| A total of 48 female flathead catfish (Pylodictis olivaris) and 35 blue catfish (Ictalurus furcatus) were collected and sacrificed from the Mississippi River during June 2007. Fish were sexed, measured, weighed, and the following tissues were sampled: blood, pectoral spines, otoliths, and ovaries. Ovaries were weighed and two sub-samples of each ovary were collected, weighed, and counted. Total number of eggs was compared in a linear regression to length, weight, age, hormone level, and GSI (gonadosomatic index). Simple linear regression analysis indicated that the best predictor of egg numbers was length and weight of flathead catfish and blue catfish. Blues: Eggs = 173.6 * length (mm) -- 82375 (p = 1.5E -14 and R2 = 0.86) and Eggs = 5899.1 * weight (kg) + 9841.5 (p = 2.08E-18 and R2 = 0.92). Flatheads: Eggs = 79.3 * length (mm) -- 34325 (p = 7.83E-21 and R 2 = 0.85) and Eggs = 2419 * weight (kg) +5437.3 (p = 5.8E-22 and R2 = 0.87). Linear regressions will assist natural resource managers with calculating recruitment and fecundity of flathead catfish. |
