spawns 15 June to 15 Aug; eggs 1/325 inch diam; average number of eggs at 

 2 1/2 inches about 2 million; larva swims for 10-12 days at 72°F before 

 setting; attaches at about 12 days old by byssus , which is retained until 

 about 1/2 inch long; burrows freely throughout life; withstands salinity of 

 1.015 to 1.022 (about 22.8°/oo to 34°/°° at 72°F) ; will repair most injuries 

 to shell; edible portion 17.85% of total live weight. An acre of ground, 

 with a moderate average of 2 quahogs 2 1/2 inches long per sg ft, contains 

 860,000 quahogs or 1,500 bu, which at spawning may release 800 billion eggs. 

 Major headings in table of contents are: NATURAL HISTORY (p. 5-29) , Anatomy, 

 Early life history. Habits, Growth Rate, Conditions affecting growth, Growth 

 tables; THE QUAHOG FISHERY (p. 29-41), Fishing grounds, Industrial practices. 

 Laws, and Quahog culture. This is one of the most comprehensive accounts in 

 existence. It applies only to Massachusetts, and some of the facts stated 

 may have been amended by later studies. - J.L.M. 

 155 



Bender, Norman K. 1976. 



The institutional structure of New York State's clam industry. Sea Grant 

 Adv. Serv. , Cornell Univ., 15 p. 



Ownership of underwater land and shellfish resources in New York State 

 traces back to royal grants and patents dated as early as 1666. These 

 patents gave the responsibility to regulate underwater shellfish lands 

 to local boards of trustees (town trustees) . The concept still holds 

 that local towns can regulate the harvest of their shellfish resources 

 in conformity with New York State Fish and Wildlife Law. Only the 

 towns of North Hempstead and Riverhead do not have their own shellfish 

 regulations, and their shellfish resources are regulated entirely according 

 to State law. New York State requires commercial clam diggers to purchase 

 a shellfish diggers permit, but recreational clammers do not need a State 

 license. Most towns, however, require licenses for commercial and recre- 

 ational diggers. Types of license, limitations which they impose, and 

 fees are listed in a table. The State of New York prohibits dredges, 

 scrapes, and mechanical dredges operated by motor driven boats on public 

 grounds. Tongs, rakes, and treading are permitted, but some limitations are 

 placed on these methods also. Gear regulations differ slightly from town 

 to town. There are also some differences in maximum commercial catch per 

 day. Public health regulations are carried out by the State. Enforcement 

 is by conservation officers of the State Dept. of Environmental Conservation, 

 State Police, and by Nassau and Suffolk County Marine Police officers and 

 town bay constables. There are large variations in public aquacultural 

 practices in New York. A State or Town agency may transplant spawner clams 

 from one area to another in an attempt to increase chances of obtaining a 

 good set. Clams are also transplanted from closed to open waters for depu- 

 ration, under State surveillance. Some towns have invested considerable 

 sums of money in these activities, especially Islip, but it is too early to 

 evaluate the degree of success of such programs. Various fishermen's organ- 

 izations also take an interest in various aspects of government programs . -J .L.M. 



156 



Bennett, Miriam F. 1954. 



The rhythmic activity of the quahog, Venus mevcenaria, and its modification 

 by light. Biol. Bull. 107(2): 174-191. 



Continuous kymograph recordings were made of opening and closing of valves 

 of Venus meroenaria from Virginia and from Massachusetts, Feb to Dec 1953. 

 Experiments were conducted in Illinois. Clams were held at temps varying 

 from 20° to 22°C. Activity showed a persisting diurnal rhythm with maxima 

 in afternoon and minima in early morning. A persistent tidal rhythm also 

 was noted, in which minimal activity corresponded with low tide in the area 

 of collection. An observed lunar cycle corresponded with the summation of 

 diurnal and tidal cycles. A group of clams held in darkness in daytime and 

 100 foot-candles at night shifted their cycles as compared to controls so 

 that phases of diurnal rhythm were 1 hr earlier, phases of tidal cycle about 

 20 hrs earlier, and phases of long-cycle rhythm 25 days ahead. The study 

 produced no evidence whether rhythms and shifts were endogenous or exogenous. 

 It is suggested that such rhythms, rather than water temp, may provide the 

 stimulus for spawning of hard clam. Greater activity in daytime may be 

 favorable for feeding, when plankton organisms are closer to the bottom. 

 - modified author's summary - J.L.M. 



45 



