To examine seasonal patterns of species presence/ 

 absence in North Atlantic estuaries, the numbers of 

 species present (ranked as "rare" or greater) were 

 counted by month and by salinity zone for the adult, 

 juvenile, larval, spawning, and egg life stages. The 

 original ELMR North Atlantic data set (Jury et al. 

 1994) was used, with revisions for Massachusetts 

 estuaries (RPI 1999). In Figure 7 (p. 20), the numbers 

 of species were averaged across estuaries and plotted 

 by month for these life stages. Although these summa- 

 ries are not statistical analyses, they do provide in- 

 sights into the seasonal and geographical distribution 

 of selected species in the estuaries: 



• The number of species appeared to be lowest in 

 the tidal fresh zone. However, this could have 

 been partially due to the fact that the selected 

 ELMR species are primarily estuarine, not fresh- 

 water. Most of the North Atlantic ELMR species 

 found in fresh water are diadromous, using the 

 tidal fresh zone as a spawning ground or corridor 

 to other breeding areas. In addition, the lack of 

 systematic faunal surveys in many tidal freshwater 

 zones contribute to this apparent lower diversity. 



Text continue* on p. 21. 



ME 





;---. 



NH 





13 



1 





15 



ft* 



MA 



\ 



c 



5 Vvf* 



Q17" 



Ai 



.'. 



#$ 



Estuaries and salinity zones^resent 



1 . Passamaquoddy Bay 



2. Englishman/Machias Bays 



3. Narraguagus Bay 



4. Blue Hill Bay 



5. Penobscot Bay 



6. Muscongus Bay 



7. Damariscotta River 



8. Sheepscot River 



9. Kennebec/Androscoggin R, 



1 0. Casco Bay 



1 1 . Saco Bay 



12. Wells Harbor 



13. Great Bay 



14. Merrimack River 



15. Massachusetts Bay 



1 6. Boston Harbor 



17. Cape Cod Bay 



Salinity zones: 

 "Tidal fresh zone (0-0.5 ppt) 

 _M| Mixing zone (0.5-25 ppt) 

 Seawater zone (>25 ppt) 

 Salinity zone not present 



* 



Figure 6. Location of 17 North Atlantic ELMR estuaries and associated salinity zones. 



16 



