Geoscience Reference
In-Depth Information
MARITIME RINGLET
GOING TO SCHOOL ON SMELTS
SMELT OCCUR on the Atlantic coast from New Jersey in the south to Hamilton Inlet, Labrador, in the north.
They are most abundant in the Canadian Maritime Provinces, however, in the middle of their range. As a child
I helped my family net smelts on their spawning runs, which was considered a rite of spring. Most studies of
their biology and distribution were done before the 1940s, when they were considered a more important food
fish. More recently, though, the large spawning population of the Miramichi has been the subject of intensive
scientific research, providing insight into the anadromous lifestyle.
American, or rainbow, smelt belong to the fish family that includes the eula-chon of the west coast and the
capelin in east coast waters. Ranging in length from 15 to 20 centimeters (6 to 8 inches), this slender fish has a
dark green or olive-green back and rainbow-colored sides—iridescent purple, blue, or pink. The lower jaw
projects beyond the upper one, and the tip of the tongue sports large teeth. As adults, smelt eat shrimplike or-
ganisms, aquatic worms, and small fishes, including juvenile herring, mummichog, and silversides.
Smelt are a schooling species and, sensitive to light and warm temperatures, tend to congregate near the
ocean bottom during the daylight hours. They leave the estuaries en masse to make their spawning runs as
soon as the ice leaves the brooks and creeks in spring. The spawning run lasts only a few weeks. Many males
die shortly after spawning, and the surviving males and females stay on the spawning ground for five to ten
days before moving downstream again. In the Miramichi system, they remain in the bay for the summer but
begin moving into the estuary in October, taking up winter residence in the lower estuary after the ice forms in
late November.
Smelt spawn at night and demonstrate a homing behavior, tending to return to the same stream, or one
nearby, year to year. They lay their eggs on the gravelly bottom, females depositing from seven thousand to
seventy thousand eggs, depending upon their size and maturity. Two males clasp the female between them dur-
ing spawning, releasing their milt simultaneously as the female releases its eggs.
The outer envelope of the egg becomes sticky on contact with the water and adheres to the gravel. When
this outer coat is torn away by the current, a portion of the egg, a little stem, sticks to the bottom, allowing the
egg to sway in the current, where it is aerated. In some cases, smelts may deposit thick carpets of eggs, and
those on the bottom are smothered, leading to high mortalities. Even when eggs receive adequate oxygen, only
about 4 percent hatch. The time required for hatching is dependent on water temperature: at 4°C (39°F) eggs
require at least fifty days to develop, whereas at 10°C (50°F) they may hatch in as little as twenty days.
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