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Depending on whom you talk to, jellyfish are either fascinating, a nuisance, a toxic menace, or some combination of the above. Jellyfish plop into the media spotlight when their presence causes beach closures, or...
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The ocean is home to a phenomenal diversity of marine organisms. They have...
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This summer, many of you have likely enjoyed feasting on crabs, be they blue,...
Zombie worms don’t crave brains: instead they seek bones. The 1 to 3 inch (2 to...

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A sea monster attacks a ship in an illustration for 20,000 Leagues Under the Sea by Jules Verne. The illustration is by publisher and artist Pierre-Jules Hetzel, who is most famous for his drawings in Verne's books. This...
Many sperm whales stranded on beaches or caught by whalers exhibit telltale...
Two bright orange anemonefish ( Amphiprion ocellaris ) poke their heads...

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Coral reefs are the most diverse of all marine ecosystems. They teem with life, with perhaps one quarter of all ocean...
The festive Christmas tree worm ( Spirobranchus giganteus ) lives on tropical coral reefs and resembles a fluffy fir tree adorned with ornaments. The multi-functional branch-like appendages are used...
These corals from the Smithsonian collections are Stephanocyathus (A.) spiniger , a solitary, deep-water stony coral species. Around 74% of all deep-water corals are solitary, living as individual...
A male mudflat fiddler crab ( Uca rapax ) waves its huge claw to impress females and threaten competitors. Only the males have the large claw. When the tide is high, fiddler crabs retreat to their...
The largest of the cuttlefish species, Australian Giant Cuttlefish ( Sepia apama ) delight scientists each year as they gather in masses to spawn in northern Spencer Gulf, northwest of Adelaide in...
In the spring of 2011, a research crew from Oceana spent two months in the brackish Baltic Sea . The Baltic faces challenges from pollution, algae blooms, over fishing, and invasive species. Oceana...
A sea star , Hymenaster pellucidus , brought up from a benthic ROV dive. View the “Under Arctic Ice” photo essay to learn more.
The lion’s mane jellyfish ( Cyanea capillata ) is the largest among the jelly species, with the largest known specimen stretching across 120 feet (36.5 meters) from its top to the bottom of its...
Two brown and purple nudibranchs ( Risbecia tryoni ), crawling in tandem on a surface encrusted with pink-colored coralline algae. These "sea slugs" live in the tropical Western Pacific Ocean. You...
The blanket octopus can rip a poisonous tentacle from a Portuguese man-o-war and wield it like a sword to ward off enemies as it soars through the ocean trailing its webbed cloak behind it...
Species of deep-sea gold coral, or Gerardia , often have a tree-like shape, as you can see in this specimen. See more pictures of coral in our Deep-sea Corals article.
Shellfish from the Chesapeake Bay are prized by seafood lovers. But the Bay's ecosystem and fisheries are threatened by human disturbances, including the introduction of non-native species. Non-...
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