The migration of rainbow smelt, a small, resilient—and delectable—fish

As the days lengthen and the snow melts, little olive-backed, silver-sided rainbow smelt unfailingly and steadfastly wiggle their way from the salty ocean into Atlantic Canadian rivers to spawn. Their arrival signals the beginning of spring and, for many folks, a much-anticipated seasonal feast.

Although the most acclaim is reserved for the legendary wild Atlantic salmon in this region, smelt are a remarkable species also deserving of appreciation. There is a symbiotic relationship, since in Newfoundland and Labrador migrating salmon will have capelin as their last meal before entering the rivers and fasting for months. In spring in the Maritimes, huge, suddenly voracious, salmon (which have not eaten since the previous summer and are now heading back to sea) can be seen each May throwing spray as they attack the shoreline-hugging smelt in shallow water.

Rainbow smelt belong to the Osmeridae family of fishes, which include British Columbia’s fabled eulachon and Newfoundland’s beloved capelin. Home includes the coastal waters of northeastern North America, the Arctic, and northwestern Canada south to Vancouver Island. Some populations have successfully established themselves inland such as those found in all five of the Great Lakes, in fact they have become invasive and problematic in some inland waters in central Canada and beyond.

Growth occurs in the ocean or open-lake environments as smelt feed on everything from tiny aquatic insects to juvenile fishes. If food is plentiful and the ingested calories convert to growth, smelt may reach upwards of 12 inches and live seven or more years.

Eventually, the need to reproduce surpasses the desire to grow larger. Hormones change and nutrients are allocated to developing eggs and sperm. In Atlantic Canada, these physiological changes combined with longer daylight hours and warming water temperatures of early spring trigger movement from near-shore marine environments into rivers and streams. Evidence suggests they may even act like Atlantic salmon, returning to the same rivers year after year.

Smelt begin searching for suitable spawning habitat upon entry into freshwater. Generally, they prefer a fast-flowing stream and a rocky bottom, but will also spawn over vegetation and debris. A female deposits tiny, pale yellow eggs, which sink to the bottom and stick to anything they touch, thanks to an adhesive coating. After fertilization and a few weeks of development, the eggs hatch at night and, while under the cover of darkness, the tiny juveniles drift downstream into nearby estuaries.

Catching and preparing smelt

While smelt are busy making the next generation, herons, eagles, ravens, mink, raccoons, and humans all flock to the rivers in hopes of grabbing a smelt “feed”. For us upright, bipedal hominids, catching smelt is relatively easy. In some rivers where migratory runs are particularly large, smelt may be caught with just your favourite baseball cap. Often, however, anglers in Atlantic Canada favour small dip nets as the tool of choice.

The technique is about as simple as it gets: peer into the water, spot a school of fish, plunge the net into the school and lift. Voila!

During the peak of migration, an angler’s net could be full to almost bursting with dozens of fish. However, with the exception of Newfoundland and Labrador, where no catch limit exists on the beach-spawning capelin, the Maritime provinces forbid a free-for-all during the smelt migration. A total of 60 per day can be harvested by dip netting in Prince Edward Island and New Brunswick, while in Nova Scotia anglers are capped at 30 smelt per person, per day.

Bar none, the most popular method of cooking smelt is by simply pan-frying them. Yet, while many larger species such as cod, halibut, and brook trout require careful filleting and de-boning, the unassuming smelt don’t demand such TLC. Other than gutting and removing the head, smelt can simply be fried whole, bones and all.

The underlying theme throughout the capture and meal preparation process is simplicity. Not only are smelt relatively easy to catch and clean, but they’re equally as simple to prepare for the dinner table. A quick dredge in a bowl of one or two eggs begins the process. From there, smelt can be coated in a salt- and pepper-seasoned flour or panko bread crumbs to create a seasoning blend to suit one’s taste. To complete the process, the coated smelt should be cooked in a pan of oil (preferably one with a high smoke point, such as peanut oil) that covers about one-half of the body. Smelt only need a couple minutes per side to cook thoroughly.

Marine ecosystem effects

While we humans certainly derive a benefit from the spring smelt migration, the potential boon for freshwater ecosystems should not be overlooked. Just as Pacific salmon provide important marine-derived nutrients to inland freshwater ecosystems in the Pacific Northwest, smelt can similarly link marine and freshwater biomes in Atlantic Canada. The one major caveat is that, unlike Pacific salmon that deliver a tremendous amount of nutrients following death in their natal rivers, smelt do not die en masse after spawning. Instead, nutrients are delivered into rivers as carbon, nitrogen, and phosphorus in excretory products, eggs (that also contain lipids), and the occasional carcass. Algae, biofilm on rocks, aquatic invertebrates and small stream-resident trout, as well as Atlantic salmon, are all examples of biota that can potentially benefit from smelt-based nutrient pulses.

Habitat threats

The successful delivery of smelt-based nutrients into rivers and streams is currently being threatened by dam construction and subsequent habitat fragmentation. Blocking access to upstream habitats is like an accident on a roadway restricting the flow of goods. Unless dams are removed or humans engineer effective fish passage structures, the long-term sustainability of smelt populations in Atlantic Canada will remain compromised. Fortunately, biologists are placing increasing emphasis on finding ways to facilitate movement around dams. Thousands of improperly installed culverts remain a huge unseen problem, however, for all migratory species. In parts of the US smelt have all but been extirpated.

Notwithstanding the future uncertainty of smelt populations in Atlantic Canada, these small, spring migrants will likely continue to persist as a cultural fixture. Despite their size, smelt are resilient. Rest assured that in 2016, anglers and river critters will be enjoying many smelt feeds of their own.