Why the herring family evolved to be the ocean's most efficient filter-feeding machines

Nature · Published 3 October 2026 Swipe more like this →

In short: The Clupeidae family, including herrings and sardines, are master survivors of the marine world. By ditching teeth for specialized gill rakers and adopting a high-speed, hydrodynamic body shape, these fish have mastered the art of filter feeding, turning the ocean's smallest plankton into the foundation for entire marine food webs.

Clupeidae is a diverse family of ray-finned fishes that includes familiar species like Atlantic and Pacific herrings. These fish are defined by their fusiform, or tapering, body shape, which is highly hydrodynamic. This physical structure allows them to achieve high bursts of speed, a critical adaptation for both evading predators and regulating their feeding intake. Because they are filter feeders, their survival depends on water passing over their gills, where long, specialized protrusions called gill rakers trap plankton and other small particles.

The evolution of their feeding mechanism is closely tied to their life cycle. During their larval stages, clupeids primarily consume phytoplankton and plant matter. As they mature, their gill rakers and body size increase, allowing them to capture larger, more substantive prey like zooplankton and copepods. Because their diet consists of these small organisms, they have little need for teeth. Where teeth are present, they are typically miniature and barely visible, as the fish do not need to cut or tear their food. This efficiency allows them to thrive in lower trophic levels, where they bioaccumulate very low levels of methylmercury compared to larger predators.

Social behavior is another hallmark of the family. Clupeids live in massive shoals, often forming dense 'bait balls' to protect themselves from a wide range of piscivorous predators, including sharks, toothed whales, and birds. They are prolific spawners, releasing up to 200,000 eggs near the water's surface, which receive no parental care. While the family concept has been refined over time—with some groups like Alosidae now classified separately—the core of the Clupeidae remains a vital economic and ecological force. From the fossil record, which traces their origins to the late Campanian or early Maastrichtian in Italy, to their current role in global fisheries, these fish remain essential to the health of marine ecosystems.

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