26 research outputs found
Fecundity of Blue Crab, Callinectes Sapidus, in Chesapeake Bay: Biological, Statistical and Management Considerations
Ovigerous blue crabs were collected from the mouth of Chesapeake Bay during the 1986 and 1987 spawning seasons. Mean carapace width was 14.7 cm; mean fecundity was 3.2×106 eggs. Fecundity was significantly related to carapace width, and did not vary significantly with developmental stage of the eggs. Mean fecundities were 2.6×106 eggs in 1986, and 4.0×106 eggs in 1987. An additive model with year and size effects described the observed fecundities reasonably well, was compact, and was easier to interpret than a multiplicative model. To fit a more general model without year effects, the authors took the mean of 1986 and 1987 results, and modeled fecundity as E=-2.25+0.38W, where E is predicted fecundity (106 eggs), and W is carapace width (cm)
Estimates of Spawning Stock Size of Blue Crab, Callinectes Sapidus, in Chesapeake Bay, 1986-1987
The 1986 spawning stock exhibited a single abundance peak, increasing from 1.0×105 individuals in early July to 9.3×106 in late July, maintaining high levels throughout the summer, and declining in the fall to 7.4×105 individuals. The 1987 spawning stock showed 2 peaks of abundance. The population reached the lesser peak, 1.0×106 individuals, in late July; the greater peak, 1.5×106, in late August. By late September, the population had declined to 6.5×105 individuals. The peak abundance of the 1987 female spawning stock was only 16% as great as the peak abundance in 1986; the 1987 spawning stock size in 1986. Variability of this magnitude calls for continued monitoring and watchful management, to prevent fishing pressure from exceeding the reproductive capacity of the stock