Fish
Sardine
Sardina pilchardus · also called pilchard
Once a year off the coast of South Africa, sardines gather into a moving mass so enormous it shows up in satellite photographs — a single migration that draws dolphins, sharks, whales, and seabirds into one of the largest predator feeding frenzies on the planet. The rest of the year, this small, unremarkable-looking fish quietly underpins entire ocean food webs and some of the biggest fisheries on Earth.
Overview
The sardine, Sardina pilchardus, is a small, silvery, schooling fish of the eastern Atlantic and Mediterranean. A filter feeder, it strains plankton from the water almost continuously while swimming in shoals that can number in the millions, a defence that makes any single fish hard for a predator to target.
The sardine run and a short, fast life
South Africa’s annual sardine run produces shoals large enough to be seen from space. Sardines live fast — maturing quickly and spawning heavily — a strategy that lets the species absorb enormous natural predation and heavy fishing pressure while staying broadly abundant.
Status
Least Concern but decreasing in some regional fisheries, where overfishing combined with natural ocean cycles has caused sharp local declines — consequences that, given the sardine’s foundational role in the food web, can ripple far beyond the fish itself.
Sardine: common questions
What exactly is the South African sardine run?
The sardine run is an annual migration in which enormous shoals of sardines move along the eastern coast of South Africa, forming shoals so large and dense that they can be detected from satellite imagery, one of the biggest aggregations of a single marine species anywhere in the world. This mass of fish attracts an intense feeding frenzy from a huge range of predators, including dolphins, sharks, seabirds, and whales, all converging on the same stretch of coastline to take advantage of the temporary but enormous concentration of food.
Why do sardines travel in such large schools?
Schooling in huge numbers, sometimes running into millions of fish, provides a strong defence against predators, since a large, densely packed, coordinated group is confusing and difficult for a predator to target effectively, a phenomenon often described as the confusion effect. Any individual sardine's chance of being the specific fish caught is diluted enormously within such a large group, and the coordinated, rapidly shifting movement of the whole school can also make it harder for predators to isolate and pursue a single target successfully.
Is a sardine the same fish as a pilchard?
In many cases, yes, particularly in Europe, where the terms sardine and pilchard are often used for the very same species, Sardina pilchardus, sometimes based simply on the size of the individual fish, with smaller fish called sardines and larger, more mature individuals called pilchards. In other parts of the world, however, the common name sardine is applied more loosely to several related but distinct small, oily, schooling herring-family fish, so the exact species referred to by the name sardine can vary somewhat depending on the region.
Why are sardines considered such an important fish commercially and ecologically?
Sardines support some of the largest fisheries in the world by total weight, supplying both tinned fish for direct human consumption and large volumes of fishmeal and fish oil used in animal feed and aquaculture, making them economically significant on a global scale. Ecologically, their enormous abundance and position near the base of the marine food web mean they convert plankton into food usable by a wide range of larger predators, so major changes in sardine numbers, whether from fishing pressure or natural ocean cycles, can have effects that ripple through entire marine ecosystems.