ECOLOGY OF BUZZARDS BAY: An Estuarine Profile 



51 



on these fish, especially when other fisheries suf- 

 fered decline. The value of the alewife fishery is 

 evidenced by the substantial number of early laws 

 and regulations in the statute books of the Com- 

 monwealth of Massachusetts protecting this re- 

 source. However, alewives and other anadromous 

 fish around the bay have lost spawning habitat or 

 access to historic spawning grounds because of ob- 

 struction of their inland migration. Alewife popula- 

 tions have declined sharply as a result. By 1913, 

 the alewife fishery in Massachusetts had declined 

 75% from its original levels (Field 1913). and present 

 levels are lower still. 



In northern waters such as those of Buzzards 

 Bay, alewives return to their spawning grounds as 

 many as three to five times to spawn, whereas in 

 southern regions they may spawn only once. Spawn- 

 ing migrations to freshwater ponds begin in late April 

 to early May depending on water temperature. Ale- 

 wife eggs are broadcast randomly at the spawning 

 site, and larvae spend only their early stages in the 

 freshwater pond, migrating out to the estuaries be- 

 ginning as early as July and continuing through fall 

 (Cooper 1 96 1 ). Although they do not overwinter 

 in the ponds, some do spend the rest of their first 

 year in the estuary before migrating to the sea 

 (Clayton et al. 1 978). More recently, alewives have 

 also been found to spawn in the brackish (up to 8 

 ppt) waters of coastal salt ponds, increasing their 

 spawning habitat over that previously reported 

 (Bourne 1983; Woods Hole Oceanographic 

 Institution, personal communication). 



Although historically caught by a variety of meth- 

 ods including gill nets, seines, and weirs, the largest 

 numbers of alewives were caught in spring by 

 nearshore weirs or by directly intercepting the fish 

 on their way upriver to spawn. Capture was ac- 

 complished by stretching nets across rivers and sim- 

 ply scooping the fish into barrels. The most fre- 

 quently identified rivers in Buzzards Bay for alewife 

 migrations are the Acushnet, Wareham, 

 Mattapoisett, Weweantic, and Agawam, referred 

 to often in the historic literature for their seasonally 

 prolific alewife catch. Alewives are still actively fished 

 today, primarily by nets as they enter the spillways 

 or streams to freshwater and coastal salt ponds. 



Blueback herring (Alosa aestivalis). Often 

 found with alewives (and commercially classified 

 together with alewives as "river herring"), blueback 

 herrings are anadromous fish and suffer similar de- 

 clining populations resulting from obstructions to 

 herring runs and the effects of pollutants on spawn- 

 ing stocks. These fish enter brackish waters to 

 spawn in spring, usually by mid-May. Being more 

 salinity tolerant, they have a reproductive advan- 

 tage over alewives in that the population is not so 

 dependent on the nursery potential of freshwater 

 areas (Chittenden 1972; Clayton etal. 1978). Ju- 

 venile blueback herrings are common throughout 

 Buzzards Bay in late summer and fall. This species 

 feeds primarily on copepods, pelagic shrimp, fish 

 eggs, and larvae. Herrings and alewives provide an 

 important prey resource for many other species of 

 fish, notably bluefish and striped bass. 



Atlantic menhaden (Brevoortia tyrunnus). 

 Accounting for the largest portion of the United 

 States catch, menhaden are primarily used for fish 

 meal and oils rather than direct human consump- 

 tion. Menhaden populations are often variable; no 

 commercial landings were recorded from 1963 to 

 1 968 in New England (Moss and Hoff 1 989). The 

 variable populations observed in Buzzards Bay may 

 be due in part to their speed and schooling behav- 

 ior, which make quantitative assessment difficult, 

 especially since catches are generally from seines. 

 They spawn at sea and in inshore waters, usually 

 between April and October, and are typically most 

 abundant in Buzzards Bay in late summer, when ju- 

 veniles are prevalent. Juveniles and adults feed pri- 

 marily in the upper water column on phytoplankton 

 through filtration. Smaller crustaceans and various 

 larvae are also consumed as the harvest of plank- 

 ton is mainly size selective, similar to collection by 

 towing a plankton net. The inshore distribution of 

 menhaden is likely the result of the concentration of 

 plankton in nutrient-rich coastal waters (Bigelow 

 and Welsh 1924). Menhaden is considered an im- 

 portant prey species for most carnivorous marine 

 fish, with a large population biomass seasonally 

 concentrated in shallow waters. 



Black sea bass (Centropristis striata). This 

 fish is a summer visitor to Buzzards Bay. migrating 



