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Atlantic thread herring

Opisthonema oglinum

Atlantic thread herring
Illustration by Into the Blue

About

The Atlantic thread herring is a small, silvery schooling fish named for a wispy filament trailing off its dorsal fin. It grows up to 38 cm long and is common in harbours and shallow coastal water.

Also known as: herring, hairy back, thread herring, thread-herring, harryback, sprat, bermuda herring, threadfin, greenback, threadfin herring

Length
20 cm · max 38 cm
Weight
max 375 g
Depth
up to 50 m

How to tell it apart

Anglers often mistake it for the scaled sardine, which shares its size, colour, and coastal waters. Check the dorsal fin: the thread herring's last ray trails off into a long, thin filament that the scaled sardine does not have.

Appearance

It has a small head, a bluish or greenish back, and silvery sides marked with 6 to 7 faint dark streaks running lengthwise. Its belly curves down more sharply than its back. A dark spot sits above the gill cover, with a larger dark spot and a row of smaller spots trailing behind it. The last ray of the dorsal fin stretches out into a long, thread-like filament.

Did you know?

Compared with most other herrings, this species has a milder taste. People eat it raw, pickled, or cooked, and anglers also catch it to use as bait.

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