Lateral Line: A "Sixth Sense" for Fish |  Evolution News

Lateral Line: A “Sixth Sense” for Fish | Evolution News

Photo credit: Pogrebnoj-Alexandroff, CC BY-SA 3.0 via Wikimedia Commons.

Have you ever heard of “lateral line”? No, it’s not a football game. It is a sensory organ that is shared by most fish, from sharks to salmon to goldfish.

From gills to tail

The sideline has been called a “sixth sense” for fish. It goes from gills to tail along the sides of the fish, right in the middle. You can see it when you catch a trout. Or in the case of a goldfish, it is visible in the picture above. One page from University of Minnesota Sea Grant describes this amazing body:

Sometimes called “the feeling of distant touch”, sidelines convert subtle changes in water pressure into electrical pulses is similar to how our inner ear responds to sound waves. Runs lengthwise down each side of the body and over the head, these pressure sensing organs help their owners avoid collisions, participate in schooling behavior, orientate towards water currents, escape predators and detect prey.

Lateral lines are composed of neuromasters (hair cells surrounded by a protruding jelly-like cup) which is usually located at the bottom of a visible pit or notch. These hair cells – the same sensory cells found in all vertebrate animals’ ears – convert mechanical energy into electrical energy when it is moved. Presumably, auditory and lateral pathways have been developed in close proximity because they share many characteristics. [Emphasis added.]

You can pull off that fish story about how it evolved. What is remarkable is that this device constitutes an analog-to-digital converter, since pressure waves (analog) are converted into electrical signals. Actually, we all have that ability in our skin, which Science reports – a fact that has inspired Stanford’s engineers to create “electronic skin”:

Human skin is dependent on cutaneous receptors such as out digital signals for tactile sensingin which the intensity of the stimulation is converted into a series of voltage pulses. We present a powerfuleffective skin-inspired mechanoreceptor with a flexible organic transistor circuit that converts pressure into digital frequency signals directly.

Back to the fish and the sideline. News from the University of Florida showed two researchers using lasers to try to understand how the sideline works. One of them, Dr. James Liao, calls it a “hydrodynamic antenna“which is” configured to receive flow signals, “according to Physical review letters. A chart at Wikipedia shows how many components are involved in this complex sensory device.

Swim muscles

Another little known fact about fish is how their muscles are arranged. Have you ever cooked salmon and wondered about those streaks in the muscle? They are called myomers. See the good diagrams and pictures Earthlife.net, who points out that “Gram for gram of fish has more muscle than any other vertebrate, a salmon or tuna can be almost 70 percent muscle, which is one reason why fish is so good to eat.” In cross section, the myomers (also called myotomes) have a 3-dimensional “W” shape, and they fit together like puzzle pieces (see a illustration from Moorpark College). This arrangement allows contraction waves to propagate on one side and then on the other, causing the familiar swimming movement back and forth (explained at. MarineBiology.org). It works pretty well because tuna can swim up to 50 miles per hour!

Fisknyheter

Speaking of muscles, it Australian Research Council asks: “Are fish the greatest athletes on the planet?” This article is willing to put a salmon against the sprinter Usain Bolt. Here’s why:

It shows that Fish are much more efficient at delivering oxygen over the whole body than almost any other animal, giving them an athletic advantage over other species.

“Fish use a mechanism, ie up to 50 times more efficient at releasing oxygen to their tissues than that found in humans, ”said the study’s lead author, Dr. Jodie Rummer of the ARC Center of Excellence for Coral Reef Studies at James Cook University.

“This is because their hemoglobinthe protein in the blood that carries oxygen, is more sensitive to changes in pH than ours and more than the hemoglobins in other animals. “

It’s hard to top it. But here’s another fishing trick to make people jealous: they can get their teeth back. Researcher at Georgia Tech have studied fish in Lake Malawi to learn how to do it in the hope that people will one day learn how to grow real teeth instead of getting false teeth. The right type of signal can “coax the epithelium to form one type of structure or the other.”

How about the fish that can stun a horse with electricity? A piece of paper in Ncommunication reported that electric eels do not just use their powers to stun prey by causing their muscles to go into uncontrollable spasms; they also have the ability to locate the prey with their electric mind.

Electric eels (Electrophorus electricus) are legendary for their ability to disable fish, humans and horses with hundreds of volts of electricity. The function of this output as a arms has been of course for centuries but it is potential role for electroreception has been overlooked. Here it is shown that electric eels use high voltage at the same time as a weapon and for accurate and fast electrolocation of rapidly moving switches and conductors. Their speed, accuracy and high frequency pulse are reminiscent of bats use a “terminal feed buzz” to detect insects.

The author, Kenneth C. Catania of Vanderbilt, points out that electric eels are “much more sophisticated than previously described.“The summary of this essay on PhysOrg explains that the double processing allows the eel to find its prey after stunning it in the murky Amazon waters where it lives. Videos in this article allow you to see the eel react in real time and in slow motion in Catania’s lab lineup. It’s good that he slowed it down, otherwise you might miss how fast the eel responds if you blink.

Conservation

Let’s finish with news on conservation. The bad news is that Coho salmon are poisoned by runoff in cities. The good news from NOAA fishing in Seattle is that they have found a simple filtration system that can eliminate the toxins and save the fish. A three-foot filter with sand, gravel, compost and bark is very effective for cleaning the water. “It is remarkable that we were able to take runoff that killed all the adult Coho in less than 24 hours – sometimes less than four hours – and make it non-toxic, even after putting several storms worth of water through the same soil mixture.”

The Pacific Ocean Aquarium in Long Beach, California, has an exhibition illustrating the situation of Steelhead, large salmonids related to the rainbow. Pollution, drought and physical barriers such as ponds and concrete canals have drastically reduced the number of these fish, which, like northern salmon, swim from the sea up freshwater rivers to spawn. The exhibition raises awareness that in humans’ efforts to improve their own lives with ponds and storm channels, they can cause devastating effects on fish and other animals.

Sockeye salmon from Fraser River, among the heroes of the Illustra documentary Living waternot doing as well as predicted, according to Seattle Times (see details in Washington Department of Fish and Wildlife report). It is only relatively recently that people have made an effort to help the fish get around our ponds with fishing ladders. One of the most innovative technologies, Live Science reports, is the new Fish Cannon from Whooshh Innovations. It can launch a large salmon over a 100 ′ pond through a flexible tube. Do you need some inspiration? See comedian John Oliver describe it Youtube and use it for other practical uses:

This article was originally published in 2015.


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