Fauna
Invertebrate

Parasitic Hyperiid Amphipod

Phronima sedentaria

Also known as Pram Bug, Barrel Shrimp

Pram bugs are translucent deep-sea crustaceans famous for hollowing out gelatinous salps to construct buoyant barrel homes. Females use powerful clawed legs to steer these floating transparent nurseries through the ocean while guarding dozens of larvae inside. Participating in massive daily vertical migrations, they ascend into upper ocean layers at night to hunt before sinking back into mesopelagic darkness.

Deep SeaTranslucentParasitoid
Parasitic Hyperiid Amphipod reference1 / 2
(c) Steve Kerr, some rights reserved (CC BY), uploaded by Steve Kerr · cc-by
—observations
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—peak records
Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Key facts
Diet & preySalps, Pyrosomes, Small copepods
Predators
  • Deep-sea fish
  • Pelagic squid
  • Seabirds
ThreatsOcean acidification and marine microplastics
HabitatsOpen ocean pelagic, mesopelagic, and bathypelagic zones
Life span1–2 years
Classification
  1. OrderAmphipoda
  2. FamilyPhronimidae
  3. GenusPhronima
  4. SpeciesPhronima sedentaria
Range & activity
Range data is not available yet.
Safe observation
Interaction riskLow
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is low
Safe to observe at a normal distance.
Responsible observation
  • Pelagic Sightings: Watch for transparent barrels drifting near the surface during blackwater night dives.
  • Gentle Handling: Leave barrel structures submerged to prevent delicate gelatinous walls from collapsing.
Related species
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