Clupeiformes

Clupeiformes is an order of ray-finned fishes (Actinopterygii) within the superorder Clupeomorpha. The group includes many small to medium-sized, pelagic species such as herrings, sardines, anchovies, and shads. They are distributed worldwide in marine and brackish waters, with several species also inhabiting freshwater. Clupeiformes typically form large schools and undertake seasonal migrations to spawning grounds, giving them a prominent role in oceanic ecosystems and global fisheries.

Morphology and taxonomy: Members are generally streamlined, silvery fishes with a relatively small mouth. The lateral line is well developed, and the caudal fin is often forked. The order comprises several families, most notably Clupeidae (herrings, shads, sardines) and Engraulidae (anchovies); other related families such as Pristigasteridae are also included in classifications.

Ecology and life history: Clupeiformes are largely planktivorous and rely on planktonic prey at various life stages. Eggs are typically pelagic and hatch into larvae that inhabit coastal and estuarine environments before moving into open waters as they mature. Their schooling behavior aids in predator avoidance and feeding efficiency.

Human relevance: They are among the most important forage fishes, forming the base of many marine food webs and supporting large commercial fisheries. Harvesting for direct consumption, fish meal, and oil is widespread, making sustainable management essential to prevent overfishing and ecosystem disruption.

Evolution and distribution: The group has a long fossil record and is present in oceans worldwide, with adaptations spanning full saltwater, brackish, and some freshwater habitats.