Asian Clams (Gold)

Asian Clams (Gold)
Learning about the golden clams that are hurting New Zealand's rivers and lakes.
The Golden Clam Arrives
The Asian Clam, also called the golden clam, is now a big problem in New Zealand's rivers and lakes. This type of shellfish comes from places like Asia, Australia, and Africa. It has spread to many places around the world, like North and South America, Europe, and now New Zealand.
In New Zealand, especially in the Waikato River, there are many of these clams. Scientists are worried because there are tens of thousands of them in just one square meter of river! These clams can hurt the local plants and animals by taking over their homes. They can also block water pipes and power stations if we don't stop them.
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How They Make Many Babies
Grown-up clams can have babies all by themselves. This means just one clam can start a whole new family. They can have babies many times a year and live for about three or four years.
Each clam can make between 1,000 and 100,000 baby clams each year. This helps them grow in numbers very quickly, making it hard to stop them from spreading.
How Clams Grow and Spread
01
From Eggs to Young Clams
After their eggs are joined, Asian clam babies grow into young clams in about 4-5 days.
02
Floating Around
These young clams float freely. They use a sticky bag to help them spread. They can stick to plants, animals, boats, and other things. This helps them travel to new places.
03
Growing Shells and a Foot
Later, they grow a shell and a tiny 'foot'. At this stage, they are so small you can barely see them.
04
Becoming Grown-Up
They become grown-up when they are three to six months old. Then they are about the size of a small pea (6-10mm) and can grow to be as big as a coin (10-30mm).
How Asian Clams Affect Waterways
Asian clams cause many problems in New Zealand's rivers and lakes. They eat tiny bits of food from the water. This means less food for other water animals that live there naturally, especially tiny water plants (phytoplankton) which are very important for the food chain.
These clams also have many babies very quickly and grow into huge groups. These big groups can block pipes and machines that use water. This happens in places like power plants, farm watering systems, and factories that clean water. When this happens, it makes things difficult for both nature and people who need to use these water systems.
Official Assessment
"Gold clams can block water pipes and machines, such as:
places that make electricity,
water pipes for farms,
water cleaning factories.
They eat tiny bits in the water and might take food away from the animals that naturally live there. We don't know yet how these clams will act in New Zealand's waters." https://www.doc.govt.nz/nature/pests-and-threats/freshwater-pests/gold-clams/
In summary, because Asian clams can make babies quickly and live easily, they have become a big problem animal in New Zealand.
Questions for Young Scientists
How do Asian Clams have many babies and spread quickly in new places like the Waikato River in New Zealand?
What problems do Asian Clams cause for animals and plants already living in New Zealand's rivers and lakes, especially by taking their food?
What dangers do Asian Clams create for things people have built in New Zealand's rivers, like pipes or power plants? How can we stop these dangers?
How do Asian Clams, when they take over, change the normal amount of tiny water plants and other important parts of the underwater food web in New Zealand's rivers and lakes?
What makes it hard to stop Asian Clams from spreading once they have settled in rivers and lakes like the Waikato River?
Answer Key
Asian clams spread rapidly because they self-fertilise, reproduce many times per year, and produce huge numbers of offspring, allowing even one clam to start a new population.
They compete with native freshwater species by filter-feeding on phytoplankton, reducing food availability and disrupting natural ecosystem balance.
Large clam populations can clog hydro dams, irrigation systems, and water treatment plants. Mitigating this requires monitoring, containment, and preventing further spread.
By consuming large amounts of phytoplankton, they can alter the aquatic food chain, reducing resources for native species and changing ecosystem structure.
Control is difficult because they reproduce fast, disperse easily, and reach high densities. Management needs long-term monitoring, public awareness, and strict biosecurity measures to limit spread.
Asian Clams (Gold)
Learning about the golden clams that are hurting New Zealand's rivers and lakes.
The Golden Clam Arrives
The Asian Clam, also called the golden clam, is now a big problem in New Zealand's rivers and lakes. This type of shellfish comes from places like Asia, Australia, and Africa. It has spread to many places around the world, like North and South America, Europe, and now New Zealand.
In New Zealand, especially in the Waikato River, there are many of these clams. Scientists are worried because there are tens of thousands of them in just one square meter of river! These clams can hurt the local plants and animals by taking over their homes. They can also block water pipes and power stations if we don't stop them.
Loading...
How They Make Many Babies
Grown-up clams can have babies all by themselves. This means just one clam can start a whole new family. They can have babies many times a year and live for about three or four years.
Each clam can make between 1,000 and 100,000 baby clams each year. This helps them grow in numbers very quickly, making it hard to stop them from spreading.
How Clams Grow and Spread
01
From Eggs to Young Clams
After their eggs are joined, Asian clam babies grow into young clams in about 4-5 days.
02
Floating Around
These young clams float freely. They use a sticky bag to help them spread. They can stick to plants, animals, boats, and other things. This helps them travel to new places.
03
Growing Shells and a Foot
Later, they grow a shell and a tiny 'foot'. At this stage, they are so small you can barely see them.
04
Becoming Grown-Up
They become grown-up when they are three to six months old. Then they are about the size of a small pea (6-10mm) and can grow to be as big as a coin (10-30mm).
How Asian Clams Affect Waterways
Asian clams cause many problems in New Zealand's rivers and lakes. They eat tiny bits of food from the water. This means less food for other water animals that live there naturally, especially tiny water plants (phytoplankton) which are very important for the food chain.
These clams also have many babies very quickly and grow into huge groups. These big groups can block pipes and machines that use water. This happens in places like power plants, farm watering systems, and factories that clean water. When this happens, it makes things difficult for both nature and people who need to use these water systems.
Official Assessment
"Gold clams can block water pipes and machines, such as:
places that make electricity,
water pipes for farms,
water cleaning factories.
They eat tiny bits in the water and might take food away from the animals that naturally live there. We don't know yet how these clams will act in New Zealand's waters." https://www.doc.govt.nz/nature/pests-and-threats/freshwater-pests/gold-clams/
In summary, because Asian clams can make babies quickly and live easily, they have become a big problem animal in New Zealand.
Questions for Young Scientists
How do Asian Clams have many babies and spread quickly in new places like the Waikato River in New Zealand?
What problems do Asian Clams cause for animals and plants already living in New Zealand's rivers and lakes, especially by taking their food?
What dangers do Asian Clams create for things people have built in New Zealand's rivers, like pipes or power plants? How can we stop these dangers?
How do Asian Clams, when they take over, change the normal amount of tiny water plants and other important parts of the underwater food web in New Zealand's rivers and lakes?
What makes it hard to stop Asian Clams from spreading once they have settled in rivers and lakes like the Waikato River?
Answer Key
Asian clams spread rapidly because they self-fertilise, reproduce many times per year, and produce huge numbers of offspring, allowing even one clam to start a new population.
They compete with native freshwater species by filter-feeding on phytoplankton, reducing food availability and disrupting natural ecosystem balance.
Large clam populations can clog hydro dams, irrigation systems, and water treatment plants. Mitigating this requires monitoring, containment, and preventing further spread.
By consuming large amounts of phytoplankton, they can alter the aquatic food chain, reducing resources for native species and changing ecosystem structure.
Control is difficult because they reproduce fast, disperse easily, and reach high densities. Management needs long-term monitoring, public awareness, and strict biosecurity measures to limit spread.