Prevalence of Cabirops orbionei (Epicaridea; Cryptoniscidae) in northern Australia: A biocontrol agent for bopyrids

Abstract

In the Gulf of Carpentaria, bopyrids cause a loss of production to prawn fisheries due to sterilization. On the east coast of Queensland, the cabiropsid hyperparasite Cabirops orbionei sterilizes bopyrids. The hyperparasite was examined as a possible biocontrol agent for bopyrids.

An ANOVA linear model using main effects only, was fitted to the data and accounted for 41% of the variability in the intensity of infection. Month, bopyrid reproductive status, prawn species, area of sampling, bopyrid species and prawn size accounted, respectively, for 10, 10, 7, 6, 5 and 3% of the explained variability. Prevalence of C. orbionei dropped from a maximum of 50% in February to a minimum of 10% in August before starting to rise again. Hyperparasitized bopyrids were usually fully sterilized by the cabiropsid. The most commonly hyperparasitized prawn was Penaeus esculentus, followed by Penaeus sernisulcatus, Penaeus longistylus and Penaeus latisulcatus; Metapenaeus endeavouri was not infected at all. Prevalence was almost uniform from Torres Strait to Halifax Bay but dropped precipitously at Cape Upstart. Epipenaeon ingens was 4-5 times more heavily infected than other bopyrid species. Prevalence of C. Orbionei rose to a maximum at 34-36 mm carapace length of prawn and dropped slowly thereafter.