aquatic invasive species

How Aquatic Invasive Species Are Hurting Our Ecosystems

Jane Marsh - June 24, 2019

We are reader-supported. When you buy through links on our site, we may earn affiliate commission.

The world consists of various ecosystems where native species to the area thrive. However, the only thing constant in the world is change. The science of evolution tells us that all organisms grow and adapt to different environments — most of these changes are for the good, but others can cause damage.

One such negative adaptation involves the introduction of aquatic invasive species into ecosystems where they compete with and eventually drive native species to extinction. As humans are responsible for the majority of the movement of these species, it is incumbent upon us to find solutions which protect all water-bound life for future generations.

What Are Aquatic Invasive Species?

An aquatic invasive species is a water-bound living organism not native to the area it infests. Think of invasive species the way you think of E-coli bacteria — when the bacteria remains in the gut where it belongs, it causes no harm, but should the germ be ingested, severe gastrointestinal consequences will follow.

Invasive species proliferate rapidly due to having no natural predators in their new environment. Because they multiply quickly in this absence, such species quickly overtake the native populations which remain prey. As a result, countless animals and plants are lost.

Which Invasive Species Threaten Marine Life?

Multiple examples of invasive species exist in both salt and freshwater environments. Because of the magnitude of the problem, listing them all proves impossible. However, here are some of the worst offenders:

  • Zebra mussels. These mussels are native to lakes in southeast Russia as well as the Black and Caspian seas. However, the species now can be found all over the globe, including the Great Lakes in the U.S. One reason this species spreads so quickly is that it can survive for 3-5 days without submersion in water. Most researchers believe the mussels become introduced to new waterways as a result of ship ballast.
  • European green crab. As the name suggests, this species is also native to Europe. However, researchers have found the species in North and South America as well as East Asian nations such as Japan. The species is a nuisance to shellfish breeders as it feeds on mussels and other crustaceans such as shrimp.
  • Lionfish. Sure, these guys are so cool to look at, one played a starring role in “Deuce Bigalow, Male Gigolo.” And in their native Pacific and Indian Oceans, they pose little harm. However, these voracious eaters who can consume well over 400,000 prey fish per year, much to the dismay of fishermen in the Gulf of Mexico, where the species now decimates prey fish.
  • House cats. Wait a second, isn’t this about aquatic invasive species? Yes, but the domestic cat preys on the macaroni penguin, an animal which spends six months out of every year at sea. During mating season, the penguins colonize along icy shores near the tip of South America where felines have learned to await their arrival.
  • Deadly algae. Killer algae resembles an underwater fern, but it’s far from innocuous. This algae is responsible for killing countless species off the west coast of the U.S. This algae often travels by attaching to boat propellers. When the boat enters uncontaminated waters, the algae spreads to them.

How Invasive Species Do Their Damage

Each ecosystem has its own unique resources. Nature in her infinite wisdom designed the planet this way so all of her creatures could get enough to eat. But Mother Nature cannot stay the hand of human beings.

Invasive species often reach their locations with the help of humans. One major method invasive species use to migrate is ship ballast. Ballast refers to the layer of sand, silt and water ships keep in their hold in order to stay upright while sailing. When ballast is released, any organisms hiding in it are released, often on the other side of the world from their origin.

Another way aquatic invasive species invade other waters is through the exotic pet trade. People buy pets like lionfish, but when they find they cannot care for them, they dump them into the sea. The same thing happens with other invasive species usually kept in aquariums. A good rule of thumb is to return fish and other marine organisms to a pet shop instead of simply dumping them in non-native waters where they spread and choke out indigenous species.

Invasive species prove dangerous because they upset the balance of resources. When an invasive species enters an area with no native predators, they compete with the existing fish and other creatures for food. As nothing kills the invasive species off, they soon win this competition, leaving surviving members of native species to starve to death.

What You Can Do to Help

The problem of aquatic invasive species has caught the interest and concern of scientists. Although World Wildlife Day passed in March, this year, the focus was upon aquatic life. The International Water Association hosts events throughout the year, so check out their calendar for those happening near you.

The United Nations has called on people to preserve marine life, and those who wish to volunteer can find opportunities with the organization. Many natural wildlife areas contain bodies of water, so consider signing up for a cleanup event near you to help find and remove invasive species.

Most of what you can do hinges upon good hygiene habits and common sense. If you use a boat for fishing or other recreation, wash it thoroughly before transporting it to a different body of water. If you go hiking in watery areas, be sure to rinse your boots afterward to avoid spreading spores from non-native species to new locations. When cleaning out an aquarium, take any living creatures (including coral and plants) back to the pet store instead of dumping them in the nearest lake or ocean.

Protecting Native Aquatic Wildlife

Aquatic invasive species can do considerable damage to native ecosystems. But since most such species infest new locations due to the actions of human beings, we have the ability to fix the problem. By practicing common sense, we can all do our part to protect the natural watery flora and fauna of the waterways we depend on for drinking, fishing and other activities.

Share on

Like what you read? Join other readers!

Get the latest updates on our planet by subscribing to the newsletter!

About the author

Jane Marsh

Starting from an early age, Jane Marsh loved all animals and became a budding environmentalist. Now, Jane works as the Editor-in-Chief of where she covers topics related to climate policy, renewable energy, the food industry, and more.