Estuary Animals & Plants

Instructor: Lauren Posey

Lauren has taught intermediate reading in an English Language Institute, and she has her Master's degree in Linguistics.

In this lesson, you will learn about estuaries. Specifically, you will learn about the different types of plants and animals that live in estuaries and make up their complex ecosystem.

What is an Estuary?

Have you ever been to a marsh? What about a mangrove forest? Both are examples of estuaries. An estuary is an area where a freshwater river or stream meets the salty ocean, creating a unique brackish water environment. These areas are protected from the full force of the ocean, which makes them great places for animals to lay eggs or raise their young. As a result, estuaries are often referred to as nurseries.

Life in an Estuary

Many different types of plants and animals live in estuaries, from birds and fish to invertebrates and plants. The specific species of animals and plants vary depending on where the estuary is located. A mangrove estuary in Florida, for example, will have different species than a salt marsh in Washington state. However, the types of wildlife you might see in an estuary are common across different locations, even if the exact species might differ.



Fish are the main type of animal that use estuaries as nurseries. The adult fish lay their eggs in the protected area, and the young fish return to the ocean or river once they are old enough to survive. Some common examples include sea bass, burrfish, and some species of stingrays.

Burrfish are one species of fish that lay their eggs in estuaries, but spend their adult lives in the ocean.

Other fish remain in the estuaries for their entire lives. Examples of these include seahorses, pipefish, and a few species of flounder. Since estuaries are limited in space, animals that spend their whole lives in them tend not to grow as large as open ocean or river fish.


All estuaries have invertebrates, or animals without spines. Some common examples include shellfish like oysters, clams, shrimp, and crabs. Oysters are extremely common in salt marshes and help filter pollutants out of the water. These creatures are also a major food source for many types of animals, including people! A lot of the shellfish (and some other fish as well) that people eat are found in estuaries. Some species live their whole lives there, while others are only present as babies before returning to the ocean or river.

Other estuary invertebrates include snails and marine worms. These animals help with decomposing organic matter by continually eating and turning over the soil. This creates the rotting plant smell common in estuaries (especially marshes), but it also keeps the soil fertile, allowing many species of plants to grow.


Birds are also a major part of estuary ecosystems. Many species regularly visit or live in these areas, taking advantage of the abundant food the estuaries provide. For example, egrets, herons, and other shorebirds are often seen in estuaries. There are also some migratory birds that use estuaries as stopping points such as sandpipers and Canada geese.

Mammals and Reptiles

While there are certainly fewer mammals in estuaries than other types of animals, they are still an important part of the ecosystem. River otters often hunt in estuaries and use the protected area to raise their young. Raccoons and opossums are also common visitors, and if you are in Alaska, you might even see a grizzly bear! Depending on the location of the estuary, both grizzly bears and black bears take advantage of the numerous food sources available.

Reptiles are also occasionally seen in estuaries. Small turtles, such as terrapins, are very common. You might also see different species of small lizards or water-dwelling snakes.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account