Where Are Sardines Found? Their Habitats and Distribution

Sardines live in cold-to-temperate coastal waters throughout much of the world, concentrated along continental shelves where nutrient-rich upwelling fuels the plankton they eat. The name “sardine” covers several closely related species spread across the Atlantic, Pacific, Indian, and Mediterranean waters, but all of them share a preference for productive, relatively shallow seas between roughly 10°C and 20°C. Their distribution shifts seasonally, tracks ocean currents, and swings on multi-decade timescales tied to large climate patterns. Understanding where sardines actually live means looking at temperature, depth, food supply, oxygen, and the dynamic coastlines that tie those factors together.

A Family of Fish, Not Just One Species

When people say “sardine,” they could be referring to any of several species. The European pilchard (Sardina pilchardus) dominates the eastern Atlantic and Mediterranean. The Pacific sardine (Sardinops sagax) ranges from Alaska to Baja California on the American side and from Japan to Southeast Asia on the western side. The South American pilchard inhabits the Humboldt Current off Chile and Peru. The Indian oil sardine (Sardinella longiceps) thrives off India’s southwest coast. And the South African sardine (also Sardinops sagax) populates the cold Benguela Current. Despite their different names and ocean basins, all of these fish gravitate toward the same type of habitat: cool, plankton-rich water over the continental shelf. The two main types of sardine are distributed in the different upwelling zones of the world, where water is cold to temperate and primary production is high.¹

Temperature Boundaries

Temperature is the single biggest factor shaping where sardines show up. For the European pilchard off Morocco, the 10°C isotherm roughly marks the northern population boundary, and the 20°C isotherm marks the southern one. Within that band, sardines occupy waters between about 13°C and 19°C depending on season and region. Research on Pacific sardine eggs off North America found that eggs were most frequently present in waters between about 11.5°C and 15.5°C, with peak probability at roughly 13°C.² Water colder than 11.5°C, freshly upwelled and very nutrient-dense, typically fell inshore of where the eggs were found. Warmer oceanic water above 15.5°C was too far offshore and nutrient-poor to support them. So sardines don’t simply chase cold water; they sit in a sweet spot between the cold, turbulent upwelling zone and the warm, food-poor open ocean.

Off South Morocco’s Atlantic coast, winter water temperatures in sardine habitat range from about 14°C to 18°C, climbing to 17–19°C in summer. These numbers shift with latitude and season, but the pattern holds everywhere sardines live: they track a moving thermal window rather than staying put at fixed coordinates year-round.

Upwelling Zones and the Food Connection

Sardines eat plankton, so their distribution tracks plankton availability more tightly than almost any other factor besides temperature. The world’s major upwelling systems, where deep, nutrient-rich water rises to the surface and triggers plankton blooms, are sardine strongholds. These include the Canary Current off northwest Africa, the Benguela Current off southern Africa, the Humboldt Current off South America, the California Current off western North America, and the Kuroshio system off Japan. In all of these regions, sardines cluster where chlorophyll concentrations are moderate, typically around 0.2 to 3 milligrams per cubic meter, rather than at the highest concentrations right at the upwelling center.²

Research off Portugal found that satellite-derived chlorophyll data tracked sardine stomach fullness over time, suggesting that the fish are closely tuned to local productivity cycles.³ In eastern boundary current systems like those off Portugal and Morocco, food limitation driven by variation in primary production is a real constraint on sardine populations. When plankton blooms shift or weaken, sardines shift with them.

Depth and Daily Vertical Migration

Sardines are pelagic fish, meaning they live in the water column rather than near the bottom, but they don’t stay at one depth all day. European pilchards off Morocco typically school at 30 to 55 meters during the day and 15 to 40 meters at night. Research off Portugal revealed something unusual about their vertical behavior: unlike most related fish (herrings, anchovies, and other clupeoids), which rise toward the surface at night, sardines off Portugal actually migrated downward after sunset, settling into a layer within 15 meters of the seabed. They dropped rapidly, within about an hour of sunset, and their tight daytime schools expanded into looser aggregations. At dawn, they rose back up and quickly reformed into compact schools.⁴ This reverse migration pattern is the opposite of what most small schooling fish do worldwide, and it may be related to predator avoidance or bottom-water temperature preferences specific to these sardine populations.

In all regions, sardines stay over the continental shelf. They rarely venture into water deeper than about 200 meters. This shelf attachment is consistent across species and oceans, keeping sardines in relatively shallow, productive coastal waters.

The Mediterranean as a Special Case

The Mediterranean Sea hosts sardines year-round, but it works differently from the open Atlantic or Pacific upwelling systems. It is a semi-enclosed basin with no major eastern-boundary upwelling, so sardines depend on localized sources of nutrients: river runoff, winter mixing, and small-scale coastal upwelling. Habitat modeling across the Mediterranean found that bottom depth and sea surface temperature were the two variables that explained the most about where sardines occurred.⁵ Suitable habitat expanded from summer to winter as sardines moved outward over the continental shelf, likely tied to their winter spawning cycle. But because the Mediterranean’s productive areas tend to be localized, sardines there don’t undertake the long-range offshore migrations seen in large upwelling systems. Their movements are shorter and more constrained by geography.

Spawning Grounds and Nursery Areas

Where sardines reproduce tells you a lot about their habitat requirements, because eggs and larvae are far more sensitive to temperature and currents than adults. Off the south Moroccan coast, European pilchard spawning areas are concentrated around Dakhla (roughly 24–25°N) and near Cintra Bay (about 23°N). Eggs appear mostly in winter at temperatures between 16°C and 18°C, and nursery grounds are located nearby, between 21°N and 22°N, in areas where the broad, shallow continental shelf limits dispersal and helps retain larvae close to shore.⁶ Shelf topography matters: a wide, gentle slope keeps larvae from being swept into deep water where survival is poor.

In the western Pacific, the Japanese sardine spawns along the Pacific coasts of both western and eastern Japan. The coastal spawning ground on the continental shelf has been estimated at 95,000 to 143,000 square kilometers depending on the year, making up roughly half to three-quarters of total spawning area. When the spawning population was very large, sardines also expanded into oceanic waters offshore of the shelf, using those deeper waters as a kind of overflow spawning ground.⁷ Egg densities in the oceanic overflow area reached much higher concentrations than on the shelf, suggesting that these fish were packed into whatever habitat was available when the population boomed.

The Kuroshio Current plays a critical role for Japanese sardine larvae. Modeling of larval transport showed that the offshore drift current driven by winter monsoon winds and the distance of the spawning ground from the Kuroshio axis had major effects on larval survival. Larvae spawned too close to the Kuroshio were swept into the open Pacific, where they typically did not survive.⁸ So spawning location relative to the current determines whether a generation thrives or is lost.

Seasonal Migration in the Western Pacific

Japanese sardine fishing grounds follow a clear seasonal migration. From around March or April, fishing grounds shift northeastward as waters warm, reaching their farthest point by August or September. They then retreat southwestward through autumn, ending by November or December at a point still somewhat northeast of where they started the year.⁹ This loop follows the seasonal warming and cooling of the northwestern Pacific and mirrors similar patterns in other sardine populations worldwide, where fish track their preferred temperature band as it shifts with the seasons.

India’s Oil Sardine

The Indian oil sardine is a tropical exception to the cool-water rule. It dominates India’s southwest coast, contributing around 13% of total marine fish production in India. These sardines operate in very shallow water, typically between 5 and 30 meters deep and no more than 200 meters from shore. Their habitat is closely tied to monsoon-driven upwelling: during the southwest monsoon, equatorward winds push surface water offshore, and cold, nutrient-rich water rises to replace it along the Kerala and Karnataka coasts.¹⁰ The sardine fishery peaks during and just after this upwelling season. When monsoon winds weaken or shift in some years, sardine catches drop sharply, demonstrating how tightly this species is coupled to a specific oceanographic event.

The South African Sardine Run

One of the most spectacular sardine events on Earth happens off the east coast of South Africa, where massive shoals of sardines move northward along the KwaZulu-Natal coast each winter, attracting dolphins, sharks, whales, and diving birds. For years, scientists assumed this was a purposeful migration by the local warm-temperate stock. Recent genetic and oceanographic work turned that story upside down. The sardines in the run are primarily of Atlantic origin, from the cold Benguela Current on the west coast of South Africa, not the Indian Ocean population.¹¹ These cold-water fish separate from the western stock and move into temporarily favorable Indian Ocean habitat during brief cold-water upwelling events along the east coast. Once the upwelling ends, they find themselves trapped in warm subtropical water that is physiologically stressful, and they face intense predation. The sardine run, in other words, is a mass migration into an ecological trap, with no apparent fitness benefit for the fish involved.

Modeling of sardine egg transport between South Africa’s western and southern coasts suggests more connectivity between the two stocks than was previously appreciated. Roughly 17% of simulated particles released on the south coast were transported to the west coast, indicating that sardines move between these regions more than managers assumed.¹² This connectivity matters for fishery management, since it means the two stocks are not as separate as catch data might suggest.

Oxygen as a Habitat Boundary

Temperature and food aren’t the only constraints. Sardine larvae actively avoid low-oxygen water. In the northern Benguela upwelling system off Namibia, sardine and anchovy larvae were found almost exclusively in water with dissolved oxygen above 2.0 milliliters per liter and oxygen saturation above 75%.¹³ This matters because upwelling systems often bring up oxygen-depleted deep water, creating oxygen minimum zones that can squeeze sardine habitat into a narrow band between the low-oxygen layer below and the warm surface above. Acoustic surveys off Peru detected a clear biological boundary at the top of the oxygen minimum zone, at around 0.8 milliliters per liter of dissolved oxygen, below which fish and other organisms essentially disappeared.¹⁴ As ocean warming expands these low-oxygen zones, usable sardine habitat could shrink even in otherwise productive areas.

Sardine-Anchovy Seesaw

Sardines and anchovies often share the same waters but don’t always coexist peacefully. In the Bay of Biscay, researchers found that spatial overlap between the two species increased when sardine biomass was high but decreased when anchovy biomass was high.¹⁵ The explanation lies in how each species occupies space: their main population patches sit in slightly different locations, and as one species expands, it pushes into the other’s territory asymmetrically. This dynamic is part of a larger global pattern. In the Pacific, ocean conditions in the mid-1970s shifted from a cool “anchovy regime” to a warm “sardine regime,” and the shift reversed back to an anchovy regime in the mid-to-late 1990s.¹⁶ These multi-decade oscillations appear to be driven by basin-wide climate patterns, including the Pacific Decadal Oscillation.

Sediment records from northern Chile show that sardine and anchovy abundances have traded off on these multi-decade to multi-century timescales for at least 250 years. Anchovy scale deposition in the sediment fluctuated in 25- to 40-year periods, while sardine abundance showed only two major peaks over the entire record, one in the late 19th century and another in the late 20th century.¹⁷ Sardine population booms appear less frequent but possibly larger in magnitude, suggesting that sardines need a particular combination of climate conditions to flourish, conditions that occur on longer cycles than the more frequent anchovy oscillations.

Climate Change and Shifting Ranges

As oceans warm, sardine habitat is on the move. Modeling of the European pilchard’s distribution under different climate scenarios projects a gradual poleward shift in the species’ center of distribution toward Norway’s coast by the end of the century. Under a high-emissions scenario, this northward expansion becomes more pronounced by 2100. Sea surface temperature, distance to the coast, salinity, and current velocity were the environmental variables with the highest explanatory power in these projections.¹⁸ This means countries in northern Europe that historically had little sardine presence may see growing sardine populations, while traditional sardine fisheries in Portugal, Morocco, and the western Mediterranean could face declining stocks as the thermal window moves away from them.

In the western Pacific, recent analysis found that Japanese sardine abundance increased over recent decades, but their distribution pattern stayed relatively stable and their estimated thermal niche did not shift between phases of the Pacific Decadal Oscillation.¹⁹ Japanese anchovy, by contrast, shifted from offshore to coastal regions and changed its thermal niche during the same period. The fact that sardines held their thermal preferences steady while anchovies adjusted suggests that the two species will respond to future warming in different ways, which could reshape the competitive balance between them.

How Habitat Models Predict Sardine Location

Fisheries scientists have gotten increasingly good at predicting where sardines will be, which matters both for sustainable fishing and for conservation. Off western Portugal, a habitat model using salinity, temperature, fluorescence (a proxy for plankton), and the acoustic backscatter from other organisms was able to predict sardine distribution reliably across multiple survey years.²⁰ The model achieved high accuracy, meaning the relationship between sardines and their environment was consistent from year to year. In the Mediterranean, models confirmed that habitat extent and sardine landings tracked each other in both summer and winter, reinforcing the idea that sardines are where their habitat is, not somewhere random.⁵

These tools are becoming essential as sardine ranges shift with changing ocean conditions. If you know what combination of temperature, chlorophyll, salinity, and depth a sardine population prefers, you can forecast where it will move as those variables change, whether season to season or decade to decade. The fish don’t have GPS, but their environmental preferences are predictable enough that the models work.