Monthly variation in recruitment, infection, size, fecundity and mating of Naobranchia variabilis (Copepoda : Naobranchiidae) parasitic on the gills of toadfish Tetractenos hamiltoni from Moreton Bay, Australia

Abstract

Naobranchia variabilis on the gills of Tetractenos hamiltoni were sampled monthly from July to June. Recruitment began in August, peaked in October, and was low from January. Most late juveniles occurred in November. Numbers of subadults declined from July, with none in October; intensity peaked during November–December. Adult prevalence and intensity declined from August, to consist only of large, mature individuals in October with many large eggs and with a large percentage of these adults shedding eggs. Adult prevalence and intensity peaked in January; average adult size and number of eggs were consistent after January. The presence of small adults from November reduced the average number and size of eggs. Adults produced at least two batches of eggs, and eggs were produced and shed all year round. At least 75% of the female N. variabilis had no male attached, but numbers of males and females in each age class were correlated. Most males on late-juvenile and subadult females occurred during the period of greatest recruitment, but was later for adult females because of the preference of males for pre-adult stages.