Subsampling Stations with High Sea Scallop Density from Video Surveying Techniques

The University of Massachusetts Dartmouth School for Marine Science and Technology (SMAST) video survey has long been conducted to estimate Atlantic sea scallop (Placopecten magellanicus) density and distribution in the Northeast United States.  Recent extreme large recruitment events have led to scallop densities as high as 4.29 scallops per m² in the Mid-Atlantic and 14.05 scallops per m² on Georges Bank, which is an order of magnitude higher than previous densities.  Individual stations had densities as high as 123.7 scallops per m².  To develop a more efficient way to assess these high density stations we used various techniques including systematically subsampling stations from the entire area surveyed and subsampling within quadrat images to estimate mean shell height and biomass.  We examined how sampling techniques for mean shell height affect total biomass estimates.  Preliminary results indicate that subsampling can produce statistically similar results as incorporating all measurements.  We are exploring the feasibility of this new sampling design for future surveys to preserve accuracy of the assessment and to have the ability to analyze data in a timely manner for consideration by stakeholders.