Sea Scallop Survey
ArcGIS Feature Service
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InPort Metadata
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Description
The standardized scallop dredge survey has been conducted since 1979 and employs a stratified random sampling design. The original NEFSC Shellfish Strata were based primarily on depth and secondarily by latitude, and locations of sampling stations were randomly selected within each stratum prior to each annual cruise. Starting in 2025, the Scallop Area Management Simulator (SAMS) areas were used as survey strata. Use of the SAMS areas as strata ensures that sampling is more useful to management. The dredge survey also implemented a spatially balanced form of stratified random sampling called Generalized Random Tessellation Stratified (GRTS) in 2025. While still a form of stratified random sampling, this method prevents random stations from being placed very close together.
Spatial Extent
Layers
| id | name | type | geometryType |
|---|---|---|---|
| 0 | SMIT_SCALLOP_STRATA | Feature Layer | esriGeometryPolygon |
| 1 | SMIT_SCALLOP_STRATA_HISTORIC | Feature Layer | esriGeometryPolygon |
Fields
SMIT_SCALLOP_STRATA
DescriptionThe current (as of 2025) NEFSC Scallop Strata (SAMS). Starting in 2025, a spatially balanced form of stratified random sampling called Generalized Random Tessellation Stratified (GRTS) was implemented, along with a switch to using Scallop Area Management Simulator (SAMS) areas as survey strata. While still a form of stratified random sampling, this method prevents random stations from being placed very close together. Use of the SAMS areas as strata ensures that sampling is more useful to management.
| name | alias | description | dataType |
|---|---|---|---|
| OID | OID | Original object ID | esriFieldTypeBigInteger |
| SURVEY_NAME | Survey name | Name of NEFSC scientific survey | esriFieldTypeString |
| SAMS | SAMS | SAMS code | esriFieldTypeString |
| NEWSAMS | New SAMS | New SAMS code | esriFieldTypeString |
| AREAKM2 | Area (sq km) | Area of strata in square kilometers | esriFieldTypeDouble |
SMIT_SCALLOP_STRATA_HISTORIC
Description
The historic (pre-2025) NEFSC Shellfish Strata. The standardized scallop dredge survey has been conducted since 1975 (annually since 1977) and employs a stratified random sampling design. The original NEFSC Shellfish Strata were based primarily on depth and secondarily by latitude, and locations of sampling stations were randomly selected within each stratum prior to each annual cruise.
| name | alias | description | dataType |
|---|---|---|---|
| OID | OID | Original object ID | esriFieldTypeBigInteger |
| SURVEY_NAME | Survey name | Name of NEFSC scientific survey | esriFieldTypeString |
| AREA | Area | Area of strata in degrees | esriFieldTypeDouble |
| PERIMETER | Perimeter | Perimeter of strata in degrees | esriFieldTypeDouble |
| STRATA_ | Strata | Strata number | esriFieldTypeBigInteger |
| STRATA_ID | Strata ID | Strata ID | esriFieldTypeBigInteger |
| A2 | A2 | A2 | esriFieldTypeBigInteger |
| STRATUM | Stratum | Stratum code | esriFieldTypeBigInteger |
| DEPTH_CODE | Depth code | Depth code | esriFieldTypeBigInteger |
| ACRES | Area (acres) | Area of strata in acres | esriFieldTypeDouble |