EVALUATION OF PORTABLE NEAR INFRA RED SPECTROPHOTOMETER TO STAGE MATURITY IN CHANNEL CATFISH  

Gonadal maturity of channel catfish varies within the same cohort of fish.  Female channel catfish with superior maturity need to be identified and staged for higher success to induce spawn wit ovulating hormones to produce channel x blue hybrid catfish fry in hatcheries.  Maturation is not synchronized in channel catfish, hence fish are handled more frequently to determine the stage of maturity.  Known methods to stage maturity in catfish are time-consuming, un-reliable, subjective, expensive, and invariably need expertise.  The only method adopted by producers is to select gravid or fully mature fish based on superior secondary sexual characteristics.  Hence, the feasibility of portable hand held Near Infra Red (NIR) spectrophotometer to objectively determine the stage of maturity in channel catfish is evaluated in this study.

A preliminary study was conducted to stage maturity in 35 catfish.  Fish were unanesthetized and held in individual soft mesh bags to obtain four abdominal scans per fish.  Distinct NIR spectral characteristics, absorbance and first derivative were observed for individual catfish and not for the soft mesh bag.  NIR spectral profiles of the soft black bag had minimal impact on individual catfish NIR spectral profiles.  The results of this study will be discussed for possible application of NIR spectrophotometer in US farm-raised catfish aquaculture.