The cycle of life: sharks’ importance for a healthy marine eco-system

A shark swimming in shallow waters.

Imagine, you’re snorkelling or swimming in the ocean, admiring a colourful reef with many different kinds of fish species. And then… Dum Da Dum Da Dum Da! A shark. Since the release of Stephen Spielbergs Jaws in 1975 people have one big fear when they swim in the sea: sharks. The species no longer just lives with a bad stereotype due to Jaws, many of its kind are at the brink to extinction. The oceans however need sharks as its immune system. It’s time that we see sharks as more than just marauding man-eaters and learn about their importance to the marine eco-system.

Sharks are some of the oldest living inhabitants of our planet. They’ve been swimming in our oceans for over 400 million years – dinosaurs have appeared on land roughly 100 million years later. As an apex predator – the top dog of the food chain – sharks control the population of their prey. When one species of fish is low in population, they switch to another food source for example and therefore allow the other species to repopulate. By preventing other species from growing too much and therefore eating limited food resources, sharks stop other species from unbalancing the eco-system.

Several sharks swimming in the ocean.
Sharks are the apex predator of the oceans. Photo: Jakob Owens I Unsplash
Several sharks swim next to a coral reef.
Without sharks, coral reefs are threatened by algae. Photo: Francisco Jesus Navarro Hernandez I Unsplash

You could say that sharks are like the Swiss army knife of the ocean: they diversify the marine eco-system, eat the sick and weak to keep the ocean healthy and due to their hunting habits, their prey has to switch feeding strategies and diets. Therefore, sharks indirectly maintain seagrass and coral reefs. When a top predator of a food chain network is removed, potentially destructive fish populations first explode in numbers. Rays for example can unroot seagrass on their hunt for bivalves which can lead to poorer quality of nursing grounds for other fish. Therefore, the number of other species decrease, and natural habitats are being destroyed. Also, with less bivalves, the oceans filtration system of phytoplankton gets destroyed. This could lead to coastal areas experiencing uncontrolled algal blooming and dead zones.

Statistic on the number of shark species
Statistic: Julia Brunner

People’s first experiences with sharks vary. When the first thing you see about a Great White is Jaws, I can’t fault you for being scared of sharks. I don’t remember the first time I came in contact with sharks as a species. I know that at one point in my childhood I saw the movie, but I also remember that my class went on a field trip in primary school to look for fossils in a stone quarry and as a gift, one of the workers there gave some of us a shark tooth. What I remember however is the first time I was completely fascinated by sharks. It was in 2019. A friend and I went to an event called Ocean Film Tour that I have visited for the past five years. It’s a movie tour that shows mostly short films made by ocean lovers for oceans lovers. And there was one movie that was just… impressive. That movie is 700 sharks.

In the movie marine biologist Laurent Ballesta and his team film the feeding habits of 700 grey sharks in the pacific atoll of Fakarava. Watch the first 40 seconds of the trailer to get a taste of the movie. Actually, I don’t think that I would be comfortable to go diving with 700 sharks around me that are in a hunting spree. The more deeply impressive it is to me to watch movies that show you these impressive creatures and tell you about them, their behaviour. The more you know about something, the less scary it becomes.

After the release of the movie Jaws in 1975, the number of sharks killed by humans increased exponentially. The author of Jaws, Peter Benchley once said: “Knowing what I know now, I could never write that book today. Sharks don’t target human beings, and they certainly don’t hold grudges.” I think it’s time that humans stop holding grudges over sharks for being in an entertainment movie released over 45 years ago. Stop hunting sharks for fun. Stop hunting sharks for their fins. The oceans need their apex predator and let’s be honest – we need them too.

Learn more about sharks

Several organisations fight for the conservation and survival of sharks in our oceans. Learn more about their work and sharks in general:

Sea Shepherd
Oceana
Defenders of Wildlife

 

Hello there! I'm Julia, co-founder of Eco-Spotlight and a freelance journalist. With Eco-Spotlight, I want to focus on sharing stories of inspirational people and positive impact, as well as learn more about the environment, and sustainability.

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