Eels on Slippery Slope
By Sadie Beaton
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| Long thought to be a separate species of fish, eel larvae are known as leptocephali. Illustration by Sydney Smith. |
The cliché “slippery as an eel” is an apt one, and not only because these long, serpentine fish sport a slick layer of mucus on their skin. Eels (Anguilliformes) are truly creatures of mystery. Though they turn up in more habitats than any other species of fish, precious little is known about them. The eel keeps many secrets, and could likely tell us much about the intimate connections between Nova Scotia’s watersheds and faraway seas – if only we could grasp them.
Eels are catadromous – fish whose lives begin and end in the ocean, but spend most of its time in freshwater rivers and lakes (the opposite of salmon). They are thought to spawn just once, at the end of their lives, deep down in the mythical-sounding Sargasso Sea, a massive seaweedy locale in the Atlantic Ocean off the coast of Bermuda. That’s the theory, anyway – no one has ever witnessed the spawning, hatching, or found the corpses of spent eels.
At the mercy of swirling currents, scientists believe that leaf-shaped eel larvae float out from the wide Sargasso Sea towards the Atlantic coasts of Europe, Central, South and North America. By the time they’ve caught a ride up the Gulf Stream to find their way towards an estuary– which can take up to three years - they’ve morphed into five centimetre long “glass eels“, translucent but for their eyes. Once they hit fresh water, they begin to darken up and mature into “elvers“, and then eventually change form again, growing over a metre long and turning yellow. These “golden eels“ rove throughout Nova Scotia’s rich watersheds in the dark of night to feed on insects, worms, molluscs, crustaceans and fish.
After traveling throughout Nova Scotia’s watersheds for anywhere from five to 30 years, the eel will metamorphose once more, into sexually mature “silver eels”. From here it is an arduous trip back to the Sargasso Sea. Hydroelectric dams, fishing weirs, and other human-made barriers often thwart their progress. Ever stubborn, their slippery skin even allows them to shimmy overland for short distances. In many areas, though, the vast majority of eels never make it back to their spawning ground.
A significant food source for fish, mammals and birds throughout Nova Scotia’s watersheds, eels have also long been important to the Mi `kmaq, for food and ceremony. Also referred to as Kat, the eel is revered for its adaptable nature and its value as food, clothing and other uses. Eels are sometimes used locally as bait, though they are considered a delicacy in many parts of Europe and Asia. Fishing weirs, nets and traps capture elvers swimming upstream, golden eels in freshwater, and silver eels on their way back to the ocean.
One of the few eel facts that we can grab onto, unfortunately, is that they are declining at alarming rates, not only in Nova Scotia, but around the world. The Committee On The Status Of Endangered Wildlife In Canada (COSEWIC) has recently declared the American Eel a species of Special Concern. Along with over fishing, dams, habitat loss, water quality degradation and climate change are also likely culprits.
The elusive eel serves as a potent reminder of the connectedness, fragility and ultimately, mystery of the underwater realm. Protecting them will challenge our ability to act both locally and globally to reconnect fragmented aquatic ecosystems and restore degraded fish habitat. Because eels are sensitive to chemical contaminants throughout the watershed, we can all help by using environmentally friendly household cleaners and avoiding pesticides. We can also demand that dams around the province are outfitted with effective “eel ladders”. Landowners can also help take care of Nova Scotia’s watersheds by employing good silviculture and agricultural practices along streambeds.
Sadie Beaton coordinates the Coastlines monthly natural history column. Much as she would like to, she cannot reveal the words of the golden eel. Coastlines is coordinated by the Coastal Issues Committee at Ecology Action Centre and supported by the Nova Scotia Habitat Conservation Fund with contributions from hunters and trappers.
Coastal Issues Committee
Phone: (902) 442-5046
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How do you like your coast? Take action on coastal issues that matter to you. The Coastal Issues Committee meets at the EAC on the last Thursday of every month at 5:30PM.
