92 



BIOLOGICAL RhPUK I 31 



fishery. They are the only one of the four major 

 shellfish species found in water deeper than about 

 3 m. Before 1 982, there were few deepwater qua- 

 hog dredge boats in Buzzards Bay, with harvesting 

 primarily conducted in shallow waters. The abrupt 

 expansion of the deepwater fishery resulted in a large 

 increase in quahog landings (Terkla et al. 1 990). 

 along with a parallel increase in landed value prices. 

 The highly prized bay scallop makes up an im- 

 portant fishery, especially in the shallower reaches 

 of the bay. Although generally carrying a relatively 

 high market price in comparison to other species, 

 the significant year-to-year variability of scallop 

 populations makes them a less dependable com- 

 mercial resource relative to the more stable qua- 

 hogs, soft-shelled clams, and oysters. The scallop 

 has only one spawning season and is relatively short 

 lived (only a couple of years on average); there- 

 fore, year-to-year populations can fluctuate sub- 

 stantially depending on the success of the previous 

 set. In addition, scallops may grow to marketable 

 size before they reach sexual maturity (Walsh et al. 

 1 978), potentially reducing the number of individu- 

 als available for spawning (Capuzzo and Taylor 

 1 979). The fishery began in the 1 870's, focusing 

 primarily on the western shore embayment of New 

 Bedford and the Acushnet River; however, because 

 of industrial contamination this area no longer pro- 

 vides the scallop resource of the past. West 

 Falmouth harbor on the eastern shore has histori- 

 cally been an area of high scallop production. In- 

 creased interest and activity have been directed to- 

 ward managing the scallop fishery in recent years, 

 with attempts to increase natural production by 

 transplanting or seeding scallops from productive 

 beds and commercial hatcheries. The apparent de- 

 cline in the population, as defined by the annual land- 

 ings (Table 5.1), has all but removed this fishery 

 from the bay in recent years; the cause of the de- 

 cline is not known. 



( )> sters. being somewhat limited in distribution 

 around the bay. represent only a small portion of 

 the total shellfishery. Although found on both shores, 

 oyster populations are not abundant. Anecdotal his- 

 torical information and the presence of shell middens 



left by the Native Americans indicates oysters were 

 once very prevalent in the bay. Most indications 

 are that overfishing of this resource is the cause of 

 long-term changes in the population, as supported 

 by declining commercial and recreational catches 

 over the past few years (Table 5.1 ). The appar- 

 ently declining populations of this and the other shell- 

 fish species have resulted in attempts to seed areas 

 such as New Bedford with stock from other areas 

 within the bay. The requirement for suitable sub- 

 strate for the settling of oyster spat has resulted in 

 the establishment of new oyster beds in areas where 

 artificial structures have been constructed, such as 

 the spillway for the hurricane barrier in New Bedford 

 Harbor. 



One of the primary threats to the Buzzards Bay 

 shellfishery (although not the shellfish) is the ever- 

 increasing number of shellfish bed closures because 

 of bacterial contamination. Routine monitoring of 

 fecal coliform bacteria is conducted by the State of 

 Massachusetts Division of Marine Fisheries; high 

 levels of coliforms (greater than 14 colonies/100 

 ml) in a shellfish area will result in bed closure. Clo- 

 sure is done primarily to protect public health; how- 

 ever, the method has come under scrutiny in past 

 years, as it does not necessarily reflect the ecologi- 

 cal health of the environment. Coliforms are easily 

 measured and although not directly harmful to hu- 

 mans are sometimes associated with other enteric 

 pathogens harmful to human health. Shellfish bed 

 closures that are due to the presence of coliform 

 bacteria have increased dramatically over the past 

 decade, paralleling the increased population growth 

 experienced in the Buzzards Bay watershed (see 

 also Chapter 6). 



Although methods of estimating shellfish catch 

 vary from town to town, total catch for Buzzards 

 Bay in 1 983 was estimated at over 9 1 .000 bushels 

 (36.3 kg/bushel). Of this. 76.000 bushels were com- 

 mercial landings. In 1 987. catch estimates increased 

 to over 136.000 bushels. 94.000 of which were 

 from commercial landings. This increase was in spite 

 of declining fishable areas available due to increased 

 closures from coliform bacteria. The value of the 

 Buzzards Bay shellfishery in 1 985 was estimated at 



