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Shell Shock!

A giant sea snail in the Bahamas is threatened by overfishing—but there’s hope it can be saved

By Jennifer Barone
From the March/April 2023 Issue

Learning Objective: Students will describe causes and effects of a sea creature’s decline, as well as solutions to increase its numbers.

Lexile: 860L; 640L
Guided Reading Level: U
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When people in the Bahamas have a celebration, queen conch (pronounced konk) is usually on the menu. This giant sea snail lives in the waters around the island nation. “It’s just not an event without conch,” says Agnessa Lundy. She’s an ocean scientist based in the Bahamas who has studied the animals.

People in the Bahamas have enjoyed dishes like conch salad and conch fritters for generations. Conch is popular with tourists who visit too. That makes conch fishing important for the local economy. Thousands of people make their living gathering the snails.

But in recent decades, conch numbers have dropped dramatically. Giant piles of empty shells line the shores of the islands. “As the population of the Bahamas has grown, demand for conch has grown too,” says Lundy. If nothing changes, both the snails and the fishers who rely on them could be in trouble.

There’s a type of seafood served at most parties in the Bahamas. It’s queen conch (pronounced konk). It’s a giant sea snail. It lives in the waters around the island nation. “It’s just not an event without conch,” says Agnessa Lundy. She’s an ocean scientist in the Bahamas. She has studied conch.   

People in the Bahamas have long enjoyed conch dishes. They include conch salad and conch fritters. Conch is popular with tourists too. That makes conch fishing important for locals. Thousands of people make their living catching the snails. 

But conch numbers have fallen in recent decades. There are giant piles of empty shells. They line the islands’ shores. “As the population of the Bahamas has grown, demand for conch has grown too,” says Lundy. Something needs to change. If not, both the snails and the fishers who rely on them could be in trouble. 

An Easy Catch

Conch are invertebrates. A hard spiral shell protects their soft bodies (see Conch Anatomy). “There’s this massive shell and the most adorable eyes you can imagine peeking out,” says Andrew Kough. He’s a biologist at the Shedd Aquarium in Chicago, Illinois.

Conch gather in herds on the seafloor. They graze on tiny plant-like organisms called algae (AL-jee). Conch also eat dead seagrass. This helps keep the ecosystem healthy.

Conch are invertebrates. Each has a soft body (see Conch Anatomy). It’s protected by a hard spiral shell. “There’s this massive shell and the most adorable eyes you can imagine peeking out,” says Andrew Kough. He’s a biologist. He works at the Shedd Aquarium. It’s in Chicago, Illinois.

Conch gather in herds on the seafloor. They graze on algae (AL-jee). It’s a tiny plantlike living thing. Conch also eat dead seagrass. This helps keep the ecosystem healthy.

© JUSTIN TUTTLE

Biologist Andrew Kough measures a conch shell to learn the snail’s age.

Conch move by pushing their bodies forward using their claw. The process is slow. It makes the snails easy to grab. “Conch can’t run away,” says Kough. Fishers can easily harvest large numbers of the animals.

Traditionally, fishers reached conch by snorkeling or holding their breath to dive. That limited the number of snails they could gather. Modern fishers have special gear for breathing underwater. That means they can dive longer and deeper to collect many more conch.

Conch push their bodies forward using their claw. They move slowly. It makes the snails easy to grab. “Conch can’t run away,” says Kough. Fishers can easily harvest large numbers of the animals.

Fishers used to snorkel or hold their breath to dive for conch. That limited the number of snails they could gather. Modern fishers have special gear. It allows them to breathe underwater. That means they can dive longer and deeper. That allows them to collect many more conch.

Dwindling Numbers

A few years ago, Kough and other scientists counted conch in the Bahamas. The researchers snorkeled while tied to boats that slowly towed them along. They examined 42 sites covering nearly a million square meters (10 million square feet) of the seafloor.

Kough and other scientists visited the Bahamas a few years ago. They counted conch there. The group snorkeled while tied to boats. The boats slowly towed them along. The scientists visited 42 sites. They studied nearly a million square meters (10 million square feet) of seafloor. 

© SHEDD AQUARIUM

A scientist snorkels and counts conch as a small boat pulls him through the water.

The researchers then compared their count with previous ones dating back to the 1980s. They realized that the conch population had shrunk dramatically over the years. In some places, the number of adult conch had dropped by more than 90 percent.

Most of the conch left on the seafloor were juveniles. That’s a problem because only adult conch can reproduce (see Conch Life Cycle). If fishers remove too many adults, the conch population may not be able to support itself. If nothing changes, the scientists warned, conch could disappear from the Bahamas within a decade.

The scientists compared their count with previous ones. The counts dated back to the 1980s. The scientists found conch numbers had fallen greatly over the years. Adult conch numbers had dropped by more than 90 percent in some places. 

Most of the conch left on the seafloor were juveniles. Conch numbers can’t grow if fishers remove too many adults. That’s because only adult conch can reproduce (see Conch Life Cycle). Conch could disappear from the Bahamas within a decade if this continues.

Finding Hope

Scientists say there’s still a chance to protect the conch’s future. One way is to create more protected areas where fishing is not allowed. Kough and Lundy think it could work. They worked on a study that found protected areas have larger numbers of mature conch. Their offspring drift into surrounding waters. That gives the whole population a boost.

Scientists say there are ways to help conch. One is to create more protected areas. Fishing would not be allowed in these spots. Kough and Lundy have studied these protected areas. They have larger numbers of adult conch. Their young drift into nearby waters. That boosts conch numbers in other areas.

JAMES QUINE/ALAMY STOCK PHOTO (FISHER); IMAGE BY SHERRY GALEY/GETTY IMAGES (CONCH SALAD)

Left: A fisher uses an ax to remove a conch from its shell. Right: Conch salad is a beloved Bahamian dish.

The government of the Bahamas has considered limiting conch fishing season. And scientists are working closely with fishers to find ways to harvest conch sustainably. For example, conch farms, where people raise conch in tanks, are growing in popularity. Snails from farms can be used for food or released into the wild.

The fate of conch in the Bahamas is still uncertain. But scientists like Kough and Lundy believe that the snails can survive. “Conch is a part of the culture that is deeply cherished,” says Kough. “We don’t want people to stop eating conch—we just need to find ways to make those traditions sustainable.”

The government of the Bahamas has also thought about limiting conch fishing season. And scientists are working closely with fishers. They want to find ways to harvest conch sustainably. For example, people can raise the snails in tanks. These conch farms are becoming more popular. Snails from farms can be used for food. Or they can be freed into the wild.

The future of conch in the Bahamas is still uncertain. But scientists like Kough and Lundy believe the snails can survive. “Conch is a part of the culture that is deeply cherished,” says Kough. “We don’t want people to stop eating conch. We just need to find ways to make those traditions sustainable.” 

video (1)
Activities (3)
Quizzes (1)
Answer Key (1)
video (1)
Activities (3)
Quizzes (1)
Answer Key (1)
Step-by-Step Lesson Plan

1. ENGAGE: Make predictions about an island’s environment based on its location.

  • Show students the Bahamas on a map. Ask whether any students have visited the Bahamas or if they have family there. If so, let these students share what the environment is like. If not, allow students to predict based on the map what the environment might be like. (For example, usually warm, has many beaches) Tell students they are going to learn about an animal that is very important to Bahamian culture.

2. EXPLORE: Integrate information from an article and video about conserving conch.

  • Play the first 20 seconds of the video “Shedd Aquarium’s Conch Research” with the sound muted. Ask students to describe what they observe about the conch (pronounced konk).
  • Preview the article’s images, then read the article and sidebars aloud while students follow along. Ask: Why are conch important? (They are part of traditional Bahamian food and help keep the ecosystem healthy by eating algae and dead seagrass.) Why are their numbers dropping? (People are gathering too many.) What are some possible solutions being considered or tried? (fishing limits, conch farms, protected areas)
  • Play the video with the sound on, asking students to listen for information that was not mentioned in the article, especially about how scientists study conch. Then ask students to share new facts they learned.

3. EXPLAIN: Identify and link causes and effects.

  • Preview the Conserving Conch activity and complete the first cause-and-effect relationship together. Discuss the fact that the effect is often observed first. Then the cause is figured out by asking “Why did that happen?” Allow students to work alone or in pairs, referring to the article as needed.

4. EVALUATE: Reinforce core ideas with a low-stakes assessment.

  • Preview the Quick Quiz. Have students complete it in pairs, referring to the article as needed. Discuss their answers.

5. EXTEND: Sort mollusks into two categories based on observable traits.

  • Explain to students that conch are in the phylum (FEYE-lum) Mollusca, which is a big category of invertebrates, or animals without backbones, that have many characteristics in common. The animals in one phylum are more closely related to each other than they are to animals in another phylum. But mollusks can also be quite different from one another. (For example, birds and mammals are categorized in the phylum for vertebrates, or animals with a backbone. Birds and mammals have some things in common and some big differences.)
  • Tell students they are going to make observations from photos and decide how to sort mollusks into two categories. Distribute the Sorting Mollusks activity. (Note: Each team needs only one copy of page 2.) To share classifications, students can tour the room to see other teams’ choices, or each group can present and other students can guess the trait that group used for sorting.

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