Service Description: The estimated presence/absence of Silverside according to data collected by the MA Division of Marine Fisheries Resource Survey, 1978-2016

Service ItemId: 10d19ec44e3840268b3525147717f610

Has Versioned Data: false

Max Record Count: 1000

Supported query Formats: JSON

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• Spring Silverside Presence (0)

Description: Data was provided by the Massachusetts Division of Marine Fisheries (DMF). Data was collected during the bi-annual (Spring and Fall) Resource Survey from 1978-2016. DMF provided the following information for every trawl: latitude, longitude, cruise number, stratum, trawling station, set dept, date of trawl, bottom temperature, number of each specie collected in net, weight of each specie. Latitude, longitude, and number of each specie collected in net data was used to create this visual. Separate data sets were made for spring data (green) and fall data (blue). Each dataset identifies the number of Silverside caught during each trawl (3781 data points in the Spring, 3450 data points in the Fall) and the location of each trawl. To effectively interpolate using Natural Neighbor and to show areas that were “Not Surveyed”, shapefile points were created along the Massachusetts border, around the Martha’s Vineyard and Nantucket border, and outside the extent of the DMF trawl. Not surveyed data points (n=311) were assigned the value, NUMi, of 0. Trawl data points where no Silverside were caught received the value of 0.1 (NUMi=0.1). All other data points where Silverside were caught kept their value as the number of Silverside caught. Natural Neighbor Interpolation Tool was then used for all these data points according to "NUMi" category. The interpolated data can be found in "Spring Silverside" and "Fall Silverside" Displayed interpolated categories were created by giving "Not Surveyed" (NUMi=0, 311 data points) and "Absent" Silverside (NUMi=0.1, no Silverside presence), their own category. Then, remaining data points were binned into the following categories based on the aggregation behavior of the species: Absent=0 Silverside Low=1-25 Silverside Medium=26-100 Silverside High=101-500 Silverside Very High=501-568 Silverside

Copyright Text: Amanda Davis and Dr. Michelle Staudinger of the Northeast Climate Science Center (NE CSC) and Brad Chase of Massachusetts Division of Marine Fisheries (MA DMF)

Spatial Reference: 102100 (3857)

Initial Extent:

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Spatial Reference: 102100 (3857)

Full Extent:

XMin: -7917243.4209
YMin: 5030431.0286
XMax: -7769500.1928
YMax: 5292072.6322
Spatial Reference: 102100 (3857)

Units: esriMeters

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