Dams and wildlife in the USA, films at Rotterdam festival

This trailer video from the USA says about itself:

This powerful film odyssey across America explores the sea change in our national attitude from pride in big dams as engineering wonders to the growing awareness that our own future is bound to the life and health of our rivers. Dam removal has moved beyond the fictional Monkey Wrench Gang to go mainstream.

Where obsolete dams come down, rivers bound back to life, giving salmon and other wild fish the right of return to primeval spawning grounds, after decades without access. DamNation’s majestic cinematography and unexpected discoveries move us through rivers and landscapes altered by dams, but also through a metamorphosis in values, from conquest of the natural world to knowing ourselves as part of nature.

This film is at the Wildlife Film Festival in Rotterdam, the Netherlands. Like this other film:

This trailer video says about itself:

‘Return of the River’ follows a group of people who attempt the impossible: to change the opinion of a town and eventually the nation to bring two dams down. The community comes to consensus, launching the largest dam removal in history, and showing the way to a more sustainable future. Infused with hope, the film explores an unlikely victory for environmental justice and restoration, unfolding on the Elwha River in Washington State.

Sharks, 450 million years ago till today

This 2014 video says about itself:

Wherein we take an adventure into the deep oceans of history in pursuit of fossilized sharks.

From the BBC:

The epic history of sharks

There are many strange sharks but their ancestors were even weirder and more wonderful than those swimming today

By Lucy Jones

3 October 2015

When you imagine a shark, you may think of a torpedo-shaped, streamlined creature with a prominent dorsal fin, a large mouth ringed by sharp, triangular teeth and a crescent-shaped tail. Jaws, basically.

Actually, the shark group of fish are widely varied. The Epaulette shark (Hemiscyllium ocellatum) can walk on land, the frilled shark (Chlamydoselachus anguineus) is flatter-bellied, adapted to hunt in the deep-sea, the tasselled wobbegong (Eurcrossorhinus dasypogon) is a carpet shark that resembles an old patterned rug and the goblin shark (Mitsukurina owstoni) is eel-like with a long dagger-shaped snout.

These are just a handful of over 500 species of shark that we know about today, each well-adapted to its particular environment.

Yet in the past, there were many more: fossil records suggest more than 3,000 types of shark and their relatives existed at one time. And some of the ancestors of modern sharks were even weirder and more wonderful than those swimming today.

Their long history starts in the late Silurian period, about 450 million years ago. It was a time when sea levels were high and coral reefs began to form. The Earth’s climate was warm and stable. Molluscs, crinoids and trilobites were some of the only living creatures on the Earth before scorpions and centipedes appeared on the land.

Around this time, sharks too appeared, evidenced by the oldest known shark scales found in Siberian deposits.

Jawed and bony fish began to diversify, including the evolution of a group of fish called acanthodians, or “spiny sharks”. These extinct fish looked like small sharks but had varying numbers of fins.

“It appears that sharks arose from within those,” says Charlie Underwood of Birkbeck University of London, UK. “Where they end and sharks begin is quite up for debate. Certainly we know that some of these acanthodians have teeth that formed in a very similar way to sharks. The teeth will grow on the inside of the mouth and move forward as they get bigger, in a sort of conveyor belt. Among these are the earliest sharks.”

Fast forward 50 million years to the Early Devonian, a warm and arid time on Earth when forests spread across the land, seed-bearing plants first appeared and the planet underwent great geological change.

This is when we have the first remains of shark teeth, from the Leonodus shark. These teeth are both small (4mm) and two-pronged, but they offer few clues as to what the Leonodus shark actually looked like. They are similar to the teeth of another shark called Xenacanthus that appeared millions of years later in the Late Devonian, leading to speculation that Leonodus, like Xenacanthus, lived in freshwater.

It may seem that teeth are not much to go by, but everything we think we know about shark evolution is from the teeth, says Lisa Whitenack of Allegheny College in Pennsylvania, US. From teeth, she says, we can learn about what environment the shark lived in, what they ate and how they are related to other sharks.

But we have to wait until 380 million years ago for the next clue to shark evolution. That comes from the braincase of Antarctilamna, a so-called lamnid shark from Antarctica. Its head, fin, spines and teeth suggest that it was eel-like.

There’s a reason the Devonian period is referred to as the ‘Age of Fishes‘. It was the time when they diversified greatly. A skeleton of the now extinct shark Cladoselache, shows just how much. It was very different from its eel-like ancestors. It was a 2m-long, torpedo-shaped shark with equal-sized dorsal fins, a short stout spine in the front, five fill slits and large eyes. It took its prey tail-first, indicating it could easily outswim its meals.

At this time, a school-bus sized group of fish called Dunkleosteus, also swam the seas. These were giant, heavily-armoured fish and may have competed for similar prey. This could have been just the trigger sharks needed to evolve further. Other armour-plated fish existed too, but it was early sharks that seemed to have something that allowed them to thrive, while these other giants died out.

Enter the golden age of sharks, 360 million years ago during the Carboniferous period. The largest predators of the sea at this time were the Chondrichthyans (cartilage fish). They had their skeletal jaws and tough scaly skin to thank for that. The enamel on their teeth was also frequently replaced.

This group included rays (close relatives of sharks), skates and a bizarre branch called the chimaeras, which featured species such as ratfish, ghost sharks and spook fish. It was within this last group, the chimaeras, that extremely weird and wonderful sharks appeared, says Underwood. “By the Carboniferous period, the majority of shark-like things are on the chimaeras branch, rather than the branch towards modern sharks.”

Prehistoric sharks certainly looked much stranger than the modern sharks we share the planet with today, even weirder than the Port Jackson, with its strange patterning and smoothed, numerous fins.

This video is called Port Jackson Sharks (Heterodontus portusjacksoni ), 4 young sharks chilling out on the sand, Sydney, Australia.

The Stethacanthus, for example, had an anvil-shaped dorsal fin on its back. “No one really knows what it used it for,” says Christopher Bird, of the National Oceanography Centre, Southampton, UK and Shark Devocean blog. It is one of many evolutionary mysteries in the shark world.

Another was the spiral-shaped tooth structure, called a tooth whorl, of the Helicoprion. These were dinner-plate sized and likely sat at the tip of the lower jaw. Some of these tooth spirals were 40cm across.

“As they grow and move into the mouth position, rather than falling out, the teeth just stay stuck to each other,” explains Underwood. “The shark doesn’t lose teeth as they move outside the mouth. So you end up with the bottom lower jaw having a big circular blade sticking out and behind that… crushing teeth. It’s a very strange arrangement.”

These bizarre traits aside, ancient sharks actually had the same basic features as the sharks we know today.

More innovation occurred at the start of the Jurassic period, 213 million years ago, when 12 new groups evolved. Sharks with flexible jaws started to appear. This meant they could feed on things that were bigger than themselves, says Bird. “They were able to exploit the newly emerging habitats as the world was changing.”

Their protruding jaws came to good use. They could eat, crunch or suck prey into their mouths. “Sharks in the Jurassic period often had teeth with a flat-ridged surface to make it easier to crunch on crunchy things,” says Whitenack.

As environments changed, sharks evolved different features. A tail fin allowed sharks to swim faster for long distances to pursue prey. Most sharks evolved a mouth under their snout, although a few species have mouths at the front of their snouts such as the frilled shark and angel shark.

Sharks were certainly tenacious. The creatures that thrived during this period survived right into the Cretaceous, often defined by its end. Sixty-five million years ago most of the dinosaurs were wiped out. Many other animals died too but sharks lived on.

And why wouldn’t they? They had already survived four other catastrophic mass extinctions. Their bodies were clearly well adapted to survive.

What’s more, they could exploit the fact that so many other creatures were wiped out. It was during these “recovery stages following historic mass extinctions” that the biggest number of new species appeared, says Bird.

Following the asteroid that wiped out the dinosaurs, for example, there was a second wave of deep-sea sharks. “The sharks are able to recolonise the water. We start seeing the cookie-cutter sharks and lantern sharks move in after this post-crisis event,” says Bird.

These also exploited new habitats following extinction events. They even managed to survive during times when the ocean lost its oxygen – including one such event in the Cretaceous period, when many other, larger, species died out. As a refuge, sharks moved deeper underwater, says Bird. And while there, they had another cunning trick. Some evolved the ability to glow in the dark.

The end of the Cretaceous gave sharks the opportunity to flourish. Not all survivors were successful though, including one giant of the sea, once thought to be a direct relative of the great white shark.

About 16 million years ago the Carcharodon megalodon first appeared. It could grow up to 16.8m and weighed 25 tonnes. Its mouth would gape open an impressive 2m, showing its 15cm-long teeth, perfect for eating everything else big in the ocean. It made the great white shark look like a goldfish in comparison.

We don’t know why the megalodon went extinct. One idea is that climate change disrupted the availability of prey. It was big, so needed to eat a lot. Any tiny change could therefore have threatened its survival. It’s likely that many factors combined to cause this giant to disappear two million years ago.

Other survivors from the Cretaceous lived on to become the sharks we know today. Hammerhead sharks for example, are among the most recent to appear in the fossil record and are assumed to be one of the last modern shark orders to evolve.

Their t-shaped heads increase lift as the sharks swim through the water, allowing them to make sharp turns. It also helps them sense more of their environment.

And we now have greater insight into how their strange-shaped heads evolved. Genetic techniques allow us to peer back in time at the evolution of modern-day sharks. In one such experiment in 2010, scientists looked at the DNA of eight species of hammerhead to build a genetic family tree going back thousands, possibly even millions, of generations.

Our study indicates the big hammerheads probably evolved into smaller hammerheads, and that smaller hammerheads evolved independently twice,” said Andrew Martin of the University of Colorado at Boulder, at the time of the study.

“As the sharks became smaller, they may have begun investing more energy into reproductive activities instead of growth.”

Recently, it has become clear that we may not even know how many sharks live in the ocean. An elusive shark called the megamouth (Megachasma pelagios), was only discovered several decades ago. In 1976 a US research vessel off the coast of the Hawaiian island of Oahu hauled up a shark nearly 5m in length, with a great fleshy mouth surrounding broad jaws.

ince then, 49 have been found all over the world. Usually they are dead when caught but one living specimen has given scientists some idea of its environment and habits. Its soft cartilage and flabby tissue suggests a slow-steady swimmer that filter-feeds on shrimp, sea jellies and small crustaceans.

But despite new species still being discovered, the very survival of sharks is under threat. Many are endangered and their biggest threat? Us. Climate change, pollution and habitat destruction are all factors affecting their numbers.

The main threat to their survival is overfishing. Humans kill many species in large quantities for meat and fins. Several are now on a list that seeks to protect endangered species from international trade (the CITES list), and includes open-water predators such as basking, whale and great white sharks, which are caught in vast quantities for meat.

Even deep-sea sharks are vulnerable. Despite the incredible features they have evolved to help them succeed, their reproduction rate is slow. That means if any are killed, the knock-on effect is huge.

Deep-sea shark species can’t recover, explains Bird. They don’t have the potential to reproduce offspring quicker than they’re being taken out. These sharks are often targeted for their liver oil. It contains a molecule called squalene, sought after by the cosmetics industry for its moisturising properties.

The International Union for Conservation of Nature (IUCN) now estimates that a quarter of sharks and rays are threatened with extinction. Although sharks have survived several mass extinctions, the rate at which their populations are being reduced by human activity is extreme and many species are not protected. In 2014, scientists said improved management of fisheries and trade is “urgently needed” to promote population recovery.

If their rate of decline continues, the future of sharks is uncertain. “We’re a new predator in the ocean,” says Bird. Sharks were once top predator but “we’re decimating their populations. One day, they may not be able to bounce back and recover.”

Seahorse in Oosterschelde estuary, video

This video shows a short-snouted seahorse in the Oosterschelde estuary in Zeeland province in the Netherlands.

Corné Bolders made this video.

Biggest weatherfish ever found in the Netherlands

This is a weatherfish video from the Netherlands.

Translated from the Dutch RAVON ichthyologists:

Wednesday, September 30th, 2015

How big is a weatherfish? A difficult question because this species is not easily found. Two years ago, a big weather loach of 29.5 centimeters was caught in the Netherlands, until recently the largest recorded specimen. That record has now been surpassed by more than one centimeter ….

On August 27, some waters were inventoried around Tiel during a fish course by RAVON at Waterschap Rivierenland. After the Waal and Linge had been visited 21 species of fish had surfaced. An ambitious challenge yet was the rare and protected weather loach, a species of highly vegetated waters with thick mud bottoms. The last location, a ditch close to Zoelen, offered just such circumstances. Initially there was despair among the students when they saw the completely overgrown ditch where water was barely seen. “Do we have to fish in this muddy ditch?”

Not much later there was suddenly a ‘big’ loach in one of the nets, success! Closer inspection showed the captive female was very large and very heavy. After exact measurement it turned out to be 30.7 centimeter in length. In the international literature, 30 centimeters is reported as the maximum for the weather loach. The only recorded instance that came close to that length was in 2013 at Zevenaar, caught by Arthur de Bruin, a female of 29.5 centimeters. To our knowledge, the individual in Zoelen is now the largest recorded specimen worldwide.

Fish atlas for northwestern Europe published

Fish Atlas of the Celtic Sea, North Sea and Baltic Sea

From Wageningen university in the Netherlands:

Fish Atlas of the Northwest European seas reveals life and distribution of fish

September 15, 2015

The Fish Atlas is an in-depth reference work on marine fish. This is the first complete overview of all marine fish species found in the North Sea, Baltic Sea, and Celtic Sea. Whereas European research mainly focuses on species of commercial interest, this atlas documents current data of all Western European fish species caught in the period 1977 to 2013.

The Fish Atlas of the Celtic Sea, North Sea and Baltic Sea presents a unique set of abundance data to describe the spatial, depth, size, and temporal distribution of demersal and pelagic fish species over an extensive marine area, together with accounts of their biology. A large number of pictures, graphs and distribution maps illustrate the text. By largely avoiding – or at least explaining – scientific terms and providing extensive references, the book should be useful for both laymen and scientists.

The quantitative information on some 200 fish taxa is derived from 72,000 stations fished by research vessels during the period 1977-2013. The area covers the northwest European shelf from the west of Ireland to the central Baltic Sea and from Brittany to the Shetlands.

Although the surveys extend beyond the shelf edge, only taxa reported at least once in waters less than 200 m are included. Typical deep-water species and typical fresh-water species are excluded. We hope this publication will contribute to gaining a better understanding of the ocean ecosystems.

The Fish Atlas of the Celtic Sea, North Sea, and Baltic Sea contains:

  • description of general goals of research-vessel surveys;
  • brief account of the oceanographic features of the three ecoregions;
  • overview of the surveys included in the analysis;
  • details on the process and interpretation of the extensive data;
  • variation of species composition by area and in time;
  • information on 201 taxa, grouped in 78 families;
  • contributions of 31 authors, affiliated with ICES surveys;
  • full-colour pictures, clear distribution maps and graphs;
  • 48 text boxes to describe additional details of general interest.

New Dutch wildlife film, review

The makers of Dutch wildlife film De Nieuwe Wildernis have made a new film, about wildlife in the south-west of the Netherlands: Holland – Natuur in de Delta. This video is the trailer. Like all the other videos in this blog post, it is by the makers of the film.

The film shows nature in the Scheldt and Rhine rivers delta. In the past 2,000 years, humans have made many changes in this region: to prevent floods, for agriculture, etc. Some of these changes have harmed wildlife. Now, the film says, some Dutch are restoring some of this damage; allowing species like beaver and sea eagle, which had been away for a long time, to return.

The new film started in the cinemas on 24 September 2015. I was at the premiere.

The first image of the film is two lines of poetry by Hendrik Marsman, on the rivers in the Netherlands.

Actress Carice van Houten and actor Bram van der Vlugt do the vocal explanation to the wildlife footage.

This is a 27 November 2014 video interview, in English, with cameraman Paul Edwards.

For the film Holland, natuur in de Delta, Paul Edwards was in the Biesbosch national park for months; filming a white-tailed eagle nest and great crested grebes.

This video, in English, is called Making of – Holland, Natuur in de Delta – Beaver scouting.

This video is about beavers as well.

So this this video.

And this video.

This video, in English, is called Making of – Holland, Natuur in de Delta – [white-tailed] Eagle Hunting.

This video is about a white-tailed eagle nest.

The film has five main characters: the sea eagle; the beaver; the hare; the scarce large blue butterfly; and the three-spined stickleback.

In the parts about sticklebacks in the film, it gets clear how human measures against flooding have made problems for wildlife. Sticklebacks are born in fresh water, but as they get older, they migrate to the sea. When the adult sticklebacks want to spawn, they have to make the long journey again, now in the reverse direction: from sea to rivers to small ditches and pools again.

Some of the stickleback footage in the film was recorded near Texel island, On their journey they meet marine life, like jellyfish and seaweed pipefishes. Then, the small fish have to pass anti-flooding locks with strong currents, to which they did not get used in their millions of years of evolution. Some sticklebacks do not manage to pass the lock. The others who do manage meet other fish, like zander, and, in small streams, brook lamprey. Finally, they arrive at places where the males can make nests for spawning.

This is a hare video.

And this video is about young hares.

And yet another hare video.

One of the supporting actors in the film is the white stork. This is a white stork video.

The grass snake, the subject of this video, is another supporting actor.

So is the great crested grebe, of this video.

And crayfish.

Another animal featuring in the film is the northern pike. This is a video about it. In one movie scene, young pikes learn that they cannot eat sticklebacks because of the spines.

The film shows the metamorphosis of the scarce large blue butterfly; never before recorded on film. Scarce large blue butterflies are very dependent on other life forms. The caterpillars are dependent, first on great burnet plants.

Great burnet, 9 June 2014

Afer great burnet, the caterpillars depend on Myrmica scabrinodis ants, when the caterpillars live as parasites, feeding on ant larvae, in the anthills. Usually in June, the caterpillars become pupae, close to the anthill exit.

Then, in July, the adult butterflies will want to break free from the pupae. They do that early in the morning, before the ants get up. As a caterpillar and a pupa, the scarce large blue smelled like an ant larva; so the usually aggressive ants did not attack it. Adult butterflies do not have that protection. So, they must fly away before the ants become active; as a butterfly does towards the end of the film.

These butterflies are also, indirectly, dependent on springtails: these are the main food of their ant hosts. This is not shown in the film in order to not make it too complex.

Scarce large blue butterfly life cycle

One of the final sentences of the film says that, like scarce large blue butterflies and other wildlife, humans are also dependent on other life forms, and should be aware of that.

Also about this film: here. And here.

Common smoothhound shark on Texel island beach

This video from Jersey says about itself:

Common smooth hound (Mustelus mustelus)

19 July 2015

Chantelle Marie De Gruchy very kindly sent in this video of a Smooth Hound that she saw whilst diving St. Catherine’s breakwater.

The smooth hound is a species of shark found throughout the British Isles which can reach 4 foot in size! They typically eat small crustaceans and molluscs but occasionally take small fish.

Chantelle is currently studying for her master’s degree in Marine Environmental Management at the University of York.

Translated from Ecomare museum on Texel island in the Netherlands today:

Shark on the beach – 22-09-2015

A special find on the beach of De Cocksdorp on Texel. There was a common smoothhound on the sand. The female had been dead for a while when she washed up. The eyes were out and there was a really fishy smell. Yet Ecomare has kept the animal; it is not every day that a shark washes up on a Dutch beach. In recent years, there seem to be again more sharks in the Wadden Sea.


The last thirty years the number of common smoothhound sharks along the Dutch coast has increased. Other shark species at the same time have gone down. This shark species can get quite large, up to 1.65 meters. The shark near De Cocksdorp was 80 centimeters. Smoothhound sharks have flat molars and are harmless to people. They live close to the coast. Usually they swim close to the sea floor where they look for crabs, shellfish and fish. They occur in the Northeast Atlantic Ocean and thus the North Sea and Wadden Sea. Along the Dutch coast they are rare.

Sharks in the Netherlands

In the North Sea you can find several species of sharks. The small-spotted catshark is the most common. Besides common smoothhound sharks also school sharks live there. Spiny dogfish is seen in some years as well. You can even encounter basking sharks, nursehounds, porbeagle sharks and Atlantic thresher sharks in the North Sea, but these are super rare.