World’s largest sea animal spotted near Lamu
By ALPHONCE GARI @alphonce2011
Marine experts have released a report showing proof of the existence of the blue whale, the world’s largest and endangered sea animal, in the offshores of Kenya’s Indian Ocean waters.
The blue whale is the largest animal to have lived on earth, with lengths greater than 30 metres, and has never been spotted off the Kenyan waters.
The new sightings were recorded by marine mammal observers during a geophysical survey conducted 120 nautical miles off the coast near Lamu.
The report, published in African Journal of Marine Science by R Barber, I Sikora and M Nimak, indicates that the marine mammal experts sighted 38 blue whales in 30 sightings.
Observations were made in the Kenyan offshore during seismic surveys from September 2014 to January 2015.
FIRST SUCH SIGHTING
The study represent the first live at-sea sightings of blue whales reported from Kenyan waters.
“All 30 sightings occurred between September and October in waters ranging from 2,990 to 4,705 metres depth,” said the report in part.
Research shows that the numbers of blue whales reduced drastically following massive exploitation in the 20th century and now stand between 3 to 11 per cent.
For this reason, the species is listed as ‘endangered’ on the International Union for the Conservation of Nature (IUCN) red list.
The research further reveals that there are no recorded strandings of blue whales in Kenya.
In the world, it is believed there are at least five subspecies of blue whale.
Those found in the Indian Ocean are the Antarctic blue whale, the slightly smaller pygmy blue whale, and the northern Indian Ocean blue whale.
According to reports by the IUCN in 2015, the Antarctic blue whale is listed as ‘critically endangered’, while the pygmy blue whale as ‘data deficient’.
According to the marine experts, the sightings during the survey suggest that the area off northern Kenya forms an important habitat for blue whales in the Indian Ocean, particularly during the end of the Southeast monsoon period.
To prove these, the seismic surveys spotted the 30 sightings of blue whales in September and October but did not see them again in the remaining period of their survey that went up to January.
FEEDING OR MIGRATING?
However, it is still not clear whether the waters off Kenya are a feeding ground for the blue whales or they were on a migratory route.
The observers also could not record the subspecies of the blue whale spotted during the series of observation due to the absence of acoustic or genetic studies
“Photo-identification matching of the photographs taken during the survey, however, could help to identify links with blue whale populations in the Indian Ocean,’’ said the report.
They recommended that further survey work is required to establish the presence of blue whale during the remainder of the year outside the current study period, especially during the earlier part of the Southeast monsoon.
The study showed that the blue whales were present in September and October but never recorded other sightings in the rest of the study period.
“The current survey was conducted at the end of the Southeast monsoon (May–October) and in the months heading into the Northwest monsoon period (December–March).
However, all 30 sightings of blue whales occurred during the first two months of the survey (September and October) at the end of the Southeast monsoon period.
During the Southeast monsoon, major upwellings of nutrient-rich waters and associated plankton productivity occur, particularly off the Somalian coast,” added the report.
In their conclusion, the experts said the fresh survey and data could help to establish whether whales are using the area throughout the monsoon season as a feeding area, or are moving through it from areas further north.
Old reports of whaling records in the 19th century, which was included in the study, indicated that blue whales were regularly reported in the western Indian Ocean off the Somali coast, especially in the Gulf of Aden during September and November.
It further states that Japanese scouting ships reported seven blue whales at 00°22′ N, 50°31′ E, offshore of the southern coast of Somalia, in March 1982.
Another report noted sightings of 18 blue whales off the coast of Somalia in October, November and December 1985.
To the experts, the 30 recorded sightings of blue whales reported represent the first known at-sea sightings of this species off the Kenyan coast.
“These observations are consistent with the knowledge of the occurrence of this species within the wider western Indian Ocean,” said the report.
MUCH STILL UKNOWN
Research says blue whales are generally associated with deep water throughout most of their range, with occurrences in shallower water usually recorded from regions with narrow continental shelves or in areas immediately adjacent to deeper water.
The marine experts also say blue whales have high energy demands and their distribution year-round is linked to areas of high productivity and high euphausiid density.
It is said that very little is known about the presence, distribution and seasonality of blue whales (and cetaceans in general) off the coast of Kenya.
The research currently conducted is based in coastal areas (Kenya Marine Mammal Network, 2013), which does little or no work at all in more remote offshore areas.
Source: The Star
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