Relationship between C/N ratio of food types and growth rate in the snail Potamopyrgus jenkinsi (E. A. Smith)

Measurements of shell growth rate showed that a difference in the population structure of Potamopyrgus jenkinsi between the northern and the southern shore of a small Dutch lake could be a result of food quality of the sediment. In further studies, a series of diets differing in organic C and N content was offered to the snails. There was no functional relationship between growth rate and C or N content of the diets. Growth rate plotted against the C/N ratios of the diets followed an optimum curve with a maximum at a C/N value of 15.9. Highest growth rate was followed by successful reproduction. In the lower C/N range, growth rate rapidly increased with small increases in C/N values. This kind of relationship supports previously disregarded findings for Artemia.