@pagophilus.orgWhat Do Harp Seals Eat?

Background

The Northwest Atlantic harp seal (Phoca groenlandica) is perceived to compete with commercial fisheries for important species such as Atlantic cod (Gadus morhua). In order to understand such presumed interactions, we must first determine what, and how much, harp seals eat. Traditionally, the diet of harp seals has been described by examining the contents of their stomachs.

The Data

Since 1941, the stomach contents of Northwest Atlantic harp seals have been recorded in 23 reports as well as in several reviews and anecdotal accounts. Stomachs from most age categories have been collected intermittently throughout their annual range, extending from Arctic waters in the summer to the Gulf of St. Lawrence during the winter (see map below). A total of 12,746 harp seal stomachs have been analyzed. Of these, 69.7% contained prey items, including at least 67 species of fish and 70 species of invertebrates.

The Diet

Clearly, harp seals eat a wide range of species. Their diet also varies with age, season, location and year.
In the North: Harp seals summering in West Greenland and northern Canadian waters (north of Nain, Labrador) feed on pelagic crustaceans, such as euphausiids, and small fishes, such as Arctic cod (Boreogadus saida), polar cod (Arctogadus glacialis) and capelin (Mallotus villosus).
In the South: During the southern (fall) migration, harp seals forage along the coast of Labrador (south of Nain) and in the Gulf of St. Lawrence (the Gulf) on a variety of fishes and invertebrates. In the St. Lawrence River they eat capelin from December to February, prior to the pupping season. Lactating females and moulting harp seals feed infrequently, although mothers forage intensively on capelin in the St. Lawrence River after weaning their pups.
Harp seals collected from nearshore waters of Newfoundland and Labrador prey upon a broad array of fish and invertebrate species, although Arctic cod is by far the most important. In Northeast Newfoundland there was a notable shift in the diet of seals aged one and older from capelin in 1982 to Arctic cod in 1986 and beyond, while Atlantic cod remained relatively unimportant throughout this period. Offshore, capelin predominate, followed by sand lance (Ammodytes sp.), Greenland halibut (Reinhardtius hippoglossoides) and other flounders.

During the northern (spring) migration, harp seals feed along the Labrador coast on a variety of species, including euphausiids, various codfishes, capelin and shrimp, while in the Gulf migrating seals feed less frequently, primarily on capelin and herring.

Atlantic cod, including the northern cod stock [Northwest Atlantic Fisheries Organization Divisions 2J3KL (see map)], is a minor component of the annual harp seal diet.

Source
Wallace, S.D and J.W. Lawson. 1997. A review of stomach contents of harp seals (Phoca groenlandica) from the Northwest Atlantic: an update. IMMA Technincal Report 97-01. 99pp.

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