Skipjack shad facts for kids

Quick facts for kids Skipjack shad
Scientific classification

The skipjack shad (Alosa chrysochloris) is a type of fish found in North America. It lives in both fresh and slightly salty (brackish) water. This fish is part of the herring family, called Clupeidae.

People call it "skipjack shad" because it often jumps out of the water when it's looking for food. Other names for it include blue herring and Tennessee tarpon. These fish mostly live in rivers and areas that drain into the Gulf of Mexico. They like clear or slightly cloudy water that is moving.

Skipjack shad travel long distances to lay their eggs. Large dams can block their journey. In the past, there were many more skipjack shad in the Upper Mississippi River. Today, you can find most of them in the Upper Mississippi River, especially below where the Ohio River joins it. They are known as "early-run" fish because they migrate to spawn in the early spring.

Where Skipjack Shad Live

The skipjack shad lives only in the United States in areas that drain into the Gulf of Mexico. This includes big river systems like the Mobile River, the ACF (Apalachicola, Chattahoochee, Flint Rivers), the Mississippi basin, and the Rio Grande basin.

Long ago, there were many skipjack shad in the upper Mississippi River. But dams were built, which made it harder for them to travel. Now, most skipjack shad are found in the upper Mississippi River below the Ohio River. In recent years, changes to the middle Missouri River have helped skipjack shad. They have spread further upstream, even to the border of Nebraska and South Dakota.

Historically, skipjack shad were also found in the northern upper Mississippi River and the St. Croix River. However, since the 1950s, only a few have been seen in Wisconsin. Because these fish migrate, dams have reduced where they can live. They cannot swim over tall dams. So, it's rare to see them in the very northern parts of the Gulf of Mexico river systems.

How Skipjack Shad Live (Ecology)

Skipjack shad are fish that travel in groups called schools. They can live in both salty and fresh water. They can swim from the ocean into fresh water to lay eggs, but they don't have to. They can also complete their whole life cycle in fresh water.

These fish love fast-moving water in rivers. They are famous for jumping out of the water. You can find them in clear or slightly cloudy water in big rivers and reservoirs. They usually stay in the current over sand or gravel bottoms.

Skipjack shad eat other smaller fish, especially other types of shad or herring. They might eat threadfin shad, gizzard shad, or young herring. Sometimes, if food is scarce, they might even eat their own kind. Young skipjack shad mostly eat insects. They can eat fish that are up to about 30-35% of their own body length.

We don't know much about what animals eat skipjack shad. But we do know that larger fish, seabirds, and humans can prey on them. In fact, fish from the herring family, like the skipjack shad, can make up a large part of what some birds eat.

Skipjack Shad Life Cycle and Reproduction

Skipjack shad lay their eggs (spawn) from early March to late April in the southern parts of their range. In the upper Mississippi River, they spawn later, from early May to early July.

Female skipjack shad can produce a lot of eggs, usually between 100,000 and 300,000 each year. They usually start spawning when they are 2 to 3 years old and about 11.8 inches (30 cm) long. They are thought to lay their eggs deep in the main river channels, over coarse sand and gravel. The water temperature for spawning is usually between 16 and 21 °C (61 and 70 °F). The eggs are simply released into the water over the river bottom.

Young skipjack shad can grow to be 75 to 150 mm (3 to 6 inches) long in their first year. Adult skipjack shad can grow up to 20 inches (51 cm) long, but they are most often found to be between 12 and 18 inches (30 and 46 cm). The oldest skipjack shad ever found was four years old.

Humans don't seem to affect the skipjack shad's life cycle much. This is because they have high population numbers and people don't fish for them very often. While dams have changed where they live, the fish still seem to be able to spawn without problems.

Protecting Skipjack Shad

In the southern parts of their range, humans don't seem to have a big impact on skipjack shad numbers. However, dams have limited where these fish can naturally travel. Skipjack shad are no longer found in large numbers in the northern parts of their range. This is because they cannot swim over big dams.

The Minnesota Department of Natural Resources (DNR) says that we need to learn more about these fish. They also state that dams stop skipjack shad from migrating in early spring. To help skipjack shad return to Minnesota and Wisconsin, where they are almost gone, special fish passages like ladders or lifts are needed at dams on the Mississippi River.

For example, a fish passage is being considered at U.S. Lock and Dam 3 near Red Wing. This could help skipjack shad move more freely in the Mississippi River. The Minnesota DNR also did surveys from 2006 to 2008 to find rare fish, including the skipjack shad. But they didn't find any skipjack shad in those surveys.

It's also important to know that two types of mussels, the ebony shell (Fusconaia ebena) and the elephant ear (Elliptio crassidens), are endangered in Minnesota. These mussels need the skipjack shad to complete their life cycle. If the skipjack shad disappears, these mussels might disappear too.

To stop their living areas from shrinking, we need to build fewer dams. Or, we need to build dams that skipjack shad can swim through. Dams also slow down the water flow, and skipjack shad prefer fast-moving water. It's also important to keep the water clear. These fish only live in clear to moderately cloudy water.

Scientists can find skipjack shad using gillnets and electrofishing. These methods work best below dams, over sand or gravel, especially during spring when the fish are spawning. It's important to study skipjack shad across all the areas where they naturally live. This helps us understand how many there are and how human changes affect them. For now, skipjack shad numbers are stable in the southern areas. But they need more help and management plans in the northern parts of their range.

About Skipjack Shad Classification

The skipjack shad is part of the Alosa group of fish. Scientists have found that the skipjack shad is one of the oldest types of Alosa fish. Other Alosa species are found in Europe and Western Asia.

See also

In Spanish: Alosa chrysochloris para niños