Reproductive Manipulation and Larval Rearing Techniques of Yellow Perch (Perca flavescens)
This thesis was conducted to evaluate the potential of obtaining yellow perch eggs and fry by controlling the reproductive cycle of broodfish and the techniques used to rear the resulting fry. Chapter 1 is a review of literature pertaining to yellow perch culture and related topics. Chapter 2 is a study of yellow perch broodstock exposed to a 6-month, artificial photothermal cycle and injected with LHRHa and pimozide to induce spawning. The mean gonadosomatic index for manipulated females was 24.2% and the mean fertility of eggs from manipulated females was 26.5%. The fertilization rate was significantly greater among strip-spawned females than tank spawned females (p < 0.05). The time to ovulation after injection showed a negative correlation (r2 = 0.505) with the mean oocyte diameter of manipulated females.
Chapter 3 is a study comparing the performance of larval yellow perch reared in a recirculating system fed only live rotifers (T1), in a recirculating system fed live rotifers and an artificial diet (T2) and in a greenwater system (T3). Survival was low in all treatments. The specific growth rate did not differ among treatments over the first 6 days. The percentage of fry with inflated swimbladders and absorbed yolksacs did not differ by day 6. While T3 larvae began ingesting food earlier than T1 and T2, the percentage of fry ingesting food did not differ among treatments by day 6 (p >0.1). The total percentage of skeletal deformities was greater in T3 than either T1 or T2 (p < 0.05) and may have been due to excessive handling of T3 larvae during hatch-out.
Chapter 4 outlines the costs associated with a yellow perch hatchery designed around photothermally manipulated broodstock. This hatchery model produces four separate spawns annually, yielding 644,000 fingerlings year-1. Including start-up, fixed and variable costs, such a facility can produce 3" (76mm) fingerlings for $0.20 fingerling-1 for the first 5 years of operation, $0.16 fingerling-1 for the second 5 years and $0.06 fingerling-1 after 10 years.