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Molecular evidence for cosmopolitan distribution of platyhelminth parasites of tunas (Thunnus spp.)


Aiken, H and Bott, NJ and Mladineo, I and Montero, FE and Nowak, BF and Hayward, CJ, Molecular evidence for cosmopolitan distribution of platyhelminth parasites of tunas (Thunnus spp.), Fish and Fisheries, 8, (3) pp. 167-180. ISSN 1467-2960 (2007) [Refereed Article]

DOI: doi:10.1111/j.1467-2679.2007.00248.x


Global distribution of platyhelminth parasites and their host specificities are not well known. Our hypothesis was that platyhelminth parasites of large pelagic fishes are common around the world. We analysed molecular variation in three different taxa of platyhelminth parasites infecting four species of tunas: yellowfin tuna (Thunnus albacares, Scombridae) from Western Australia, southern bluefin tuna (Thunnus maccoyii, Scombridae) from South Australia, Pacific bluefin tuna (Thunnus orientalis, Scombridae) from Pacific Mexico and northern bluefin tuna (T. thynnus, Scombridae) from two localities in the Mediterranean (Spain and Croatia). Comparisons of ITS2 and partial 28S rDNA demonstrated two congeneric species of blood flukes (Digenea: Sanguinicolidae) from multiple hosts and localities: Cardicola forsteri from southern bluefin and northern bluefin tunas, and Cardicola sp. from Pacific bluefin and northern bluefin tunas; and a gill fluke, Hexostoma thynni (Polyopisthocotylea: Hexostomatidae), from yellowfin, southern bluefin and northern bluefin tunas. Partial 28S rDNA indicates that a second type of fluke on the gills, Capsala sp. (Monopisthocotylea: Capsalidae), occurs on both southern bluefin and Pacific bluefin tunas. This appears to be the first report of conspecific platyhelminth parasites of teleosts with a wide-ranging geographical distribution that has been confirmed through molecular approaches. Given the brevity of the free-living larval stage of both taxa of flukes on the gills (H. thynni and Capsala sp.), we conclude that the only feasible hypothesis for the cosmopolitan distribution of these flatworms is migrations of host tunas. Host migration also seems likely to be responsible for the widespread occurrence of the two species of blood flukes (Cardicola spp.), although it is also possible that these were translocated recently by the spread of infected intermediate hosts. © 2007 The Authors.

Item Details

Item Type:Refereed Article
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Fisheries sciences
Research Field:Aquaculture
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - aquaculture
Objective Field:Fisheries - aquaculture not elsewhere classified
UTAS Author:Aiken, H (Mr Hamish Aiken)
UTAS Author:Nowak, BF (Professor Barbara Nowak)
UTAS Author:Hayward, CJ (Dr Craig Hayward)
ID Code:46381
Year Published:2007
Web of Science® Times Cited:60
Deposited By:TAFI - Aquaculture
Deposited On:2007-08-01
Last Modified:2009-09-22

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