Blue whales can be affected even by sounds that are outside their vocalisation range, according to a new study.
Mariana Melcon and colleagues from the Scripps Institution of
Oceanography observed the response of blue whales in the Southern
California Bight to mid-frequency sounds created by military sonar,
which occur between 1000Hz to 8000Hz, much higher than blue whale calls,
which are 100Hz and lower.
They collected thousands of hours
of recordings over two summers, and found that, when mid-frequency
active (MFA) sonar (which is used to find submarines) was active in the
region, blue whales' low-frequency vocalizations, known as "D-calls",
dropped by almost half: a sign, the authors posit, that despite being
well outside the whales' vocalization range, such relatively
high-frequency sounds are within their hearing range.
One
possible explanation for being able to hear sounds of such high
frequency, Melcon and colleagues suggest, "is that it may be
advantageous, for instance, to hear their predators, ie. killer whales,
which vocalize in the same frequency range as MFA sonar," Discovery News
reported.
Conversely, when confronted with the noise of
shipping, which does largely fall within their vocalization range, the
whales increased their D-calls - which "may be the vocal response of the
animals to overcome the noise".
This new research just published in the online open-access journal PLoS One.
The Central Marine Fisheries Research Institute (CMFRI) in collaboration with the Institute of Marine and Antarctic Studies (IMAS), University of Tasmania, will conduct an international workshop on 'Preparing for climate change on marine systems in Australia and India' from March 6-10 in the city.
Michael Carter,
consul commercial and trade commissioner of Australia at Chennai will
inaugurate the workshop at 10 am on Tuesday. Seven scientists from
Australia led by Stewart Frusher, associate professor, IMAS, will
participate in the workshop. The Indian team of 14 scientists will be
led by G Syda Rao, director, CMFRI.
Funded by the
Australia-India Strategic Research Fund, the aim of the workshop is to
bring together an inter-disciplinary research team from both countries
to improve understanding on the impacts of climate change on marine
resources and stakeholders.
Both these regions have been identified as global warming hotspots.
The Union environment and forests ministry (MoEF) will demarcate the no-go areas for mining within a month. However, this time around, they have been rechristened as "inviolate areas".
The exercise will be carried out by a panel chaired by environment and forest secretary T Chatterjee.
The original no-go demarcation was scrapped since the coal ministry and
industry had complained about it. Earlier, it was decided by Group of
Ministers (GoM), headed by finance minister Pranab Mukherjee, to instead demarcate "inviolate areas", where mining would not be permissible.
In the GoM meeting held on Thursday, it was decided that the process of
demarcating the inviolate zone would be conducted within a month. The
Chatterjee-led panel has been tasked to chalk out fresh criteria for the
demarcation process that would decide how liberal the new regime is.
GoM members also pushed hard for a revaluation of the environment
ministry's decision not to open Mahan and Chhatrasal captive coal blocks
in Madhya Pradesh. The ministry has been asked to review its decision
for which another panel will be sent to the sites.
Mahan had been allocated to the Aditya Birla Group and Essar
in a joint venture, and the firm has made substantial investments in
their power plants based on separate environment clearances. While the
environmental clearance did put conditions about securing forest
clearance, the GoM members noted that no concern had been raised for
long, besides companies had pumped funds into the projects.
Chhatrasal block has been allocated to the Reliance Ultra Mega Power Project but the environment ministry's statutory Forest Advisory Committee had recommended against clearing the venture as it impinges upon the Rihand reservoir apart from other concerns.
The GoM would consider the two blocks' fate once the panel submits its report in 10 days.
The GoM also discussed if power projects could be given clearance
without assessing the environmental and forest implications of the
linked coal blocks. It was suggested that a decision could be taken
based on a pool of coal supply being assured in advance as long as the
quality of the mineral needed for the particular power project was
available in the pool.
The entire Western Ghats
must be considered as ecologically sensitive, especially to ensure the
sustainability of the rivers of the Indian Peninsula, the Madhav Gadgil
Committee report has said. Peninsular rivers such as the Krishna,
Godavari and Cauvery that drain the Deccan Plateau and flow eastwards
originate in the Western Ghats.
"Hundreds of shorter perennial
monsoon fed west flowing rivers like Sharavati, Netravathi, Periyar and
the Bharathapuzha travel through steeper and more undulating topography
before emptying into the Arabian Sea.
A rough estimate reveals that 245 million people in the five Western
Ghats states directly depend on these rivers for their diverse water
needs. Geographically, the Western Ghats is the catchment for river
systems that drain almost 40% of the land area in India," reads the
report. According to the report, the Ghats meets all these criteria and
so deserve to be protected in its entirety.
The Western Ghats Ecology Expert Panel report
Part II has now been placed unofficially in the public domain. The
committee, which prepared the report was headed by noted ecologist
Madhav Gadgil. Though the report was submitted in August last year, the
union ministry of environment and forests has been reluctant to make it
public.
The recommendation of declaring the entire ghats that traverse through the six states of Tamil Nadu,
Kerala, Karnataka, Goa Maharashtra and Gujarat would mean a complete
ban on mining and stricter green laws for other industries such as power
and agriculture. The panel has based its recommendation on various
studies carried out by scientists and institutions across the six
states, geo-spatial database, etc.
By:times of india
