Dr Gerry Goeden's Swimming With Dolphins: 2013

Friday, 6 December 2013

The Origin of Whales and Dolphins

Whales and dolphins belong to a group of animals called cetaceans. All cetaceans live in water today but their ancestors were land animals.

The closest relative to today’s cetaceans is the hippopotamus. Whale ancestors left the land about 50 million years ago and became the baleen whales (plankton feeding) and toothed whales (fish and squid eaters) of today.

Humpback Whales

What did the early whales look like and how did they live?

The first fossils were found in the

United States

and were so different from modern whales that they were described as a reptile (dinosaur). Because of their size, they were named Basilosaurus, or king lizard. Many fossils were found with an average length of 18 metres and scientists believed that they may have reached 45 metres. Fossils have been found in Pakistan and

Egypt

and may have given rise to early worship of crocodile-like gods.

They were so different from modern whales that they were described as a reptile (dinosaur).

But they weren’t lizards!

We now know that the fossil Basilosaurus was a whale that probably hunted in shallow seas between 34 and 40 million years ago. It was about 18 metres long and the biggest animal on Earth at that time.

It had small paddle like hind fins that were left over (vestigial) from what were once legs. They were so small that the Basilosaurus probably swam more like a snake than a modern whale.

We can be very certain (look at the teeth) that Basilosaurus was an aggressive and dangerous predator. Careful examination of the skeleton suggests that Basilosaurus may not have been a long distance swimmer and probably could not dive to great depths. Its head and teeth are reminiscent of a crocodile’s and it may have hunted in a similar way; surprise attacks in shallow water or swimming down unfortunate prey.

Another 30 million years of evolution finds us sharing the planet with 81 species of whales from the metre long Hector’s dolphin to the Blue Whale, the largest animal to have ever lived on Earth.

Blue Whale and its calf

Killer whales in a pod.

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Tuesday, 1 October 2013

WHALES IN CHRISIS; KILLER WHALES AND WHALE KILLERS

I've been spending a lot of time with the Chinese White Dolphins in the bay. My hope is that they will gradually accept me and I'll be able to get some photos and watch their underwater behavior. Although they are safe here I am reminded that whales are far from safe in the world's oceans.

The White or Humpback Dolphin

Whales are among the most spectacular creatures on Earth and most 'enlightened cultures' have voted to protect them from unnecessary harm. In fact, science has clearly shown that many species are endangered or are on the brink of extinction. Laws have been passed and whales are protected; right?

Although some species are recovering, many whales are in as much danger today as they were a century ago during the days of whaling. Let’s have a look at the major threats faced by whales today.

Naval Defense

The U.S. Navy among other armed forces is experimenting with high power sonar that can detect the presence of submarines throughout the world’s oceans. These bursts of sound can reach 240 decibels (billions of times more powerful than the level that causes hearing damage in humans). During testing off the California coast, noise from one of the Navy's low-frequency sonar systems was detected across the full width of the northern Pacific Ocean.

Dolphins and whales are known to use their biosonar to locate fish, navigate, and communicate with each other. When the U.S. Navy began testing their high power sonar strange things started to happen.

Stranded Sperm Whale

The Navy’s most widely used sonar systems operate in the mid-frequency range. Evidence of the danger caused by these systems surfaced dramatically in 2000, when whales of four different species stranded themselves on beaches in the Bahamas.

In 2003, the U.S. Navy conducted sonar tests off the Coast of Washington. The whales in the area were monitored by biologist making underwater recordings. One pod of killer whales almost beached themselves in an effort to get away for the intense sound bursts made by the Navy’s sonar. By the Navy's own estimates, even after 500 kilometres, these sound bursts can retain an intensity of 140 decibels -- a hundred times more intense than the level known to affect the behavior of large whales.

A pod of Killer Whales

Several whales from this pod have since died at a young age. In other locations beached whales have suffered physical trauma, including bleeding around the brain, ears and other tissues.

Pilot whales are very social animals and form close and lasting bonds with each other. In Florida, as mass stranding of pilot whales was observed. The whales were so weak they had to be supported to prevent drowning. There were no apparent lesions or reason for this large group of whales to beach themselves.

Stranded Pilot Whales

Was this a stranding due to the U.S. Navy’s testing of sonar in the area?

The beaked whale is a deep diving whale. It has been recorded at 1,999 metres in a dive lasting over 70 minutes. These deep diving whales use their biosonar for navigation and to locate food.

A Beaked Whale

Beaked whales in the Bahamas stranded themselves in large numbers; again with no apparent reason. The U.S. Navy had conducted a sonar exercise in the immediate area prior to the strandings of this rare whale. Was this another coincidence?

The bowhead whale weighs in excess of 60 tonnes and is one of the biggest whales in the world. There are only about 350 bowhead whales left in a sub-population that migrates past Greenland for a short time during the summer months.

Bowhead Whales

The whales produce sound frequencies between 50-300 hertz to locate masses of krill and to communicate between each other.

What would happen to this small group of bowheads if they were exposed to the Navy’s sonar exercises?

Hunting of Whales

The I.W.C. (International Whaling Commission) was setup in 1946 to oversee the commercial harvesting of whales on a global basis.

Since the late 1970s, however, the I.W.C. has become dominated by governments that are largely opposed to the practice of commercial whaling. The result of this shift led to the eventual adoption of a moratorium on commercial whaling in 1986. The moratorium has never been lifted and whale populations are slowly recovering. In 1994 the Southern Ocean Whale Sanctuary

was created to enhance protection into the future.

So has the whaling stopped? Not exactly.

Butchering a Bowhead Whale aboard a whaling ship

Let’s go through the ‘official’ list. Remember that other countries would like to resume whaling and many whales are killed and not reported.

COUNTRY	WHALING SITUATION
Canada	Carried out by various Inuit groups, meat obtained from this whaling is commercially sold through shops and supermarkets
Caribbean	Allows natives of Bequia to catch up to four Humpback Whales per year using traditional hunting methods
Faroe Islands	Around 950 Long-finned Pilot Whales, some Northern Bottlenose Whale, and Atlantic White-sided Dolphin.
Greenland	Catch around 175 whales per year, making them the third largest hunters in the world after Norway and Japan
Iceland	Quota is set to 30 minke whales and nine Fin Whales
Indonesia	Lamalera and Lamakera, half of the catch is kept in the village; the rest is traded
Japan	Japan’s controversial scientific whaling program takes about 600 whales per year
Norway	Norwegian whalers have been allowed to hunt a quota of 1,052 Minke Whales a year. Catches are usually less
Russia	Permitted under IWC regulation to take up to 140 Gray Whales. The Soviet Union had been systematically underreporting. They caught 48,477 Humpback Whales rather than the 2,710 it officially reported (1948-73)
United States	Carried out by Alaska natives, takes around 50 Bowhead Whales a year
Total	Permitted whaling kills about 3000 per year (8 per day)

Collisions and Fishing Gear

Ship’s propeller cuts

The World Wide Fund for Nature claims that 90% of all Northern Right whales being killed are from ship collisions. Behind collisions with ships, getting tangled in discarded fishing gear is the next biggest problem. The U.S. Government enacted legislation in 2007 to protect the North Atlantic Right Whale from fishing gear. This species is endangered with only 350 remaining.

Propeller cuts in a Right Whale

Sunday, 15 September 2013

SONAR AND WHALE STRANDINGS

I was recently speaking with a group of students visiting from Mexico when one asked, "Why do whales beach themselves?" The answer isn't an easy one!

Sonar comes from the contraction of the phrase, ‘sound navigation and ranging’. In more technical terms active sonar is the use of sound sent out into the water and then reflected to determine the location of an object. Passive sonar makes use of listening for sounds and triangulating their source. The development of sonar was for military purposes but a co-researcher of mine uses passive sonar (does not emit sound) for location, counting, and identification of whales.

Does sonar cause whale strandings?

Two thousand years ago Aristotle wrote: “It is not known why they sometimes run aground on the seashore; for it is asserted that this happens rather frequently when the fancy takes them and without any apparent reason'.”

Clearly there have been reasons for whale strandings before the advent of military sonar. This does not prove that military sonar is not responsible for some of the strandings today.

When active sonar is used an intense burst of sound is released underwater. These sweep the ocean like a floodlight, revealing objects in their path as echoes return to the source.

French F70 frigates are fitted with VDS (Variable Depth Sonar) type DUBV43 or DUBV43C towed sonar

These bursts of sound can reach 240 decibels (billions of times more powerful than the level that causes hearing damage in humans). During testing off the California coast, noise from one of the Navy's low-frequency sonar systems was detected across the full width of the northern Pacific Ocean.

How Sonar Harms Whales

By the Navy's own estimates, even after 500 kilometres, these sound bursts can retain an intensity of 140 decibels -- a hundred times more intense than the level known to affect the behavior of large whales.

Many of these beached whales have suffered physical trauma, including bleeding around the brain, ears and other tissues.

A 1986 West Australian stranding of False Killer Whales

These injuries are similar those resulting from underwater explosions or barotraumas (injury from pressure). I have seen these injuries and provided forensic evidence in legal cases dealing with underwater explosives. They found that many more animals were affected, injured, or chased from the area. Scientists are concerned about the cumulative effect of these bursts of sound on marine animals.

“The Navy’s most widely used sonar systems operate in the mid-frequency range. Evidence of the danger caused by these systems surfaced dramatically in 2000, when whales of four different species stranded themselves on beaches in the Bahamas. Although the Navy initially denied responsibility, the government's investigation established that mid-frequency sonar caused the strandings.” according to the Natural Resources Defense Council. Similar mass strandings have occurred in the Canary Islands, Greece, Madeira, the U.S. Virgin Islands, Hawaii and other locations.

Can we build less dangerous sonar?

It is possible to build sonar systems that use frequencies or power levels that will not harm whales. The problem is that we are ethically unable to carry out research that would deliberately harm whales so we can measure the effects. We can not have controlled exposure experiments because at least 20% of the test animals would have to be stranded, injured, or die to meet statistical analysis requirements.

A Supreme Court decision in the U.S.A. (2000) stopped the U.S. Navy from testing powerful sonar systems in most of the world's oceans after a federal judge ruled that it could "irreparably harm" whales, dolphins and fish. This decision does not relate to other Navies.

The other issue has to do with military competition and security. Supporters of more powerful sonar will claim that we are putting whale safety ahead of national safety if we limit what only some countries can test.

Humpback whales are among the marine mammals effected by sonar.

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Friday, 23 August 2013

DOLPHIN INTELLIGENCE AND CAPTIVITY

Emory University neuroscientist Lori Marino spoke about dolphin intelligence at the American Association for the Advancement of Science conference (AAAS) in San Diego, on Feb. 21, 2010.

"Many modern dolphin brains are significantly larger than our own and second in mass to the human brain when corrected for body size," Marino says.

Some dolphin brains have features related with complex intelligence in other mammals including a large expanse of neocortical volume that is more convoluted than our own.

"Dolphins are sophisticated, self-aware, highly intelligent beings with individual personalities, autonomy and an inner life. They are vulnerable to tremendous suffering and psychological trauma," Marino says.

This raises lots of questions for the aquarium industry where dolphins are kept for entertainment and educational purposes.

"Our current knowledge of dolphin brain complexity and intelligence suggests that these practices are potentially psychologically harmful to dolphins and present a misinformed picture of their natural intellectual capacities," Marino says.

Marino worked on a 2001 study that showed that dolphins can recognize themselves in a mirror -- a finding that indicates self-awareness similar to that seen in higher primates and elephants.