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Environmental Factors Affecting Growth in Venus mercenaria 1
Author(s) -
PRATT DAVID M.,
CAMPBELL DONALD A.
Publication year - 1956
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1956.1.1.0002
Subject(s) - bay , growth rate , salinity , environmental science , mercenaria , silt , phytoplankton , oceanography , sediment , ecology , biology , nutrient , geology , mathematics , paleontology , geometry
The results of a five years’ study of variations in quahog growth rates in Narragansett Bay are summarized. Linear increments are inversely proportional to initial length over the size range 35–70 mm (greatest dimension), whereas volumetric increments in this range are approximately constant. Growth in some parts of the Bay is three times as fast as in others. Most of the year’s growth occurs before mid‐July, and growth rates showed no significant variation from year to year. Annual increments in Narragansett Bay are considerably greater than at Prince Edward Island, and they appear to fall in the same general range as those reported for New Jersey and the south side of Cape Cod. The effects of various environmental factors on growth have been investigated over a three‐year period. Growth was not appreciably influenced by existing differences in current speed, dissolved oxygen content, or salinity of the bottom water. Temperature imposes an upper limit to the potential rate of growth, which is negligible below 10°C and rises with increasing temperature at least to 23°C. Comparisons of growth rates with phytoplankton concentrations suggest that small diatoms, either living or as detritus, are an important source of quahog nutrition in these waters. Growth is retarded in sediments with a high silt‐clay content. This effect is discussed in relation to the concomitant reduction in sediment permeability, the possible accumulation of inhibitory substances, and the necessity for more frequent clearing of the animals’ filtering apparatus.