Laserfiche WebLink
<br />Anita M. Martinez 2 <br />ABSTRACT <br />Appro~amately 65% of razorback suckers (Xyrauchen texanus) hatched at Colorado <br />Division of Wildlife's (CDOW) Fish Research Hatchery (FRH) in 1993 exhibited fin <br />deformities. A subsample of razorback suckers hatched from eggs obtained in 1994 were <br />used in feeding trials to determine if feed brand and type (nutrition) caused these <br />deformities. Other possible causes considered in the study design included environmental <br />factors and genetic predisposition. Four razorback suckers, two males and two females <br />were spawned at the Horsethief Wildlife Refuge, Grand Junction, Colorado. Each of the <br />four crosses of known parental identity were assigned to lots and transferred to the FRH <br />for hatching and rearing. Three subsets of 200 larvae from each cross were fed different <br />commercial diets. All lots fed Fry Feed Kyowa grew more quickly than lots fed Hatchfry <br />Encapsulon or Hatchfry Encapsulon supplemented with Spirulina. Growth between all lots <br />fed the latter iwo diets were similar with no apparent benefit realized from Spirulina <br />supplementation. Upon termination of the feeding trial all experimental larvae e~fiibited <br />varying degrees of fin deformity. Larvae not included in the feeding trial rarely displayed <br />fin deformities though they received the same diet, Fry Feed Kyowa, and were reared in <br />the same trough as their siblings. Because feed, environmental conditions and parents <br />were identical during each trial these deformities were attributed to handling stress. <br />