Biologically Important Areas


Overview of BIA II

Biologically Important Areas (BIAs) represent areas and times in which cetacean (whales, dolphins, and porpoises) are known to concentrate for activities related to reproduction, feeding, and migration, as well as the known ranges of small and resident populations. BIAs can be used to better understand and predict how individual marine mammals are likely to respond to or be impacted by disturbances, and where populations may be more susceptible to certain types of impacts. BIAs may be used like any other scientific information to support analyses and decisions, as appropriate, for the purposes of environmental planning, compliance, and protection. BIAs are compilations of the best available science and have no inherent or direct regulatory power.

In the BIA II effort, NOAA, with the support of the U.S. Navy, convened a working group of regional cetacean experts who have updated and revised the BIAs identified in Van Parijs et al. (2015) using new methods and scoring protocols described in Harrison et al. (2023) that improve the utility, interpretability, and consistency of the BIAs by designating an overall Importance Score for each BIA. Seven regional manuscripts, which will be available in the Identifying and Comparing Important Areas for Marine Sustainable Use and Conservation Research Topic of Frontiers in Marine Science, include the maps and scores for the BIAs, by region, and narratives describing the rationale and information upon which several representative BIAs (across types and scores) are based. Currently finalized regional manuscripts and an updated interactive BIA map are available in the panel to the right.  

Defining and Scoring BIAs

Regional cetacean experts were asked to compile the best available information from scientific research studies, Indigenous knowledge, local knowledge, and community science to identify areas that are biologically important to cetacean species (or populations), either seasonally or year-round. Using the methods outlined in Harrison et al. (2023), experts identified an overall Importance Score for each BIA that considers: 1) "Intensity" - the intensity and characteristics underlying an area's identification as a BIA; and 2) "Data Support" - the quantity, quality, and type of information, and associated uncertainties, upon which the BIA delineation and scoring depends. Importance Scores range from 1 to 3, with a higher score representing an area of higher intensity and data support. Each BIA identified in the BIA II effort is also scored for boundary uncertainty and spatiotemporal variability (dynamic, ephemeral, or static).


Reproductive Areas (R-BIA)

Areas and times within which a particular species selectively mates, gives birth, or is found with neonates or calves.

Feeding Areas (F-BIA)

Areas and times within which aggregations of a particular species preferentially feed. These either may be persistent in space and time or associated with ephemeral features that are less predictable but are located within a larger area that can be delineated. 

Migratory Routes (M-BIA)

Areas and times within which a substantial portion of a species is known to migrate; the route is spatially restricted.

Small and Resident Population (S-BIA)

Areas and times within which small and resident populations occupy a limited geographic extent.

Watch List Areas

BIA II scoring protocols included a specific mechanism for Regional cetacean experts to identify "watch list" areas that they believe may be BIAs, but that currently lack sufficient information to reliably delineate and score. The watch list areas identified and mapped for each region may be found below, and the supporting information may be found in the regional manuscripts. Watch list areas help identify information gaps and needs.