Eel ladder


Eel ladder

An eel ladder is type of fish ladder designed to help eels swim past barriers, such as dams and weirs or even natural barriers, to reach upriver feeding grounds. (Many eels are catadromous, living in fresh water but spawning at sea.) The basic design of an eel ladder has the eel swim over the barrier using an eel ascending ramp, which provides the eels a climbing substrate to "push against" while slithering upstream. For some higher barriers, elevator-style systems are also used.

An eel ladder typically consists of four parts: an "eel ascending ramp", a "supporting structure", a "water-feeding system", and a "side gutter". The side gutter provides an attraction flow to draw eels toward the ladder, the water-feeding system ensures the proper flow of water to the gutter and the ramp, and the supporting structure mounts the ladder to the barrier.

The eel ascending ramp can be a fairly simple constructions, such as a hollowed out tree filled with recycled fishing net, or a more complex structure designed to accommodate specific species or ages of eels. For example, the Canadian company Milieu Inc. manufactures eel ascending ramps made of moulded ABS with undulating side walls and staggered studs throughout the length of the ramp. These studs form the substrate the eels push against during the climb over the barrier.

See also

* Fish ladder
* Fish migration
* Eel story

External links

* [http://www.milieuinc.com/gallery1.htm Milieu Inc. eel ladder] at the St. Ours Dam (Richelieu River, Québec)
* [http://eel-pass.eu Fish-Pass sarl eel ladder and elevator systems]
* [http://www.chicopeeriver.org/eelway/index.html Dwight St. Dam Eelway project] (Chicopee River, Massachusetts)


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • eel ladder — a fish ladder designed to help eels over dams and weirs. A substrate is provided for the eels to push against when slithering upstream. A fish elevator may be part of the process at high dams. See also eel ascending ramp …   Dictionary of ichthyology

  • Eel life history — The eel is a long, thin bony fish of the order Anguilliformes. Because fishermen never caught anything they recognized as young eels, the life cycle of the eel was a mystery for a very long period of scientific history. Although there have been… …   Wikipedia

  • eel ascending ramp — part of an eel ladder, this ramp has structures against which the eels can push to ascend. The ramp may be simply a hollowed out tree filled with old fish nets or a commercial product made of plastic with an undulating surface and studs …   Dictionary of ichthyology

  • Fish ladder — Fishways, most commonly called fish ladders but also known as fish passes and in Australia also referred to as fish steps, are structures on or around artificial barriers (such as dams and weirs) to facilitate diadromous fishes natural migration …   Wikipedia

  • Pelagic fish — A school of large pelagic predator fish (giant trevally) sizing up a school of small pelagic prey fish (anchovies) Pelagic fish live near the surface or in the water column of coastal, ocean and lake waters, but not on the bottom of the sea or… …   Wikipedia

  • Demersal fish — Bluespotted ribbontail ray resting on the seafloor Demersal fish live on or near the bottom of the sea or lakes.[1] They occupy the sea floors and lake beds, which usually consist of mud, sand, gravel or rocks …   Wikipedia

  • Fish migration — Many species of salmon are anadromous and migrate long distances up rivers and streams to spawn. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres… …   Wikipedia

  • Marine habitats — Coral reefs provide marine habitats for tube sponges, which in turn become marine habitats for fishes Littoral zone …   Wikipedia

  • Fishery — See also: fishing and fishing industry A salmon fishery with salmon spawning within the Becharof Wilderness in southern Alaska. Generally, a fishery is an entity engaged in raising and/or harvesting fish, which is determined by some… …   Wikipedia

  • Crab fisheries — Crabbing redirects here. For the process in woollen textile finishing by that name, see decatising. For the aircraft landing maneuver of that name, see crosswind landing. Crab boat from the North Frisian Islands working the North Sea Crab… …   Wikipedia