Shark Tourists Are Damaging The Species' Ability To Hunt and Reproduce

Shark tourism—where people pay to swim and have up-close encounters with the animals—may be hindering the species' ability to hunt and reproduce, a study has found.

Whale sharks are a slow-moving species of carpet shark, known for their gentle nature. Because of this, and their impressive size and appearance, whale shark tourism is popular around the globe, particularly in Mexico and Australia.

The species is important for the ocean's ecosystem. However, their population numbers have been declining in recent years.

Now a study published in Scientific Reports has found that human interactions with whale sharks could be harming them.

"At this stage it is difficult to say exactly how concerning the findings are. The shifts in behavior observed in the presence of humans mean that these sharks are going to be using more energy, and spend less time performing natural foraging behaviors," study author Joel Gayford of Imperial College London, in the U.K., told Newsweek.

"As whale sharks gather in these areas specifically to forage and build up energy stores, disrupted feeding during this time may have important consequences for subsequent movement patterns. Future studies will of course be needed."

To assess the effect on the species, scientists, led by Gayford and colleagues, looked to see if the sharks' behavior changed when a swimmer—mimicking the movements of a tourist—entered the water in the Bay of La Paz, Mexico.

A total of 20 videos were analyzed with a swimmer, compared to 19 videos that were taken of the sharks swimming alone.

Overall, the sharks displayed an increase in disturbed behavior patterns when a swimmer was in the water.

The whale sharks appeared to move in fast, zigzag movements, similar to when the species is trying to avoid predators, the study noted. It was clear that when a swimmer was present, the whale sharks were using more energy as a result of being disturbed.

Scientists believe these conditions are making it harder for whale sharks to forage. The behavior may also hinder reproductive success, the study reported.

"Whale sharks feed on plankton, and as such they play an important role in regulating the abundance of many other species, both plankton and the other species that depend upon this food source," Gayford said.

"Moreover, whale sharks are migratory and help to transfer nutrients between different ecosystems. If the disrupted behavior observed in this study alters the distribution or movement patterns of whale sharks, or their abundance in specific areas, the potential impacts extend far beyond whale sharks themselves to the entire marine ecosystems."

While there have been previous studies into the effects of tourism on the species, the ecological impacts are not fully understood, the study noted.

Prior research has found that in areas where there is a lot of shark ecotourism there has also sometimes been a decrease in species found. Based on these fresh findings, the authors say this needs to be studied more thoroughly.

They suggested that behavior patterns of the shark be assessed first, before swimmers are allowed into the water with the animals.

The study also recommends that regulated distances between the tourist and the shark, be looked over, in order to allow species enough space.

"We are not claiming that ecotourism is bad for sharks, or that it should be stopped. Ecotourism plays an important role in shark conservation and will continue to do so in the future," Gayford said.

"Rather, we are suggesting that the rules and regulations surrounding shark ecotourism should be reviewed regularly, taking into account scientific studies such as this one. Many more studies are required before we will fully understand the ecological implications of shark ecotourism."

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