogenetic embryos developed to the blastocyst stage, no iSCNT embryo developed beyond the 6-cell stage. In Experiment 2, the cleavage rate did not vary between the TSA (50 nM)-treated and non-treated whale iSCNT embryos (30.5 vs. 32.3%, respectively). Moreover, it did not vary between the TSA-treated iSCNT and SCNT embryos (30.5 vs. 32.0%, respectively). Only one TSA non-treated iSCNT embryo developed to a compacted morula with 20 nuclei. One TSA-treated whale SCNT embryo developed to the 8-cell stage, and out of five whale iSCNT embryos, a 6-cell stage embryo was positive for whale DNA. In conclusion, bovine oocytes have the ability to support development of sei whale nuclei up to the 6-cell stage.