Placeholder Image

字幕列表 影片播放

  • Somewhere in the world, a plant or animal species becomes extinct every day.

  • And the pace at which our natural environments and ecosystems are being destroyed just keeps increasing.

  • One creature under threat is the Lake Sturgeon.

  • The Lake Sturgeonis from a family of a prehistoric fish that have lived in North America’s freshwater lakes and rivers for millions of years.

  • Many of Canada's Aboriginal peoples relied heavily on the Lake Sturgeon as a source of food.

  • Early European settlers found new uses for the abundant Sturgeon, as fertilizer, livestock feed and even as a source of fuel.

  • But today, its numbers have declined so drastically, the Lake Sturgeon is struggling for its survival.

  • Lake Sturgeon populations are widespread throughout North America, with potential habitats ranging from western Alberta to the St. Lawrence in Quebec, and from southern Hudson Bay to the lower Mississippi.

  • Today, the Lake Sturgeon is considered threatened in many US states and Canadian provinces, and is being considered for protection under Canada's Species at Risk Act.

  • The Lake Sturgeon prefers cold water and is found in the near shore areas of large lakes and rivers.

  • It is a bottom dweller, and feeds on leeches, clams, small fish and a variety of insects.

  • The Lake Sturgeon is also known to travel long distancessometimes over hundreds of kilometers - just to reach suitable spawning grounds.

  • Lake Sturgeon can grow up to two and a half meters and can live to be 150 years old.

  • However, unlike most fish, the Lake Sturgeon doesn’t begin spawning until it is quite old – 15 years for the males and 25 for the females.

  • Once mature, they may spawn every three to four years.

  • This means that despite its longevity, the Lake Sturgeon produces far less offspring than most other fishes.

  • Over the past century, commercial fishing has caused significant declines in many Lake Sturgeon populations.

  • For several decades they were heavily over-fished for their oil and later their caviar, which left much of the fish as waste.

  • Lake Sturgeon populations are still recovering from the decimation of over-fishing.

  • And because the Sturgeon only spawns every three to four years, it will take a great deal of time for the species to recover.

  • In some places, the Lake Sturgeon is still fished beyond legal limits.

  • However, strong education campaigns that promote catch and release have had a positive impact.

  • More recently, the direct and indirect effects of hydro dams have become the most significant threat to this fish.

  • Dams are formidable barriers that can stop the Lake Sturgeon from successfully reaching its spawning grounds.

  • Hydro developers across Canada are currently working hard to find solutions to maintain access and natural flow patterns.

  • Other threats to species recovery include: pollution, poaching and the introduction of invasive plant and animal species into the sturgeon’s natural habitat.

  • Cottage developments are also adding new threats, as infilling, crib docks and manmade beaches reduce the amount and quality of good fish habitat in these once secluded natural areas.

  • No one knows what will happen if we lose the Lake Sturgeon, or any other species.

  • The Earth’s ecosystems are delicate and complex.

  • Losing any species changes the natural dynamics and impacts all other parts of the ecosystem.

  • Extinct is forever, so it is important to act now - because there is no second chance.

Somewhere in the world, a plant or animal species becomes extinct every day.

字幕與單字

單字即點即查 點擊單字可以查詢單字解釋

B2 中高級

保護加拿大的鱘魚湖 (Protecting Canada's Lake Sturgeon)

  • 406 26
    Bing-Je 發佈於 2021 年 01 月 14 日
影片單字