Laserfiche WebLink
<br />Muth <br /> <br />Fertilized razorback sucker eggs (1 day old, postfertilization) were obtained from <br />Dexter National Fish Hatchery and Technology Center, New Mexico, in March 1992 and <br />1993. Eggs were incubated in well water at 170C and examined twice daily. Otoliths <br />(sagittae and lapilli) were first observed in developing embryos about 3 days after <br />fertilization, 3 days before hatching. <br />The single-mark experiment started 1 day after otoliths were first present in the <br />embryos. A total of 1,440 viable eggs was divided into 72 experimental groups (two <br />maintained as controls), each with 20 specimens. Marking and rearing were conducted in <br />250-ml plastic cups placed in a covered water bath at 170C. Eggs were immersed in <br />solutions of 5, 15, 25, 35, 50, 150, 250, 350, or 450 mg ALC/I distilled water or 50, 150, <br />250, 350, or 450 mg TC/I distilled water. Alizarin complexone was first dissolved in 3-5 ml <br />of a 1-N KOH solution then diluted to volume (Tsukamoto, 1988); TC was soluble in water. <br />Each test solution was adjusted to pH 6.8-7.2 with tris buffer. Immersion durations for each <br />ALC or TC concentration were 12, 18, 24, 30, and 36 h. Eggs were removed from test <br />solutions immediately after treatment and incubated in well water. Larvae were reared for 3 <br />days after hatching, and those surviving to the end of rearing were counted and fixed and <br />preserved in 100% ethanol. Five preserved larvae were randomly selected from each <br />experimental group for mark examination. Sagittae and lapilli were extracted, mounted <br />whole in glycerin on glass slides, and examined with incident UV light under a compound <br />microscope for presence and intensity of the fluorescent mark. Intensity of the mark in <br />otoliths from each larva examined was ranked as absent, faint, lucid, or bright with <br />respective values of 0, 1, 2, or 3. Values were averaged within each sample of five fish, <br /> <br />3 <br />