Using ultrasonography to identify late-stage maturity in rainbow trout

摘要

Morphometric measurements by ultrasonography have been used to determine gonad- and follicle size in many species of fish for purposes of sex identification and estimating the stage of maturation. However, Gregory M. Weber and Timothy D. Leeds of theNational Center for Cool and Cold Water Aquaculture, Kearneysville, West Virginia, have been using a portable ultrasound system (SonoSite MicroMaxx, L25e/13-6 MHz transducer) to identify female rainbow trout (Oncorhynchus mykiss) that are close to ovulation and to assess testis size in neo-males treated with salmon pituitary extract to induce maturation at or shortly after 1-year of age.