Trophic Explanations for Non-Recovery of Atlantic Cod (Gadus morhua) in the Northwest Atlantic

R. Steele \ Oceans First, Issue 3, 2016, pgs. 31-37

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Abstract: In the early 1990s, the Atlantic cod stock in the Northwest Atlantic collapsed due to overexploitation by the Atlantic cod fishery. Since then, the stock has failed to recover to its natural population. This paper explores how a trophic cascade brought about from the initial removal of the cod from the Northwest Atlantic ecosystem can explain the cod’s inability to recover. The reduction in cod population allowed the abundance of harp seals and grey seals (natural predators of cod), to increase due to a reduction in competition for the role of apex predator. Furthermore, key cod prey species in capelin and zooplankton suffered a decrease in abundance due to the collapse of the cod population. As a result, cod face increased predation, a limited amount of available prey, and increased competition for their ecological niche. This has undoubtedly slowed the recovery of Atlantic cod in the Northwest Atlantic.