In commercial ponds, numbers of Diceratocephala boschmai, a temnocephalid ectocommensal
on the crayfish Cherax quadricarinatus, were lowest in spring (October-December) and highest
in autumn (April). Worm numbers on host crayfish increased over the summer breeding period
(December-April) when moulting stopped and decreased during the winter (April-October) when
hosts were moulting. The number of worms correlated positively with host size. P>D. boschmai
showed low host specificity in the laboratory. Worms developed and deposited eggs on five different
species of Cherax (C. cuspidatus, C. depressus, C. destructor, C. tenuimanus and C. quadricarinatus).
Worms did not survive on the shrimp Macrobrachium spp. because of the grooming habits of these hosts.
The health of crayfish was not significantly affected by infestations with D. boschmai. Worms were not
found in the branchial chamber and so were not associated with respiratory distress. They ate damaged
crayfish eggs but did not attack healthy eggs.
Aeration level in HDPE-lined nursery ponds that optimizes yield and production cost of preadult redclaw crayfish, Cherax quadricarinatus
