require estuaries during their life cycle) is for offshore 

 life stages and does not adequately describe estuarine 

 distributions (Darnell et al. 1983, NOAA 1985a). 



Only a few comprehensive sampling programs collect 

 fishes and invertebrates with identical methods across 

 groups of estuaries within a region (Hammerschmidt 

 and McEachron 1986). Therefore, most existing es- 

 tuarine fisheries data cannot be compared among 

 estuaries because of the variable sampling strategies. 

 In addition, existing research programs do not focus on 

 how groups of estuaries may be important for regional 

 fishery management, and few compile information for 

 species having little or no economic value. 



Because life stages of many species use both estua- 

 rine and marine habitats, information on distribution, 

 abundance, temporal utilization, and life history char- 

 acteristics is needed to understand the coupling of 

 estuarine, nearshore, and offshore areas. To date, a 

 national, comprehensive, and consistent data base of 

 this type does not exist. Consequently, there is a need 

 to develop a program which integrates fragments of 

 information on marine and estuarine species and their 

 associated habitats into a useful, comprehensive, and 

 consistent format. The ELMR program was designed 

 to help fulfill this need by developing a uniform nation- 

 wide data base on selected estuarine species. Results 

 complement NOAA efforts to develop a national estua- 

 rine assessment capability (NOAA 1985b), identify 

 information gaps, and assess the content and quality of 

 existing estuarine fisheries data. 



Data Collection and Organization 



Volume /contains detailed distribution and abundance 

 data for 44 fish and invertebrate species in 31 Gulf of 

 Mexico estuaries, and a complete discussion of the 

 methods used to compile these data. However, a brief 

 description of methods from Volume I is presented 

 here to aid interpretation of distribution and relative 

 abundance tables included in the species life history 

 summaries presented in this report. Figure 2 summa- 

 rizes the major steps taken to collect and organize 

 information on the distribution and abundance of fishes 

 and invertebrates in Gulf of Mexico estuaries. The 

 following sections provide an overview of the estuary/ 

 species selection process, and development of the 

 ELMR data base. 



Selection of Estuaries. Thirty estuaries of the Gulf of 

 Mexico (Table 1 , Figure 3) were initially selected from 

 the National Estuarine Inventory (NEI) Data Atlas: 

 Volume I (NOAA 1985b). However, Florida Bay was 

 added to the NEI, and to the ELMR program, because 

 of its importance as habitat for Gulf of Mexico fishes 

 and invertebrates. Data on the spatial and temporal 

 distributions of species were initially compiled and 

 organized based on three salinity zones delineated for 

 each estuary in the NEI; tidal fresh (0.0 to 0.5 parts per 

 thousand (%o)), mixing (0.5 to 25.0% o ), and seawater 

 (>25.0%o). The ELMR Gulf of Mexico data base is now 

 being revised and updated for five biologically relevant 

 salinity zones (Bulger et al. 1993, Christensen et al. 

 1997, NOAA 1997). While some Gulf of Mexico 

 estuaries do not contain all salinity zones (e.g., Laguna 

 Madre has no mixing or tidal fresh zone), they were 



Outputs 



Compile 



Estuary 



Information 



Prepare 



Species/Estuary 



Data Sheets . 



Develop 

 Life History 

 Summaries 



Peer Review: 

 Data Verification 



Figure 2. Major steps to complete the Gulf of Mexico ELMR study. 



