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U.S. Department of the Interior. 1956. 



A preliminary report on fishery resources in relation to the hurricane 

 damage control program for Narragansett Bay and vicinity, Rhode Island and 

 Massachusetts. U.S. Fish Wildl. Serv. , Off. River Basin Stud., Boston, 

 Mass., 34 p., 2 append. (Unpubl . report signed by D. R. Gascoyne, Regional 

 Director.) 



In 1956 very little evidence existed on the relation of hard clam to temp, 

 02 or salinity. With few exceptions research on hard clam has taken place 

 only within the last 10 yrs (e.g., 1945-1955) . Limited funds have slanted 

 this research toward management studies. Studies of growth, population 

 dynamics, reproduction, and predation have been thought much more important 

 than studies of tolerance to environmental change. Surveys of standing 

 stocks of hard clam in upper Narragansett Bay were planned as a pre- 

 liminary to future studies, but funding was terminated in Sept 1956. In 

 1953 R.I. became the largest producer of hard clam of all Atlantic coast 

 states. Since that time the catch has averaged more than 4 1/2 million lbs 

 of shucked meats/yr, which is more than 1/4 of the Atlantic coast catch, 

 with landed value of about $1.75 million/yr. In 1954 hard clam accounted 

 for 43% of landed value of all fishery products landed in R.I. The harvest 

 in R.I. is taken largely with hand-operated gear, mostly bullrakes and tongs. 

 Rakes usually are used in soft bottom and deep water, tongs in hard bottom 

 and shallow water. The other 5% of the catch is taken with mechanical 

 dredges. Under State law mechanical dredges can be used only in certain 

 areas of the Bay and only at certain seasons. In 1955, 2,837 shellfish 

 licenses and 41 mechanical dredging, licenses were issued. The catch was 

 sold through 30 licensed dealers. In addition, non-commercial diggers take 

 quahogs for their own use. Their numbers are not known. Commercial hand 

 diggers worked about 5 hrs/day and 4 days/wk for a daily return of $10-12. 

 Commercial clamming reached a peak in August and a low in January. Clamming 

 was prohibited between sunset and sunrise. Legal size is a clam that will 

 not pass through a 1 1/2 in diam ring. Clams were sold in 2 commercial size 

 groups. Smaller quahogs were known as "necks" and brought the higher price 

 (at that time about 10* per lb) and were usually eaten raw. "Large" clams 

 brought about 3 l/2<?/lb and were used in chowder and for canning. Necks 

 were in the size range 47 to 66 mm (1 3/4 to 2 1/2 in) long. Clams over 

 66 mm long were "large". "Sublegal" clams, less than 47 mm long, also 

 were taken in surveys, but the gear did not take clams smaller than 15 mm, 

 which are about 1 yr old. Clams 15 to 4 6 mm are 1 to 3 yrs old, those 47 

 to 66 mm (necks) are 3 to 6 yrs old, and those over 66 mm 6 to 20 yrs or 

 more. Surveys were made of about 38,483 acres in that part of Narragansett 

 Bay roughly north of 41°36'N Lat. Sampling was done with a small clam-shell 

 construction bucket, which covered an area of about 5 ft" 2 and dug deep 

 enough to catch all quahogs. Sampling by this method was not possible in 

 water shallower than 5 ft, which it was planned to sample later by other 

 means. All quahogs taken were measured. Stations were on a grid 900 feet 

 apart in lines oriented N-S and E-W. The survey occupied 1,960 stations 

 from late 1955 to July 1956. It was found that hard clams are distributed 

 fairly generally over upper Narragansett Bay. No area was completely barren. 

 Most were in water 5 to 2 5 ft deep. But distribution was irregular, and 

 setting seemed to occur in patches, which may be influenced by current 

 patterns, bottom sediments or general hydrography. The Providence River, 

 all of which is closed to clamming by pollution, had the most general 

 distribution of all 3 size groups, probably because harvesting is forbidden. 

 In the heavily industrialized area, however, clams were almost completely 

 absent. In the rest of the Bay distribution ranged from dense to almost 

 barren. Distributions of size grades are illustrated on charts. Densities 

 ranged from 0.48 to 17.6 quahogs/f t2 . Large clams were most abundant, necks 

 next most abundant, and sub-legals least. Density in the Providence River 

 was more than 3 times the average for the entire upper Bay and nearly 7 

 times the least dense area. Relative numbers of the three size categories 

 varied with area. No area other than Providence River had more than 1 

 clam/ft2. No area had more sub-legals than either of the other 2 sizes, and 

 only 2 had more necks than large. In general, hard clams were more closely 



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