Relationships among black marlin, Makaira indica, in eastern Australian coastal waters, inferred from parasites

Abstract

Parasites of black marlin, Makaira indica, from Queensland coastal waters were examined in order to evaluate their usefulness as biological tags providing information on host movements. Sixty-three black marlin were sampled between 1987 and 1989 from five localities between Cape Moreton in southern Queensland and Lizard Island in the north. Black marlin carried 31 parasite taxa of which 21 were new host records, including one new species, Maricostula makairi Bruce & Cannon, 1989. Multi-dimensional scaling and cluster analysis of data on eight parasite taxa considered to be long-lived indicated that juvenile black marlin in Queensland coastal waters are isolated from the adults of Lizard Island. There was a tendency for parasite infections to increase with latitude within a cohort of juvenile fish, which is consistent with a hypothesis of southerly migration in coastal waters. Information from nine short-lived parasite taxa suggested that similar short-term movements by juveniles and adults, but with recently matured males at around 50 to 80 kg showing greater association with the adult population; these latter results were interpreted as, not a mixing of the juvenile and adult subpopulations, but an acquisition of short-lived infections by adults, similar to those of the juvenile marlin, during movement into shelf-edge water for spawning.