Growth, fecundity, and egg size of least brook lamprey, Lampetra aepyptera

Eight geographically-diverse (33 degree 11'N to 39 degree 14'N) populations of least brook lamprey (Lampetra aepyptera ) varied significantly in density of larvae and mean length of metamorphosing and adult lampreys (101-152 mm). Absolute fecundity (503-5900 eggs) did not change significantly with stage of post-larval development, egg dry weight increased to stage 6, the penultimate stage of metamorphosis. Relative fecundity (250-1124 eggs per gram total body weight) decreased significantly with increasing length within two streams. Conversely, mean egg dry weight (0.09-0.24 mg, stages 6-8) increased with maturanl length within 3 streams, and decreased with maternal among streams. In populations where spawning occurs at a small body size, females produce comparatively fewer but larger eggs.