Abstract
Sea lamprey (Petromyzon marinus) larvae were individually marked with subcutaneous injections of latex dye and maintained in the laboratory from June 1988 to February 1989 at tank densities of 10, 50, and 100 larvae per 0.3 m2 of substrate. Growth, measured as change in total length and weight, varied widely among individuals: change in length during a 3-month period differed by as much as 17.0 mm within one tank of 10 larvae. Despite individual variation, growth decreased significantly with increasing density: the mean increase in length (± standard error) over the 8-month period was 17.3 ± 3.0, 4.3 ± 1.5, and −1.4 ± 1.0 mm at low, medium, and high density, respectively. The initial length or the sex of an individual at the end of the experiment had little or no effect on growth. Mortality was negligible (1.6%), and could not be significantly correlated with density, size, or sex. The overall sex ratio was 33% male, and did not vary significantly with tank or density.
Published Version
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