Hunt for world's last giant fish as researchers find clues in ancient photographs
Memories and archival photos reveal fish were once bigger than they are today.
Giant long-lived fish that filled our oceans a century ago have disappeared from all but the most remote corners of our seas. “Historical photos, human memories and data show [fish are] much smaller than they used to be,” evolutionary biologist Dr Asta Audzijonyte revealed.
There’s no mystery as to where they went. When Yahoo News asked Audzijonyte, her answer was blunt. “We just ate them. It’s really very simple. We caught them all and we ate them. Because generally, everybody wants to catch a big fish,” she said.
As the Marine Research Fellow at the University of Tasmania’s Institute of Marine and Antarctic Studies (IMAS), Audzijonyte is investigating how the loss of the giants of the oceans has skewed the balance of underwater ecosystems, and what we can do to bring them back.
She's hunting for the last strongholds of giant fish so their impact on the oceans can be studied. And working with a colleague, she is searching for clues in old documents and ancient, grainy images to better understand how our depleted oceans once looked.
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Most anglers unaware of how big fish used to be
Most people don’t even know about the problem, because they weren’t alive to witness how the oceans used to look.
“In old photos you see people with fish that are adult man size — they’re holding these gigantic groupers. All of these fish are mostly gone. Almost every species that is not protected and that is targeted, their size structure is really strongly truncated” she said.
“We don't even know how the ocean should look. We have lost the perception, and we shifted our baselines, and think this is how it should be.”
Reason remaining large fish are in danger
With fishing technology dramatically improving over the last 30 years, the problem will only escalate. “There are places where they have survived… and it’s one of my goals to try and find these bright spots where we do have recovery happening,” Audzijonyte said.
As she locates these rare places, the location will need to be kept secret to stop anglers from raiding them.
“Unfortunately, a lot of remote places are now also decimated. They are being affected very much by recreational fishing and illegal and unregulated fishing as well,” she said.
“Because now people have access to really good boats and they can go everywhere, so places that used to be safe have been affected over the last few years.”
Is it okay to catch large fish?
In Tasmania, where Audzijonyte is now based, the sand flathead used to grow up to 50 centimetres, but recreational fishing has impacted the species so severely it’s now hard to find them above the minimum size limit of 35 centimetres. Bag limits have been introduced to try and combat the problem and stop the species continuing to decline.
Audzijonyte believes the solution to the problem of targeting large fish lies in education. With climate change adding further pressure to marine ecosystems, it’s these long-lived individuals that are better poised to withstand higher temperatures and extreme conditions.
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She’s developed a game that gives players a better understanding of what a healthy ocean should look like, rather than what we’ve become adjusted to.
“Recreational fishing is really affecting size and diversity. But we wondered how would you tell people not to catch a big fish? They all want to do it. And nobody wants to listen to some preaching scientists telling them not to,” Audzijonyte said.
“So we thought we would develop a game where people discover it themselves. Yes, you can catch big fish, but you also need to keep some of them in the ocean.”
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