American eels may be misunderstood… but they do get respect
MY FASCINATION started innocently one summer night when I was in my teens. My dad and I were staying at an old hunting camp in Dean, NS; I had fished all day for trout and got nothing. As dusk descended, my fishing line got tied into knots and as I was tending to my predicament in the dark, with my hooked worm sitting idly on the river bottom, something pulled so hard that my rod bent nearly in half, and then fell limp. Upset at the loss of this potential trophy I forged on and, to my surprise, the resistance was still there. After a delightful struggle, I landed an American eel. I have yet to achieve a better tug-of-war with a fish—the hook was virtually bent straight.
No other fish so common in Eastern Canadian waters inspires such a range of emotional reactions. Eels may be reviled, as some kind of slimy creature from the deep, or revered, as God-like. Kerry Prosper, community research coordinator for the Social Research for Sustainable Fisheries group at St. Francis Xavier University, in Antigonish, NS, and member of the Paq’tnkek community, says, “the First Nations people of Atlantic Canada have an important cultural relationship with American eel, and consider it a spiritual being.” (See “Mi’kmaq Practice,” page 22.)
Indeed, eels have been an important resource for communities along the eastern seaboard for centuries. James Prosek, author of Eels: An Exploration, from New Zealand to the Sargasso, of the World’s Most Mysterious Fish, describes the first meeting of native North Americans with European pilgrims and says that, rather than turkey and cranberry sauce “it’s likely that this food item (eel) was on the table of that very first Thanksgiving dinner.”
The American eel (Anguilla rostrata) is one of 18 Anguillid species throughout the world and is in the class Osteichthyes, which means fish with a bony skeleton. Outside their elongated, snake-like appearance, eels are not that different from common fish like trout, salmon, bass, tuna and mackerel.
Fascinating life cycle
American eels are catadromous, meaning they’re born in saltwater; they complete most of their lives in fresh/brackish water rivers and lakes, then return to the sea to spawn. This is the opposite of the better-known anadromous Atlantic salmon, which hatch in freshwater, live their lives at sea and return to freshwater to spawn, but similar to the anadromous Pacific salmon in that American eels are also thought to die after spawning. The spawning of American eels has never been witnessed, despite more than a century of attempts—and indeed little was known about them until the early 20th century. However while newly hatched eels arrive at continental rivers from their spawning grounds, no adults have been seen returning with them. So it’s assumed that they too must die after spawning.
These fish start life in the Sargasso Sea, in the Atlantic Ocean, off the east coast of Florida and south of Bermuda, and migrate along the east coast of North America. In Canada, they’re found in most freshwater rivers and estuaries that are accessible from the Atlantic Ocean, extending west to the Great Lakes and north to Newfoundland and Labrador. Some eels have been introduced in other parts of Canada—the Saskatchewan River, for example—for recreational fishing.
Once eels mature, ranging from six to 12 years, from August to December they leave their rivers and estuaries and undergo a fantastic migration back to the Sargasso Sea to spawn. They may follow a path of increasing water temperature and salinity, which are higher there in winter than any other place in the Atlantic Ocean. Once there, they locate a mate via pheromone detection, and spawn.
It’s thought that females produce two to 20 million eggs each. Eggs hatch into transparent, willow-leaf shape larvae, called leptocephali, which drift in ocean currents for a year before reaching the Grand Banks, when they metamorphosize into second-stage larvae, beginning to resemble the shape of the adults. They are completely transparent, except for their black eyes, and thus known as glass eels. Their migration to fresh water rivers and estuaries is guided by olfactory cues—they swim towards food, as well as other eels.
During this time a greyish-black pigment begins to appear, and they are now known as elvers. For two to three years, the elvers continue their upstream migration and become fully pigmented with a colour that appears yellowish-green on the dorsal side—and thus are known as yellow eels. These eels are opportunistic carnivores that forage, mostly at night, for dead or dying insects, but also hunt and prey on organisms such as crustaceans, clams, worms, small fish, frogs and dead animal material.
When eels encounter large, usually dead, prey, they use rotational feeding to tear off portions of flesh; by twisting their bodies and spinning to generate shear force they remove pieces of food much the same as a crocodile does.
Sexually mature eels, known as silver eels, typically weigh approximately 150 g (0.3 lb) for males and 500 g (1.1 lb) for females, although much larger eels (more than 4 kg) have been caught in Atlantic Canada. The dramatic difference in adult body size between males and females is called “sexual dimorphism,” and is common in many fish species. At this final stage of development, mature eels begin downstream migration to salt water and subsequently to the Sargasso Sea to spawn, fuelled primarily by high body fat reserves.
Unfortunately, like many fish populations, wild eel stocks are in sharp decline. According to David Cone, biology professor at Saint Mary’s University, in Halifax, the greatest threat to populations in Atlantic Canada currently is the invasive gas bladder parasite (Anguillicoloides crassus), thought to have been introduced through importation of infected Japanese eels for aquaculture in North America. Dr. Cone explains that this infection reduces the success of eels making the long migration back to the sea to spawn, subsequently diminishing the growth of wild populations. “If we lose eels, we lose significant integrity of our local aquatic ecosystems and all of the cultural benefits they provide,” he says.
There are economic benefits as well. The largest eel fishery in Canada is along the St. Lawrence River, where silver eels are harvested; fisheries exist in Atlantic Canada for yellow eels. Mature eels are typically sold live, smoked or frozen to small niche markets in North America or exported to Western Europe, where consumer demand is high for smoked, jellied or marinated eels. Some are exported to Asia, where they are generally processed into kabayaki (grilled eel).
Glass eels and elvers are primarily shipped to Asia and Europe, and mixed with other species as seedstock for eel aquaculture. American eels are also farmed in Atlantic Canada, with one farm in each of Nova Scotia, New Brunswick and Newfoundland.
This chance encounter with an eel some three decades ago sparked a life-long wonder and fascination that led me to a career studying fish biology, and a graduate thesis specifically on aquaculture and the nutrition of our local American eel. Although I’m not convinced a cactus is cuddly, I would argue that eels are charming, Dr. Seuss.