ECOLOGY OF BUZZARDS BAY: An Estuanne Profile 



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and migrate to fresh water to spawn. Living prima- 

 rily in salt water, anadromous fish such as alewives, 

 blueback herrings, white perches (Morone 

 americana), and rainbow smelts (Osmerus 

 mordax) migrate up tidal streams to brackish and 

 freshwater systems where, after spawning, the fry 

 hatch and eventually return to the sea. Except for 

 rainbow smelt, which migrate from February through 

 April, migration begins in early March or April (when 

 the water temperatures of inland rivers and streams 

 begin to warm up relative to colder waters offshore) 

 and generally continues into June. Anadromous fish 

 typically return to the place where they were 

 hatched, although it is not entirely clear how they 

 identify any particular stream except perhaps by the 

 unique water chemistry that may be associated with 

 one area versus another. Anadromous fish runs within 



the Buzzards Bay watershed are shown in Table 

 4.11. 



Successful fish runs have common characteris- 

 tics: an unimpeded connection between creeks, 

 ponds, lakes, rivers, or streams and the sea; suffi- 

 cient volume and depth of flow to enable fish to 

 overcome periodic obstructions within the run such 

 as fish ladders, natural falls, or logjams; good wa- 

 ter quality in the spawning area; and. of course, an 

 availability offish. Because fish in their early life 

 stages are very vulnerable to fluctuations in their 

 spawning or nursery environment, relatively con- 

 stant environmental conditions such as temperature 

 and salinity can be important to successful 

 recruitment. Industrial pollution also has local im- 

 pacts on anadromous fish, such as in New Bedford 

 Inner Harbor where several historically productive 



Table 4.11. Anadromous fish runs of Buzzards Bay. (From Massachusetts Department of 

 Environmental Quality Engineering 1978 ) 



