A study shows the new map for Hammerhead sharks

In the world’s warming oceans, survival is becoming a moving target. For large hammerhead sharks, climate change isn’t just changing new waters. It is redrawing a  map of where they can live. 

A recent study by Santos et al. explores how shifting environmental conditions and ocean acidification are altering habitat for three Hammerhead species; scalloped hammerhead, smooth hammerhead and great hammerhead. 

Using advanced habitat modeling, researchers tracked the sharks and found that the oceans will no longer resemble what the sharks evolve in. 

For the scalloped and smooth hammerheads, the position there is clear. As ocean temperatures rise, particularly the tropical regions they inhabit are projected to be less suitable. The breeding and nursery grounds would be lost, creating an unstable population. 

The great hammerhead is more complex, in some regions the species may benefit from elevated temperatures. As warming waters open new areas at higher latitudes. The gain would be temporary. Even the suitable habitats begin to shrink with climate change, showing that no species is immune to environmental disruptions. 

Marine species moving in response to temperature changes is not new. Many ocean animals track cooler waters as their environment warms. But for large predators like Hammerhead sharks, the shifts can be more complex. Migration routes, feeding patterns and breeding grounds are all affected. 

Future projections show that suitable habitats for hammerheads are towards higher latitudes and away from equatorial regions. This trend is called the poleward shift, and could redefine where sharks are commonly found. 

Habitat shifts could complicate conservation efforts. Marine protected areas are often designed based on where species live today. As hammerheads leave, they may leave protected zones and enter regions with higher fishing pressure. Sharks already face intense threats from overfishing, this shift could further accelerate their decline. 

As top predators, hammerhead sharks play a key role in maintaining the balance of the ocean food webs. Changes in the location of hammerheads could ripple through ecosystems. Affecting prey species and altering ecological dynamics. 

As the ocean is warming, hammerheads are being pushed out of their homes. Whether they find new homes, and humans protect the spaces, may determine their future. 

Source: Santos C. et al “Shifts in the habitat suitability for large hammerhead sharks under climate change” 2024