Bocaccio (PugetSoundGeorgiaBasinDPS)

Nearshore Habitat Program, Washington State Department of Natural Resources (DNR), Aquatic Resources Division (AQR)

Nearshore critical habitat is defined as occurring from the shoreline from extreme high water out to a depth no greater than 30m (98 ft) relative to mean lower low water. These geospatial data show it extended out to 30 meter depths as defined by the 30 meter contour developed using gridded depth data from The Nature Conservancy. This 30 meter depth contour was also used to define where the nearshore critical habitat aligns with designated deepwater critical habitat.

These data were created through a series of processing steps. The initial source data were a depth grid obtained from The Nature Conservancy in 2013. It is a compilation of depth data from 4 different source data sets. It included data from Tombolo / the Canadian Hydrographic Survey / NOAA (Aschoff et al., 2013), NOAA's National Geophysical Data Center (NGDC) Tsunami DEM (Lim et al., 2012), D. Finlayson's topography / bathymetry (2005), and NOAA's National Geophysical Data Center's (NGDC's Coastal Relief Model, 2003).

Using ArcGIS Advanced version 10.1, Spatial Analyst (an extension to ArcGIS), and the Benthic Terrain Modeler (BTM), also an extension to ArcGIS (Wright D.J., et al. 2012), the 30 meter grid was run through the Vector Ruggedness Measure (VRM) script resulting in a rugosity grid data set. These gridded rugosity values (30 meter resolution) were developed using a neighborhood analysis with a 3 grid cell neighborhood. The resultant rugosity values were grouped into two bins using the geometric interval method (Price, 2011). Rugosity values of 0.001703 or higher were deemed to be "high rugosity". They served as anchor points for deepwater critical habitat.

Three geoprocessing generalization tools were used on the high rugosity areas to develop deepwater critical habitat designations. High rugosity grid cells were converted to polygons. Then, the Smooth Polygon tool with the polynomial approximation with exponential kernal smoothing algorithm was run on these polygons with a 600 meter tolerance. The results of this procedure were then buffered using 200 meters. The buffered results were aggregated using the "aggregate polygons" tool with an aggregation distance of 600 meters. In some cases, this last step produced very thin corridors between larger critical habitat designations. Where the corridors were less than 100 meters in width, they were eliminated.

In the San Juan Islands area, rocky habitat was mapped by Greene et al. If these areas were not already included in the critical habitat designation, they were included in by either: 1) incorporating mapped rock into immediately adjacent deepwater critical habitat or 2) a 200-meter buffer was run on those rocky areas that were immediately adjacent to areas already defined as critical habitat and those buffered areas were included into deepwater critical habitat.

NOAA Fisheries / WCR collected credible fish observations. In some instances, these points fell in locations that had not been captured in the designations in the previous steps. Where that was the case, the fish observation points were buffered by 200 meters and the resultant areas were incorporated into the final designation areas.

Some additional steps were performed. Where there were small resultant non-adult critical habitat polygons that were 0.25 square miles in area or less in waters deeper than 30 meters and having low rugosity, these areas were incorporated into surrounding "deepwater" critical habitat. Also, isolated polygons representing depths deeper than 30 meters that were smaller than 0.25 square mile in area and entirely surrounded by only nearshore critical habiat were incorporated into nearshore critical habitat (for bocaccio) making those areas more cohesive.

Deepwater critical habitat designations are in 30 meter depths or deeper. The gridded depth data from The Nature Conservancy mentioned above was used to generate a 30 meter depth contour which was used to define where nearshore critical habitat (for boc