The effects of small-scale closed areas on the Atlantic sea scallop <i>Placopecten magellanicus</i> in Maine

ABSTRACT Objective Closed areas are commonly used in fisheries management to rebuild marine species. Large-scale closed areas (&amp;gt;10 km2) have proven effective in rebuilding offshore Atlantic sea scallop Placopecten magellanicus populations in the U.S. federal fishery; however, little is known about the effect of small-scale, inshore closed areas (&amp;lt;10 km2) on sea scallops. This study, which involved a multi-sector collaboration, sought to evaluate the effect of small-scale closed areas on the Atlantic sea scallop in Maine. Methods Between 2013 and 2017, annual scuba surveys were conducted to assess the density and shell height (SH) of adult scallops inside and adjacent to two closed areas. Spat abundance was also determined with the use of spat bags at one of the closed areas. Results We observed larger SHs, a pulse of juvenile scallop (SH &amp;lt; 70 mm) recruitment in 2014, and potential settlement to the seabed in one of the closed areas but not in the adjacent open area; however, results were not statistically significant in all years. Conclusions Atlantic sea scallops are broadcast spawners, with increasing reproductive output as size increases. With a greater number of larger scallops in closed areas, there could be higher rates of successful reproduction, meaning that closed areas may be a larval source in coastal waters. However, oceanographic models and genetic analyses would be needed to test this hypothesis and further explore inshore scallop population dynamics. Ultimately, small-scale closed areas could prove to be a useful tool in management if areas with suitable habitat are selected and if closure implementation and duration align with successful recruitment events.