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Analysis

  • Data will be analyzed in a specialized program, EchoView. Survey design was created with geostatistics in mind (Figure 1 below). 
  • Anticipated results include relative biomass measurements, spatial and temporal variation of schools, and spawning ground identification (Figure 2 below). 
  • Future directions could include surveying zooplankton, groundfish, fish behavior, such as vertical migration, and continued herring surveys. 
  • With a few years of herring survey data, it may be possible to use these results for more accurate and reliable quotas for area 1A (Figure 1 under Introduction).


Figure 1: Data from off of Portland, Maine (September 2012). The red line at the bottom of the image is the seafloor (200 feet at deepest point below school on left). Above that are two schools of fish. the stronger the color, the denser the school of fish. It is possible to make out individual fish (blue arcs) near the edges and below the schools. Echogram represents 1 nautical mile. Echogram created in Echoview.


Figure 2: Acoustic backscatter results from week 1 of survey over the entire study site. Color and size represent Nautical Area Scattering Coefficient (NASC) which can be used as a proxy for biomass in the water column. These results are from early in the season (September 12, 2012) and show that there are more fish in the northern region than in the southern region.