Sea Trout – Fragments of the Past

August 3, 2021 by No Comments

One hundred and fifty years ago, “sea trout” of the Atlantic provinces included two species, Salvelinus alpinus, and Salvelinus fontinalis.

Arctic char (S. alpinus) now exist in small numbers slotxo1way in New Brunswick and GaspĂ©, and more substantial populations inhabit Newfoundland, northern Quebec, and Labrador. “Speckled” or “brook” trout (S. fontinalis) are widespread, from Labrador south to the Appalachian Mountains of North Carolina.

These days, “sea trout” in eastern waters can include introduced brown trout (Salmo trutta) or transplanted rainbow trout (Oncorhynchus mykiss). Sea-run rainbows are called “steelhead” in Western Canada. Browns and rainbows were introduced in the late 1800s. Both species have established breeding populations in parts of the east.

Saltwater is a lifestyle choice for many salmonids born with downstream access. The term “landlocked” is often misapplied to populations that live in fresh water by choice. Sometimes downstream or upstream passage is blocked. In other cases these landlocked species, like the Atlantic salmon of the Shubenacadie River, have the option to leave, but some choose to stay in freshwater. This usually happens when freshwater habitats offer abundant food resources and other elements critical for survival. On the Shubenacadie, fall spawners come from the Bay of Fundy and from lakes. There are some genetic differences, but it’s hard to determine if saltwater habits are habitat-driven or destined by genes. There may be a genetic propensity driving some folks to buy Volvos.

Speckled trout remain a common freshwater fish in Atlantic Canada. Many trout stay inland and never descend to estuaries. However, if seasonal habitats become limited or if juvenile populations become ovecrowded in small streams, competition for limited food and space in relatively short, sterile Atlantic rivers might prompt a young trout to journey downstream to the estuary. Sea-run speckled trout moved north, colonizing new rivers as the glacial ice sheet receded about 12,000 years ago. The fresh water form most likely evolved from sea-run ancestors.

What is the sea life of a brook trout? Sixty years ago, H.C. White studied a population near the Moser River, on Nova Scotia’s eastern shore. He found they descended that river during April and May, when they were angled in the inner estuary in large numbers. In the harbour they fed upon minnows, elvers, isopods, amphipods, and sand worms. On average these trout spent about two months (64.5 days) of the year at sea. Some wandered 13 km (8 miles) or more from their home stream, and even ascended other streams. Local fishermen reported seeing schools of trout in water 1.5 to 3 m (5-10 ft) deep around the inner islands off the coast near Moser River. Trout were also observed in groups around some private wharves on the mainland coast where fish were being cleaned. White documented that sea-run speckled trout travel in schools along the coast, feeding upon various fish species and crustaceans. Trout were observed darting about as if feeding, while schools moved quickly past. Schools usually had the same size trout, probably a reflection that large trout have a tendency to eat small trout. White also noted fewer schools of larger fish. Many were angled from clear sea water along rocky shores. Their backs were a light blue-green, sides silvery and bellies pearl-white. This colouration blended with the background so well that they were hard to see.

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