Bopyrid parasite Epipenaeon ingens Nobili as a biological marker for the banana prawn, Penaeus merguiensis de Man

E. ingens was found on about 1% of banana prawns, P. merguiensis, from the south-eastem corner of the Gulf of Carpentaria, but was absent from prawns taken north of the Staaten River. Prawns evidently became infected when they were juveniles in the estuaries, as there was a strong correlation between parasite length and host length and no immature parasites were found on adult prawns. The bopyrid is apparently long-lived and thus makes a convenient biological marker for prawns coming from the south-eastem estuaries. Extensive migrations of adolescent banana prawns appeared unlikely as nursery rivers contributed prawns to adjacent offshore grounds.