Bomb Detectors Pick Up Sounds From Pygmy Blue Whales Thriving in the Indian Ocean

The group of "Chagos" pygmy blue whales discovered only last year in the Indian Ocean might still be unknown to us if it weren't for underwater listening devices set up to monitor nuclear bomb tests.

And now, researchers from the UNSW Sydney have analyzed over two decades' worth of recordings to conclude that the frequency of these pygmy blue whales' peculiar songs has grown over time.

The researchers tentatively proposed that the data reveal populations of the sub-species may be on the increase after being driven to near-extinction in the 20th century because real sightings of the pygmy blue whales are still exceedingly uncommon despite their 24-meter length.

Pygmy blue whales thriving in the Indian ocean

(Photo : Jake Gaviola/Unsplash)

They sought to establish links between the existence of Chagos whales and several other elements, including food sources, sea surface temperatures, and shifting weather patterns like the El Nio Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD).

They were able to piece together a pattern of behavior and migratory that corresponded with different levels of food abundance and the sea temperature of each area, which were about 200 kilometers apart, by comparing the whale song frequency documented by the two sets of hydrophones placed at the northwest of Diego Garcia and the southeast of the island.

The researchers are worried about the impacts of climate change on rising water temperatures, which might have an impact on their major food supply, krill, even if this may be good news for scientists and environmentalists.

The Comprehensive Nuclear-Test-Ban Treaty Organization, which put the devices in 2002, installed the devices, and according to lead author Lyra Huang, "we used up to 18 years of acoustic recordings of the Chagos whales from the data we acquired from the UN organization, CTBTO," as per ScienceDaily.

Additionally, we found that whales have different seasonal patterns on the west and east sides of the island.

Experts found that first, whale songs have increased throughout the study at both locations, and second, that whales are primarily on the south-eastern side from September to November before migrating to the north-western side, where they remain until February.

In particular, the researchers discovered a positive association between the amount of chlorophyll-a on the southeast side of the island and an increase in the presence of Chagos whales, as well as a decrease in sea-surface temperatures, during the period when these animals tend to choose this location.

Lots of chlorophyll-a might be a sign that there is more food available at certain times for the whales, according to Professor Tracey Rogers, a co-author, and specialist on how animals deal with changing environments.

This is due to the fact that high chlorophyll-a concentrations indicate a large amount of phytoplankton.

Additionally, because krill graze on phytoplankton, it is a desirable feeding ground for whales.

Also Read: For the First Time in 40 Years, Blue Whales Return to Spain's Atlantic Coast

Advancement of scientifically-based marine conservation

Large, completely protected marine regions are shown to help preserve important species and may oftentimes undo the negative effects brought on by people, as per PEW.

Additionally, marine protected areas (MPAs) can increase fish populations, benefit nearby ecosystems ecologically, protect predators, keep ecosystems stable, and aid in the preservation of societies with strong links to the sea.

Many nations have established extensive MPAs that are completely protected in the last ten years.

Action must be taken immediately because ocean health is falling more quickly than at any other time in human history.

The information indicated that more oceans must be preserved in order to stop this negative trend.

Less than 8% of the world's oceans are currently protected by MPAs, and only about 50% of those are fully or highly protected MPAs, which can help replenish biodiversity, increase resiliency to the effects of climate change, ensure long-term economic growth for local economies, and protect cultural and traditional practices in coastal and island communities.

Indigenous peoples, community leaders, nongovernmental organizations (NGOs), and government officials are increasingly calling for the protection of at least 30% of the ocean by 2030, a goal that many scientists believe mankind must reach in order to ensure the long-term sustainability of our planet.

Governments from all across the world have made great strides toward new, extensive marine conservation pledges and designations that span more than 3.4 million square kilometers of some of the world's most ecologically important seas since June 2021.

These include Tristan da Cunha, French Polynesia, the French Southern, and Antarctic Lands, and Australia's Cocos (Keeling) and Christmas Islands.

Additionally, important marine protection increases for the Cordillera de Coiba, Cocos Island, and the Galápagos Islands were each declared by Ecuador, Costa Rica, and Panama.

Related article: Blue Whales of Antarctica Seen Again in South Georgia After Near Extinction