From frequent contact with people, sharks become larger and meaner

(ORDO NEWS) — Tiger sharks are one of the largest predatory fish in the oceans, among which three-meter specimens are often found.

It is not surprising that places where there are many such animals attract tourists more strongly.

Now scientists have found that fish that come into contact with people more often than others grow larger and more aggressive than their congeners.

There is a special place in the Bahamas called Tiger Beach. Naturally, there can be no tigers in Central America, and this place got its name thanks to another dangerous predator – the tiger shark.

The sea off the coast of the Bahamas is clean, the depth is only about five meters, so the sharks are easy to spot.

In addition, tour operators specifically attract these predators by regularly throwing bait into the water.

After studying the sharks most frequently seen on Tiger Beach, an international team of scientists from Brazil and the United States found that these fish had larger bodies and higher hormone levels than their relatives who spend less time near the shore.

Thus, for the first time it was found that mass tourism has a positive effect on the health of sharks.

At Tiger Beach, scientists mostly met large sexually mature females, many of which were pregnant. It seems that the abundant food (due to scattered baits) had a good effect on their health.

Their blood had more nutrients than their counterparts living in the open ocean.

Thanks to tiny sensors implanted under the skin, scientists were able to track the movements of fish for three months. Judging by the data received, the juveniles stayed away from the beach. Seasoned individuals mainly interacted with tourists.

Compared to other sharks, fish at Tiger Beach have unexpectedly high levels of hormones. The level of testosterone was three times higher, estradiol – four times, and corticosteroids – 16.4 times.

Presumably, due to the dense accumulation of relatives with whom they have to compete for food, sharks were forced to behave more aggressively, which led to a hormonal surge.

So far, scientists cannot draw unambiguous conclusions about the positive impact of tourism on the health of sharks.

To do this, they would need animal blood samples taken before sharks were used to attract guests in the Bahamas.

However, the results of the study look optimistic and may encourage people living in shark habitats to benefit not from the sale of shark fins, but from tourism.

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