The species within each guild were used to assess each 

 others' relative abundance based on the following 

 steps: 



Step 1 . For each species within a guild, each life stage's 

 occurrence by month was assessed in each salinity 

 zone. In any given community, some species are more 

 abundant than others. Based upon the relative abun- 

 dance of species within a guild, six ELMR relative 

 abundance rankings can be described: 

 Highly Abundant — species is numerically domi- 

 nant relative to other species within a guild. 

 Abundant — species is often encountered in substan- 

 tial numbers relative to other species in a guild. 

 Common — species is generally encountered, but not 

 in large numbers; distribution may be patchy. 

 Rare — species is present, but not frequently encoun- 

 tered. 



Not Present — species or life stage is not found, 

 questionable data as to identification of species, or 

 recent loss or degradation of habitat suggests absence. 

 No Information Available — no data available, and 

 after expert review it was determined that even an 

 educated guess would not be appropriate. 



Step 2. Within a guild, it was determined which 

 species had the highest abundance at any time of the 

 year in a particular salinity zone. This species (or 

 several species) was considered to be the "guide spe- 

 cies" based upon its numerical dominance during 

 much of the year. This species will normally be 

 ranked as "highly abundant" during months when its 

 occurrence peaks. However, in some situations, if the 

 guide species was considered to be less than highly 



abundant (but still the most abundant species in this 

 salinity zone), a lower ranking (e.g., abundant or 

 common) was used, and other species rankings were 

 adjusted accordingly. 



Step 3. Next, a hierarchical ranking of the remaining 

 species in the guild was constructed based on the 

 ELMR ranking scheme. This hierarchy considered the 

 species peaking approximately one order of magni- 

 tude below the guide species' peak to be abundant 

 during months of maximum occurrence. Rare spe- 

 cies/life stages are those that are definitely present 

 but not frequently encountered in a given month or 

 salinity zone. This procedure establishes relative 

 abundance categories for each species within a guild. 

 As each species' abundance fluctuates between these 

 categories during the year, so will its relative abun- 

 dance ranking. Also, it can be seen that this ranking 

 procedure does not always indicate months of peak 

 occurrence for a given species' life stage. 



In cases where quantitative data sets were available, 

 the original ELMR methodology (1988-1994) gener- 

 ally used an "order of magnitude" analysis to derive 

 relative abundance rankings (Figure 4). As an ex- 

 ample, ELMR relative abundance levels for shallow- 

 water fishes in Wells Harbor, Maine, were derived 

 from survey data reported by Ayvazian et al. (1992). 

 In this field study, bag-seines and trawls were utilized 

 for several months to sample nearshore and open- 

 water habitats and the catch data for shallow water 

 fishes. The numerical data were transformed into 

 categorical data using these algorithms: 



Estuarine 



spatial 

 framework: 



Species life 



history 

 information: 



Relative 

 abundance 

 methodolgy: 



1985-1994 



Three 



salinity 

 zones, 

 annual- 

 averaged 



1995-1998 



n 



Life history 

 summaries 

 and tables 



Qualitative 

 relative 



abundance 

 ranking 





Five salinity 



zones, 



four 



seasons 



Habitat 



Suitability 



Index (HSI) 



modeling 



Quantile 



ranking 



using 



quantitative 



data sets 



Geographic 



Information 



System 



(GIS) 



Spatial Outputs 



Seasonal 



abundance 



maps by 



estuary, 



species 



Regional 



abundance 



maps by 



species 



Estuarine 



Habitat 



Suitability 



maps by 



species 



Figure 4. Evolution of the ELMR program, 1985-1998. 



10 



