When the researchers tagged the baby sharks, they discovered a kind of shark nursery

Mother sharks do not look after their babies. White sharks of around 1.5 meters are born and are then expected to fend for themselves.

In a new American study, researchers found that baby sharks and young sharks aged 1-6 years hung out together in shallow water in a kind of shark nursery, without adults present. The study was done right at Padaro Beach near Santa Barbara in California.

22 young white sharks were tagged with sensors so that the researchers could monitor their movements.

They found that the young white sharks choose warm water, somewhere between 16 and 22 degrees, and that they congregate in shallow water, less than 10 meters deep, in an area that stretched a kilometer out from the coast.

Sun licked on the surface of the water

According to the marine scientists behind the study, it is one of the largest and most detailed of its kind.

– You rarely see great white sharks gather like this in other places, says Professor Christopher Lowe at California State University, one of the researchers behind the study.

The sensor data also showed that the baby white sharks dived deepest around morning and evening, probably in search of food. In the afternoon, they often lay right on the water’s edge in the sun, perhaps to increase their body temperature.

When the water was warmer, the sharks spread out more and swam deeper than when the water was cooler – then they moved closer to each other on the surface.

Protect the sharks

The researchers do not know why white sharks have chosen this particular area of ​​the California coast or why they gather in groups in warm and shallow water.

An advantage may be that it provides protection against other predators. The warm water and all the time spent in the sun at the surface perhaps provide optimal growing conditions, they suggest.

The study is important in terms of the protection of great white sharks, the researchers believe, especially in view of the fact that the water in the sea is getting warmer due to climate change. It is also important in terms of avoiding negative encounters between sharks and people.

A familiar pattern

That a species stays in shallower and warmer water near the coast in a kind of “birth room” is not new, says Claudia Junge at the Institute of Marine Research.

Lemon sharks in the Bahamas, for example, often stay close to shore in areas with mangroves.

– This is common for several species because it provides protection from other predators and from adult individuals from the same species that can be threatening, the marine researcher tells forskning.no.

Pregnant females enter shallower waters and give birth, then run away while the young remain in the slightly more protected area.

But this is the first study she has seen that shows that baby white sharks also do this.

In addition, the baby lemon sharks in the Bahamas move over several small areas in an overall larger area than the baby great white sharks.

– It is interesting that the baby white sharks are in a small area, and that everyone moves there, says Junge.

A good start

Junge says that other types of tagging, such as satellite tags, could provide even more detailed data about the baby sharks’ behavior.

In their own studies on the porbeagle shark, Junge and colleagues tagged 19 fish with satellite tags and close to a hundred fish with acoustic tags – the same type that the shark researchers from California have used. That was all it took to get good data.

The American study with its 22 white sharks is a good study, especially since it covers a fairly small area, Junge believes. She is also impressed by how much data the researchers have managed to collect. Nevertheless, more is needed to understand where young white sharks generally like to stay.

It also varies how many marks you need to figure things out.

In the research project Sharks on the Move, Junge and colleagues have so far tagged more than 30 fish from three shark species found in Norwegian waters, brugde, åpgarrann and porbeagle. There is great variation between the species, the porcupines do roughly the same things, while the brugde behave in completely different ways.

Don’t build a wind farm here

Junge completely agrees that the study is important for the protection of great white sharks.

– If this is an important area for white sharks, then you might not want to build, for example, a hotel complex or a wind farm there, she says.

– It is important to know these places, especially where fish stay in an early life phase where they are most vulnerable in terms of survival. It is important to protect these areas.

This applies not only to newborn sharks, but also to the pregnant females that come in to give birth, Junge points out.

– You don’t want bycatch of a pregnant female fish that is just about to give birth to the next generation. It is extremely important to identify these habitats, for all species.

When it comes to people who want to go swimming along the coast, Junge is less concerned.

– It is good to know about movement patterns and habitat preferences for sharks, but we are not on their menu.