7145 (2) - Laserfiche WebLink

Home Browse Search

. - ~-~. cradling the head is a tech~;ique tl.at seems to quiet charnel catfish duri.nt; dandling but works adversely with razorback sucker adults. Millen suckers are grasped by the "tail" they immediately struggle. The method that Seemed to work best'was'to cradle the fish under the head and under the peduncle area. The adults are susceptable to seining, the fish are docile and can be circled with a seine without difficulty. This test gave indications-that razorback suckers may be intermittent spawners during the late winter and early spring. Observations and microsopic examinations of the ovaries showed no clear-cut differences in eggs with the exception of one female that clearly showed two sizes of eggs. Tl~e results from hormone injections and observations of ebgs is t11e major basis for. this hypothesis. The eggs obtained from females would contain eggs that were over- ripe, eggs-that were viable and eggs that appeared to be too green to be fertilized. There were two factors that may have influenced the spawning; and e~;g viability in a negative manner. The transport of the fish from Lake Mohave when they were ripe. Observations of the eggs that were ovulated on arrival showed that these eggs were overripe. The trauma of capture and transfer may have influenced abnormal spawning and egg viability. The age of the fish most probably influenced the spawning success of these fish. Five females were dissected after death that exhibited ovaries that were atrophied and most probably would never spawn again. Experience with other species have shown that old broodfish do not perform well. The time of year that ripe fish were obtained most probably lead an ef- feet on their spawning in the ponds. The water temperatures in our ponds vary greatly during this time of year and termperatures as much as 10° to 12oF below that of the water from which they were removed could only have had 18