1485 



Prakash, A., J. C. Medcof , and A. D. Tennant. 1971. 



Paralytic shellfish poisoning in Eastern Canada. Bull. Fish. Res. Bd. Canada 

 177, 87 p. 



Outbreaks of paralytic shellfish poisoning are common in eastern Canada. Over 

 200 illnesses and 23 deaths have been reported since 1880. Affected areas are 

 middle and lower reaches of Bay of Fundy and lower estuary of St. Lawrence 

 River. Poisonings occur mainly in summer and are associated with abundance of 

 the dinof lagellate Gonyaulax tamarensis . Soft clams and blue mussels have 

 accounted for about 90% of the cases, but 14 shellfish species have shown 

 toxicity, including Mercenaries (Venus) mercenaries. Hard clam has not been 

 implicated in poisonings and is not rated as a paralytic shellfish poisoning 

 hazard. The report brings together all pertinent information then available on 

 the subject and includes an extensive reference list. - J.L.M. 



1486 



Pratt, David M. 1953. 



Abundance and growth of Venus mercenaria and Callocardia morrhuana in 

 relation to the character of bottom sediments. Sears Found., J. Mar. 

 Res. 12(1) : 60-74. 



A survey of Narragansett Bay showed that hard clams were most abundant in 

 mud bottoms, but this was related to the presence of large particles such 

 as shell and rock as minor constituents. Since current velocity is related 

 to sediment particle size, it was thought that current velocity determined 

 abundance of clams. Clams were planted in the bottom of the bay in 

 adjacent boxes containing sand or sandy-mud. Clams living in sand grew 

 24% faster than clams in an adjacent box of sandy-mud. - D.L. 



1487 



Pratt, D. M. 1974. 



Attraction to prey and stimulus to attack in the predatory gastropod 

 Urosalpinx cinerea. Mar. Biol. 27(1): 37-45. 



In running water Mercenaria mercenaria was not very attractive to Urosalpinx . 

 Of 9 species tested, 6 were considerably more attractive. In standing water 

 more drills were attracted to M. mercenaria than to any other experimental 

 animal, although more holes were drilled in 3 other species. Effluents from 

 living prey, as well as tactile stimuli, are important stimuli to predators. 

 - J.L.M. 



1488 



Pratt, D. M., and Donald A. Campbell. 1955. 



Benthonic productivity project, summary. Ref. No. 55-10, ONR, Biol. Branch. 



List only . 



1489 



Pratt, D. M., and D. Campbell. 1956. 



Environmental factors affecting growth in Venus mercenaria. Limnol. 

 Oceanogr. 1 (1) : 2-17. 



Growth of hard clam in Narragansett Bay, expressed as shell length 

 increments, was inversely related to initial length. Different parts of 

 the bay showed up to threefold variations in growth during a year. 

 Growth varied little from year to year at the same location. Most 

 growth occurred before mid-July. Growth in Narragansett Bay was greater 

 than at Prince Edward Island and comparable to growth reported in 

 New Jersey and Cape Cod's south side. Differences in current velocity, 

 dissolved oxygen and salinity had little effect on growth. Growth was 

 negligible below 10°C and increased with rising temperature to 23°C. 



415 



