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BIOLOGICAL REPORT 31 



Company in 1 890. Each new proposed project was 

 larger than the one before, and all had their own 

 plans for dealing with the extreme currents that 

 would be created by the differences in tidal range 

 between the bays. Finally work began in earnest in 

 1 909 with plans to include locks abandoned in fa- 

 vor of a larger canal (primarily due to fear of freez- 

 ing in the stagnant locks). Five years later the canal 

 opened under private operation (Cape Cod Canal 

 Company), and the waters of Buzzards and Cape 

 Cod bays were joined. 



The new canal was not without its problems; 

 the swift current caused by its limited width (30.5 

 m) necessitated good maneuvering by ships, and 

 many boats hit the banks of the canal. Frequently 

 two large ships could not pass easily in opposite 

 directions. During World War I, the canal received 

 new attention in 1 9 1 7 after a German submarine 

 sank a tug and a string of barges off of Orleans 

 (Cape Cod). The increased war-time shipping that 

 resulted overburdened the canal's capacity, requir- 

 ing the Federal Government to take over opera- 

 tions and perform emergency improvements and 

 dredging. When World War I ended, the canal was 

 sold to the U.S. Government, which began major 

 expansion projects from 1932 to 1940, creating 

 the system seen today. During this time, the canal 

 was widened from 30.5 to 1 46 m at bottom level, 

 making it the widest sea-level canal in the world. It 

 was deepened to 9.8 m, and the approach channel 

 was extended out to 28 km. The two highway draw- 

 bridges were replaced with fixed level bridges (the 

 Bourne and Sagamore bridges), and a railroad 

 drawbridge was replaced by a vertical lift bridge. 

 Tolls were not charged for these bridges, yet the 

 utility of the canal (foreseen in 1776 and 18 12) was 

 confirmed during World War II when German sub- 

 marines routinely prowled the coast. The canal is 

 now operated and maintained by the U.S. Army 

 Corps of Engineers, Engineering Division, New 

 England. 



Although significantly improved after widening, 

 the Cape Cod Canal still represents a significant 

 navigational challenge. One of the major difficulties 

 for shipping lies in the very strong tidal currents ex- 

 perienced throughout the passage. These currents 



result from the large differences in phase and am- 

 plitude of tides in Cape Cod Bay versus Buzzards 

 Bay, with a mean tidal range in Cape Cod Bay of 

 2.8 m versus 1 .2 m in Buzzards Bay. Currents main- 

 tain a regular reversal approximately every 6 h. the 

 westerly current being the stronger (due to the higher 

 tidal amplitude of Cape Cod Bay), with velocities 

 averaging 3.5 knots (6.5 km/h), or 4 knots (7.4 

 km/h) during spring tides. The passage of large and 

 small ships alike is closely monitored with extensive 

 coordination, especially for larger ships such as tank- 

 ers or cruise ships transiting the canal, to minimize 

 the chance for accidents that threaten not only hu- 

 man safety but also the health of the environment. 



6.1.2. Overfishing 



Although it is often difficult to separate the im- 

 pacts of overfishing from natural population varia- 

 tions as the cause for the declines in many Buzzards 

 Bay fisheries, it is nevertheless clear that overfish- 

 ing may be an important causative factor. Commer- 

 cial finfish populations were already being overfished 

 in the late 1 800's with Baird ( 1 873) attributing di- 

 minished fish populations in major part to the in- 

 tense pound net and weir fisheries in southeastern 

 Massachusetts. There were 30 weirs in the bay 

 alone, whose shoreline covers only about 1 0% of 

 the Massachusetts coast but accounted for 95% of 

 the total Massachusetts menhaden catch in 1 876 

 (Goode 1 879). In an attempt to restore the popu- 

 lation, net fishing was banned in Buzzards Bay in 

 1 896, and the ban continues today. Unlike in most 

 populated coastal regions where gill netting and 

 trawling continue to deplete many fish stocks, the 

 Buzzards Bay finfishery has been protected for 

 nearly the last century. 



However, the major present fishery, shellfish, has 

 certainly been damaged by overfishing in many ar- 

 eas, specifically in nearshore areas. Nearshore 

 shellfishing in Buzzards Bay functions more as aquac- 

 ulture, with management practices undertaken over 

 the past few decades to encourage healthy popula- 

 tions and allow depleted stocks to recover. Seed- 

 ing programs are conducted, especially for quahogs, 

 all around the perimeter of the bay, with beds closed 



