The Role of Closed Areas in Rebuilding Monkfish Populations in the Gulf of Maine

The use of fish closures as a management tool to protect juvenile fish habitat and adult spawning grounds has become increasingly popular, although knowledge of the direct effects of marine closures on juvenile fish populations is limited. Given that monkfish landings account for a considerable percentage of the monetary value derived from the groundfish fishery in new England, investigating the factors that influence monkfish population dynamics will assist managers in sustaining this important natural resource. We conducted bottom-trawl surveys to determine the effects of closure status [inside vs. outside the Western Gulf of Maine Closure Area (WGMCA)] and habitat type (mud bottom in isolation from gravel or cobble bottom vs. mud that is next to these more complex habitats) on the distribution, abundance, and diet composition of monkfish (Lophius americanus) in the Gulf of Maine. Surprisingly, the abundance of adult monkfish did not differ in vs. out of the closure, and juvenile monkfish were more abundant outside of the WGMCA, where they also exhibited higher feeding intensity and consumed more prey biomass. Monkfish diet and condition results implied that the boulder and ledge bottom is essential monkfish habitat and that these effects were independent of the WGMCA.