Observation on the Propagation of Flathead Catfish in the San Marcos State Fish Hatchery, Texas

Although flathead catfish were very popular fish with the anglers of Texas, very little effort was made in the hatchery system to propagate these fish until about ten years ago. First, flatheads taken from lakes and rivers were used for brood fish. Repeated failures to get these fish to spawn, however, prompted hatchery personnel to rear offspring from some of the few spawns obtained from the feral fish so that hatcheryreared flatheads could be used for brood fish. This proved to be successful since eight pairs of hatchery-reared brood fish produced seven spawns the first year they were used and 11 spawns out of 12 pairs of these fish were obtained the next year. Hormone injections were not required to obtain these spawns. The hatchery-reared brood fish couldn't be sexed successfully until the fourth year, and no spawns were obtained until the fourth year, indicating this might be the time that sexual maturity is reached. Flatheads spawn during the month of May, at the San Marcos, Texas, hatchery. Water temperature is usually about 72 to 75 degrees Fahrenheit at this time of year. The pens and spawning jars used for channel catfish culture are used for spawning flatheads. Jars were checked every two days for spawns, and when a spawn was found, the jar wasn't checked again for six or seven days. After the eggs hatched, the jar was removed to a holding vat and left there until the yolk sacs of the fry were absorbed. The fry were then placed in one-half-acre rearing ponds. It was discovered that female brood fish should be removed immediately after spawning to keep them from being killed. The rearing ponds were fertilized with 50 per cent protein meat and bone meal before introduction of the fry, to produce food for them. It was discovel'ed that veg-etation and crayfish should be eliminated from rearing ponds to obtain maximum recovery. The three types of fish used for forage were gambusia, fathead minnows, and goldfish. Ponds without crayfish produeed as many as 2,865 fingerlings that measured from three and one-half to four inches in length and weighed 10 ounces to the hundred. Future plans call for an attempt to eliminate all crayfish from the rearing ponds and to again use gambusia, fathead minnows, and goldfish as forage. Artificial hatching of eggs will also be attempted.

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