scholarly journals Body size data collected non-invasively from drone images indicate a morphologically distinct Chilean blue whale (Balaenoptera musculus) taxon

2020 ◽  
Vol 43 ◽  
pp. 291-304 ◽  
Author(s):  
MS Leslie ◽  
CM Perkins-Taylor ◽  
JW Durban ◽  
MJ Moore ◽  
CA Miller ◽  
...  
Keyword(s):  
Body Size ◽  
Southern Hemisphere ◽  
Body Length ◽  
Tail Length ◽  
Intraspecific Diversity ◽  
Conservation Strategies ◽  
Balaenoptera Musculus ◽  
Blue Whale ◽  
Blue Whales ◽  
Size Data

The blue whale Balaenoptera musculus (Linnaeus, 1758) was the target of intense commercial whaling in the 20th century, and current populations remain drastically below pre-whaling abundances. Reducing uncertainty in subspecific taxonomy would enable targeted conservation strategies for the recovery of unique intraspecific diversity. Currently, there are 2 named blue whale subspecies in the temperate to polar Southern Hemisphere: the Antarctic blue whale B. m. intermedia and the pygmy blue whale B. m. brevicauda. These subspecies have distinct morphologies, genetics, and acoustics. In 2019, the Society for Marine Mammalogy’s Committee on Taxonomy agreed that evidence supports a third (and presently unnamed) subspecies of Southern Hemisphere blue whale subspecies, the Chilean blue whale. Whaling data indicate that the Chilean blue whale is intermediate in body length between pygmy and Antarctic blue whales. We collected body size data from blue whales in the Gulfo Corcovado, Chile, during the austral summers of 2015 and 2017 using aerial photogrammetry from a remotely controlled drone to test the hypothesis that the Chilean blue whale is morphologically distinct from other Southern Hemisphere blue whale subspecies. We found the Chilean whale to be morphologically intermediate in both overall body length and relative tail length, thereby joining other diverse data in supporting the Chilean blue whale as a unique subspecific taxon. Additional photogrammetry studies of Antarctic, pygmy, and Chilean blue whales will help examine unique morphological variation within this species of conservation concern. To our knowledge, this is the first non-invasive small drone study to test a hypothesis for systematic biology.

scholarly journals Blue whale (Balaenoptera musculus musculus) genome: population structure and history in the North Atlantic

2021 ◽  
Author(s):  
Sushma Jossey ◽  
Oliver Haddrath ◽  
Livia Loureiro ◽  
Burton Lim ◽  
Jacqueline Miller ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
North Atlantic ◽  
Conservation Strategies ◽  
Balaenoptera Musculus ◽  
Blue Whale ◽  
Genetic Diversity And Structure ◽  
Population Structuring ◽  
The Impact ◽  
Blue Whales

Knowledge of genetic diversity and structure is essential for developing conservation strategies for endangered species. The advances in museum genomics can assist in better understanding the effects of over-hunting on the genome by comparing historical to present-day samples. Blue whales were hunted to the point of near extinction in the mid-twentieth century. Herein, we use whole genome sequencing to elucidate the poorly understood population structure of North Atlantic (NA) blue whales (Balaenoptera musculus musculus). We generated a de novo genome assembly of 2.49 Mbp for a NA blue whale (N50 of 1.46 Mb) to analyze 19 whole genomic sequences and 28 complete mitochondrial genomes. We included present-day and historical samples (earliest from 1900) from the Atlantic and Antarctica to understand the impact of whaling on the genetic diversity. We found low population structuring, but high genetic diversity, suggesting a single, panmictic population in the NA. We identified gene flow from fin whale to blue whales, accounting for ~3.5% of the genome. Introgression between blue and fin whales was observed in all the present-day samples but were lacking in some whales sampled early in the 20th century, which suggests increasing disruption in mate choice concomitant with decline in blue whale population. We also assembled and analyzed the transcriptome and revealed positive selection of oncogenes, which may be involved in reduced cancer rates in this largest of mammals ever known. Our sequencing and population structuring studies provide a genomic framework to guide ongoing conservation strategies for this iconic species.

scholarly journals From conservation genetics to conservation genomics: a genome-wide assessment of blue whales ( Balaenoptera musculus ) in Australian feeding aggregations

2018 ◽  
Vol 5 (1) ◽  
pp. 170925 ◽  
Author(s):  
Catherine R. M. Attard ◽  
Luciano B. Beheregaray ◽  
Jonathan Sandoval-Castillo ◽  
K. Curt S. Jenner ◽  
Peter C. Gill ◽  
...  
Keyword(s):  
Population Structure ◽  
Adaptive Divergence ◽  
Balaenoptera Musculus ◽  
Blue Whale ◽  
Conservation Genomics ◽  
Next Generation Sequencing Technology ◽  
Genome Wide ◽  
A Genome ◽  
Wide Range ◽  
Blue Whales

Genetic datasets of tens of markers have been superseded through next-generation sequencing technology with genome-wide datasets of thousands of markers. Genomic datasets improve our power to detect low population structure and identify adaptive divergence. The increased population-level knowledge can inform the conservation management of endangered species, such as the blue whale ( Balaenoptera musculus ). In Australia, there are two known feeding aggregations of the pygmy blue whale ( B. m. brevicauda ) which have shown no evidence of genetic structure based on a small dataset of 10 microsatellites and mtDNA. Here, we develop and implement a high-resolution dataset of 8294 genome-wide filtered single nucleotide polymorphisms, the first of its kind for blue whales. We use these data to assess whether the Australian feeding aggregations constitute one population and to test for the first time whether there is adaptive divergence between the feeding aggregations. We found no evidence of neutral population structure and negligible evidence of adaptive divergence. We propose that individuals likely travel widely between feeding areas and to breeding areas, which would require them to be adapted to a wide range of environmental conditions. This has important implications for their conservation as this blue whale population is likely vulnerable to a range of anthropogenic threats both off Australia and elsewhere.

scholarly journals Multiple pygmy blue whale acoustic populations in the Indian Ocean: whale song identifies a possible new population

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Emmanuelle C. Leroy ◽  
Jean-Yves Royer ◽  
Abigail Alling ◽  
Ben Maslen ◽  
Tracey L. Rogers
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
Tropical Indian Ocean ◽  
Blue Whale ◽  
The North ◽  
Central Indian Ocean ◽  
Commercial Whaling ◽  
The Indian Ocean ◽  
And Migration ◽  
Blue Whales

AbstractBlue whales were brought to the edge of extinction by commercial whaling in the twentieth century and their recovery rate in the Southern Hemisphere has been slow; they remain endangered. Blue whales, although the largest animals on Earth, are difficult to study in the Southern Hemisphere, thus their population structure, distribution and migration remain poorly known. Fortunately, blue whales produce powerful and stereotyped songs, which prove an effective clue for monitoring their different ‘acoustic populations.’ The DGD-Chagos song has been previously reported in the central Indian Ocean. A comparison of this song with the pygmy blue and Omura’s whale songs shows that the Chagos song are likely produced by a distinct previously unknown pygmy blue whale population. These songs are a large part of the underwater soundscape in the tropical Indian Ocean and have been so for nearly two decades. Seasonal differences in song detections among our six recording sites suggest that the Chagos whales migrate from the eastern to western central Indian Ocean, around the Chagos Archipelago, then further east, up to the north of Western Australia, and possibly further north, as far as Sri Lanka. The Indian Ocean holds a greater diversity of blue whale populations than thought previously.

scholarly journals Seasonal Occurrence of Sympatric Blue Whale Subspecies: the Chilean and Southeast Indian Ocean Pygmy Blue Whales With the Antarctic Blue Whale

2021 ◽  
Vol 8 ◽  
Author(s):  
Gary Truong ◽  
Tracey L. Rogers
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
Lower Latitude ◽  
Seasonal Patterns ◽  
Austral Winter ◽  
Blue Whale ◽  
Acoustic Data ◽  
The Pacific ◽  
The Antarctic ◽  
Blue Whales

There are multiple blue whale acoustic populations found across the Southern Hemisphere. The different subspecies of blue whales feed in separate areas, but during their migration to lower-latitude breeding areas each year, Antarctic blue whales become sympatric with pygmy and Chilean blue whales. Few studies have compared the degree of this overlap of the Southern Hemisphere blue whale subspecies across ocean basins during their migration. Using up to 16 years of acoustic data, this study compares the broad seasonal presence of Antarctic blue whales, Chilean blue whales, and Southeast Indian Ocean (SEIO) pygmy blue whales across the Pacific and Indian Oceans. Antarctic blue whales were sympatric with the other two blue whale subspecies during the migrating season of every year. Despite this overlap, Chilean and pygmy blue whale detections peaked earlier during the austral autumn (April–May) while Antarctic blue whale detections peaked later during the austral winter (June). Chilean (Pacific Ocean) and SEIO (Indian Ocean) pygmy blue whales showed similar seasonal patterns in detections despite occurring in different ocean basins. Though we have shown that Antarctic blue whales have the potential to encounter other blue whale subspecies during the breeding season, these distinct groups have remained acoustically stable through time. Further understanding of where these whales migrate will enable a better insight as to how these subspecies continue to remain separate.

Opportunistic sightings of blue whales off Sydney, Australia

2021 ◽  
Author(s):  
Vanessa Pirotta ◽  
Robert Harcourt
Keyword(s):  
Marine Mammals ◽  
New South ◽  
Short Note ◽  
Balaenoptera Musculus ◽  
Blue Whale ◽  
South Wales ◽  
Tasman Sea ◽  
Migratory Movements ◽  
The Antarctic ◽  
Blue Whales

ABSTRACT Two subspecies of blue whale occur in Australian waters, (1) the pygmy blue whale (Balaenoptera musculus brevicauda) and (2) the Antarctic blue whale (Balaenoptera musculus intermedia). Understanding blue whale presence in Australian waters is critical to ensuring Australia’s protection of these marine mammals as both subspecies were heavily exploited during historical whaling. This short note documents pygmy blue whale sightings in New South Wales waters over the last 18 years. Observations were opportunistically made via citizen science and verified by scientists. Sightings in this note contribute to our limited knowledge of pygmy blue whale distribution along the east coast of Australia and may help understand the migratory movements of New Zealand pygmy blue whales off Australia and in the Tasman Sea. Overall, information presented in this note contributes to Australia’s national and international conservation efforts to protecting blue whales as a migratory and threatened species.

scholarly journals Past and present distribution, densities and movements of blue whales Balaenoptera musculus in the Southern Hemisphere and northern Indian Ocean

Mammal Review ◽  
2007 ◽  
Vol 37 (2) ◽  
pp. 116-175 ◽  
Author(s):  
T. A. BRANCH ◽  
K. M. STAFFORD ◽  
D. M. PALACIOS ◽  
C. ALLISON ◽  
J. L. BANNISTER ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
Balaenoptera Musculus ◽  
Northern Indian Ocean ◽  
Present Distribution ◽  
Blue Whales

scholarly journals The GWAS Analysis of Body Size and Population Verification of Related SNPs in Hu Sheep

2021 ◽  
Vol 12 ◽  
Author(s):  
Junfang Jiang ◽  
Yuhao Cao ◽  
Huili Shan ◽  
Jianliang Wu ◽  
Xuemei Song ◽  
...  
Keyword(s):  
Body Size ◽  
Body Length ◽  
Body Height ◽  
Tail Length ◽  
The Body ◽  
Chest Circumference ◽  
Luciferase Reporter ◽  
Functional Genes ◽  
Meat Production ◽  
Hu Sheep

Body size is an important indicator of growth and health in sheep. In the present study, we performed Genome-Wide Association Studies (GWAS) to detect significant single-nucleotide polymorphisms (SNPs) associated with Hu sheep’s body size. After genotyping parental (G1) and offspring (G2) generation of the nucleus herd for meat production of Hu sheep and conducting GWAS on the body height, chest circumference, body length, tail length, and tail width of the two groups, 5 SNPs associated with body height and 4 SNPs correlated with chest circumference were identified at the chromosomal significance level. No SNPs were significantly correlated to body length, tail length, and width. Four out of the 9 SNPs were found to be located within the 4 genes. KITLG and CADM2 are considered as candidate functional genes related to body height; MCTP1 and COL4A6 are candidate functional genes related to chest circumference. The 9 SNPs found in GWAS were verified using the G3 generation of the nucleus herd for meat production. Nine products were amplified around the 9 sites, and 29 SNPs were found; 3 mutation sites, G > C mutation at 134 bp downstream of s554331, T > G mutation at 19 bp upstream of s26859.1, and A > G mutation at 81 bp downstream of s26859.1, were significantly correlated to the body height. Dual-luciferase reporter gene experiments showed that the 3 SNPs could significantly impact dual-luciferase and gene transcription activity.

scholarly journals First confirmed sightings of Blue Whales Balaenoptera musculus Linnaeus, 1758 (Mammalia: Cetartiodactyla: Balaenopteridae) in the Philippines since the 19th century

2021 ◽  
Vol 13 (3) ◽  
pp. 17875-17888
Author(s):  
Jo Marie Vera Acebes ◽  
Joshua Neal Silberg ◽  
Timothy John Gardner ◽  
Edna Rex Sabater ◽  
Angelico Jose Cavada Tiongson ◽  
...  
Keyword(s):  
19Th Century ◽  
Geographic Location ◽  
The Philippines ◽  
Balaenoptera Musculus ◽  
Blue Whale ◽  
Photo Identification ◽  
Range Edge ◽  
Ocean Productivity ◽  
The 19Th Century ◽  
Blue Whales

For over two centuries there were no records of Blue Whales Balaenoptera musculus in the Philippines. Whalers recorded Blue Whales in the Philippines in the 19th century, and the next confirmed sighting in the country was of a mother and calf in 2004.  Since then 33 subsequent Blue Whale sightings of potentially one individual were recorded between 2004 and 2019, all within the central region of the Philippines around the Bohol Sea.  This individual, recognized through photo-identification, was sighted on at least 13 occasions during eight different years: 2010, 2011, 2012, 2015, 2016, 2017, 2018, and 2019.  The geographic location and timing of the sightings (January to July) suggest that Blue Whales in the Philippines may extend the outer range edge of the Indo-Australian population that migrate between western Australia, Indonesia, and East Timor.  Blue Whale sightings in the Bohol Sea coincide with times of high ocean productivity, although further investigation is needed to determine if they are actually feeding in this region.  Acoustic studies and photo-identification matching with other Blue Whale catalogues will clarify the stock identity of Blue Whales in the Philippines and their relation to the rest of the Blue Whale population, with implications for the conservation of this endangered species across multiple jurisdictions.

Blue Whale (Balaenoptera musculus) Skin Contains Eumelanin and Pheomelanin

2019 ◽  
Vol 45 (1) ◽  
pp. 88-98 ◽  
Author(s):  
Blanca Morales-Guerrero ◽  
Diane Gendron ◽  
Laura M. Martinez-Levasseur ◽  
Karina Acevedo-Whitehouse
Keyword(s):  
Balaenoptera Musculus ◽  
Blue Whale

scholarly journals PSVIII-17 Assessment of conformational changes across three parities in sows

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 221-222
Author(s):  
Melanie D Trenhaile-Grannemann ◽  
Ronald M Lewis ◽  
Stephen D Kachman ◽  
Kenneth J Stalder ◽  
Benny E Mote
Keyword(s):  
Body Size ◽  
Body Length ◽  
Conformational Changes ◽  
Repeated Measures ◽  
Fixed Effects ◽  
Random Effect ◽  
Joint Angles ◽  
Body Depth ◽  
Conformation Changes ◽  
Over Time

Abstract Conformation-based sow selection is performed prior to reaching mature size, yet little is known about how conformation changes as growth continues. To assess conformation changes, 9 conformational traits were objectively measured at 12 discrete time points between 112 d of age and parity 3 weaning on 622 sows in 5 cohorts. The 9 traits included 5 body size traits (body length, body depth at the shoulder and flank, and height at the shoulder and flank) and 4 joint angles (knee, hock, and front and rear pastern). Data were analyzed with a repeated measures model (SAS V 9.4) including cohort and time point as fixed effects, sire as a random effect, and heterogeneous compound symmetry as the covariance structure. Sire variance ranged from 0.16 (body depth shoulder) to 2.00 (body length) cm2 for body size traits and 2.28 (rear pastern) to 4.22 (front pastern) degrees2 for joint angles. Cohort had an effect on all traits (P < 0.05). All traits displayed changes over time (P < 0.001). Size traits increased between 112 d of age and parity 3 weaning (64.16 vs. 107.57 cm, 26.62 vs. 44.14 cm, 23.32 vs. 36.92 cm, 46.10 vs. 73.55 cm, 49.36 vs. 77.47 cm for body length, body depth shoulder and flank, and height shoulder and flank, respectively); however, they fluctuated within parity by increasing during gestation and decreasing at weaning. Knee angle decreased (164.12 vs. 150.72 degrees) while fluctuating within parity by decreasing in the second half of gestation and increasing after weaning. Front and rear pastern angles decreased over time (60.89 vs. 53.74 degrees and 64.64 vs. 55.50 degrees for front and rear pastern, respectively), while biologically negligible change was observed in hock angle (148.63 vs. 147.48 degrees). Sow conformation changes throughout life, and these changes may require consideration when making selection decisions.

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