For seven years Vaughn Bursey and John Tinley (above) of Smiling Valley Aquaculture have pursued and persevered their passion for aquaculture by farming marron freshwater crayfish. Mike Burgess visits them to find that this year - thanks to the knowledge gleaned from years of trial and error - they expect to produce up to 80 000 juveniles and 1 500kg edible marron from their 1,2ha of ponds