189 



Bricel j , Vera Monica. 1979. 



Fecundity and related aspects of hard clam (Meroenaria meroenaria) repro- 

 duction in Great South Bay, New York. A thesis presented to the Graduate 

 School in partial fulfillment of the requirements for the degree of Master 

 of Science in Marine Environmental Sciences, State University of New York 

 at Stony Brook, xi + 9 8 p. 



In artificial spawning an optimum gamete ratio of approximately 1.8 x 10 

 sperm/100 eggs was determined. Unfertilized spawned ova ranged from 50 to 

 97 urn and were characterized by a bimodal size-frequency distribution. 

 Clams from Long Island Sound had somewhat smaller ova than those from Great 

 South Bay. Although individual fecundity varied widely among individuals, 

 correlation between length and fecundity of clams from Great South Bay was 

 significant. Fifteen to 25% of the variation in fecundity was attributed 

 to the difference in size of clams. No significant differences in fecundity, 

 size of eggs, or larval survival were detected between clams from two diverse 

 Bay habitats. Laboratory spawning tends to underestimate natural fecundity. 

 Sex ratio was approximately 50:50. The smallest clam to spawn was a sublegal 

 female 33.1 mm in length. Seed clams were capable of producing viable spawn, 

 but fecundities were extremely low. It can be concluded that a continuing 

 shift to smaller sizes as a result of heavy harvesting could significantly 

 reduce total egg production and setting in the Bay. There is no evidence 

 to support a decline in egg production with increasing age. Large cherry- 

 stones or chowders may be used alternatively in spawner transplant programs, 

 since no significant difference in fecundity was found between the two size 

 groups. Littlenecks contribute the largest amount of eggs to total popula- 

 tion fecundity because they are dominant in numbers in the Bay. It can be 

 roughly estimated that only one out of approximately 29 million eggs sur- 

 vives to become a legal-sized clam. The maximum number of eggs produced by 

 a large cherrystone is about 8 times that of a seed clam. The minimum legal 

 size should be reexamined, or regulatory efforts be directed to preserve 

 larger clams in some uncertified areas. - J.L.M. 



190 



Bricel j , V. M., and R. E. Malouf. 1980. 



Aspects of reproduction of hard clams, Meroenaria meroenaria , in Great South 

 Bay, New York. Natl. Shellf. Assn., Abstracts, Technical Session: 16 

 (abstract) . 



Optimum gamete ratio of approximately 1.8 x 10 sperm/100 eggs was determined. 

 Unfertilized spawned ova ranged from 50 to 97 um and were characterized by 

 a bimodal size- frequency distribution. Egg production among individuals was 

 highly variable, but correlation between size (length) and egg production was 

 significant; 15 to 25% of the variation in fecundity was attributable to the 

 difference in size of clams. Maximum egg production recorded for a single 

 female over the spawning season was 16.8 million eggs. No significant dif- 

 ferences in fecundity, size of eggs, or larval survival were detected between 

 clams from two diverse bay habitats. Laboratory spawning tends to under- 

 estimate natural fecundities. Sexes were approximately equal. The smallest 

 clam to spawn was a sublegal female 3 3.1 mm long. Seed clams produced viable 

 spawn but had extremely low fecundities. - J.L.M. 



191 



Brown, Carolyn. 1974. 



A pigment-producing pseudomonad which discolors culture containers of embryos 

 of a bivalve mollusk. Chesapeake Sci. 15(1) : 17-21. 



A recurring pink discoloration at the bottom of polyethylene buckets contain- 

 ing hard clam, Meroenaria meroenaria\ r embryos was produced by a red-pigmented 

 pseudomonad. Discoloration was not a problem, but number of bacterial cells 

 was of concern. Below 10-^ cells/ml of culture of clam embryos the bacterium 

 was not detrimental to clams, but at higher concentrations embryonic devel- 

 opment decreased or clams died. Chloramphenicol and neomycin were effective 

 controls and they did not have adverse effects on clam embryos. - modified 

 author's abstract. - J.L.M. 



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