Clownfish on video


This video says about itself:

18 November 2016

Thanks to the Disney/Pixar movie Finding Nemo, virtually everyone has heard of the clownfish. Jonathan travels the Pacific to investigate the behavior of real clownfish. Even though they don’t actually talk in real life, they are beautiful and fascinating fish to observe.

JONATHAN BIRD‘S BLUE WORLD is an Emmy Award-winning underwater science/adventure program that airs on public television in the United States.

Gull, crow eat trout


This 29 November 2016 video shows a lesser black-backed gull and a carrion crow, feeding on a dead trout on the bank of the Oostvoornse Meer lake in the Netherlands.

What people ate when North Sea was land


Doggerland people, reconstruction

Translated from Historiek.net in the Netherlands:

Archaeologists discover menu of the hunter-gatherers of ‘Doggerland

Editors – November 1, 2016, 15:51

Some 8000 years ago mainly freshwater fish was on the menu of the hunter-gatherers of Doggerland “the drowned landscape between the Netherlands, England and Denmark. This conclude Dutch archaeologists based on isotopic analysis of prehistoric human skeletal remains from the North Sea.

The discovery gives clues about the occupation of this vast landscape drowned in the middle Stone Age (Mesolithic) and the effects of climate change on earlier societies.

Preferring fish

The isotopic study was conducted by the University of Groningen, the National Museum of Antiquities, Stone Foundation and the National Cultural Heritage Authority. It shows that for the Doggerland residents in a period of 4000 years the menu, between 9500 and 6000 BC., gradually changed from mostly meat to mostly fish. Especially freshwater fish was eaten a lot, as well as small animals such as otter, beaver and waterfowl.

The study is based on measurements of stable isotopes. These are variations of atoms having a certain value. The value of some isotopes, such as nitrogen and carbon, changes according to the position in the food chain. A real meat-eater has a different isotopic signature than someone who eats seafood or someone in a fresh water wetland.

The detected change in the composition of the Doggerland menu is associated with the drowning landscape between the Netherlands, England and Denmark, after the last ice age. Between 9500 and 6000 BC. the climate warmed and sea levels rose on average about two meters per century. That is about ten times faster than today.

The low-lying North Sea basin was filled with water. Previously it was thought that this drowning of land and the rising waters forced residents further inland, or forced them to specialize in a marine diet. The isotopic measurements showed that they were eating more fresh water fish. This suggests, according to the researchers, that the people were not scared away, but rather continued to live in the vast wetlands which then arose in the deltas of Meuse, Rhine and Thames. Precisely because it was a nice place and one could find enough food.

Treasury of our coast

The bone material which is used for the isotope analysis is taken from the North Sea. Since the last few years there have been many prehistoric findings there. The material is not only retrieved with fishing nets but is mainly found in the reclaimed sand for coastal defenses and major projects such as the Second Maasvlakte and the Zandmotor. This sand comes from the North Sea floor and contains the remains of a vast and largely unexplored prehistoric landscape. Although research on the spot is awkward, the results show that there is a wealth of data.

Shark senses research


This video says about itself:

7 October 2016

In the Bahamas, Jonathan joins shark biologist Dr. Stephen Kajiura from Florida Atlantic University to perform an experiment which demonstrates how the electrosensory system of sharks works.

JONATHAN BIRD‘S BLUE WORLD is an Emmy Award-winning underwater science/adventure program that airs on public television in the United States.

Ancient placoderm fish, new discovery


A 423-million-year-old armored fish from China had jaws that resemble those of modern land vertebrates and bony fish. Picture by Dinghua Yang

From Science News:

Ancient armored fish revises early history of jaws

Placoderm fossil had skull bones like those of many modern vertebrates

By Meghan Rosen

2:00pm, October 20, 2016

A freaky fish with a head like a dolphin and a body like a tank may be to thank for human jaws.

The discovery of a 423-million-year-old armored fish from China suggests that the jaws of all modern land vertebrates and bony fish originated in a bizarre group of animals called placoderms, researchers report in the Oct. 21 Science.

Along with a different placoderm fossil from 2013, the new find, named Qilinyu rostrata, is helping rewrite the story of early vertebrate evolution, says paleontologist John Maisey of the American Museum of Natural History in New York City, who was not involved with the work.

“We’ve suddenly realized we had it all wrong,” he says.

The jaws of humans — and dogs, salmon, lizards and all other bony vertebrates — contain three key bones: the maxilla and premaxilla of the upper jaw, and the dentary of the lower jaw.

“Anything from a human being to a cod has recognizably the same set of bones in the head,” says study coauthor Per Ahlberg, a paleontologist at Uppsala University in Sweden. The big question, he says, is “Where did these bony jaws come from?”

More than a hundred million years before dinosaurs walked the Earth, fishes called placoderms thrived under water. Scientists knew that these armored fishes were early jawed animals, but their jaws were unusual:  “They look like sheet metal cutters,” Ahlberg says. “They’re these horrible bony blades that slice together.”

The blades, called gnathal plates, looked so peculiar that most scientists thought that the three-part jaw of humans originated in an early bony fish and that placoderms were just a funny little side branch in the vertebrate family tree. “The established view is that placoderms had evolved independently and that our jaw bones must have a separate origin,” Ahlberg says.

Placoderms are a highly debated group of animals, says paleontologist Martin Brazeau of Imperial College London. No one quite knew where to place them.

In 2013, Ahlberg and colleagues found a new clue in a 419-million-year old fossil that had the body of a placoderm, but the three-part jaw of a bony fish. Such an animal, called Entelognathus primordialis, “could never have been predicted from the fossil record,” says paleontologist Gavin Young of Australian National University in Canberra.

That work bolstered the idea that placoderms weren’t, in fact, their own odd group that dead-ended hundreds of millions of years ago — some were actually the ancestors of bony fish (and thus humans). But it was just one fossil, Ahlberg notes. “You don’t want to draw too big of conclusions from one animal.”

Two animals, though, is a different story. Qilinyu, the new fossil Ahlberg and colleagues describe, had an armored skull and trunk and was probably about the length of a box of tissues. Like Entelognathus, Qilinyu has a three-part, bony fish–like jaw, though the creature looks a bit more like a typical placoderm, Ahlberg says. The two fossils “form almost perfect intermediates” between placoderms and bony fishes, he says. Ahlberg and his colleagues suspect the key jaw elements of bony fish (and all land vertebrates) evolved from those bony blades of placoderms.

“This is part of our own early evolutionary history,” Ahlberg says. “It shows where our own jaws came from.”

Maisey puts it another way: “We are all fundamentally placoderms.”

See also here.

Great white shark invades cage, doesn’t harm diver inside


This video from Mexico says about itself:

Great White Shark Cage Breach Accident

13 October 2016

**This may not be appropriate for our younger viewers.**

This is not our usual kids content and Gabe and Garrett did not go on this trip, this video is from my trip to Guadalupe Island (I’m their dad).

On a recent great white shark cage diving trip we experienced a very rare event, a shark breaching the side of the cage. What might appear to be an aggressive great white shark trying to attack the cage, this is not the case. These awesome sharks are biting at large chunks of tuna tied to a rope. When a great white shark lunges and bites something, it is temporarily blinded. They also cannot swim backwards.

So this shark lunged at the bait, accidentally hit the side of the cage, was most likely confused and not able to swim backwards, it thrust forward and broke the metal rail of the cage.

There was a single diver inside the cage. He ended up outside the bottom of the cage, looking down on two great white sharks. The diver is a very experienced dive instructor, remained calm, and when the shark thrashed back outside the cage, the diver calmly swam back up and climbed out completely uninjured.

The boat crew did an outstanding job, lifting the top of the cage, analyzing the frenzied situation, and the shark was out after a few long seconds. Everyone on the boat returned to the cages the next day, realizing this was a very rare event. The boat owner, captain, and crew are to be commended for making what could’ve been a tragic event into a happy ending. I’m sure God and luck had a bit to do with it too!

I want to return next year for another great white shark adventure!