Sharks have existed more or less unchanged for millions of years

Business Insider
Shark populations off the east coast of Australia have been declining over the past 55 years with little sign of recovery, according to research published in the journal Communications Biology.
Coastal shark numbers are continuing a 50-year decline, contradicting popular theories of exploding shark populations, according to an analysis of Queensland Shark Control Program data.
University of Queensland and Griffith University researchers analysed data from the program, which has used baited drumlines and nets since 1962 to and now covers 1,760 km of the Queensland coastline.
Chris Brown from Griffith’s Australian Rivers Institute says the results show consistent and widespread declines of apex sharks — tiger white sharks and hammerheads — along Queensland’s coastline.
“We were surprised at how rapid these declines were, especially in the early years of the shark control program. We had to use specialist statistical methods to properly estimate the declines, because they occurred so quickly,” says Brown.
“We were also surprised to find the declines were so consistent across different regions.”
Some species, such as hammerhead sharks, were recognised internationally as being at risk of extinction.
“Sharks are an important part of Australia’s identity. They are also survivors that have been around for hundreds of millions of years, surviving through the extinction of dinosaurs,” he says.