How Many Fish Are Swimming in Our Oceans?

Get ready. We’re about to reveal one of the biggest mysteries of the seas: how many fish live in the ocean? You’ll be gob-smacked!

Two-thirds of the planet’s surface is the ocean, and the fish population is vital for our survival as it provides a critical food source. You can consider the ocean our lifeblood. And oceans are the home to so many amazing animals, but overfishing and climate change threaten their habitats. Let’s dive deep into the fish world and hook you with unbelievable facts.

How many fish are in the ocean? World’s fish population

Let’s start with the numbers: According to WorldAtlas, scientists estimate that 3.5 trillion fish are swimming around our oceans (however, the number fluctuates depending on factors and estimates).

That’s 3,500,000,000,000 indvidual fish! In words, that’s three trillion five hundred billion fish.

We are 8 billion human beings, and that’s 437.5 fish for every person on earth. Sounds like a lot, right? But consider the scenario where every person eats a fish every day; then, we would run out of fish in less than 15 months. In other words, we need to conserve the number of fish, or we’ll overfish the oceans quickly.

Factors that affect the fish populations

Overfishing: One of the biggest threats to fish worldwide is overfishing. When we fish too much, it can ruin the ecosystem balance and cause a population decline. Especially fisheries using underwater nets catch much fish as an unnecessary bycatch.

Climate change: quick and sudden changes in the habitats, such as warmer water and higher water acidity, can harm fish as they are sensitive to habitat changes. For example, some fish die shortly after being captured and placed in an aquarium because of distress, or they cannot acclimate to their new artificial habitat.

Pollutants and waste: Since we have evolved into an agricultural and highly industrial society, it also creates a lot of waste as a byproduct. Some of these are pollutants that end up in rivers and oceans. Plastic has become an increasingly significant problem that floats around in the sea and doesn’t break down. Recently, deep-sea explorers found a beer bottle at the deepest point of the ocean, which shows how much our activities on land impact the habitats of the sea.

How many fish species are there?

Did you know there are more than 32,000 known species of fish worldwide? (According to National Geographic). That is a lot of fish species to consider when considering conservation and fishing methods. But it’s not all doom and gloom when considering how many species there are. With such a wide range of fish, some are more resilient to changes and will evolve and adapt. Scientists also discover new fish species yearly as they map and explore more of the ocean’s depths, such as the Mariana Trench. 

Two hundred years ago, some of the most intelligent people believed that no marine life could survive in the darkness and pressure of the deep sea. However, it turns out that many deep-sea fish species thrive in those conditions that people thought were unlivable.

Marine Life Conservation Efforts

Here’s the good news: People are spreading awareness, creating protected marine areas, and promoting sustainable fishing methods and other conservation efforts which may benefit the fish populations and ecosystems of the sea.

Here are some things you can do to help:

• Conserve your water use so there is less wastewater in the sea.
• Reduce your pollutants, so less ends up in the ocean
• Reduce your waste so that less of it ends up in the sea.
• Fish responsibly by targeting specific fish instead of using nets that can catch unintended fish as bycatch.

Frequently Asked Questions