Adults were defined as reproductively mature individu- 

 als, juveniles as immature but otherwise similar to 

 adults, and spawning adults as those releasing eggs 

 and sperm. There were a few exceptions to these 

 defined life stages, such as mating in blue crab, and 

 parturition in cownose ray. These exceptions are 

 discussed in the Life History Notes section of this 

 report, pp. 13-16. 



For well-studied species such as striped bass, quanti- 

 tative data were used to estimate abundance levels. 

 For many species, however, reliable quantitative data 

 were limited. Therefore, regional and local experts 

 were consulted to estimate relative abundances based 

 on the above criteria. Several reference or "guide" 

 species with abundance levels corresponding to the 

 above criteria were identified for each estuary. These 

 guide species typified fishes and invertebrates belong- 

 ing to a particular life mode (e.g., pelagic, demersal) or 

 occupying similar habitats. Once guide species were 

 selected, other species were then placed into the 

 appropriate abundance categories (not present, rare, 

 common, abundant, highly abundant) relative to the 

 guide species. These data represent relative abun- 

 dance levels within a specific estuary only; relative 

 abundance levels across Mid-Atlantic estuaries could 

 not be determined. 



In some cases, the final level of abundance assigned 

 to a species was determined by asking regional and 

 local biologists for expert opinions based on their 

 knowledge of individual species within an estuary. This 

 effort complemented quantitative studies and greatly 

 increased reliability of abundance information. The 

 quality of relative abundance information varied be- 

 tween estuaries as well as species. As a result, 

 temporal resolution was greater in well-studied estuar- 

 ies. Nevertheless, the relative abundance data shown 

 in the data summaries are the best that could be 

 synthesized from agency reports, academic studies, 

 and expert reviews. 



Data Verification. Approximately two years were 

 required to develop the 1342 data sheets (Figure 4) 

 and consult with regional and local experts for the 22 

 estuaries studied. Nearly all of the data sheets were 

 carefully reviewed during consultations or by mail. 

 These consultations complemented the literature and 

 published data sets compiled by NOAA. One hundred 

 twenty scientists and managers at fifty institutions were 

 consulted, and their names and affiliations are listed in 

 Appendix 3. Local experts were especially helpful in 

 providing estuary/species-specific information. They 

 also provided additional references and contacts, and 

 identified additional species to be included in the ELM R 

 data base. 



Results 



Presence/Absence ofELMR Species in Mid-Atlan- 

 tic Estuaries. Table 3 (pp, 8-9) was developed to 

 readily convey the occurrence of each of the 61 ELMR 

 species in each of the 22 Mid-Atlantic estuaries. This 

 table depicts the highest relative abundance of the 

 adult or juvenile life stage of each species, in any 

 month, in any salinity zone within each estuary. The 

 spawning, egg, and larval life stage categories are not 

 considered. This table also suggests the zoogeo- 

 graphic distribution of species among Mid-Atlantic es- 

 tuaries. 



Data Summaries. The information compiled for each 

 species and each estuary (1342 data sheets) was 

 organized in three data summaries (pp. 19-190). Tables 

 4 and 5 provide graphic presentations of the spatial and 

 temporal distribution and relative abundance by life 

 stage for each species and estuary. The information 

 shown represents the usual spatial and temporal distri- 

 bution of a species in a particular estuary. 



Spatial distribution arid relative abundance. Table 4 

 (pp. 21-65) summarizes the distribution and relative 

 abundance for each species by life stage, in each 

 estuary by salinity zone. This table combines data over 

 the twelve months, showing the highest level of abun- 

 dance during the year for each life stage by salinity 

 zone. 



Temporal distribution. Table 5 (pp. 67-155) summa- 

 rizes the temporal distribution of each species by 

 month and life stage for each estuary. This table 

 combines data over the three salinity zones, showing 

 the highest level of abundance for each stage by 

 month. 



Seasonal Comparisons. To examine general sea- 

 sonal abundance patterns, the numbers of species 

 ranked as "common" or greater were counted by month 

 and by salinity zone for adults, juveniles, and larvae. In 

 Figure 5, the numbers of species were plotted by 

 estuary. In Figure 6, the numbers of species were 

 averaged across estuaries and plotted by month. Al- 

 though these summaries are not statistical analyses, 

 they do suggest trends in the seasonal distribution of 

 selected species in the estuaries: 



• The number of species appears to be higher in some 

 estuaries than in others (Figure 5). However, not all of 

 the 61 species are found throughout the Mid-Atlantic 

 region. For example, Atlantic salmon and Atlantic cod 

 occur only in the northernmost portion of the region. 



• The numbers of species appears to be lowest in the 

 tidal fresh zone (Figures 5 and 6). However, this is 



