Scientists Examined Ancient Shark Teeth To Get A Glimpse Into What The Marine Ecosystem Was Like In The Past

In comparison, the ecosystem of today is less resilient. Modern sharks in Brazil are eating all kinds of prey from different levels of the food web.

This may be because the number of fish species has declined, so sharks have become less picky about what they’re snacking on.

When researchers centered their focus on one particular species—the sand tiger shark—they discovered that it had gotten bumped up in the food chain over time.

Now, it’s one of the top predators in the ecosystem. There aren’t as many sand tiger sharks left to compete for food, so they are all aiming for bigger and better prey that is higher up on the food chain. In 2018, sand tiger sharks in Brazil were declared critically endangered due to overfishing.

However, it is unclear whether overfishing is what actually caused the sharks’ diets to shift. Stable isotope analysis can only show what changes have occurred.

It can’t explain why they happened. Without further research, scientists can’t say for sure why sharks are eating differently now than they were hundreds of years ago.

The change in the marine ecosystem is worth looking into more deeply as the planet’s climate warms at an unprecedented rate.