Relative abundance rankings may not be compa- 

 rable between estuaries and regions. 



Relative abundance rankings are intended to char- 

 acterize a "typical" year; therefore, Lnterannual 

 and real-time variations are not encompassed. 



Revising and Updating the ELMR Data Base 



Although the national ELMR data base was com- 

 pleted in 1994, regional components have been peri- 

 odically updated to reflect temporal trends in species 

 abundance, and to take advantage of new or im- 

 proved resource surveys. These updates are based on 

 the analysis of new fishery-independent data sets, 

 and other specialized data sources. Updates within a 

 particular state or region have been initiated in re- 

 sponse to specific needs, such as the development of 

 Environmental Sensitivity Index (ESI) maps for 

 HazMat response (oil spill) planning for the states of 

 North Carolina, Georgia and Massachusetts (RPI 1996, 

 1997). Updates in the Gulf of Mexico and Southeast 

 regions have been initiated in response to the need to 

 designate Essential Fish Habitat (EFH) under the re- 

 vised Magnuson-Stevens Fishery Management and 

 Conservation Act (NOAA/GMFMC 1998). Table 1 (p. 

 2) summarizes the status of these updates on a re- 

 gional basis. The improved data base is also being 

 incorporated into NOAA's National Coastal Assess- 

 ment and Data Synthesis Framework (C A&DS), which 

 will integrate national data sets for 138 estuaries within 

 a spatial framework with analytical capabilities (Or- 

 lando 1999). 



To further refine the spatial resolution of the ELMR 

 framework, a multivariate methodology (Bulger et al. 

 1993) was applied to derive five bio-salinity zones in 

 four "salinity seasons" for Gulf of Mexico and South- 

 east estuaries (Christensen et al. 1997). The refined 

 salinity zone spatial framework is an extension of the 



salinity characterization studies completed for Gulf of 

 Mexico and Southeast estuaries (Orlando et al. 1993, 

 Orlando et al. 1994). Precipitation, flow gage data, 

 and monthly salinity averages were evaluated to de- 

 termine which months would be used to represent the 

 high, low, and transitional salinity periods. A contour 

 modelling procedure was applied to the data to de- 

 velop the seasonal salinity zones for each estuary. 

 Figure 19 depicts the five bio-salinity zones in four 

 seasons derived for Galveston Bay, Texas (Clark et al. 

 1999). 



ELMR data for the adult and juvenile life stages of 

 species have been revised based on recent resource 

 surveys using trawl and other fishery-indpendent 

 monitoring gear. The revised ELMR data were then 

 linked with the seasonal estuarine bio-salinity zones 

 for the Gulf of Mexico and Southeast regions, and 

 incorporated into a Geographic Information System 

 (GIS) to enable spatial organization of the data and to 

 generate maps. The general procedure for these up- 

 dates is depicted in Figure 18, and can be summarized 

 as: 



(1) Map catch data using GIS. 



(2) Model catch data in seasonal salinity zones based 

 on species salinity range. 



(3) Peer review of data and maps. 



A standard protocol has been developed to derive 

 ELMR relative abundance rankings from fishery-in- 

 dependent monitoring (FIM) data (Christensen and 

 Monaco 1997). 



Data preparation. The acquired FIM data are sorted 

 by time (year/month), and location. All associated 

 hydrological data are joined with the biological data 

 sets using a relational data base managment system to 



Plot species catch 

 within estuary 



Model seasonal 

 salinity zones 



Peer-review 

 species maps and data 



Final ELMR database 

 and map products 



Figure 18. Schematic methodology for revising and updating ELMR database. Relative abundance values are 

 derived from fisheries-independent data, seasonal salinity zones are derived from time-series salinity data, and 

 ELMR data and digital geographies are merged to generate map products which are then peer-reviewed. 



47 



