Cordell Bank National Marine Sanctuary facts for kids
Quick facts for kids Cordell Bank National Marine Sanctuary |
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| Location | Cordell Bank, California, United States |
| Area | 1,286 sq mi (3,330 km2) |
| Established | 1989 |
| Governing body | NOAA National Ocean Service |
The Cordell Bank National Marine Sanctuary is a special underwater place off the coast of California. It protects a huge area of ocean, about 1,286 square miles (3,331 square kilometers), filled with amazing marine wildlife.
This sanctuary is built around Cordell Bank, which is like an underwater mountain. It's about 50 miles (80 kilometers) northwest of San Francisco. The top of this underwater mountain is only about 115 feet (35 meters) below the ocean surface.
Cordell Bank was first discovered in 1853 by the U.S. Coast Survey. It was named after Edward Cordell, who explored the area more closely in 1869. This important area has been protected as a sanctuary since 1989. It's one of 13 National Marine Sanctuaries in the United States that work to keep our ocean healthy.
The special mix of ocean conditions and the unique shape of the underwater land here create a rich and diverse home for many sea creatures. The sanctuary is a vital spot for many animals, including migrating marine mammals, birds, and fish. Cold, nutrient-rich water from the deep ocean rises here, providing lots of food for everything from tiny plants to giant whales.
To keep this area safe, certain activities are not allowed. For example, you cannot remove oil or gas, take bottom-dwelling creatures, dump waste, or remove historical items. Because of the deep water and strong currents, SCUBA diving is not recommended here.
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How did Cordell Bank form?
Cordell Bank began forming about 93 million years ago. It was once part of the Sierra Nevada mountains! Over millions of years, the Earth's plates have been slowly grinding past each other at the San Andreas Fault. The Pacific Plate moves north, and the North American Plate moves south. This slow movement broke off parts of the Sierra Mountains and carried them northward. Cordell Bank was one of these pieces.
Today, Cordell Bank is still moving about 1.2 inches (3 centimeters) each year. Long ago, between 20,000 and 15,000 years ago, the sea level was much lower. This meant that most of Cordell Bank was actually above water, like a true island! Now, it's mostly made of granite and rises from soft sand and mud on the ocean floor. Just 7 miles (11 kilometers) from Cordell Bank, the ocean floor drops to over 1 mile (1.6 kilometers) deep.
When was Cordell Bank discovered?
For a long time, Cordell Bank was a mystery. Native American people and early settlers in California didn't need to go far from shore to find food. So, they didn't know about this underwater mountain. Many European sailors even sailed right over it without realizing it was there!
In the mid-1800s, people started exploring the California coast more carefully to make shipping safer. Cordell Bank was first discovered in 1853 by George Davidson of the US Coast Survey.
In 1869, Edward Cordell was sent to find more information about this "shoal" (a shallow area) west of Point Reyes. He found the area by following the many birds and marine mammals that gathered there. To measure the depth, he used a simple method: he lowered a heavy lead weight on a line until it hit the bottom, then measured how much line he had let out.
People knew it was a good fishing spot, but not much was known about its marine life until a big expedition in 1977. A research group called Cordell Expeditions led this effort. For 10 years, divers explored the bank, documenting all the amazing creatures living there. Their work helped everyone understand how special Cordell Bank was, which led to it becoming a sanctuary.
Later, in 2015, the sanctuary was made even bigger! Its borders were expanded to include more ocean area, helping to protect even more marine life.
What animals live at Cordell Bank?
Cordell Bank is a bustling underwater city for many different animals!
Marine Mammals
Over 26 types of marine mammals visit the sanctuary's waters. This includes amazing creatures like whales, dolphins, seals, and sea lions. Cordell Bank is one of the most important feeding grounds in the world for endangered blue and humpback whales. These giant whales travel all the way from Mexico and Central America to eat tiny shrimp-like creatures called krill that gather near the bank.
You might also see large groups of Pacific white-sided dolphins. Other visitors include California sea lions, northern elephant seals, northern fur seals, and Steller sea lions. They all come here because there's so much food, like krill, squid, and young fish. Even Leatherback sea turtles swim through these waters.
Seabirds
Cordell Bank is also a major feeding spot for seabirds flying by. It's sometimes called the "Albatross capital of the world" because 5 out of the 14 main types of albatross have been seen here. The most common are the black-footed albatross and sooty shearwater. It's also one of the few places where you might spot a short-tailed albatross, which is extremely rare. This species was almost extinct after World War II, but now there are about 1,000 of them in the world.
Fish
The bank is full of fish! Flatfish, like sanddabs, live on the muddy seafloor. Many other fish, both alone and in schools, find safe places among the rocky parts of the bank. Cordell Bank is home to more than 246 types of fish. This includes 44 kinds of rockfish, which can range from small 8-inch pygmy rockfish to large 3-foot yelloweye rockfish.
Even though it's far from shore, people who enjoy sport fishing often come to Cordell Bank to catch fish like albacore and salmon.
Why is Cordell Bank so rich in life?
This unusual underwater mountain is surrounded by deep waters on three sides. This allows deep, nutrient-rich water to flow up over the shallower parts of the bank. Here, there's enough sunlight for tiny ocean plants (called phytoplankton) to grow through photosynthesis.
The ocean's seasons play a big role in the life at Cordell Bank.
- Spring: Strong winds push surface water away from the coast. This causes cold, nutrient-rich water from the deep ocean to rise up. These nutrients help tiny ocean plants grow, which are the base of the entire food web. More plants mean more food for everything else!
- Late Summer and Fall: The strong winds calm down. Warmer, less nutrient-rich water from the south flows in.
- Winter: Big storms mix the deeper water with the surface water. This helps to spread nutrients, temperature, and saltiness evenly throughout the water.
