Parks Canada
Symbol of the Government of Canada

Saguenay–St.Lawrence Marine Park

Intermediate Layer

Illustration of the intermediate layer of the water column. On the right, a cliff where blue mussels cling. In the water, shoals of Atlantic herring, capelin and sand lance. At the top of the image, illustrations of krill and copepods. Krill Copepods Blue MusselBlue MusselBlue Mussel Atlantic Herring Sand Lance Capelin

Sand Lance

Sand Lance

Kingdom: Animal
Division: Vertebrate
Classification: Fish
Types of fish species in the marine park: 70

Description:  The name "sand lance" was inspired by its slender body. Its pointed snout and long fins clearly distinguish it from capelin for which it is often mistaken. Its length varies between 20 and 25 centimetres.

Habitat:  In the Northwestern parts of the Atlantic Ocean, and as far as the Hudson Bay, Labrador and Greenland. They are often found along coastline waters.

Population:  The sand lance is a "forage species" which numerous other species, including salmon and cod, depend on for food.  

Reproduction: Takes place in shallow waters during the winter. Each female spawns thousands of eggs on sandy sea beds. Upon hatching, the larvae will become part of the zooplankton. Feeding habits: Mainly composed of copepods and other small organisms.

Range: Moves over short distances to rest or find food.

Did you know?
The sand lance likes to bury itself in sand to rest or hide. AN ABUNDANT RESOURCE! Sand Lance fishing is largely untapped in Canada. This fishery is a major resource that still remains to be studied.

 

 

Copepods

Copepods

Kingdom:  Animal
Division:  Invertebrate
Classification:  Crustacean

Description:  Tiny egg-shaped crustacean that floats freely as a zooplankton. Its name means that it has small oar-shaped legs. Copepods are usually no bigger than a grain of rice.

Habitat:  Present in every type of aquatic environment, from ponds to oceans. In the estuary, it lives mainly near shorelines where it finds abundant sources of food.

Population:  Overly abundant. It is at the bottom of the food chain and plays a key role in keeping ecosystems in balance.

Reproduction:  Depending on the species, mating either takes place year-round or according to the season and the number of eggs laid can vary from one species to another, i.e. from a few dozens to a few hundred. 


Feeding habits:
  According to species, it feeds on microscopic plankton that it filters, grazes on, or captures. 

Movement:  Currents enable it to drift from one place to another. 

Did you know? The copepod is the most abundant crustacean on the planet.

REMEMBER: Copepod populations can vary significantly, depending on water temperature and availability of food. Therefore, monitoring climate change is of the utmost importance!

 

 

Krill

Krill

Kingdom: Animal
Division: Invertebrate
Classification: Crustacean

Description: Resembles tiny shrimp of about 35 millimetres long. Part of zooplankton, krill is a free-floating microorganism that is part of the animal kingdom (eggs, larvae, adults).

Habitat: Found everywhere around the world in cold and salty waters.

Population:  Lives in immense schools measuring up to 100 kilometres long and 1 to 7 kilometres wide! Important source of food for various species, including the humpback whale. The marine park is one of the richest krill sites in the Northwestern Atlantic.

Life expectancy: 6 years.

Feeding habits: Microscopic algae (phytoplankton).


Movement: Schools drift freely with currents. Krill undergoes a daily migration. During the day, it descends to the bottom and at night, comes back  to the surface to eat. 

Did you know? Krill glows in the dark thanks to special light producing organs called "photophores".

REMEMBER: Climate changes can have a significant affect on the environment, water properties and habitat, which

 

 

Atlantic Herring

Atlantic Herring

Kingdom: Animal
Division: VertebrateClassification: Fish
Types of fish species in the marine park: 70

Description: Slender silver-coloured body that turns somewhat bluish on the back.

Length: Up to 35 centimetres.

Habitat: Newfoundland's coastal waters and the Estuary and Gulf of St. Lawrence.

Population: Moves about in enormous schools measuring up to many kilometres long. Species on which many predators are dependent, i.e. a "forage species".

Reproduction: Females lay between 20 000 to 100 000 eggs in seafloor mud.

Life expectancy: 18 years and up.



Feeding habits:
Mainly composed of zooplankton, such as krill and copepods.

Range: Herrings swim from the Gulf to the estuary twice a year (spring and fall) to reproduce. 

Did you know? Herring is one of the most abundant fish in the world. 

REMEMBER: Due to overfishing of herring off Newfoundland's coasts, quotas have been introduced to limit the number of fish caught.

 

 

Capelin

Capelin

Kingdom: Animal
Division: Vertebrate
Classification: Fish

Description: Fish with a green olive coloured back. Belly and sides turn silver over time. Length: from 20 to 25 centimetres long. Maximum weight: 52 grams.

Habitat: Cold fresh or salt waters. Lives in large shoals to depths up to 725 metres.

Population: Very large shoals live in the marine park. It is a staple for many other species; referred to as a "forage species". 

Reproduction: Between May and June, capelins congregate on sandy sea bottoms to reproduce and lay eggs in the sand. When this occurs, the waves throw many of them onto the beach, a process called "rolling". Females lay from 6 000 to 12 000 eggs.

Life expectancy: Approximately 10 years.

Feeding habits:  Microorganisms such as zooplankton (krill, copepods) and small invertebrates.

Movement: Around April, capelins migrate from the Gulf of St. Lawrence to spawn on beaches; Gaspésie and Côte-Nord shorelines being the most popular.

Did you know? Each year, 1 million tonnes of capelin are eaten by predators in the Gulf of St. Lawrence.

REMEMBER: The food base of the capelin's diet can be disturbed by climate changes.

 

 

Blue mussel

Blue Mussel

Kingdom: Animal
Division: Invertebrate
Classification: Mollusk

Description: Composed of 2 identical smooth valves (bivalves). Measures 5 centimetres. The outside of the shell is usually bluish and glossy. Inside the shell, the meat of the mussel is often pink or orange (female) or whitish (males).

Habitat: The cold waters of the Northern Atlantic and Pacific Oceans. Can be found in shallow surface waters and up to depths of approximately 10 metres.

Population: Very abundant in the St. Lawrence Estuary.

Reproduction: During the summer, mussels release their eggs or sperm in the water and whitish or orange clouds can be observed. Thus, fertilisation takes place in the water column. 



Feeding habits:
Mussels feed on plankton by filtering it from water particles.

Movement: Young mussels can detach themselves and relocate by using their feet to crawl or by drifting in the water column. Adult mussels use their "byssal" fibres to attach permanently to firm surfaces.

Did you know? Usually the most harvested, the blue mussel is often the one consumers can buy in grocery stores. In 2003, 20 510 tonnes of blue mussels were produced in Canada.

REMEMBER: The blue mussel is sensitive to environmental contaminants because it needs to filter its food before eating it.