The 100-year-old Fish

 2 species of freshwater fish that live over 100 years confirmed.

New research on why these relatives of giant fish don’t age.

North America’s Buffalo Fish are ‘Wonderful fish that can live over 100 years in the right conditions’

In new research published in the academic journal Scientific Reports on October 20^th 2023, the Smallmouth Buffalo Fish (Ictiobus bubalus) and the Black Buffalo (Ictiobus niger) living in the wide expanses of North America have been confirmed to live for over 100 years.

From brown to blue-tinged, these fish come in a variety of colours, until just a few years ago were thought to be able to live for 2 and a half decades. However in research published in 2019, it was found that the Bigmouth Buffalo Fish (Ictiobus cyprinellus), weighing up to 35 kilograms, can live up to 112 years. On top of this, in January 2023, a 127-year-old Bigmouth Buffalo fish was found in Canadas Saskatchewan province. As far as we know, of about 12,000 species of freshwater teleost fish, this is the longest living.

Following this, we know of 3 types of Buffalo fish that can live for a century. As far as we know, the only other genus with 3 species that can live over 100 Is the Sebastes of the saltwater mebal genus.

Furthermore, we have found that Buffalo fish that live to around 85-90 years old, get better with age and actually have superior stress responses and immune function than the younger ones.

This discovery supports recent research findings that overturned the previous prevailing theory on Buffalo fish. Buffalo fish is a genus of 5 types of freshwater fish indigenous to North America has become popular targets of bowfishing – catching fish by shooting them with a bow-like tool – but haven’t been researched that much until now.

‘To put it simply, the buffalo fish doesn’t adhere to our preconceptions’ says Alec Lackmann, fish specialist of Minnesota University and leader of this research. ‘They have betrayed our expectations.’

The giant fish that live in desert lakes

In this current research, from July 2018 to July 2023, dozens of fishermen caught a total of 222 Buffalo fish in the Apache Lake the desert of in eastern Arizona. Researchers then humanely killed 23 of these and estimated their age by analysing the otolith taken from the fishes’ ears.

Otoliths are a structure that fish use to hear and feel vibrations underwater. New layers of calcium carbonate are formed on this periodically so we are able to estimate ages of these fish much like we would for a tree.

As a result, the researchers discovered that over 90% of the Buffalo fish in the Apache Lake were over 80 years old. They also found individuals aged over 100 from Smallmouth Buffalo, Bigmouth Buffalo and Black Buffalo fish.

The remaining 199 were fished using hooks with either small barbs or no barbs at all. All of them were returned to the lake once their photo was taken. 129 of these were weighed.

‘Of the large river-dwelling fish, there are species that grow to over 50 years old, like the Sturgeon and Alligator Gar’ said Nathan Farnau, the curator of fish and invertebrates of Georgia Aquarium.

‘However, I was really excited to hear that they had discovered fish that could live to be over 100’. Farnau is currently not part of this research.

 

The ‘Oddity’ that has been alive since 1918

According to Lackmann, the most interesting point of all, was that these fish did not originate in Arizona.

The natural habitat of the Bigmouth Buffalo fish ranged from Canada’s Saskatchewan province to North America’s Texas and Louisiana. The Smallmouth Buffalo and Black Buffalo fish in addition to the previous range, are also found in Canada’s Ontario, North America’s New Mexico and part of Mexico.

In 1918, Roosevelt Lake, one of the Salt river Dam lakes, was established as commercial fishing industries as one in a chain of plans, and around 400 Buffalo fish were shipped by train to Arizona. After that, the Apache Lake was created and then some of these fish migrated downstream. Lackmann said that it’s highly possible that the fish in Apache Lake came from a breeding facility in Iowa.

According to Lackmann, the results of this investigation suggest that the very fish that were initially transported are still living in the Salt River system now.

‘That Dam lake is in a desolate, desert like environment, but despite that they have been able to live for over 100 years’ says Lackmann. ‘Just try to imagine being a creature, captured and being let loose in such an environment. You’d think you wouldn’t live too long, right?’

The fish indifferent to aging, where is this Fountain of Youth?

Most of it is still unclear, but since they need a extremely particular environment, it can take tens of years to successfully breed these Buffalo fish. Was it precisely for this reason that they evolved to live such long lives? Lackmann says it’s a response to the long periods of time between breeding.

In the Saskatchewan province in Canada, these Buffalo fish only attempt to lay eggs during the narrow window of time during a rare period when the water level drastically changes. Due to this, they can go for upwards of 50 years without leaving descendants behind.

‘One of the great questions surrounding the Buffalo fish is how they managed to achieve their amazingly long lifespans. What exactly is their secret fountain of youth?’

One way to find the answer to this question is likely in the understanding of how they, become more resistant to stress and how their immune system becomes stronger as they grow older. This was identified in the research on the Bigmouth Buffalo fish, published in the April 2021 edition of Scientific Reports.

Older Bigmouth Buffalos are better at repelling bacteria than younger individuals. On top of this, the proportion of leukocytes and lymphocytes in the bloodstream of older individuals is lower. This indicates that stress levels are lower in these individuals.

‘In the best-case scenario, they can live to see 100. It’s marvellous.’ Says Lackmann.

That being said, the protection of Buffalo fish is a matter of priority, he states. In the mid north west, these fish are the target of fishermen and so their numbers have been dropping. Despite this, there are no restrictions on this, even in Arizona.

‘Right now, you can go to Arizona, catch a buffalo fish, and then take it home as is’ says Black. ‘Personally, I think these fish should be protected immediately.’

Source: news.yahoo.co.jp