The role of spiny dogfish in the northeast United States continental shelf ecosystem: How it has changed over time and potential interspecific competition for resources

Ecosystem based modeling was used to determine the ecological role of spiny dogfish (. Squalus acanthias), an opportunistic predator, in the northeast United States marine environment. Two time periods were modeled; one when spiny dogfish populations were depressed and one after recovery. According to our results, the ecological role of spiny dogfish has changed over time. During the depressed time period, spiny dogfish were not a keystone species and had little impact, positive or negative, on other species/groups in this ecosystem. Spiny dogfish currently have one of the highest trophic levels in this ecosystem and are akeystone species, having a high prey overlap with commercially depleted Atlantic cod (. Gadus morhua). Spiny dogfish appear to have responded well to changes in this ecosystem caused by fishing and perhaps environmental change or a combination of both, while other species in the region have not. This is important, as spiny dogfish could now be potentially out competing commercially valuable and highly depleted populations of groundfish for resources. Based on our results, we suggest fisheries managers should look toward ecosystem based management measures in the future in order to actively and properly manage the ecosystem as a whole.