specimen was removed on the vessel within an 

 hour of capture. One cm-thick sHces were dis- 

 sected from the central body mass of each speci- 

 men and immersed in a vial of fixative appropri- 

 ate for the histochemical test. Samples were then 

 transported to the NMFS laboratory at Oxford, 

 MD, where slides were prepared for microscopic 

 examination. The following histochemical tests 

 were performed: 



1. Inorganic iron. Perl's (1867) reaction, re- 

 ported in Casselman (1959), to produce ferric 

 ferrocyanide from ferric ions (Fe^^^). 



2. Arsenites and arsenates. The method of 

 Castel (1936), reported in Pearse (1972), to 

 precipitate the cupric salts of arsenites and 

 arsenates (As*^^, As^^"^^'- 



3. Lead. The method of Cretin (1929), called 

 the chromate method from a reaction with 

 neutral potasssium dichromate, was used, to- 

 gether with the rhodisonate method (Pearse 

 1972). Both methods are reported in the latter 

 paper. 



4. Copper. A method is reported by Uzman 

 (1956) to localize copper by direct treatment of 

 the tissues with rubianic acid. After examin- 

 ing the results of this treatment, the intensifi- 

 cation technique to release copper "bound" 

 proteins suggested by Uzman (1956) was also 

 tried. 



Results 



Hard clams were generally more easily col- 

 lected at the New Dorp Beach and Horseshoe 

 Cove sites than at Ward Point. Bottom substrata 

 in the dredge with the clams was predominantly 

 a black silty-sand at New Dorp Beach and a rela- 

 tively clean sand with some shell at Horseshore 

 Cove, but at Ward Point, shell (mostly from oys- 

 ters) was a major component of the black mud 



substrata. Live oysters were taken only at Ward 

 Point and their soft body tissues were decidedly 

 green. 



Shell and Weiglit Measurements 



Table 1 summarizes the mean, standard devia- 

 tion, and number of clams for all measurements 

 of clam shell dimensions, weights, and percent 

 solids taken during the study. Values for Ward 

 Point were consistently lower than those for 

 Horseshoe Cove or New Dorp Beach where the 

 values were similar to one another. Student's '7" 

 test revealed no significant difference in mea- 

 surements between Horseshoe Cove and New 

 Dorp Beach (P > 0.05), but a significant differ- 

 ence in all measured parameters was found be- 

 tween clams sampled in these areas and at Ward 

 Point (P <0.01) (Table 2). 



Age Observations 



For Ward Point, age determinations were made 

 for the 5 smallest (collected 13 January 1975), the 

 5 largest specimens (collected 19 June 1974), and 

 8 specimens (collected 24 April 1974) which ap- 

 proximated the overall mean shell length. For 

 New Dorp Beach, similar determinations were 

 made for the 5 smallest (collected 21 February 

 1974), the 5 largest (collected 22 May 1974), and 

 13 specimens (collected 1 October 1974) which 

 approximated the overall mean shell length. 

 Some shells in the 24 April 1974 Ward Point and 

 1 October 1974 New Dorp Beach samples were 

 not prepared for age determination, because 

 severe shell erosion at the umbonal area indi- 

 cated tha. early age lines would be incomplete. 



Two differences were apparent. Firstly, none of 

 the clams from Ward Point was older than 14 

 years, whereas clams at New Dorp Beach were as 

 old as 20 years. Secondly, clams at Ward Point on 



Table 1 . — Measurements of ttie shell and meats of Raritan Bay hard clams, Merce- 

 nana mercenaria , collected in 1974 and 1975. 



655 



