NSW Department of Primary Industries
Grafton Aquaculture Centre

Jeff graduated with 1st Class Honours in Marine Biology at the University of NSW in 1984 and then worked as a research assistant/technician and laboratory manager (5 years) at the UNSW and Sydney University in Australia, and the University of New Hampshire in the USA.  In November 1993, Jeff graduated with a Masters in Aquaculture from Deakin University. Since then Jeff has worked in Indochina (2 years) as a fisheries adviser for APHEDA– an overseas development agency, and finally as the aquaculture biologist (over 6 years) at Australian Native Fish Pty Ltd. in Grafton.  Jeff began his Ph.D (UNE) in 2003 at Grafton Aquaculture Centre where he is currently writing up at the NMSC , (National Marine Science Centre) in Coffs Harbour.

GENETIC IMPROVEMENT OF FARMED SILVER PERCH Bidyanus bidyanus.  

Aquaculture has grown rapidly in Australia with the value of production predicted to reach $2.5 billion by 2010.  However, compared to our agricultural production, which is based on a variety of highly bred and cultivated plants and livestock strains and breeds, fish grown are basically undomesticated and poorly suited for intensive farming. Genetically improved stock has a crucial role to play in increasing aquaculture production in Australia. 

A genetic improvement program, aimed at improving growth rates and involving cross-breeding, mass selection and heritability studies commenced at Grafton Aquaculture Centre in January 2004. Cross-breeding was used to determine if crosses between wild strains of silver perch from the Murray River (M) and Cataract Dam (C) result in hybrid vigour (heterosis) and disease resistance.   

The M _male x C_female was the best performer under different feeding regimes, densities and stocking sizes in cages (112 days) and ponds (115 days) over summer and an indoor RAS (114 days) during winter 2004. Mid and best parent heterosis (MPH, BPH) for final weight was higher in M_male x C_female (ponds, MPH, 20.86%, BPH, 16.02%; cages, MPH, 14.57%, BPH, 8.8%) than C_male x M_female which performed better in ponds (MPH, 15.59%; BPH, 10.96%) than in cages (MPH, -3.89%; BPH, -8.73%). Uniformity of growth was also best in M_male x C_female which had the smallest coefficient of variation in both cages and ponds. Better growth of M_male x C_female was attributed to greater appetite; consuming 24.12% and 18.21% more feed in RAS tanks than the mid parent and best pure bred, respectively. There was a decrease in dominance over time. The increased appetite of the M _male x C_female could be used as a tool by industry to improve the early growth of silver perch. 

Pure lines of M and C were also established in 2004 for mass selection and two groups, selected (S – top 25% by length) and unselected (US - control line) established at two ages for grow-out to sexual maturity. All groups (F1 generation) were produced in summer 2006 and reproductive traits (Gonadosomatic index, oocyte size, fecundity, spawning success, fertilisation rate, hatchability, egg and larval size) compared.  A 90 day growth study to compare the performance of the two S and US lines in cages and ponds over the fingerling phase has been completed with the grow-out currently in progress.