Northern pike, underwater video

This video shows a northern pike.

Diver Harry Brummelhuis made it in a lake in Almelo in Overijssel province in the Netherlands.

Rare Nevadan Death Valley fish, how old?

This video from the USA says about itself:

29 July 2015

Devils Hole pupfish are the world rarest fish Jennifer Mutz reports for UNLV’s Studio G.

From the BBC:

Death Valley fish a ‘recent arrival’

By Jonathan Amos BBC Science Correspondent

4 hours ago

One of the most extraordinary fish species in world may not be as old as once thought.

The Devil’s Hole pupfish survive in 32-degree Celsius water in a rock shaft in Death Valley in the US.

Previous studies suggested they could have become separated as a distinct population more than 10,000 years ago.

But the latest genetic analysis points to the pupfish being resident in their unique habitat for perhaps only a few hundred years at most.

Christopher Martin and colleagues tell a Royal Society journal that the revelation raises interesting questions as to how the animals got into their present location.

There are other pupfish populations in Death Valley but for any of those to have colonised Devils Hole they would somehow have had to cross one of the driest, hottest deserts on Earth.

“My best guess is that they got in there during some extreme flooding event,” Dr Martin, a scientist from the University of North Carolina at Chapel Hill, told BBC News.

“The ages we’ve come up with for the Devils Hole fish do overlap with the great flood of 1862, which was the largest rainfall event ever recorded for California/Nevada.

“We also know that pupfish eggs are adhesive and will stick to vegetation, so it’s possible they came in stuck on birds’ legs.”

It is not beyond possibility that the fish were directly moved by Native Americans at some point.

The Devils Hole pupfish (Cyprinodon diabolis) were once dubbed the “rarest fish on the planet” because their numbers were so limited. As few as 35 individuals have been counted in the past.

They certainly live a precarious existence. Their rock pool is more than 100m deep, which means they must spawn on a narrow shelf near the surface.

Food takes the form of algae, but this is in short supply for two months of the year when sunlight does not fall on the water’s surface. A mass die-off is a regular occurrence.

The geological evidence suggests the rock pool opened to the surface about 60,000 years ago, and that large regions of Death Valley were under water some 10,000 years. This would have enabled pupfish populations in the region to move more freely.

Some of the first genetic analyses that tried to age the distinctiveness of Cyprinodon diabolis looked at mitochondrial DNA – genetic material held in the “energy factories” in cells. This DNA incorporates mutations at a regular rate through the generations, and can be used as a kind of clock. But the approach is notoriously sensitive to the calibration rules that are applied to the analysis.

Early mtDNA efforts suggested Cyprinodon diabolis might have been a separate species for 2-3 million years. But the geological indicators rule this out.

For their study, Dr Martin and his team deployed the very latest genomic techniques, analysing thousands of genetic markers and using demographic models that took into account the variation that exists within and across pupfish populations. Calibration was applied from what appeared to be more solid data based on pupfish diversity in Mexico.

The research estimates that Devils Hole was colonised between 105 and 830 years ago.

“They are special fish,” said Dr Martin. “The ecology of the Devils Hole is reflected by the very phenotypic distinctiveness of these pupfish. They have not only reduced aggression and a darker metallic colouration, but they have completely lost their pelvic fins. We don’t know whether the loss of this major appendage is due to the effects of severe inbreeding over time or if it’s adaptive in this habit.”

The study is published in Proceedings of the Royal Society B.

Beached sperm whales’ food investigated

This 13 January 2015 video is about sperm whales, stranded near beach pole 12 on Texel island in the Netherlands, being transported.

This week, six beached sperm whales died on Texel.

Scientists are investigating the contents of the stomachs and intestines of the dead whales.

They found many squid parts, and also proof that the whales had eaten anglerfish. One of the animals had swallowed a big longline fishing hook, but it apparently had not harmed him.

Shark nursery discovery off New York

This video from the USA says about itself:

27 June 2014

Another exciting Shark Academy introduces viewers to the Sand Tiger shark, an animal with a confusing name and the peculiar reproductive strategy known as “intrauterine cannibalism.”

From Blue York in the USA:

Shark Nursery Discovered Off New York

January 5, 2016

Turns out juvenile sand tiger sharks cut their (many) teeth in the New York area.

Scientists and veterinarians working for WCS‘s New York Aquarium have discovered a nursery ground for the fearsome-looking but non-aggressive fish in the near shore waters of Long Island’s Great South Bay.

“Sand tiger shark pups are not born here but migrate from down south to spend the summers as juveniles in New York’s coastal waters,” said Dr. Merry Camhi, Director of the NY Seascape program, WCS’s local marine conservation program.

The Great South Bay shark nursery provides juvenile sand tiger sharks ranging from several months to five years in age with a place to feed and grow. A nursery also gives juvenile sharks protection from predators, including other sharks.

After birth off the southeastern United States (sand tiger sharks give birth to live young as opposed to laying eggs), the juvenile sharks migrate north in the spring and spend the summer in New York waters before returning south in the fall.

Only a handful of sand tiger shark nursery grounds have been identified, one of which is in the waters of Massachusetts.

The discovery was made by researchers who have collected a wealth of information on sharks in local waters over the past four years through the use of acoustic tags, devices that enable scientists to remotely track marine animals as the animals move about.

There are still many unknowns about the nursery. Scientists are not sure how much of the bay is used by these sharks, the number of young sharks in the bay each summer, or what the sharks are eating.

New freshwater fish Red List in the Netherlands

This video from Britain says about itself:

European bitterling (Rhodeus amarus) Underwater UK

9 March 2015

Scattered in England and Wales, with key populations established in north-west and eastern England. Likely to have been introduced for ornamental reasons, its introduced range in GB is linked to the presence of Unionid mussels required for reproduction. The species is endangered in parts of its native range (water pollution, weed clearing, and stocking of predatory fish).


Translated from the Dutch RAVON ichthyologists:

13 January 2016 – As of January 1, 2016, the new Red List of Fish came into force. RAVON carried out the analysis for species living in fresh water. Of the more than 40 species that breed within the Dutch borders there are 19 in the new Red List. Almost as many as the previous Red List in 1997. It is hopeful that the degree of threat for some species has decreased.

How are the freshwater fish?

For the Dutch Red List, a comparison is made between the population size in the baselines of 1950 and the current situation. The first Freshwater Fish Red List was drawn up in 1997 (and revised in 2004). Compared to this list, there are five new species to the new Red List, two species (smelt and bleak) because they have declined; two species (river lamprey and sea lamprey) because it has turned out that they reproduce in the Netherlands; and one species (Cottus rhenanus) which has recently been established as a separate species. Two species (bitterlings and Leucaspius delineatus) are no longer on the Red List because they have increased and probably also because they seem far more widespread as a result of better identification than previously suspected.

Stickleback searches place for wintering, video

Jos van Zijl made this video in early January 2016 near Zevenaar in the Netherlands.

It shows a stickleback, looking for a place to winter.

Fifteen-spined sticklebacks: here.

Curaçao Caribbean marine life, video

Jesper Buursink made this video, 105 meter under the Caribbean sea surface, near Curaçao island. On the right, a Caribbean chicken-liver sponge. In the center, a moray eel and a red lionfish.