Alosidae

Pacific sardine

Sardinops sagax

Each passing year carries summer migrations farther north

• Blue
• Gray
• Silver
• Tropical
• Coastal
• Nearshore
• Globally widespread
• Marine fish
• Fusiform
• Compressed cross-section
• Medium
• Tropical fish

Playing an indispensable keystone ecological role in coastal upwelling biomes across the Pacific basin, the Pacific sardine is a prolific pelagic clupeoid that forms colossal, shimmering bait balls. Its slender, cylindrical, spindle-shaped torso displays an iridescent blue-green dorsal surface that reflects changing daylight, blending into gleaming silver flanks and a white belly. A classic diagnostic hallmark is a horizontal row of one to two dozen small, distinct black dots strung along the upper flank where the dark back meets the silvery side. Equipped with specialized, densely set comb-like gill rakers, it swims rhythmically through nutrient-rich currents with open mouth to filter diatoms, dinoflagellates, and copepods from seawater. Circum-Pacific in coastal upwelling systems from California and Chile to Japan and Australia, it roams coastal shelves from surface churn down to two hundred meters depth. Supporting marine food webs by fueling seabirds, pinnipeds, dolphins, and tunas, maximum recorded total length reaches forty centimetres.

Sources: NOAA Fisheries — Pacific Sardine, Sardinops sagax