Sharks migrate for various reasons, including seasonal changes, mating, feeding, and temperature changes in the water.
Some species of shark, such as the great white, migrate long distances to find warmer waters.
Many shark species are known to migrate in common with numerous land, air, and sea animals.
However, unlike land animals or birds that are comparatively easy to observe, scientists have historically been challenged to track sharks’ movements underwater.
Why do sharks migrate? Advances in satellite tagging have increased the understanding of sharks’ behavior somewhat.
Scientists believe that shark migration patterns are associated with four main causes: mating, giving birth, feeding, and in response to seasonal temperature changes.
We will answer the question “why do sharks migrate” by looking at these specific circumstances. We will also consider the most studied of all the migratory sharks, the famous great white shark.
So read on, and we will delve into this fascinating and mysterious behavior.
The 4 Causes of Shark Migration
Migration refers to the movement of animals from one region to another and is observed in all animal groups. However, scientists’ understanding of the specific migration mechanism (for example, how are sharks able to migrate?) remains relatively vague.
Scientists, fishermen, and scuba divers have long believed that sharks migrate when they have observed them seasonally disappearing and then reappearing at a location.
Satellite tagging data has allowed scientists to see specific animals traveling significant distances. This has cleared up some mysteries about where the sharks were disappearing to.
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For example, although they had been observed moving, it was thought that great white sharks always stayed locally in coastal waters to feed on nearby sea lions and elephant seal populations.
However, tagging has shown that individuals often migrate over many thousands of miles.
Studies often only track a small number of individuals making hard evidence challenging to find.
More extensive studies are needed for each shark species to uncover all the mysteries of their migration. However, we can reasonably assume that the reasons why sharks migrate fall into these four categories.
1. Sharks Migrate To Mate
Some shark species are believed to migrate long distances to find a mate and reproduce. For example, sandbar sharks (Carcharhinus plumbeus) have been observed arriving to mate in significant numbers in spring off the east Florida coast.
Blue sharks (Prionace glauca), a deep water requiem shark, are thought to migrate to subtropical waters in early summer to mate before returning to more temperate waters.
Another requiem shark, the blacktip shark (Carcharhinus limbatus), is seen to migrate in their thousands to the waters close to the Florida shore every winter to mate.
The reproduction cycle of the great white shark (Carcharodon carcharias) is still largely unknown.
However, scientists have tracked tagged sharks traveling considerable distances to reach the eastern Pacific’s subtropical open ocean regions. While the reason for their visiting the sea west of Baja California is uncertain, this could be for mating
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2. Sharks Migrate To Give Birth
Once mating has taken place, it is thought that many shark species migration patterns will include a journey to give birth.
Once mating has taken place, the female sandbar sharks, for example, will move north and travel to northwestern estuaries and bays, including Delaware Bay, to give birth to their pups.
Blue sharks appear to give birth in temperate waters, and it has then been observed that juvenile females seem to move north while young males head south.
A study in the 1990’s observed that several female lemon sharks (Negaprion brevirostris) seemed to return about every two years to a lagoon in the Bahamas to give birth.
After carrying out an extensive study over eighteen years, genetic sampling and tagging showed that female sharks over fifteen years old were returning to the same lagoon to give birth as they had been born.
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The research demonstrated that while the adult lemon sharks weren’t seen in the lagoon at other times of the year, the females were visiting their birthplace to give birth.
Pregnant great white sharks have been tracked from their Guadalupe Island mating grounds for 24 months in the open ocean until they traveled to the sea off Baja, California, to give birth.
After the shark pups had been born, the females were then seen to return to Guadalupe Island to mate once more.
Other studies involving great white sharks have shown high numbers of juveniles in waters of the North Atlantic off the state of New York.
It is suggested that pregnant females visit the area in the summer months to give birth and that its food-rich shallow oceans make the perfect nursery.
3. Sharks Migrate to Find New Feeding Grounds
The leading cause of many animal migrations is the pursuit of suitable food sources.
For sharks, this could be following fish movements that migrate to different locations throughout the year. Oher sharks may follow the travels of marine mammals, including seals and sea lions, who move following fish and temperature changes.
Great white sharks are seen off the coast of California in locations such as Año Nuevo and the Farallon Islands in Spring, where they will feed on elephant seal pups, a nutritious high-fat food source.
The same great white shark population is thought to travel to the most northern extents of their range during the summer when they travel as far as the southern Alaskan islands on the eastern Pacific coast of the United States following the seals.
Great white sharks have been tracked over thousands of miles moving between feeding grounds. These travels to find the best food use vast amounts of energy, so this migration must result in significant amounts of food to be worthwhile.
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4. Sharks Migrate Because of Seasonal Changes in Temperature
Cold-blooded sharks are relatively sensitive to water temperature, and some migration patterns are thought to occur as sharks try to stay in their favored temperature range.
Some sharks’ high metabolic rate, including the great white and shortfin mako (Isurus oxyrinchus), allows them to generate their own heat.
This lets these sharks tolerate a much greater range of temperatures which lets them focus on traveling to lower temperatures where the food sources are prioritized over chasing heat.
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Climate change seems to play its part in sharks’ temperature-related migration patterns. The tiger shark (Galeocerdo cuvier) is being driven from its usual areas by increasing temperatures.
During particular warm periods, tiger sharks have been found in waters off the northeast coast of the United States that would have historically been too cold for them.
A research team has tracked tiger sharks migrating approximately 400 kilometers / 250 miles further north for each 1°C increase in average water temperature.
Climate change-driven movements of apex predator sharks into previously unvisited waters could significantly impact their regular fish and wildlife populations.
Are All Sharks Migratory?
No, not all sharks are migratory. Sharks consist of more than 470 species and exhibit an extensive range of different behaviors.
Some sharks are solitary and only meet for breeding or in rich hunting grounds. Others live in social groups which travel and exist together for their entire lives.
Local sharks, including nurse sharks (Ginglymostoma cirratum) and some reef sharks, are considered not to migrate. This group will usually stay around the same location and only travel a maximum of about 160 kilometers / 100 miles from a central point.
Pelagic sharks, including tiger sharks, the blacktip shark, and sandbar sharks, migrate along coastal waters, following food and temperature across a distance of about 1,600 kilometers / 1,000 miles.
Species including great white sharks, blue sharks, and mako sharks are known as highly pelagic and will migrate over many thousands of miles each year.
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What Season Do Sharks Migrate In?
Some sharks could be regarded as being in an almost constant state of migration as they travel from place to place for mating, reproduction, and food during their entire life history.
Others have a more predictable schedule that you can follow. The blacktip shark, for example, can be seen migrating along the eastern seaboard of the United States between North Carolina and Florida during late winter and early spring every year. Their arrival is known locally in Florida as “shark season” and is eagerly predicted.
As sharks often move due to water temperature, you can reasonably predict that many species will be seen further from the equator in warmer months and closer as it is colder.
Tagged great white sharks are seen to leave the Cape Cod area in late autumn to spend their winter in the warmer waters off the southeastern United States and in the Gulf of Mexico.
Where Do Sharks Migrate To?
When asking why do sharks migrate, many people are interested in knowing where sharks migrate to.
As we have seen, shark migration is driven by several factors, so depending on the species, their migration paths can be led by what sharks like to eat, the temperature, or where they will be able to mate and give birth.
The migration of the blacktip shark along the eastern United States coastline seems to be driven primarily by water temperature.
In fact, as water temperatures in their northern habitats have risen, some blacktip sharks have been observed to stop migrating south at all.
Great white shark migration for food can be predicted by the location of near shore habitats with large populations of suitable mammals, including seals and sea lions.
Migrations to the same areas to give birth may be down to the fact that these locations have historically produced sufficient food in safe places for a population of juvenile sharks to flourish.
How Far Do Sharks Migrate?
The distance that sharks migrate depends hugely on their species. Great white sharks have frequently been observed to migrate as far as 4,000 kilometers / 2,500 miles each year between the central California coast and the Pacific Ocean.
On the other hand, coastal pelagic sharks may only travel around a maximum of 1,600 kilometers / 1,000 miles per year for their migration.
How do Great White Sharks Migrate Such Huge Distances?
The extensive migrations of great white sharks can cause them to travel across vast distances of open ocean where food sources can be extremely scarce.
Researchers from the University of Hawaii and the Hopkins Marine Station realized that great white sharks use large supplies of fat stored in their livers to fuel their long journeys.
The liver of the great white can make up as much as a quarter of its body weight, and 90% of it is beneficial lipid fats.
In the absence of blubber-rich seals, sea lions, or whales to eat, the shark’s livers are metabolized to give them the energy to swim.
Once the shark has reached their version of an Outback Steakhouse where the sea mammals are abundant, it can refuel its livers stores.
Shark Migration Frequently Asked Questions
Q: How Far Do Great White Sharks Travel?
A: Great white sharks have been seen to have long migrations of at least 4,000 kilometers / 2,500 miles each year during their migrations.
Q: How Far Do Sharks Travel in a Day?
A: While not known for sure, it’s been estimated that great white sharks could travel at least 80 kilometers / 50 miles in a day.
Q: Do Sharks Hibernate or Migrate?
A: Sharks often migrate to warmer areas to reach their preferred water temperature. Sharks aren’t known to hibernate, but some are thought to sleep somehow.
It’s suggested that sharks who need to swim constantly to get oxygen-rich water to their gills go through periods of relaxation and activity, resting parts of their bodies while still breathing.
Q: Do Sharks Migrate in the Winter?
A: Yes, many shark species will migrate to warmer waters in the winter to stay in their preferred water temperature or seek food.
Q: How Cold Can a Shark Survive?
A: This depends on the type of shark. For example, salmon sharks (Lamna ditropis) can live in waters of just 2°C / 36°F in the North Pacific, thanks to their high metabolic rates. Great white sharks seem to enjoy waters that are no cooler than about 12°C / 53°F.
Conclusion
As we’ve considered why do sharks migrate, we’ve seen that it is a combination of four reasons: mating, giving birth, to find food, and following their preferred water temperature.
There’s a lot that marine sciences don’t understand about sharks’ lifecycles, including their migration patterns. As further research is carried out, we might learn more about the lives of these fascinating creatures.
Additionally, as climate change impacts their existence, we will need to understand how sharks might need to adjust their behavior to accommodate changes in ocean temperature and the location of their preferred feeding grounds. Sharks may have to migrate to new areas, affecting fish and human populations.
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British-born Dan has been a scuba instructor and guide in Egypt's Red Sea since 2010.
Dan loves inspiring safe, fun, and environmentally responsible diving and particularly enjoys the opportunity to dive with sharks or investigate local shipwrecks.
When not spending time underwater, Dan can usually be found biking and hiking in Sharm's desert surroundings.