scholarly journals Structure and Steroidogenesis of the Placenta in the Antarctic Minke Whale (Balaenoptera bonaerensis)

2013 ◽  
Vol 59 (2) ◽  
pp. 159-167 ◽  
Author(s):  
Motoki SASAKI ◽  
Yoko AMANO ◽  
Daisuke HAYAKAWA ◽  
Toshio TSUBOTA ◽  
Hajime ISHIKAWA ◽  
...  
Polar Biology ◽  
2008 ◽  
Vol 31 (12) ◽  
pp. 1509-1520 ◽  
Author(s):  
Kenji Konishi ◽  
Tsutomu Tamura ◽  
Ryoko Zenitani ◽  
Takeharu Bando ◽  
Hidehiro Kato ◽  
...  

2014 ◽  
Vol 217 (16) ◽  
pp. 2851-2854 ◽  
Author(s):  
A. S. Friedlaender ◽  
J. A. Goldbogen ◽  
D. P. Nowacek ◽  
A. J. Read ◽  
D. Johnston ◽  
...  

Polar Biology ◽  
2013 ◽  
Vol 37 (2) ◽  
pp. 205-215 ◽  
Author(s):  
Kenji Konishi ◽  
Takashi Hakamada ◽  
Hiroshi Kiwada ◽  
Toshihide Kitakado ◽  
Lars Walløe

2014 ◽  
Vol 60 (1) ◽  
pp. 62-67 ◽  
Author(s):  
Motoki SASAKI ◽  
Yoko AMANO ◽  
Daisuke HAYAKAWA ◽  
Toshio TSUBOTA ◽  
Hajime ISHIKAWA ◽  
...  

2021 ◽  
Author(s):  
Marcos Rossi-Santos ◽  
Diego Filun ◽  
William Soares-Filho ◽  
Alexandre Paro ◽  
Leonardo Wedekin

Acoustic methods can provide important data on the occurrence and distribution of migratory species. Information about Antarctic Minke whale (Balaenoptera bonaerensis) occurrence in the winter breeding grounds is scarce, mostly limited to old records from whaling stations before 1960’s international moratory, such as Costinha Station in Northeastern Brazil (6° S / 34° W). This work describes the occurrence of the Antarctic minke whale (AMW) through Bio-duck acoustic detections in the Santos Basin, South-Southeastern Brazil (22º and 28º S / 42º and 48º W), registered between November 12 and December 19, 2015. AMW calls were detected for 12 days. We detected and classified 9 different Bio-duck calls in Brazilian coast waters, evidencing a high diverse acoustic behaviour for the minke whale breeding ground. This is the first study to describe the acoustic diversity of AMW vocalizations in lower latitudes, constituting important information to the conservation and management of cetaceans and their habitat. Therefore, our study presents the foremost acoustic evidence of the Antarctic minke whale in Brazil, utilizing high technological passive acoustic methods, such as autonomous underwater vehicle (SeaGlider) sampling.


Polar Biology ◽  
2021 ◽  
Vol 44 (2) ◽  
pp. 259-273
Author(s):  
Céline Cunen ◽  
Lars Walløe ◽  
Kenji Konishi ◽  
Nils Lid Hjort

AbstractChanges in the body condition of Antarctic minke whales (Balaenoptera bonaerensis) have been investigated in a number of studies, but remain contested. Here we provide a new analysis of body condition measurements, with particularly careful attention to the statistical model building and to model selection issues. We analyse body condition data for a large number (4704) of minke whales caught between 1987 and 2005. The data consist of five different variables related to body condition (fat weight, blubber thickness and girth) and a number of temporal, spatial and biological covariates. The body condition variables are analysed using linear mixed-effects models, for which we provide sound biological motivation. Further, we conduct model selection with the focused information criterion (FIC), reflecting the fact that we have a clearly specified research question, which leads us to a clear focus parameter of particular interest. We find that there has been a substantial decline in body condition over the study period (the net declines are estimated to 10% for fat weight, 7% for blubber thickness and 3% for the girth). Interestingly, there seems to be some differences in body condition trends between males and females and in different regions of the Antarctic. The decline in body condition could indicate major changes in the Antarctic ecosystem, in particular, increased competition from some larger krill-eating whale species.


2020 ◽  
Author(s):  
Yoshihiro Fujise ◽  
Luis A. Pastene

We review the scientific information on whales that could be indicative of historical and current changes in the ecosystem in the Indo-Pacific sector of the Antarctic. The increased krill availability in the middle of the past century as a result of the heavy harvesting of the larger baleen whale species could have been translated into better nutritional conditions for the Antarctic minke whale, resulting in a decreasing trend in the age at sexual maturity and an increasing trend in recruitment rate and hence total population size between approximately 1940 and 1970. This nutritional condition has deteriorated more recently, as revealed by a decrease in energy storage and stomach content weight since the 1980’s; these changes coincide with appreciable increases in the abundances of humpback and fin whales, which were heavily harvested in the first half of the past century. The historical demographic changes observed in the Antarctic minke whale are consistent with the pattern to be expected under the krill surplus hypothesis, with minke whales now again competing with other (recovering) baleen whale species for krill. However, these minke whales could also be using alternative feeding areas (e.g. polynias within the pack-ice) in response to the increase in abundance and geographical expansion of these other large whale species. This could provide an alternative explanation for indications from sighting surveys and population models of a decrease and then re-stabilisation of minke whale abundance in open water areas since the 1970s.


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