scubaseason
Critically Endangered· population decreasing· assessed 2019

Scalloped hammerhead

Sphyrna lewini

Sighting evidence at Yabiji Reef, Okinawa

Scalloped hammerhead

Photo: Kris Mikael Krister · CC BY

One of the most socially complex sharks on the planet, scalloped hammerheads form large aggregations at seamounts and offshore pinnacles during warmer months. Their broad cephalofoil houses an array of electroreceptors that make them exceptionally effective predators of fish and squid. Classified as Critically Endangered on the IUCN Red List due to targeted finning and bycatch.

Evidence at this site

No confirmed records on file at this site

Scalloped hammerhead is listed as a curated species here based on historical reports.

How is this calculated?

Sighting evidence is compiled from iNaturalist observation records within a set proximity radius, filtered for quality-grade observations. “Last confirmed” is the date of the most recent research-grade record. Record count covers a rolling 24-month window. Confidence reflects record count, recency, and consistency of seasonal signal.

Also seen at other sites