American eels (Anguilla rostrata)are another essential part of the Jones River ecology. Like river herring, american eel populations have recently declined. The same types of threats have impacted both of these species - migration obstacles (dams), over harvesting, water quality, and reduced habitat to name a few. However, so little is known about eels that it has been difficult for scientist to pinpoint population numbers, trends, and impacts.
Both river herring and eels fall into the category of 'diadromous' fish, meaning that they spend part of their life in salt water and part in fresh water. Most of us are familiar with how this relates to river herring, salmon, and other fish that afe born in freshwater, migrate out to sea, then return years later to spawn in the same waters where they were born. These are a subset of the diadromous known as 'anadromous'. Eels fall into the other subset - 'catadromous' fish. Eels are born somewhere out in the Sargasso Sea, a region out in the middle of the North Atlantic. The tiny newborn eels then find their way all the way back to the eastern coast of the Americas. For reasons unknown, they branch off and swim up thousands of different rivers along the coast. They continue to migrate upstream as far as possible until finding good safe habitat to grow. Female eels may spend as much as 40 years in our local streams and lakes growing to up to 5 feet. Then on a dark rainy fall night (when you are least likely to notice) masses of eels slither back down the rivers and head out to the Sargasso to spawn and start it all over again.
This year, JRWA and DMF have begun tracking eels in our watershed. We had some fun wrangling eels over 2 1/2 feet long. We unexpectedly found thousands of eels trying to climb the Wapping Road Dam when the water levels dropped. In 2010 we'll be increasing our efforts to understand local Eel populations. And of course we are working hard to revive the conditions needed for their survival.
