Scientists find that little white sharks like to stay close to the coast

Remember #BabyShark? No, this isn’t a wildly catchy children’s song that’s taking the internet by storm. Earlier this year, social media was awash with stunning drone footage of newborn great white sharks.

Now, marine scientists have shown for the first time that juvenile great white sharks choose warm, shallow waters to congregate within a kilometer of the coast.These results were published in Frontiers of Marine Scienceis important for protecting great white sharks, especially as climate change increases ocean temperatures, and for protecting the public from the negative impacts of shark encounters.

Nursery near central california

Great white shark babies (“pups”) do not receive any maternal care after birth. In the study, conducted near Padaro Beach near Santa Barbara in central California, pups and young were gathered in a “nursery” without adult company.

“This is one of the largest and most detailed studies of its kind. Because large numbers of juvenile fish share nearshore habitat around Padaro Beach, we can understand how environmental conditions affect their movements,” said senior author Dr. Christopher Lowe explain.

“You rarely see great white sharks displaying this type of protective behavior elsewhere.”

In 2020 and 2021, Lowe and his team used darts to tag a total of 22 teenagers with sensor transmitters. These are females and males aged between one and six years old. Great white sharks can live between 40 and 70 years.

Sensor transmitters instantly measure local water pressure and temperature and track the location of each juvenile fish by sending an acoustic “ping” to an array of receivers spread out along approximately 5.5 square kilometers of coastline. These methods were approved by the University’s Animal Care and Use Committee and the California Department of Fish and Wildlife.

Tracking ceases during the winter when the juvenile fish temporarily leave for offshore waters. The researchers used an autonomous underwater vehicle to collect further data on the temperature distribution of the local water body. They then used artificial intelligence to train 3D models of teenagers’ temperature and depth preferences.

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The results showed that juvenile fish dive deepest at dawn and dusk, when they may be feeding on skates, skates, schooling fish and other small bony fish. They move closest to the surface – to depths between zero and four meters – in the afternoon when the sun is hottest, possibly to increase their body temperature.

“We found that juvenile fish directly change their vertical position in the water column to maintain a 16 to 22°C or, if possible, between 20 and 22°C.

Prefer shallow waters

The results show that the temperature distribution in these waters is constantly changing, meaning that juvenile fish must constantly move to stay within this optimal range.

The authors concluded that juvenile great white sharks spend most of their time in much shallower waters than adult great white sharks. The latter is rarely observed in nurseries.

The results also show that the temperature distribution in three dimensions strongly affects the horizontal distribution of juvenile fish. When the seafloor temperature is higher, juvenile fish will spread to greater depths, and when the deeper water is colder, juvenile fish will spread towards The sea is closer.

What researchers don’t yet know is what benefits pups and young receive from congregating in nurseries in the first place. One advantage may be predator avoidance.

“Our results indicate that water temperature is a key factor in attracting adolescents to the study area. However, many locations along the California coast have similar environmental conditions, so temperature is not the whole story. Future experiments will look at individual relationships, e.g. to see Are certain people moving in tandem between daycares,” Spurgeon said.