The Sea Lamprey is an invasive species that has disrupted fish populations in the Great Lakes. Where did it originally come from?

• A. It was native to North America and spread by rivers.
• B. It originally came from the Atlantic and invaded the Great Lakes.
• C. It originated in the Arctic and migrated south.
• D. It was introduced accidentally to the Pacific.

Answer: (B)

The key idea here is that invasive species often originate far from where they cause problems and reach new areas through human-made connections. The Sea Lamprey comes from the Atlantic Ocean, not North America, and it entered the Great Lakes by moving through canal systems and seaways that connect Atlantic waters to the Great Lakes, such as the Saint Lawrence Seaway and related canal routes. This human-assisted pathway allowed a saltwater-adapted species to establish itself in a freshwater system, leading to declines in native fish populations. The other options don’t fit because the lamprey isn’t native to North America, isn’t Arctic in origin, and isn’t from the Pacific.