How many sea scallops are there and why does it matter?

Abstract

Oceanic conditions along the Atlantic Coast of North America are changing rapidly. Surface water temperatures in the Gulf of Maine have increased faster than 99% of the global oceans, and major infrastructure projects, including the largest windfarm in the world, are under development along this seaboard. In Canada and the US, the Atlantic sea scallop (Placopecten magellanicus) supports lucrative fisheries, which were originally founded on an extensive scientific framework focusing on stock assessment. The sea scallop is an ideal sentinel species, as it is highly sensitive to changes in marine conditions. We used a drop camera system to estimate the number and size of scallops, as well as the distribution of their reproductive potential, over 70,000 km2 of the continental shelf in 2016–2018, an area that nearly covers the entire range of this species. In total, we estimated that there were 34 billion individual scallops (95% confidence limits: 22–46 billion) within the species’ range. In this paper, we examine the role of the sea scallop as a baseline sentinel species that can be used to measure the impacts of environmental change and anthropogenic developments.