How mandarin fish feed, new research


This June 2019 video says about itself:

Quick facts about one of the most vibrantly colored tropical reef fish! The mandarinfish (mandarin dragonet, Synchiropus splendidus, blue (green) mandarinfish).

Synchiropus splendidus is a Pacific ocean species.

However, there are unrelated other fish, also called mandarinfish: Asian freshwater species.

This aquarium video shows feeding of Hydrolycus armatus, Chinese perch (Siniperca chuatsi), and Polypterus endlicheri.

Siniperca chuatsi is also called mandarinfish.

From the Forschungsverbund Berlin in Germany:

Born to be a cannibal: Genes for feeding behavior in mandarin fish identified

July 9, 2020

Some mandarin fish species (Sinipercidae) are pure fish-eaters, which feed exclusively on living juvenile fish — also of their own species. A research team led by the Chinese Huazhong Agricultural University (HZAU) and the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) has described the genome of four mandarin fish species and thus also identified genes for cannibalistic eating behaviour. Knowledge of the connections between the genome and feeding behaviour is of interest for sustainable aquaculture.

Most fish larvae feed on easily digestible, small zooplankton. Not so some species of mandarin fish. These are pure “fish-eaters” already after hatching and feed on young fish of other fish species and on conspecifics. This cannibalism leads to a high mortality rate of juvenile fish and to economic losses in aquaculture.

32 genes make the difference to cannibals

The researchers compared the genome sequences of different species of mandarin fish and were thus able to trace the evolution of 20,000 genes over a period of 65 million years. They were able to link many genes with species-specific characteristics. “For 32 of these evolving genes, we were able to experimentally demonstrate different gene expression in mandarin fish species that are common to other food and in pure fish-eating species,” explains Ling Li, one of the first authors of the study and guest scientist from HZAU at the IGB.

Rapid evolutionary adaptation in predatory behaviour

Mandarin fish are aggressive predators. During the complex genome analysis, the researchers identified so-called candidate genes that are associated with particularly high aggression and affect behaviour. “Our genome analyses show the evolutionary development of mandarin fish. They have adapted rapidly to changing environmental conditions, especially with regard to their feeding behaviour. Today, some mandarin fish species are more aggressive predators than others due to their genetic predisposition,” says Prof. Xu-Fang Liang from HZAU.

“Research on the relationship between the genetic code and feeding behaviour is an important basis for the sustainable aquaculture of these fish. In future, fish farmers will be able to use marker-based selection to choose fish for breeding where the genome indicates less predatory behavior — and thus reduce losses,” summarises Dr. Heiner Kuhl, leading bioinformatician of the project from the IGB.

High-throughput genome research at IGB

The reference genome for Siniperca chuatsi is one of the highest quality fish genomes to date. It was analysed using third-generation sequencing techniques and has very high sequence continuity and almost complete reconstruction of the 24 chromosomes. The high-quality reference genome enabled the cost-efficient sequencing of three other species from the Sinipercidae family by means of comparative genomics. This approach to create genome sequences for entire taxonomic families of organisms could serve as a blueprint for large-scale genomic projects.

Where camels store their water


This 30 June 2020 video says about itself:

Where Do Camels Store Their Water?

When camels drink, they do so at a rate that would kill most other animals. But where does all of that water go? Hint: It’s not their humps!

Hosted by: Michael Aranda.

Nurseryfish video


This 20 June 2020 video says about itself:

Nurseryfish Dads Give Their Young a Headstart… Literally

Happy Father’s day! Today we’re talking about the fintastic Nurseryfish, which is one of the best dads you can fish for.

Thanks to Dr. Tim Berra for teaching us more about these amazing fish as well as providing such awesome pictures!

Hosted by: Hank Green

These fish live in Asia and Australia.

How betta fish fight, new research


This 2016 video says about itself:

The Complete Betta Fish Life Cycle in 3 Minutes

Love is beautiful. Betta fish love is uniquely beautiful. Watch their life evolve from courtship, eggs, fry to adulthood in this glittering video.

From PLOS:

Fighting fish synchronize their combat moves and their gene expression

Betta fish opponents undergo similar brain changes that become more synchronized after longer fights

June 17, 2020

When two betta fish are fighting for dominance, not only do their attacks mirror each other, but the gene expression in their brain cells also starts to align. The new findings, published June 17th in PLOS Genetics by Norihiro Okada of Kitasato University, Japan, may explain how the fish synchronize their fighting behavior.

The fighting fish Betta splendens is famous for its aggression, but opponents typically stop fighting after assessing the other’s abilities to avoid any serious injuries. The small freshwater fish is commonly used to study aggression in the lab, and it employs a handful of standard tactics like mouth-locking, bites, strikes and swimming to the surface to gulp air. In the new study, researchers observed that during a fight, two male opponents modify their actions to match the aggressive behavior of the other, leading to tightly synchronized battles.

Furthermore, when the researchers analyzed the brains of both opponents, they observed that the fish also synchronized which genes were turned on or off in brain cells. The fighting pair had similar changes in gene activity related to learning, memory, synapse function and ion transport across cell membranes. The synchronization was specific to a fighting pair and became stronger after fighting for an hour compared to a 20-minute fight, suggesting that the degree of synchronization was driven by fighting interactions.

The new study takes a neurogenomic approach to the old question of how animals synchronize their behavior. Similar mirrored behaviors also occur during mating, foraging and cooperative hunting, and these behaviors may also trigger synchronized brain changes in the pairs of animals. “One of my future plans is to elucidate what happens in the male-female interaction of fish on the molecular level,” said author Norihiro Okada.

The findings suggest that even though the betta fish are fighting each other, sometimes to the death, their brains may be cooperating at the molecular level.

Giant jellyfish’s dangerous stings


This 2009 video is called Nemopilema nomurai.

From the American Chemical Society in the USA:

What makes a giant jellyfish’s sting deadly?

June 10, 2020

With summer on the way, and some beaches reopening after COVID-19 shutdowns, people will be taking to the ocean to cool off on a hot day. But those unlucky enough to encounter the giant jellyfish Nemopilema nomurai (also known as Nomura’s jellyfish) might wish they had stayed on shore. Now, researchers reporting in ACS’ Journal of Proteome Research have identified the key toxins that make the creature’s venom deadly to some swimmers.

Found in coastal waters of China, Korea and Japan, Nomura’s jellyfish can grow up to 6.6 feet in diameter and weigh up to 440 pounds. This behemoth stings hundreds of thousands of people per year, causing severe pain, redness, swelling, and in some cases, even shock or death. The jellyfish’s venom is a complex brew of numerous toxins, some of which resemble poisons found in other organisms, such as snakes, spiders, bees and bacteria. Rongfeng Li, Pengcheng Li and colleagues wanted to determine which of the many toxins in the jellyfish’s venom actually cause death. The answer could help scientists develop drugs to counteract jellyfish stings.

The researchers captured N. nomurai jellyfish off the coast of Dalian, China, and collected their tentacles, which contain the venom. They extracted venom proteins and separated them into different fractions using chromatography. By injecting each protein fraction into mice, the team identified one that killed the animals. Autopsies revealed damage to the mice’s heart, lungs, liver and kidneys. The researchers used mass spectrometry to identify 13 toxin-like proteins in this lethal fraction. Some of the jellyfish proteins were similar to harmful enzymes and proteins found in poisonous snakes, spiders and bees. Instead of any one toxin being lethal, it’s likely that multiple poisons work in concert to cause death, the researchers say.

Sambar deer in Asia, video


This 2 June 2020 video says about itself:

This week on Candid Animal Cam, we’re talking about the sambar deer, a species of deer found in the Indian subcontinent, South China, and Southeast Asia.

Did you know that male adult sambar deer and pregnant or lactating females have a hairless red spot located mid-way down their throats that sometimes oozes a white liquid? Biologists suggest the sore spot may be linked with glandular activity.

And shout out to our writer and biologist Romi Castagnino, who hosted, produced and shot this video!

All living hyena species, video


This 31 May 2020 video says about itself:

All (Extant) Hyena Species

Hyenas or hyaenas are any feliform carnivoran mammals of the family Hyaenidae.

With only four extant species, it is the fifth-smallest biological family in the Carnivora, and one of the smallest in the class Mammalia.

1- Spotted Hyena
(Crocuta crocuta)
It is also known as the laughing hyena. It is the largest hyena (extant) species.

2- Striped Hyena
(Hyaena hyaena)
It is the smallest of the ‘’true’’ hyenas.

3- Brown Hyena
(Hyaena brunnea)
It is currently the rarest species of hyena.

4- Aardwolf
(Proteles cristata)
It is also called “Maanhaar jackal” or Civet Hyena, based on its habit of secreting substances from its anal gland, a characteristic shared with the civet.

Music: Night Driver (YouTube Audio Library)

How young great tits grow up, video


This 10 April 2020 video says about itself:

Nesting To Learning To Fly Of Great Tit Chicks (Breeding Process)

The great tit (Parus major) is a passerine bird in the tit family Paridae. It is a widespread and common species throughout Europe, the Middle East, Central and east across the Palearctic to the Amur River, south to parts of North Africa where it is generally resident in any sort of woodland; most great tits do not migrate except in extremely harsh winters.

Until 2005 this species was lumped with numerous other subspecies. DNA studies have shown these other subspecies to be distinctive from the great tit and these have now been separated as two distinct species, the cinereous tit of southern Asia, and the Japanese tit of East Asia. The great tit remains the most widespread species in the genus Parus.