梅根·林奇 & Kadijah斯宾塞, Master’s Students, Bard Center for beplay世界杯投注al Policy
Background & 美国鳗鱼的生活
美国鳗鱼, the only freshwater eel found in North America, 有逆循环的生命周期吗, meaning it begins its life in the ocean, migrates to freshwater to mature, and eventually returns to the ocean to spawn. Their large geographic range and unique life cycle make American Eel populations susceptible to a variety threats and makes it difficult to discern the severity of each threat on population numbers. Major threats include barriers to migration from dams, 寄生虫, 过度捕捞, 城市化污染, 和气候变化. 因为它们的数量减少了, the International Union for Conservation of Nature (ICUN) added the American Eel to its Red List in 2014.
The life of every 美国鳗鱼 begins in the Atlantic Ocean’s Sargasso Sea. 一旦孵化, the eel larvae drift towards the Atlantic Coast of the United States with assistance from the Gulf Stream Current. By the time the larvae have reached the coast, they will have transitioned into glass eels, which is the juvenile life stage of the 美国鳗鱼. 到达海岸后, 的小, transparent eels will seek out estuaries that will bring them toward freshwater rivers and streams.
Within a few weeks of entering estuaries, 就像哈德逊河, the eels will develop into Elvers, 第二幼年阶段. Most Elvers will move inland seeking freshwater habitats. 到达这些内陆栖息地, Glass eels and Elvers are able to ascend certain barriers, 如瀑布, and absorb oxygen through their skin in order to travel briefly over land.
For more information on American 鳗鱼 and the threats they face, visit the following websites:
2022世界杯下注的鱼 & Wildlife Service: American Eel Overview
IUNC Red List of Threatened Species
SC Department of Natural 资源: American Eel Overview
It is at this stage that the migrating eels find over 100 tributaries of the Hudson River Estuary, 包括电锯杀手. 然而, 一旦鳗鱼进入电锯杀戮, both natural and manmade barriers impede their ability to migrate upstream. The first barrier that the eels approach is the lowest waterfall. Eel density above this first barrier is just 10% of what it is below the waterfall. The installation of an eel ladder on the next barrier, 下面的锯杀大坝, 促进通道, but to a lesser extent than would be possible without a barrier. 进一步上游, the area between the Annandale Dam and second lowest waterfall has not been thoroughly sampled. it is expected that eels are present at a very low density.
American Eel populations in North America have drastically declined in recent years, making it important that they are able to access upstream habitats to mature before returning to the Sargasso Sea to spawn. This is possible through the inclusion of eel ladders. The eel ladder at 下面的锯杀大坝 has passed 1,293 eels since it was operationalized in 2006 through a project with the Department of Conservation Hudson River Estuary Program. The potential addition of an eel ladder on the Annandale could further facilitate upstream passage and support the eel population.
Additional efforts to conserve 美国鳗鱼s in the 看到杀 include a monitoring program coordinated with the DEC. 每年春天, 团队的科学家, students and community members use special nets and traps to collect eels in the 看到杀, as well as other Hudson River tributaries. 鳗鱼数过了, 重, and released in order to accurate eel population data to decision makers.
Micro hydro intern and BCEP graduate student, Kadijah斯宾塞, had the opportunity to participate in an eeling session in the 看到杀 this past spring. 穿上水靴之后, Kadijah and a group of students gained first hand experience in field methodology while also learning more about the local ecosystem. During the session, 54 eels were caught weighing an average of 0.每条15克.