Navigation Links
The pitch of blue whale songs is declining around the world, scientists discover
Date:12/9/2009

The sound level of songs blue whales sing across the vast expanses of the ocean to attract potential mates has been steadily creeping downward for the past few decades, and a scientist at Scripps Institution of Oceanography at UC San Diego and his colleagues believe the trend may be good news for the population of the endangered marine mammal.

Mark McDonald of WhaleAcoustics in Bellvue, Colo., along with John Hildebrand of Scripps Oceanography and Sarah Mesnick of NOAA Fisheries Southwest Fisheries Science Center studied blue whale song data from around the world and discovered a downward curve in the pitch, or frequency, of the songs. The decline was tracked in blue whales across the globe, from off the Southern California coast to the Indian and Southern Oceans.

"The basic style of singing is the same, the tones are there, but the animal is shifting the frequency down over time. The more recent it is, the lower the frequency the animal is singing in, and we have found that in every song we have data for," said Hildebrand, a professor of oceanography in the Marine Physical Laboratory at Scripps.

The study's results are published in the most recent issue of the journal Endangered Species Research.

The researchers examined a list of possible causes for the frequency dropfrom climate change to a rise in human-produced ocean noiseand believe it may be explained by the increase of blue whale numbers following bans on commercial whaling activities.

While the function of blue whale songs is not known and scientists have much more to learn, they do know that all singers have been determined to be males and that the high-intensity, or loud, and low-frequency songs propagate long distances across the ocean. Blue whales are widely dispersed during the breeding season and it is likely that songs function to advertise which species is singing and the location of the singing whale.

In the heyday of commercial whaling, as blue whale numbers plummeted, it may have been advantageous for males to sing higher frequency songs, the researchers believe, in order to maximize their transmission distance and their ability to locate potential mates (females) or competitors (other males).

"It may be that when (blue whale) densities go up, it's not so far to get to the closest female, whereas back when they were depleted it may have been that the closest female was a long way away," said Hildebrand.

In the 1960s, when blue whale numbers were substantially reduced and recordings of the animals were first made, there may have been a tradeoff in which the male suitors chose to sing higher frequencies that were louder and heard over greater distances, Hildebrand said. In more recent years, as population sizes have increased, it may now be more advantageous for males to sing songs that are lower in frequency rather than louder.

"When they make these songs they need to use most of the air in their lungs," said Hildebrand. "It's like an opera singer that sees how long he can hold a note. The (male) songs are made to impress the females and/or other males, so I think that's how the boy blue whales are impressing the girls, or are showing off to other boys: by making a loud and long song."

The scientists say the same downward pitch phenomenon may be true in other whales such as fin and humpbacks, but the blue whale song, with a comparatively easier song to analyze, is a good springboard to study other species. Hildebrand says such knowledge about whale songs could be important in monitoring whale populations and recovery efforts.

During the study the researchers analyzed thousands of blue whale songs divided into at least 10 worldwide regions. These include the Northeast, Southwest and Northwest Pacific Ocean; the North Atlantic; the Southern Ocean near Antarctica; and the North and Southeast Indian Ocean. Blue whale songs have been recorded for the last 45 years through scientific and military applications by seafloor seismometers tracking regional earthquakes and dedicated whale acoustic recording packages.


'/>"/>

Contact: Mario Aguilera
scrippsnews@ucsd.edu
858-534-3624
University of California - San Diego
Source:Eurekalert  

Related biology news :

1. Perfect pitch in humans far more prevalent than expected
2. Study finds pitching mound height affects throwing motion, injury risk
3. Carnivorous plants use pitchers of slimy saliva to catch their prey
4. Rocket science leads to new whale discovery
5. Getting a leg up on whale and dolphin evolution
6. New species discovered on whale skeletons
7. Bycatch whaling a growing threat to coastal whales
8. NOAA researchers: Blue whales re-establishing former migration patterns
9. UIC biologists use DNA to study migration of threatened whale sharks
10. Right whale sedation enables disentanglement effort
11. Mama whales teach babies where to eat
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
The pitch of blue whale songs is declining around the world, scientists discover
(Date:1/22/2016)... DUBLIN , January 22, 2016 ... has announced the addition of the  ... to their offering. --> ... of the  "Global Behavioral Biometric Market ... --> Research and Markets ( http://www.researchandmarkets.com/research/4lmf2s/global_behavioral ...
(Date:1/20/2016)... , Jan. 20, 2016   MedNet Solutions ... the entire spectrum of clinical research, is pleased to ... MedNet,s significant achievements are the result of the company,s ... iMedNet eClinical , it,s comprehensive, easy-to-use and ... --> Key MedNet growth achievements in ...
(Date:1/13/2016)... --> --> ... report titled - Biometric Sensors Market - Global Industry Analysis, ... to the report, the global biometric sensors market was valued at ... US$1,625.8 mn by 2023, expanding at a CAGR of ... the biometric sensors market is expected to reach 1,799.6 ...
Breaking Biology News(10 mins):
(Date:2/8/2016)... ... 08, 2016 , ... Bulk food product inspection systems are ... stages of the production process. Despite frequently inspecting loose product prior to packaging, ... such as sacks of dry powders. , Mettler-Toledo Product Inspection's brand-new white paper ...
(Date:2/8/2016)... , February 8, 2016 ... Genetics" or the "Company"), the ultra-rapid Point-Of-Care (POC) molecular diagnostics ... Mark its Chlamydia trachomatis (CT) test to be launched on ... IVD Directive (98/79/EC), the CT test is now cleared for ... --> The launch of the io® CT test ...
(Date:2/5/2016)... -- On Thursday, February 11, 2-1-1 San Diego ... and disaster services, and the Community Information Exchange ... coordination and service delivery for the community to better ... better connect service providers to the information they can ... has handled more than 2.5 million connections ...
(Date:2/4/2016)...  Sangamo BioSciences, Inc. (NASDAQ: SGMO ), the ... Edward Lanphier , Sangamo,s president and chief executive officer, ... ZFP Therapeutic ® development programs and an overview ... on Thursday, February 11, 2016, at the Leerink Partners ... is being held in New York ...
Breaking Biology Technology: