Posts Tagged ‘Hawaii’


Researchers found the first known hybrid between a rough-toothed dolphin and a melon-headed whale near Kauai, Hawaii.


Rough-toothed dolphins.


Melon-headed whales.

By Jessie Yeung

Scientists from the Cascadia Research Collective have discovered a rare dolphin-whale hybrid off the coast of Kauai, Hawaii, according to a report published last week.

The marine mammal monitoring program, funded by the US Navy, first spotted the animal in August 2017. The team tagged various species, including commonly seen rough-toothed dolphins and rarer melon-headed whales.
However, researchers soon noticed that one tagged animal that looked a little odd. Although it had a typical melon-headed whale’s dorsal fin shape and dorsal cape, it was also blotchy in pigmentation and had a sloping forehead, more reminiscent of a rough-toothed dolphin.

A genetic sample soon confirmed their suspicions: it was a hybrid of the two species, the first to ever be found.The cross-species hybridization may seem bizarre, but is made possible by the fact that melon-headed whales aren’t actually whales. They belong to the Delphinidae family, otherwise known as oceanic dolphins, which also includes orcas and two species of pilot whales.

It also isn’t the first discovery of hybridization in the family
— there have also been cases of bottlenose dolphin/false killer whale (Pseudorca crassidens) hybrids, known as Wolphins, and common/bottlenose dolphin hybrids.

This is the first confirmed hybrid between rough-toothed dolphins and melon-headed whales. However, though it’s an exciting discovery, researchers point out it is not, as commonly thought, a new species.

“While hybridization can at times lead to new species, most of the time this does not happen,” Cascadia researcher Robin Baird told CNN, pointing that there was only a single hybrid found this time.

Some hybrid animals, such as the mule — a hybrid of a male donkey and female horse — are mostly sterile and therefore cannot propagate easily.

The dolphin-whale hybridization is especially surprising in this region, as a sighting of melon-headed whales had never before been confirmed near the Pacific Missile Range Facility (PMRF) navy base.

The hybrid was only traveling with one companion — a melon-headed whale. This, too was unusual, given that melon-headed whales typically travel in groups of 200-300. The solitary pair were “found associating with rough-toothed dolphins,” the report read.

The odd pair and their closeness to the other dolphins have led the researchers to speculate that the accompanying melon-headed whale is the hybrid’s mother.
The research team will return to Kauai next week, hoping to confirm their theory.

“If we were lucky enough to find the pair again, we would try to get a biopsy sample of the accompanying melon-headed whale, to see whether it might be the mother of the hybrid, as well as get underwater images of the hybrid to better assess morphological differences from the parent species,” said Baird.

The US Navy is required to monitor these species as part of the Marine Mammal Protection Act and the Endangered Species Act.

They do so through the Cascadia Research Collective, which conducts photo identification, genetic analyzes, and acoustic monitoring to determine the abundance of odontocetes, also known as toothed whales.

https://www.cnn.com/2018/07/30/us/dolphin-whale-hybrid-intl/index.html

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Large boulders 2 metres across and weighing 10 tonnes could soon begin blasting out from Kilauea, the erupting volcano on Hawaii’s Big Island. But the biggest imminent threat to residents could arise if the volcano starts spewing ash to heights of 6000 metres or more.

The conditions are similar to those when Kilauea last erupted in 1924, which showered the island in ash for several months. “That’s what I would guess will happen next,” said Don Swanson of the Hawaiian Volcano Observatory, in a press conference video issued on 9 May.

Kilauea has been unusually active since late April. On 30 April, the floor of the lava lake at the volcano’s summit collapsed.

The lava has been draining ever since. By 9 May, and following a 6.9-magnitude earthquake on 3 May, it had already plunged almost 300 metres into the vertical shaft below. The lava is now below the level of water-saturated rock at 600 metres above sea level. “Since the earthquake, the lava lake has dropped in a very steady manner, at 2.2 metres per hour,” said Swanson.

Steam explosions

Because the lava has sunk so low, water is now draining into the empty shaft that it previously occupied. The walls of the crater are red hot, so the water is instantly turning to steam, which is now bellowing in white clouds from the volcano summit.

What happens next is difficult to predict, said Swanson. But there could be explosions. If large rocks fall from the unstable walls of the shaft, they could block it, in which case pressure from steam will build up underneath and cause an explosion.

Once the “plug” is blown out, the steam can escape again unimpeded, until the plug is restored by rock falls.

The result would be a series of explosions followed by hiatuses. That’s what happened in 1924: there were 60 explosions over the course of four months or so.

Boulders and ash

Any explosion can produce a variety of “ejecta”, said Swanson. “You can get rocks ejected like cannonballs, weighing up to 10 tonnes and 2 [metres] in diameter,” he said.

The good news is that these boulders should fall within about a kilometre of the summit. This area is deserted. Smaller rocks the size of softballs could impact a bit further away, albeit still not far enough to reach people’s homes. But tinier fragments a fraction of an inch wide could reach peopled areas. “They would sting, but not be lethal,” says Swanson.

The most important hazard is fine ash, which can block thoroughfares and accumulate on buildings. In 1924, ash landed on railway tracks and made them too slippery for trains to run on safely.

“It’s a nuisance, especially if it goes on for several weeks,” said Tina Neal of the Hawaiian Volcano Observatory at the press conference. “I’ve been in many ash falls myself, and the most difficult bit is keeping it out of your eyes.”

Meanwhile, lava fountains and steam continue to spew copiously from cracks on the island, reaching heights of 30 metres. By Monday, there were 19 fissures in total. So far, more than 30 properties have been destroyed by lava, and 2000 residents remain evacuated.

https://www.newscientist.com/article/2168913-hawaiis-erupting-volcano-may-blast-out-10-tonne-cannonballs/