Distribution

American shad are anadromous fish (moving from the sea to spawn in freshwater) found along the Atlantic coast of North America from Newfoundland to Florida. Large spawning runs used to occur in the Shubenacadie and Annapolis rivers (also Saint John, Petitcodiac and Miramichi), but they are found in many Maritime coastal rivers. They have been introduced along the Pacific coast and now range from Alaska to California.

Physical Characteristics

The American shad, like the alewife (gaspereau), is a member of the herring family with the following characteristics:

• slender and silvery-coloured with a blue-green metallic hue on the back;
• has a black spot, similar to the alewife, located on the side, just behind the head - on the shad, this spot is followed by several smaller dark spots;
• the eye has an obvious eyelid;
• a row of scales known as scutes form a sharp "sawbelly" edge along the midline of the belly;
• there is no lateral line.
• American shad can grow to 76 cm (30 in) and weigh 6.8 kg (15 lb). However, adults found in Canadian rivers are usually 45-50 cm (18-20 in) long and weigh from 1.4-2.7 kg (3-6 lb).

American shad can migrate up to 3,000 km in one season!

The flesh of the American shad is very tasty. Did you know the scientific name for shad comes from the Saxon word "allis", an old name for the European shad, and the Latin sapidissima meaning "most delicious"?

The French common name for this fish is alose savoureuse or "savoury shad".

The world angling record for American shad weighed 5.1 kg (11.2 lb) and was caught in the Connecticut River, Massachusetts, in 1986.

Scientific studies show that shad from all eastern U.S. rivers spend some time in the Bay of Fundy.

The American shad lives for several years at sea before returning to spawn in the stream or river where it hatched. Shad avoid cold temperatures, preferring to stay in water that is 80øC or warmer. Much of their migration and behaviour is determined by water temperature and currents.

Each spring, schools of shad, using their sense of smell, begin to migrate up coastal rivers and tributaries when water temperatures reach 12øC.

Spawning in the Maritimes occurs during June and July in water temperatures of 13-20øC. Migration stops in temperatures over 20øC. American shad do not usually travel upstream as far as the alewife.

They spawn in rivers at night in mid-water areas with a wide range of bottom types. The eggs are about 3 mm across and drift along with the current to hatch in 8-12 days, depending on the temperature.

A female can produce anywhere from 60,000 to 600,000 eggs. Shad in Canadian rivers usually produce about 130,000 eggs. Many shad in the Maritimes are repeat spawners, however southern populations of shad die after spawning.

Young shad spend their first summer in the river feeding on insects and crustaceans. They swim near the bottom in water as deep as 3.7-4.9 m (12-16 ft), but at night they are found near the surface. When they migrate to sea in the fall, they have grown to a size of 7.5-12.5 cm (3-5 in). They migrate to the sea as river temperatures drop.

At sea, shad live in schools moving to areas with bottom temperatures that are 7- 13øC. They stay near the bottom during the day, dispersing at night to all depths. Immature and spawned-out adults remain offshore in areas like the Bay of Fundy until winter, when they move farther out to sea in order to stay in preferred water temperatures. At sea they eat zooplankton (tiny invertebrates that live in the water), small bottom crustaceans, and occasionally small fish. Most shad mature at age 4 or 5 when they are about 48-53 cm (19-21 in) long. Shad can live up to 13 years.

Although not a major food source for other animals, shad are eaten at sea by seals, sharks, blue-fin tuna, kingfish, and porpoises. Young shad in freshwater are eaten by bass, American eels and birds.

Published With Funding from the Canada-Nova Scotia Cooperation Agreement on Economic Diversification, Resource Competitiveness Program.