Oarai Kuroshio Hovering Sharks
Oarai Coast, Kuroshio–Oyashio Convergence, Ibaraki, Japan · Asia · ocean_reef
About this place
Investigate Kuroshio–Oyashio frontal productivity and Carcharias taurus gastric air-gulping neutral buoyancy.
For kids: Dive where warm and chilly ocean currents meet—and discover gentle sand tiger sharks that gulp surface air to float weightlessly!
Oarai Kuroshio Hovering Sharks · 360° Habitat Camp
What to look for
- Rocky reef hovering canyon — Carcharias taurus gastric hydrostatics. Centre the rocky surge gully where Carcharias taurus suspends at neutral buoyancy
- Kuroshio–Oyashio baitball vortex — Shiozakai frontal phytoplankton bloom. Locate the pelagic schooling fish aggregation fueled by frontal mixing
- Tooth-strewn rippled sea floor — Polyphyodont conveyor-belt dentition. Scan the sandy reef base accumulating shed cuspidate gripping teeth
Source: Hussain (1989) & Bone & Roberts (1969); Smale (2005), Marine and Freshwater Research — Carcharias taurus gastric air buoyancy & rocky-reef aggregations.
Ask together: When you hold a big breath of air in a swimming pool you float right up—how much air would a shark gulp to float steady halfway down without sinking OR bobbing?
Field quiz
Kids' question: How does a sand tiger shark float weightlessly in place without sinking, even though sharks have no swim bladder?
- It swims up to gulp a bubble of surface air and holds it inside its stomach
- It ties buoyant seaweeds around its tail
- Its skeleton is made of hollow dry cork
Answer
It swims up to gulp a bubble of surface air and holds it inside its stomach
Adults' question: What makes Carcharias taurus unique among all known sharks in its mechanism of hydrostatic buoyancy control?
- Gulping atmospheric air at the surface and retaining a regulated gas pocket in the stomach
- Secreting pressurized helium gas from the rectal salt gland
- Calcifying hollow gas chambers inside the dorsal fin spines
- Continuous supersonic tail oscillation at 60 Hz
Answer
Gulping atmospheric air at the surface and retaining a regulated gas pocket in the stomach
360° photo: AsPJT, CC0
See it live: Live check: Oarai Hovering Sand Tiger Shark Cam
- By day
- Hovering sand tiger sharks, sandbar sharks & schooling coastal fishes Compare the slow, near-hovering tailbeat frequency of Carcharias taurus with faster obligate ram-ventilating carcharhinid sharks nearby.
- By night
- Nocturnal cruising sharks gliding effortlessly in dim moonlight-blue water Ampullae of Lorenzini along the rostrum detect nanovolt bioelectric fields during nocturnal foraging bouts.
Other language: Русский