Ocean animal migrations
Describe ocean migrations linked to food and breeding. Some southern humpback whales travel between Antarctic feeding grounds and warmer breeding waters. Many female sea turtles nest near their hatching area. Routes vary, and some journeys cover thousands of miles.
What a learner can do afterwards
- Describe at least one example of marine animal migration in detail
- Explain that migrations are driven by seasonal food availability and breeding needs
- Explain that some ocean migrations cover thousands of miles, while routes and distances vary
1 · Read
Migration is a repeated journey between places, often linked to seasons. It can help ocean animals reach food or places to breed. A young fish drifting to a new reef may be moving to a new home. One such journey alone does not show a repeated migration.
Some southern humpback whales feed near Antarctica during summer. They eat krill, tiny shrimp-like crustaceans. Many travel to warmer tropical waters in winter to breed and give birth. They return to cold feeding waters as the seasons change. Routes vary, and some one-way journeys cover thousands of miles.
Many female sea turtles travel from feeding areas to nesting areas. They often return near the beach or region where they hatched. This does not mean the exact same patch of sand. They come onto land to lay eggs. Routes and distances vary between species and individuals.
A round trip includes the journey there and the journey back. If each part is 2,000 miles, add them: 2,000 + 2,000 = 4,000 miles. The number line counts total distance travelled, so both journeys add distance.
To find how much farther one route goes, subtract the shorter distance from the longer distance. Imagine one-way routes of 2,400 miles and 900 miles: 2,400 - 900 = 1,500 miles farther. Compare two one-way distances or two round-trip distances, rather than mixing them.
Ocean migrations are repeated journeys linked to food and breeding. Routes vary. Some cover thousands of miles, and many female sea turtles nest near their hatching area.
The readings adapt Te Papa Tongarewa's "Ocean traffic and jigsaw puzzles" and "Save the krill, save the world". Supplemental TED-Ed videos are "The secret lives of baby fish" by Amy McDermott and "How giant sea creatures eat tiny sea creatures" by Kelly Benoit-Bird.
More to read
Ocean traffic and jigsaw puzzles
A whale's journey can cross places used by ships. Shipping lanes can overlap feeding areas, breeding areas and migration routes. A collision with a ship or its propeller can injure or kill a whale.
Ships also make underwater noise. That noise can cover the sounds whales use to communicate. It can disturb animals and make feeding or sheltered nursing areas harder to use.
Researchers track whales to learn where they travel and how they respond to busy waters. Te Papa's whale displays also help visitors understand these threats. Knowing a migration route helps people understand how human activity affects the animals using it.
Save the krill, save the world
Krill are small, shrimp-like crustaceans. Many baleen whales eat them. Large krill swarms in Antarctic summer waters provide food for whales that travel to those feeding grounds. Humpback diets vary between places; krill are not every whale's only food.
Whales return nutrients to the water through their waste. Near the surface, these nutrients can help phytoplankton grow. Phytoplankton are tiny organisms that make food using sunlight, and krill eat them. This recycling of nutrients is called the whale pump.
People harvest krill too. Heavy harvesting and changes in ocean conditions can affect the food available to whales and other animals. Protecting feeding grounds and managing catches can help protect food that migrating animals rely on.
Explore more
2 · Watch
Take it off screen
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.