This bryde’s in a complicated knot

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A whale that gets washed ashore becomes an object of entertainment for the people and the media alike. Except for the instant curiosity it generates, whales, however, get little attention. Even from marine conservation biologists and taxonomists in the country.

It’s here the path-breaking finding of two researchers from the state becomes significant which for the first time confirms that Indian coast is still home to Bryde’s whales, a species of baleen whales, the third largest marine mammal.

Interestingly, Bryde’s whale is listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Scientifically termed Balaenoptera edeni, this species is also listed as Data Deficient by International Union for the Conservation of Nature and Natural Resources (IUCN).

“The precise identification would go a long way in strengthening the conservation efforts of these whales,” Dr. A. Biju Kumar, Department of Aquatic Biology and Fisheries who led the research along with Dr.Sanil George, Rajiv Gandhi Centre for Biotechnology opined.

Dr. Biju and Sanil resorted to DNA bar-coding technique to arrive at the new finding. The technique, according to them, offers quick identification of specimens through the sequencing of genes in the mitochondria inside the cell. Interestingly, it’s for the first time, anyone in the country has documented the deaths of whales and the cause.

In the last two years, eight whales were washed ashore at Edayar and Cheriyathura beaches (Thiruvananthapuram), Thanni and Kollam beaches (Kollam), Chavakkad beach (Thrissur), Kondotty beach (Malappuram) and Azheekkal beach (Kannur).

Even as the presence of Bryde’s whales in the Indian coastal waters is a heartening development, the researchers who carried out DNA bar-coding on four whales which landed in Kerala coast are miffed by the fact that the phenomenal increase in sea traffic is posing severe threat to their survival.

“We could see that many whales landed here had sustained serious injuries after they’re hit by the ship propellers,” Dr. Biju disclosed. Whales globally are threatened by anthropogenic encroachments such as contaminants or intensive sound disturbances which derange their natural behavior.

“But in the Indian coast, the primary reason for their killing could be attributed to ship-hit,” Biju said. Whales could be hit by different types of vessels which vary in size. However, most lethal injuries are caused by vessels longer in size and travelling at 14 knots or faster.

The research carried out by Biju and Sanil suggests that collision between ships and whales are more common than previously thought. However, no effort is made to compile the frequency of such collisions, types of vessels involved, speed of the vessels when the whales were hit and whales’ behavior before being hit.

“Massive injuries on stranded ship-struck whales suggest that large vessels are the principal sources of severe injuries in whales. In the case of the stranded whale at Thanni beach, a deep injury was noticed on its back which could be due to ship hit,” Biju said.

Vessel collisions, interestingly, are considered an important source of mortality for Bryde’s whale in New Zealand waters. So, it’s not surprising, the research carried out by Biju and Sanil even while confirming the presence of this species in the Indian coastal waters finds that large vessels pose a severe threat to their survival.

“Ship strikes can reduce the number of whales that are small in population. So, it would be beneficial to reduce the vessel speed in areas where special caution is needed,” Biju suggested. However, experts in shipping business dismiss it as a futile suggestion.

“You can’t fix the speed limit for a vessel. Its speed is determined by various factors including the current. Everyone knows it’s the poachers who pose the biggest threat to whales. The number of ship-hit whales is insignificant compared to the ones poached for commercial purposes,” an expert pointed out.

Biju, meanwhile, says a greater emphasis should be placed on complete necropsies of stranded animals which would determine the cause of death and other underlying factors in the fatality to make the investigation more reliable. “This will give us greater ability to evaluate and alleviate the impact of anthropogenic interactions,” he said.

It’s estimated that 120 species of marine mammals are present in the world’s oceans of which 30 are in Indian coastal waters including whales, dolphins, one species each of porpoise and sea cow. The charismatic mega-fauna, however, is an endangered population today due to a history of commercial use for blubber, meat, ivory and fur.