| The Chinese mitten crab, Eriocheir sinensis, invaded California's waterways in 1992 and used its strong reproductive capabilities to expand into the San Francisco Delta waterways. Female reproductive characteristics were examined to understand the population explosion. Ovarian weights doubled from September (6.0 +/- 0.4g) to October (11.3 +/- 0.42g), remaining constant through February. Similarly, the gonadosomatic index (ovary weight divided by body weight) doubled from September 4.0 +/- 0.27% to October 8.0 +/- 0.25% and then remained constant. Vitellin (Vn), a yolk protein, was isolated and characterized: (1) using FPLC, the molecular mass (MM) was 618 +/- 0.08kDa; and (2) using SDS-PAGE to reveal four subunits 144 +/- 2.5kDa, 102 +/- 1.7kDa, 88 +/- 4.0kDa, and 79 +/- 1.3kDa. Developed anti-Vn antiserum was used in Western blot analysis demonstrating specificity to Vn, and its precursor, vitellogenin (Vg); and to develop an ELISA used to measure hemolymph Vg levels. The ELISA had an effective range of 1--300 ng. Mean Vg levels doubled from September (1.64 +/- 0.99mg/ml) to October (3.60 +/- 0.94mg/ml), then remained constant. All data indicate that E. sinensis females are most gravid from October to February. |
