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With more than 30,000 different types of fish, the ocean is filled with a colorful display of incredible sea creatures. Fish are vertebrates, and while they were initially thought to be unintelligent due to their small brain size, scientists now recognize them as living things. Able to socialize and communicate with other fish, these sea creatures are even older than the dinosaur wax. So just how old is the world’s oldest fish? We will discover the oldest fish in the world and see how they compare to other aquatic animals.
When did fish first appear on Earth?
Fish are vertebrates, an animal with a backbone that has adapted to life under water. Today there are more species of fish on Earth than all mammals, birds, reptiles and amphibians combined. Fish have been around for more than 450 million years, making them essential to Earth’s aquatic ecosystems. Compare that to the lifespan of mammals that have only been on Earth for about 200 million years.
Fish are classified into three groups: super class Agnatha (jawless fish), class Chondrichthyes (cartilage fish) and super class Osteichthyes (bony fish). Despite their differences, all fish share specific characteristics that set them apart from all other life.
These include having a backbone, using gills to breathe in oxygen, having scales to protect their bodies, fins for swimming, and being cold-blooded.
There are exceptions to these definitions of fish, however, including the opah, a warm-blooded fish, and lungfish that use lungs instead of gills to breathe.
Fish can live in many waters, including: freshwater lakes and rivers as well as saltwater oceans. With so many different types of fish in the ocean, some are less than an inch long while others, like the whale shark, can grow to more than 15 meters in length and weigh 15 tons.
In their natural habitat, fish spend most of their time hunting and grazing for food and many fish are also fast swimmers. Some of the fastest swimmers include marlin that can swim at 50 miles per hour and sailfish that can reach 68 miles per hour.
Fish lifespan: how long do fish usually live?
The average lifespan of fish ranges from 5 years to 100 years, some exceptional species live well beyond the age of humans.
With so many different species of fish in the world, this answer to how long they live depends on a few factors. For starters, each species of fish has a different average lifespan. Average life also varies depending on whether they have a fresh water or saltwater fish and the quality of the natural habitat in which they live.
In the wild, fish can get quite old. Some freshwater fish, like the lake sturgeon of the Great Lakes can live to be about 100 years old. paddle fishing have been recorded to live to be about 55 years old, while freshwater fish only live to be about 6-8 years old, depending on food availability and water temperature.
By comparison, the ocean has been home to a wide variety of fish for many millions of years and is known to have some of the longest-lived fish species. The lifespan of sailfish is about 5 years, but they can live up to 13-15 years. red drum can live up to 60 years while mahi-mahi only lives between 4 and 5 years.
The oldest fish in the world
The oldest fish in the world is the greenland shark, with a 392-year-old female specimen being the oldest ever discovered. With a lifespan of at least 272 years, Greenland sharks are now the longest-living vertebrates known on Earth, according to scientists.
How do scientists know how old Greenland sharks reach? The answer comes from using radiocarbon dating on eye samples from 28 Greenland sharks. After collecting and analyzing these samples, scientists found.
- Greenland sharks become sexually mature at age 156 (give or take 22 years)
- And the oldest shark in their sample was somewhere between 272 and 512 years old. Taking a midpoint of that estimate yields a oldest Greenland shark age of 392 years.
- Which means the oldest of the 28 sharks scientists have studied could have been born as early as 1501, which was just 9 years after Christopher Columbus’ famous expedition to the Americas.
Greenland sharks (somniosus microcephalus) are native to the Arctic and the North Atlantic and can grow up to 7 meters in length and weigh up to 1,200 pounds. Unlike many other shark species, whose age can be determined by the growth bands on their vertebrae, the Greenland shark’s vertebrae do not show these bands. Instead, scientists must determine their age by removing layers of the lens from its eyes, as they continue to grow throughout their lives, along with radiocarbon dating the tissue at the center of the shark.
Unlike many other fish species, the Greenland shark lives at a much more leisurely pace.
The shark has a slow metabolism, adapted to swimming in deep, cold water. This slow metabolism, according to scientists, explains their long life. Due to the shark’s slow growth rate and slow movement, they cannot begin to reproduce until they are more than a century old.
More Incredible Species of Ancient Fish
In addition to the Greenland shark, there are a number of long-lived fish species.
- The oldest companion fish is the koi fish. The oldest koi fish ever recorded was a pet named Hanako who lived to be 226 years old before dying in 1977.
- The oldest freshwater fish is the bigmouth buffalo. The oldest bigmouth buffalo was 112 years old. Scientists discovered their age by removing small pieces of their fins and then carbon dating. They found that in a sample of 386 bigmouth buffalo, 5 were older than 100 years. In the United States, only 1.73 people per 10,000 reach the age of 100, meaning the thick-billed buffalo outlives humans!
- The oldest prehistoric fish is the lungfish. As we noted earlier, lungfish are unique in that they lungs instead of gills to breathe. Lungfish ancestors have been around for more than 380 million years. A lungfish at the Shedd Aquarium in Chicago called “Granddad” died in 2017 at the age of 84. It is believed that lungfish are capable of living over 100.
Fish Conservation and Overfishing
Fish play a very important role in the planet’s ecosystem. Around the world, people of many different cultures have hunted and continue to hunt for fish as a food source. Fish have become one too popular pet, with fish being the third most popular pet in American households alone.
As of September 2016, the International Union for Conservation of Nature (IUCN) lists 643 endangered fish species. Unfortunately, the disappearance of many species is due to various factors such as overfishing, pollution, habitat loss and climate change. While the Greenland shark was once hunted for its live oil, the majority of Greenland sharks that end up in fishing nets today are accidental.
Still, many species of edible fish, such as cod and tuna, are subject to overfishing, making it difficult for populations to breed quickly enough to make up for the loss. Since fish help maintain the delicate balance of many ecosystems, fish conservation helps keep this beautiful species alive. As nutrient contributors fertilizing both seagrass and algae to help them grow.
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