Fisheries Distribution Mapping & Analysis Portal (DisMAP) - NOAA

Posted on: 5/23/2022 - Updated on: 8/03/2022

Posted by



The NOAA Fisheries Distribution Mapping and Analysis Portal (DisMAP) provides easy access to information to track and understand distributions of marine species in the U.S. Marine Ecosystems. Launch the portal to explore, visualize and interact with information on marine species distributions.

The geographic, or spatial extent, over which a species is found to occur, is its distribution. Understanding how species are distributed in space and time and the factors that drive spatial patterns in distribution and abundance are central questions in ecology and important for species conservation and management.

A major impact of changing climate and ocean conditions is the large-scale shifts in distributions of many marine species as they attempt to remain within their preferred environmental conditions (e.g., temperature). These shifts in distribution pose a central challenge to fisheries managers as they can and already are affecting commercial and recreational fisheries, and the economies of communities that rely on them.

The Distribution Mapping and Analysis Portal (DisMAP) consolidates data on species distributions into one user-friendly and interactive website. It provides tools for exploring changes in marine fish and invertebrate distributions through time. Our mission is to:

  • Improve ease of access to and exploration of species distribution data
  • Support decision-makers to use this spatial data for insight and informing decisions, such as fishing closed areas, marine protected areas, allocations, stock boundaries, survey designs
  • Foster sharing and exchange of practices and ideas among scientists working on species distribution modeling.

DisMAP provides access to distribution information for more than 800 marine species caught in NOAA Fisheries bottom trawl surveys in five regions in the United States (Northeast, Southeast, Gulf of Mexico, West Coast, and Alaska). In this first version of the portal all species distribution products are derived from NOAA Fisheries regional bottom trawl survey data. They do not take into account alternative sources of fisheries data such as long-line, plankton, video, or fishery-dependent surveys. Because of this, distribution products are not available for the Pacific Islands or Caribbean regions at this time as those regions do not have bottom-trawl surveys; however incorporating these additional data sources is an area of interest for future releases.

The portal provides information on three key indicators used to track and explore shifts in species distributions:

  • Distribution of biomass in space and time (i.e., distribution surface)
  • Center of biomass
  • Range limits

The distribution surface provides information on how much of the species is expected to be present at any given location within a particular area of interest. This surface forms the basis for the calculation of the other two indicators. The center of biomass (centroid or center of gravity) is a common way to represent the central location (latitude, longitude, or depth) of a population. It is calculated as the biomass-weighted average location (latitude, longitude, or depth) of the population. Tracking this indicator through time provides information on the direction (north vs. south, deeper vs. shallower) in which the population is moving. Tracking changes in range limits is also a useful indicator of species distribution shifts. Range limits are the edges of a species distribution; for instance, the northern most and southernmost latitudes at which the species is found. Changes in range limits, particularly the difference between the northern and southern range limits, can indicate if a population is undergoing range expansions (increasing distance between range limits) or contractions (decreasing distance between range limits).


NOAA Fisheries

Managing Organizations

NOAA is an agency that enriches life through science. Our reach goes from the surface of the sun to the depths of the ocean floor as we work to keep citizens informed of the changing environment around them. From daily weather forecasts, severe storm warnings and climate monitoring to fisheries management, coastal restoration and supporting marine commerce, NOAA’s products and services support economic vitality and affect more than one-third of America’s gross domestic product.