In the Water: Mollusks
Queen conch
Aliger gigas
Jumplinks:
About
This charismatic marine snail thrives in the warm, tropical waters around Saba and throughout the Caribbean, often living in seagrass meadows on the seafloor. Their stunning, spiral shells are made of calcium carbonate and often have a cream-colored exterior with glossy pink or orange inside. They spend their days cruising across the ocean floor in search of food, with young conch munching on seagrass and detritus in the sediment, while adults feed primarily on a range of long-stranded algae.
These snails can grow to be 30 cm/1 foot long and weigh up to 2.3kg/5 pounds. But growing that large takes a long time — queen conchs generally live to be 25–30 years old, reaching their full size around the age of 4. Yet another reason to be a fan of this snail: their eyes. Queen conchs have long, otherworldly eye-stalks that can move around independently of one another. True conchs like the queen have comparatively better eyesight than most other snails and slugs, and studies have found that some species of true conchs have at least six different cell types within their retinas. Conchs’ complex eye structures can help them detect contrast between an object and its background, which is extremely helpful when it comes to detecting approaching predators.
Speaking of which, what eats a snail this big? Some of their primary predators include nurse sharks, eagle rays, spiny lobsters, and … humans. Queen conchs are prized for their edible meat, and in many of the places they’re native to, conservation stakeholders and community-members are in active conversations about how to help queen conchs recover from overfishing.
Header image by @zahnerphoto (CC-BY-NC).
This species is:
Native
Why that matters:
Native species are those that evolved in the region naturally, without human influence. That means they’re specifically adapted to Saba’s habitat, and play a key role in island biodiversity. When we lose native species, gaps appear in the ecosystem. That leads to cascades of additional extinctions, and to the loss of the ecosystem services (food, clean air and water, flood and coastal protections, and more) that we humans rely on.
Credit: @zahnerphoto, iNaturalist (CC-BY-NC).
iNaturalist Observations
Where locals, researchers, and visitors have seen this species.
Google / Imagery © 2023 CNES / Airbus, Landsat / Copernicus, Maxar Technologies, U.S. Geological Survey, iNaturalist Map data @2023
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Ask a Scientist
Question: How do queen conchs actually eat?
Answer: The queen conch uses a long, snout-like proboscis armed with a radula (ribbon of teeth) inside the tip to nip chunks of algae, slurp diatoms, and consume decomposing seagrass. As a conch matures, it shifts its diet away from diatoms, small algae, seagrass detritus, and other organics in the sediment to munching only on long, thin threads of macroalgae as an adult.
Chrissy Piotrowski
Invertebrate Zoology Collections Manager, California Academy of Sciences
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