Smelt are small, silvery forage fish, typically measuring 7 to 8 inches long, and are highly valued for their delicate flavor. The annual smelt run is a remarkable natural event: a mass, synchronous upstream migration from larger bodies of water into smaller tributaries that signals the arrival of spring. This migration is highly anticipated by both wildlife observers and recreational harvesters. The timing of the smelt run is a complex interaction of biological necessity and environmental cues, making it an unpredictable phenomenon from year to year.
The Biological Imperative: Smelt Spawning Cycle
The smelt run is fundamentally a spawning migration, representing a life-cycle imperative for the species. Many populations are anadromous, meaning adults live in saltwater but migrate to freshwater rivers and streams to reproduce, similar to salmon. Other populations, particularly those in the Great Lakes, are adfluvial, spending their adult lives in large lakes and migrating into tributary streams to spawn.
Smelt are generally reproductively mature at age two. A single female can produce tens of thousands of adhesive eggs, which are broadcast over sandy or gravel bottoms in the spawning stream. After fertilization, the eggs stick to the streambed and hatch in a few weeks. The larvae then drift downstream to the larger body of water to mature.
Feeding virtually ceases during this migration as the fish focus all energy on reproduction. While some individuals may die shortly after spawning, some adults can survive to participate in subsequent runs. This migration is a genetically driven push to ensure the next generation is laid in the necessary freshwater environment.
Regional Timing of the Annual Run
The precise timing of the smelt run depends highly on geographic location, but it generally occurs during the early spring thaw.
Great Lakes
For the vast populations inhabiting the Great Lakes, the migration typically begins shortly after the ice breaks up, spanning from late March through the end of April. Runs in Lake Michigan tributaries are often observed during this window, while Lake Superior runs tend to happen slightly later, usually in the last two weeks of April.
Atlantic Coast
On the Atlantic Coast, where anadromous populations are common, the spawning migration takes place in the spring, moving from the ocean into coastal rivers and estuaries. In New England, the run generally peaks when water temperatures are suitable, often coinciding with early spring tides. This timing can range from late winter to late spring, with some management regulations defining the spawning season as March 15 to June 30.
Pacific Northwest
In the Pacific Northwest, where species like the eulachon are found, the migration usually happens in the spring, often in March or April. The exact return to rivers in this region can be sporadic and vary greatly year to year due to ocean conditions and water flow. The spring thaw and resulting increases in water volume are important regional cues, making the run a short, intense event lasting only about three weeks in a given area.
Environmental Factors Dictating Migration
The start of the smelt run is determined by specific, measurable environmental conditions, primarily water temperature, rather than a calendar date. The migration is typically initiated when the water temperature in the spawning tributaries reaches 40 to 50 degrees Fahrenheit (4 to 10 degrees Celsius). In the Great Lakes, for example, the run often begins when the temperature reaches 42 to 44 degrees Fahrenheit (5 to 7 degrees Celsius).
The volume and flow of water, linked to the spring thaw and snowmelt, also signal the start of the migration. Excessive rainfall and resulting freshets can sometimes halt upstream movement or force fish back downstream until conditions stabilize. Changing day length, known as photoperiod, is an additional environmental cue that helps prepare the smelt for spawning.
Smelt are sensitive to light, which influences their behavior. The most intensive part of the spawning migration generally occurs at night, often between 10 p.m. and 2 a.m., as the fish move into shallower stream beds to deposit their eggs. The combination of cold water temperature, spring flow, and darkness creates the optimal conditions for the mass spawning event.
Practicalities of Smelt Harvesting
Participating in the smelt run involves the use of simple harvesting gear. The most common method for recreational harvesters is the use of a dip net or a small seine net. A dip net is a manually operated net, often with a rigid circular frame, used to scoop the dense schools of fish moving upstream in the tributaries.
Anyone planning to harvest smelt must first check local and state fishing regulations, as rules regarding gear, limits, and timing vary widely.
Regulations and Licensing
Many jurisdictions require a valid fishing license for harvesting smelt for personal use, even if they are not classified as a “baitfish.” Regulations often specify the maximum size of a dip net, especially when fishing near the mouth of a tributary, and may impose daily possession limits, sometimes measured in quarts. Some areas also restrict the hours of operation, with many coastal areas prohibiting nighttime recreational dip netting to protect the spawning fish.
The delicate, cucumber-like scent of a freshly caught smelt is a hallmark of the run. The fish are traditionally prepared by being lightly breaded and pan-fried whole. Smelt must be cooked, as consuming them raw carries the risk of parasites.