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FAQs

Following are FAQ related to CRRL science.

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What are zebra mussels and why should we care about them?

Zebra mussels are an invasive, fingernail-sized mollusk that is native to fresh waters in Eurasia. Their name comes from the dark, zig-zagged stripes on each shell.Zebra mussels probably arrived in the Great Lakes in the 1980s via ballast water that was discharged by large ships from Europe. They have spread rapidly throughout the Great Lakes region and into the large rivers of the eastern...

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What are zebra mussels and why should we care about them?

Zebra mussels are an invasive, fingernail-sized mollusk that is native to fresh waters in Eurasia. Their name comes from the dark, zig-zagged stripes on each shell.Zebra mussels probably arrived in the Great Lakes in the 1980s via ballast water that was discharged by large ships from Europe. They have spread rapidly throughout the Great Lakes region and into the large rivers of the eastern...

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How can the spread of zebra mussels be prevented?

The USGS documents the zebra mussel's geographic distribution and studies its behavior and biology. The resulting information is critical in helping to develop strategies aimed at containing and controlling the mussel's spread. Meanwhile, catching and transporting zebra mussels for use as bait, food, and aquarium pets is highly discouraged.We also encourage good boat hygiene:Wash your boat off...

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How can the spread of zebra mussels be prevented?

The USGS documents the zebra mussel's geographic distribution and studies its behavior and biology. The resulting information is critical in helping to develop strategies aimed at containing and controlling the mussel's spread. Meanwhile, catching and transporting zebra mussels for use as bait, food, and aquarium pets is highly discouraged.We also encourage good boat hygiene:Wash your boat off...

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What is tamarisk?

Tamarisk is an invasive shrub or small tree that is found across the American West. Also known as saltcedar, tamarisk favors sites that are inhospitable to native streamside plants because of high salinity, low water availability, and altered streamflow regimes created by dams. Researchers debate the extent of tamarisk’s negative impacts, but this invasive species can and does alter habitat...

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What is tamarisk?

Tamarisk is an invasive shrub or small tree that is found across the American West. Also known as saltcedar, tamarisk favors sites that are inhospitable to native streamside plants because of high salinity, low water availability, and altered streamflow regimes created by dams. Researchers debate the extent of tamarisk’s negative impacts, but this invasive species can and does alter habitat...

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Are salmon endangered worldwide?

No, salmon are not endangered worldwide. For example, most populations in Alaska are healthy. Some populations in the Pacific Northwest are much healthier than others. These healthy populations usually occupy protected habitats such as the Hanford Reach on the Columbia River and streams of Olympic National Park.Learn more: Questions and Answers about Salmon

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Are salmon endangered worldwide?

No, salmon are not endangered worldwide. For example, most populations in Alaska are healthy. Some populations in the Pacific Northwest are much healthier than others. These healthy populations usually occupy protected habitats such as the Hanford Reach on the Columbia River and streams of Olympic National Park.Learn more: Questions and Answers about Salmon

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How do salmon know where their home is when they return from the ocean?

Salmon come back to the stream where they were 'born' because they 'know' it is a good place to spawn; they won't waste time looking for a stream with good habitat and other salmon.Scientists believe that salmon navigate by using the earth’s magnetic field like a compass. When they find the river they came from, they start using smell to find their way back to their home stream. They build their...

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How do salmon know where their home is when they return from the ocean?

Salmon come back to the stream where they were 'born' because they 'know' it is a good place to spawn; they won't waste time looking for a stream with good habitat and other salmon.Scientists believe that salmon navigate by using the earth’s magnetic field like a compass. When they find the river they came from, they start using smell to find their way back to their home stream. They build their...

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How far do salmon travel?

Salmon first travel from their home stream to the ocean, which can be a distance of hundreds of miles. Once they reach the ocean, they might travel an additional 1,000 miles to reach their feeding grounds.Learn more: Questions and Answers about Salmon

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How far do salmon travel?

Salmon first travel from their home stream to the ocean, which can be a distance of hundreds of miles. Once they reach the ocean, they might travel an additional 1,000 miles to reach their feeding grounds.Learn more: Questions and Answers about Salmon

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How long do salmon usually live?

Most salmon species live 2 to 7 years (4 to 5 average). Steelhead trout can live up to about 11 years.Learn more: Questions and Answers about Salmon

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How long do salmon usually live?

Most salmon species live 2 to 7 years (4 to 5 average). Steelhead trout can live up to about 11 years.Learn more: Questions and Answers about Salmon

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How many species of salmon are there and how large can they get?

There are seven species of Pacific salmon. Five of them occur in North American waters: chinook, coho, chum, sockeye, and pink. Masu and amago salmon occur only in Asia. There is one species of Atlantic salmon.Chinook/King salmon are the largest salmon and get up to 58 inches (1.5 meters) long and 126 pounds (57.2 kg). Pink salmon are the smallest at up to 30 inches (0.8 meters) long and 12 pounds...

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How many species of salmon are there and how large can they get?

There are seven species of Pacific salmon. Five of them occur in North American waters: chinook, coho, chum, sockeye, and pink. Masu and amago salmon occur only in Asia. There is one species of Atlantic salmon.Chinook/King salmon are the largest salmon and get up to 58 inches (1.5 meters) long and 126 pounds (57.2 kg). Pink salmon are the smallest at up to 30 inches (0.8 meters) long and 12 pounds...

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When can salmon be seen migrating to their spawning area?

Most Pacific salmon can be seen migrating from spring though fall, depending on the species. Most adult Atlantic salmon migrate up the rivers of New England beginning in spring and continuing through the fall as well, with the migration peaking in June. Learn more: Questions and Answers about Salmon

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When can salmon be seen migrating to their spawning area?

Most Pacific salmon can be seen migrating from spring though fall, depending on the species. Most adult Atlantic salmon migrate up the rivers of New England beginning in spring and continuing through the fall as well, with the migration peaking in June. Learn more: Questions and Answers about Salmon

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Where are salmon most endangered?

Certain populations of sockeye salmon, coho salmon, chinook salmon, and Atlantic salmon are listed as endangered. Sockeye salmon from the Snake River system are probably the most endangered salmon. Coho salmon in the lower Columbia River may already be extinct. Salmon are not endangered worldwide. For example, most populations in Alaska are healthy. Some populations in the Pacific Northwest are...

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Where are salmon most endangered?

Certain populations of sockeye salmon, coho salmon, chinook salmon, and Atlantic salmon are listed as endangered. Sockeye salmon from the Snake River system are probably the most endangered salmon. Coho salmon in the lower Columbia River may already be extinct. Salmon are not endangered worldwide. For example, most populations in Alaska are healthy. Some populations in the Pacific Northwest are...

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Why are there so few salmon left?

There are many reasons for the decline in salmon populations. Logging an area around a stream reduces the shade and nutrients available to the stream and increases the amount of silt or dirt in the water, which can choke out developing eggs. Dams cause fish to die from the shock of going through the turbines and from predators that eat the disoriented fish as they emerge from the dam. Overfishing...

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Why are there so few salmon left?

There are many reasons for the decline in salmon populations. Logging an area around a stream reduces the shade and nutrients available to the stream and increases the amount of silt or dirt in the water, which can choke out developing eggs. Dams cause fish to die from the shock of going through the turbines and from predators that eat the disoriented fish as they emerge from the dam. Overfishing...

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Why do salmon change color and die after they spawn?

Salmon change color to attract a spawning mate. Pacific salmon use all their energy for returning to their home stream, for making eggs, and digging the nest. Most of them stop eating when they return to freshwater and have no energy left for a return trip to the ocean after spawning. After they die, other animals eat them (but people don't) or they decompose, adding nutrients to the stream...

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Why do salmon change color and die after they spawn?

Salmon change color to attract a spawning mate. Pacific salmon use all their energy for returning to their home stream, for making eggs, and digging the nest. Most of them stop eating when they return to freshwater and have no energy left for a return trip to the ocean after spawning. After they die, other animals eat them (but people don't) or they decompose, adding nutrients to the stream...

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