EurekAlert: baby sharks prefer to stay near the shore
At the beginning of this year, social networks came alive with amazing pictures of a newborn great white shark made by drone.
Now, for the first time, marine life researchers have confirmed that juvenile white sharks prefer warm, shallow waters to congregate within one kilometer of shore. These findings, published in the journal Frontiers in Marine Science, have important implications for the conservation of the great white shark population, especially in the face of climate change and rising ocean temperatures, as well as for ensuring the safety of the population from possible collisions with predators, reports the science portal EurekAlert!.< /p>
After birth, great white shark pups are left without maternal care. In a population studied off the beach near Santa Barbara in central California, young sharks gather in «nurseries» without adults.
“This is one of the largest and most detailed studies of its kind. Thanks to the large number of juveniles living near Padaro Beach, we can understand how the environment influences their movements,” said senior author of the study, California State University professor Dr. Christopher Lowe.
In 2020 and 2021, Lowe and his colleagues tagged 22 juvenile sharks with sensors. The tagged individuals included females and males ranging in age from one to six years. Great white sharks can live from 40 to 70 years. The sensors monitored water pressure and temperature in real time and tracked the location of each shark using acoustic pulses transmitted to an array of receivers over an area of about 5.5 square kilometers along the coastline. These methods were approved by the university's Animal Welfare Committee and California Fish and Wildlife.
Tracking was suspended during the winter when the juveniles temporarily went to sea. Scientists collected additional water temperature data using an autonomous underwater vehicle. They then used artificial intelligence to create a 3D model of the sharks' temperature and depth preferences.
The results showed that the sharks descended to greater depths at dawn and dusk, likely to hunt rays and other small fish. Closer to the surface, at depths of zero to four meters, they moved in the afternoon when the sun was most active, perhaps to maintain their body temperature.