scholarly journals Decline in body condition in the Antarctic minke whale (Balaenoptera bonaerensis) in the Southern Ocean during the 1990s

Polar Biology ◽  
2021 ◽  
Vol 44 (2) ◽  
pp. 259-273
Author(s):  
Céline Cunen ◽  
Lars Walløe ◽  
Kenji Konishi ◽  
Nils Lid Hjort
Keyword(s):  
Model Selection ◽  
Body Condition ◽  
Model Building ◽  
Research Question ◽  
Information Criterion ◽  
The Body ◽  
Antarctic Minke Whale ◽  
Minke Whales ◽  
Balaenoptera Bonaerensis ◽  
The Antarctic

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.

scholarly journals Mysterious bio-duck sound attributed to the Antarctic minke whale ( Balaenoptera bonaerensis )

2014 ◽  
Vol 10 (4) ◽  
pp. 20140175 ◽  
Author(s):  
Denise Risch ◽  
Nicholas J. Gales ◽  
Jason Gedamke ◽  
Lars Kindermann ◽  
Douglas P. Nowacek ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Conclusive Evidence ◽  
Antarctic Minke Whale ◽  
Minke Whales ◽  
Antarctic Waters ◽  
The Subject ◽  
Balaenoptera Bonaerensis ◽  
Acoustic Recording ◽  
The Antarctic

For decades, the bio-duck sound has been recorded in the Southern Ocean, but the animal producing it has remained a mystery. Heard mainly during austral winter in the Southern Ocean, this ubiquitous sound has been recorded in Antarctic waters and contemporaneously off the Australian west coast. Here, we present conclusive evidence that the bio-duck sound is produced by Antarctic minke whales ( Balaenoptera bonaerensis ). We analysed data from multi-sensor acoustic recording tags that included intense bio-duck sounds as well as singular downsweeps that have previously been attributed to this species. This finding allows the interpretation of a wealth of long-term acoustic recordings for this previously acoustically concealed species, which will improve our understanding of the distribution, abundance and behaviour of Antarctic minke whales. This is critical information for a species that inhabits a difficult to access sea-ice environment that is changing rapidly in some regions and has been the subject of contentious lethal sampling efforts and ongoing international legal action.

scholarly journals Estimation of the feeding record of pregnant Antarctic minke whales (Balaenoptera bonaerensis) using carbon and nitrogen stable isotope analysis of baleen plates

Polar Biology ◽  
2021 ◽  
Vol 44 (3) ◽  
pp. 621-629
Author(s):  
Mayuka Uchida ◽  
Ippei Suzuki ◽  
Keizo Ito ◽  
Mayumi Ishizuka ◽  
Yoshinori Ikenaka ◽  
...  
Keyword(s):  
Growth Rate ◽  
Stable Isotope ◽  
Antarctic Krill ◽  
Isotope Analysis ◽  
Stomach Contents ◽  
Annual Growth Rate ◽  
Pleuragramma Antarcticum ◽  
Minke Whales ◽  
Balaenoptera Bonaerensis ◽  
The Antarctic

AbstractAntarctic minke whales (Balaenoptera bonaerensis) are migratory capital breeders that experience intensive summer feeding on Antarctic krill (Euphausia superba) in the Southern Ocean and winter breeding at lower latitudes, but their prey outside of the Antarctic is unknown. Stable isotope analyses were conducted on δ13C and δ15N from the baleen plates of ten pregnant Antarctic minke whales to understand the growth rate of the baleen plate and their diet in lower latitudes. Two to three oscillations along the length of the edge of the baleen plate were observed in δ15N, and the annual growth rate was estimated to be 75.2 ± 20.4 mm, with a small amplitude (0.97 ± 0.21 ‰). Bayesian stable isotope mixing models were used to understand the dominant prey that contributed to the isotopic component of the baleen plate using Antarctic krill from the stomach contents and reported values of Antarctic coastal krill (Euphausia crystallorophias), Antarctic silver fish (Pleuragramma antarcticum), Australian krill spp., and Australian pelagic fish spp.. The models showed that the diet composition of the most recent three records from the base of the baleen plates (model 1) and the highest δ15N values in each baleen plate (model 2) were predominantly Antarctic krill, with a contribution rate of approximately 80%. The rates were approximately 10% for Antarctic coastal krill and less than 2.0% for the two Australian prey groups in both models. These results suggest that pregnant Antarctic minke whales did not feed on enough prey outside of the Antarctic to change the stable isotope values in their baleen plates.

scholarly journals Whales as Indicators of Historical and Current Changes in the Marine Ecosystem of the Indo-Pacific Sector of the Antarctic

2020 ◽  
Author(s):  
Yoshihiro Fujise ◽  
Luis A. Pastene
Keyword(s):  
Marine Ecosystem ◽  
Recruitment Rate ◽  
Minke Whale ◽  
Past Century ◽  
Baleen Whale ◽  
The Past ◽  
Antarctic Minke Whale ◽  
Minke Whales ◽  
Nutritional Conditions ◽  
The Antarctic

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.

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 ◽  
...  
Keyword(s):  
Minke Whale ◽  
Antarctic Minke Whale ◽  
Balaenoptera Bonaerensis ◽  
The Antarctic

Decline in energy storage in the Antarctic minke whale (Balaenoptera bonaerensis) in the Southern Ocean

Polar Biology ◽  
2008 ◽  
Vol 31 (12) ◽  
pp. 1509-1520 ◽  
Author(s):  
Kenji Konishi ◽  
Tsutomu Tamura ◽  
Ryoko Zenitani ◽  
Takeharu Bando ◽  
Hidehiro Kato ◽  
...  
Keyword(s):  
Energy Storage ◽  
Southern Ocean ◽  
Minke Whale ◽  
Antarctic Minke Whale ◽  
Balaenoptera Bonaerensis ◽  
The Antarctic

A note on minke whales (Cetacea: Balaenopteridae) in Uruguay: strandings review

2020 ◽  
Vol 21 (1) ◽  
pp. 135-140
Author(s):  
Eduardo Juri ◽  
Meica Valdivia ◽  
Paulo Cesar Simoes-Lopes ◽  
Alfredo Le Bas
Keyword(s):  
Atlantic Ocean ◽  
Minke Whale ◽  
Balaenoptera Acutorostrata ◽  
Southwest Atlantic ◽  
Antarctic Minke Whale ◽  
Minke Whales ◽  
Important Region ◽  
The Common ◽  
The Antarctic ◽  
Common Minke Whale

The minke whale is the smallest of the living rorquals and is widely distributed in the tropical, temperate and polar waters of both hemispheres. In the western Southwest Atlantic Ocean there are two currently recognised species, the dwarf form of the common minke whale, Balaenoptera acutorostrata unnamed subsp. and the Antarctic minke whale B. bonaerensis. All stranding records and collected specimens of minke whale on the coast of Uruguay were reviewed and analysed. Between 1962 and 2018, 33 records were gathered in a non-systematic way, 22 specimens of B. acutorostrata and 11 of B. bonaerensis. It was found that most animals were discovered alive or recently dead and assigned as neonates/young calves. This supports the hypothesis that Uruguayan coasts are part of an important region for reproduction and breeding for the species.

scholarly journals Feeding rates and under-ice foraging strategies of the smallest lunge filter feeder, the Antarctic minke whale (Balaenoptera bonaerensis)

2014 ◽  
Vol 217 (16) ◽  
pp. 2851-2854 ◽  
Author(s):  
A. S. Friedlaender ◽  
J. A. Goldbogen ◽  
D. P. Nowacek ◽  
A. J. Read ◽  
D. Johnston ◽  
...  
Keyword(s):  
Minke Whale ◽  
Foraging Strategies ◽  
Feeding Rates ◽  
Filter Feeder ◽  
Antarctic Minke Whale ◽  
Balaenoptera Bonaerensis ◽  
The Antarctic

Decrease in stomach contents in the Antarctic minke whale (Balaenoptera bonaerensis) in the Southern Ocean

Polar Biology ◽  
2013 ◽  
Vol 37 (2) ◽  
pp. 205-215 ◽  
Author(s):  
Kenji Konishi ◽  
Takashi Hakamada ◽  
Hiroshi Kiwada ◽  
Toshihide Kitakado ◽  
Lars Walløe
Keyword(s):  
Southern Ocean ◽  
Stomach Contents ◽  
Minke Whale ◽  
Antarctic Minke Whale ◽  
Balaenoptera Bonaerensis ◽  
The Antarctic

scholarly journals A SPECIES DISTRIBUTION MODEL OF THE ANTARCTIC MINKE WHALE (BALAENOPTERA BONAERENSIS)

2022 ◽  
Author(s):  
Volodymyr Tytar
Keyword(s):  
Sea Ice ◽  
Chlorophyll A ◽  
Southern Hemisphere ◽  
Species Distribution ◽  
Sea Ice Concentration ◽  
Chlorophyll A Concentration ◽  
Antarctic Minke Whale ◽  
Ice Concentration ◽  
Balaenoptera Bonaerensis ◽  
The Antarctic

The Antarctic minke whale (Balaenoptera bonaerensis) is regarded a Southern Hemisphere endemic found throughout the Southern Hemisphere, generally south of 60°S in austral summer. Here they have been routinely observed in highest densities adjacent to and inside the sea ice edge, and where they feed predominantly on krill. Detecting abundance trends regarding this species by employing visual monitoring is problematic. Partly this is because the whales are frequently sighted within sea ice where navigational safety concerns prevent ships from surveying. In this respect species-habitat models are increasingly recognized as valuable tools to predict the probability of cetacean presence, relative abundance or density throughout an area of interest and to gain insight into the ecological processes affecting these patterns. The objective of this study was to provide this background information for the above research needs and in a broader context use species distribution models (SDMs) to establish a current habitat suitability description for the species and to identify the main environmental covariates related to its distribution. We used filtered 464 occurrences to generate the SDMs. We selected eight predictor variables with reduced collinearity for constructing the models: mean annuals of the surface temperature (ºC), salinity (PSS), current velocity (m/s), sea ice concentration (fraction, %), chlorophyll-a concentration (mg/m³), primary productivity (g/m3/day), cloud cover (%), and bathymetry (m). Six modeling algorithms were test and the Bayesian additive regression trees (BART) model demonstrated the best preformance. Based on variable importance, those that best explained the environmental requirements of the species, were: sea ice concentration, chlorophyll-a concentration and topography of the sea floor (bathymetry), explaining in sum around 62% of the variance. Using the BART model, habitat preferences have been interpreted from patterns in partial dependence plots. Areas where the AMW have particularly high likelihood of occurrence are East Antarctica, NE of the Weddell Sea, areas around the northern tip of the Antarctica Peninsula, areas bordering the Scotia–Weddell Confluence. Given the association of AMWs with sea ice the pagophilic character of their biology makes them particularly vulnerable to climate change and a perfect biological indicator for tracking these changes.

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