This series of maps broadly characterizes commercial fishing vessel activity in the Northeast based on Vessel Monitoring System (VMS) data from 2006 through 2019. The relative amount of vessel activity is indicated qualitatively from high (red) to low (blue). The National Marine Fisheries Service (NMFS) describes VMS as “a satellite surveillance system primarily used to monitor the location and movement of commercial fishing vessels in the U.S.”
The maps do not necessarily distinguish between fishing activity, vessel transit, and other vessel activities. Some maps show vessel activity at less than four or five knots—a speed threshold that was determined with industry input to attempt to better highlight fishing areas. Nevertheless, those maps still likely show some non-fishing activities that occur at low speeds, such as processing catch, sorting, drifting, or idling in port. The most accurate interpretation of these maps is that they indicate relative levels of fishing vessel presence for federal fisheries that require VMS monitoring.
The lack of historical data and relatively short timeframe of this map preclude consideration of historical fishing areas. It also does not illustrate more recent or future changes in fishing activity resulting from changing environmental and economic conditions, fisheries management, and other important factors.
The data provided by NMFS contained the day/month/year, the geographic coordinates of the vessel at the time of transmission, speed over ground, and the vessel’s declaration code, which signifies fishery plan, program within that plan, and associated area identifier or gear-type information. These data then were aggregated by combining all program codes within each fishery plan.
The limitations of the data used to produce these maps should be understood prior to interpretation of this map.
VMS data is subject to strict confidentiality restrictions. Therefore, the map shows the density of vessel locations following the removal of individually identifiable vessel positions. The process of removing sensitive vessel locations followed the “rule of three” mandated by NMFS Office of Law Enforcement (OLE). The details of this filtering process vary between individual data products; see the metadata for each layer to see more detail on filtering processes used. A statistical method to normalize data was used on the subsequent density grids and data values represent standard deviations. While legends are consistent across products, values represent high or low areas of vessel activity specific to each dataset. This process can result in the maps showing vessel activity that seems anomalous, e.g. single data points in areas where multispecies fishing isn’t common, because three data points occur in a given 100m by 100m square. This is usually because of transit lines that overlap in a given cell while nearby cells contain less than three data points.
The most recent data were updated and posted on Northeast Ocean Data in fall of 2022, and they will continue to be updated as described in the 2016 Northeast Ocean Plan.
Support for Regional Ocean Planning
For information about how these data and maps were developed with stakeholder input and will be used to support regional ocean planning, please refer to the Northeast Ocean Planning website or contact us at firstname.lastname@example.org.