Round Herring

The Round Herring (Etrumeus teres, genus Etrumeus) is a small pelagic fish in the herring family notable for its unusually cylindrical, rounded body shape compared to the laterally flattened profile typical of most herrings and sardines. It occurs widely in temperate and subtropical coastal waters around the world, including the western Atlantic, Mediterranean, and parts of the Indo-Pacific, with several closely related regional species and subspecies recognized within the genus. Round Herring form large offshore schools and are an important prey species for a wide range of predatory fish, seabirds, and marine mammals, while also supporting localized commercial fisheries in some regions.

Round Herring are distinguished from other herring-family fish primarily by their body shape.

• Cylindrical, rounded cross-section rather than the strongly flattened, blade-like body of typical herrings and sardines
• Smooth belly lacking the sharp keel of scutes seen in sardines and shad
• Large eye and a blue-green back fading to silvery flanks with no distinct spotting
• Deeply forked tail and a single dorsal fin set near the middle of the back
• Typical adult length 15-25 cm, with a more torpedo-like silhouette than co-occurring sardines

Round Herring inhabit temperate and subtropical continental shelf waters worldwide, typically occurring over sandy or open bottoms at depths from near the surface down to around 200 meters. They favor cooler, well-mixed offshore waters and often form schools some distance from shore, moving inshore seasonally to spawn. The genus includes regional populations and closely related species across the western Atlantic, eastern Pacific, Mediterranean, and parts of the Indo-Pacific, each adapted to local shelf conditions. Round Herring tend to occupy deeper, more offshore water than shallow coastal sardines and anchovies.

Round Herring school in open water over the continental shelf, feeding on planktonic copepods and other small crustaceans filtered through fine gill rakers. Spawning occurs seasonally, typically in warmer months, with pelagic eggs released offshore that drift with currents until hatching. The species grows relatively quickly and forms large, cohesive schools that provide protection from the many predatory fish, seabirds, and marine mammals that feed heavily on it. As an offshore forage fish, Round Herring occupies an important position in shelf ecosystems, transferring energy from plankton to higher trophic levels across its range.