(Originally posted 1/11/17 on Read With The Gringa)
The gringa recently read a report published by researchers who discovered that the larvae of cardinalfish, a favorite community aquarium fish, use the Earth’s magnetic field to navigate in the wild. Considering that tiny little fish are not prone to use telescopes to navigate by the stars, this should really come as no surprise to these scientists.
Now, the gringa wants to know just how important this scientific discovery is. I mean, think about it. Consider how much money and time was invested. Will this knowledge do the world any darn good? Does it really matter, in the grand scheme of things, that these tiny little fish babies can find their way back home through a few miles of underwater coral reefs or brackish shallows? Will this somehow contribute to making the world a better place?
What’s the value of discovering that fish larva, about the size of my thumbnail, has a compass in its brain? Is it really a big deal to discover that fish possess a brain compass just like birds and whales? Did scientists in Australia think that it was well worth the dough to abduct a bunch of baby cardinalfish from their home, dump them in a tank and screw around with their internal magnetic compass with a device that altered the magnetic field around the tank?
So, scientists managed to get the little buggers all confused and yet they started orienting themselves just as expected. The tiny fish babies still managed to point their way homeward even though researchers tried to trick them. The gringa thinks maybe the baby fish are simply smarter than the scientists.
One genius scientist came to the conclusion that because of the study, the researchers now know that “these baby fish actually have brains.” Good grief. A cheap dis-section of a single critter could have told you that. Was that all the knowledge gleaned from this enormous expense and effort? No, they also found that they are strong swimmers who are so intent on getting home they will swim against extremely strong currents. But couldn’t that have been observed in their natural habitat and not require abduction and torture by tinkering with their tiny brains? Okay, enough already. Let’s get down to the nitty-gritty, scientific community. Does messing about with the brains of baby fish do the world any good?
Well, the scientists think that this will help them develop better techniques to preserve and protect coral reef fish habitats and the fish who live there. But HOW? Well, the gringa’s tracked down a few technologies related to magnetics that are saving threatened and endangered species:
Magnetic Signature Imprint: To repopulate waters that are bereft of fish that once thrived, many species are being raised in captivity and released as adults in the native environment of their wild ancestors. However, since they did not begin their life in a particular area, they have no reference point for “home”. Often, the adult life of fish is spent roaming open water. But in their brain is imprinted the place they call home. That’s where they return for breeding the next generation. Captive bred species need to know where to go to get busy and make families. Trying to re-introduce them to the wild is a big fail if they die without returning to the right natural habitat to reproduce.
Enter University of North Carolina biologist, Ken Lohmann and his dial-a-magnetic-field contraption. In theory, this device can re-program a biological compass with GPS precision so fish know where to go. Basically it mimics the biological imprint that occurs when a fish is born or hatched in their natural habitat. It’s kind of like when you order from Amazon, enter your delivery address and they slap a sticker with that code on your package. No matter where that package is in the world, it knows EXACTLY where it’s supposed to end up. Lohmann had a successful test with sea turtles and is ready to give it a go with several different threatened and endangered salmon species.
Magnetic Repellant Salvation: Over-fishing has impacted many species in terrible ways. Not only are food fish and sport fish decimated on purpose by irresponsible fishing, but, quite often, unintended fish victims lose their lives by being in the wrong place at the wrong time. But Eric Stroud has a solution. And, surprisingly enough, he believes the solution to over-fishing is all in the hook.
Sounds crazy. Seems if you want to solve an over-fishing problem a better hook would be the last thing on your list to spend time and money developing. However, it’s not a better hook that Stroud is talking about. It’s a smarter hook!
Rather than design a hook that attracts certain fish, he has developed a metal combination that repels certain species. It seems, through his experiments, that he discovered that sharks hate magnets. Magnets drive them crazy. What started out as a project to develop shark repellants to protect swimmers has turned into a project to protect threatened aquatic species. Now, instead of protecting people from sharks, he’s protecting sharks from people.
There are lots of shark species that are in serious trouble of over-fishing. Quite often sharks are caught by accident. I mean, the same type of hook that can snag a big tuna or enormous halibut will do for a shark. And when you toss a baited hook in the water, the shark doesn’t know he isn’t invited to the party. Besides, sharks aren’t stupid. You think you’re the only one in the ocean looking for a tasty tuna or hefty halibut? When a shark sees a baited hook in the water he’s smart enough to know an easy meal is on the way. Snag a tuna and you might just snag a shark that’s trying to burgle your catch.
Since most fish could care less about a magnetic hook, this gadget has seen quite a bit of success when tested. Several countries testing the hook with real fishing activities have seen a drop in accidental shark catches by as much as 70%. That’s impressive!
In the end, it looks like research of tiny fish brains is well worth the investment.
Image Credit: The Reef Tank