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Chapter 2 - Coastal Ecosystemsare shown as presence or absence only, although in somegeographies more fine scale delineations (such as continuous/discontinuous;thick, medium, or thin; or root orabove ground biomass/unit area) are available and theseattributes are preserved in the dataset. Some states haveonly one year of data, while others have several, collectedin subsequent or consecutive years. Consequently, two differentseagrass datasets were compiled: total historical seagrasscoverage and the most recent available year of data.For this report, seagrass presence in the most recent yearof data is presented, outlined by a 2-point line for graphicaldisplay. Coastal salt pond data was summarized from2008 Natural Heritage Program Element Occurrences.Finally, the diversity of benthic habitats was characterized,by depth, grain size, and seabed form, offshore to 1,000m (see Chapter 3 for further information). Unfortunately,data were lacking for several of these parameters for theCanadian portion of the region, so the Fundy CSUs werenot characterized for these attributes. The variables andthe attribution method are briefly presented in a summarytable (Table 2-2).Assessment of CSU ConditionIndicators of both shoreline condition and water qualitywere examined within the estuaries for which there wereconsistent coast-wide data. For shoreline condition, theproportion of man-made vs. natural shoreline within eachCSU was calculated, derived from the ESI. The numberof man-made structures per unit of shoreline was determinedto be another appropriate indicator, but found thatthe relevant NOAA dataset was inconsistent with respectto date and sometimes incomplete.Nearshore land use is a relevant potential indicator ofboth shoreline condition and water quality. The amountof developed land in the nearshore zone was calculated fortwo areas: the area adjacent to the shoreline that was lowerthan 2 m elevation and for the area within 300 m horizontaldistance of the shoreline. These two measures generallytrack each other but the former can be particularlyhelpful when considering potential impacts of sea levelrise. Finally, the amount of developed andagricultural land and impervious surface was calculatedwithin each CSU watershed. These watersheds do notexactly coincide with those used by NOAA in theirEstuarine Eutrophication Assessments. Maps for thelatter are provided for comparison and in many casescorroboration. The condition variables are briefly presentedin Table 2-3.Characterizing Nearshore ShellfishAssemblagesDespite the commercial importance of these target species(except ribbed mussel), reports of population distribution,abundance, and health status are not available consistentlyregion-wide. To address questions of distributionand abundance, two metrics were examined for nearshoreshellfish assemblages. Presence/absence of each species(where data were available) was documented for each bayto examine distribution. As a proxy for population status,NOAA’s National Marine Fisheries monthly commerciallandings statistics was analyzed.DistributionThe primary source for distribution data was the 1995National Shellfish Register of Classified ShellfishGrowing Waters (NOAA 1997). The 1995 Register is themost recent, and only regional, dataset for shellfish distributionand abundance in the Northwest Atlantic. Otherstate and local shellfish datasets were identified, but a lackof consistent standards, spatial coverage, and availabilityrendered these sources unusable for this assessment. Indeveloping the 1995 Register, NOAA worked with stateshellfish resource managers to identify nearshore shellfishwaterbody areas, resulting in a catalogue of about2,900 discrete areas from Maine to North Carolina. Statemanagers were asked to rank each waterbody, known asClassified Shellfish Areas (CSA), for the relative abundanceof each shellfish species compared with all otherstate waterbodies.The CSA database was found to contain many entriescoded as “Not Reported,” for non-managed shellfish specieslike blue mussel and ribbed mussel. Mussel abundancewas reported for less than 1% of areas across the region.Northwest Atlantic Marine Ecoregional Assessment • Phase 1 Report 2-23