has Artemia parthenogenetica
been introduced into western Australia through human agency?
K. McMaster, A. Savage, T. Finston, M.S. Johnson, B.
Knott-2002
In: Abstracts from the 8th International
Conference on Salt Lakes, 23-26 July 2002, Zhemzhuzhny, Republic of
Khakasia, Russia
Populations of Artemia parthenogenetica have been
known for several decades to occur in coastal salt lakes at Rottnest Island
and Lake Hayward, and in salterns at Port Hedland and Shark Bay. The origins
of these populations have been interpreted as due to introductions by
humans. Further, within the past ten years, populations of A.
parthenogenetica have been found in playa salt lakes in the hinterland of
south western Western Australia where none had been recorded in previous
salt lakes studies. In the absence of unambiguous historical records of the
contrary, we question the initial hypothesis that these brine shrimp
populations result from translocations by humans. The coastal salt lakes of
Western Australia are visited annually by large numbers of waterbirds
migrating from Asia/Siberia which have the potential to transport cyst
stages of brine shrimp. We used allozyme analysis to identify the clonal
types (multi-locus genotypes), clonal frequencies, genotypic diversities (GO)
and genotypic identities (IG) of six populations (three coatal,
three inland), and as a basis for analysis of clonal relationships. One
clonal type dominated all except the Rottnest Island population. The
Rottnest population had the highest genotypic diversity and genotypic
identity furthest removed from the remaining five populations, but shared
some clonal types with the Shark Bay population. The inland and Lake Hayward
populations were characterised by little genetic diversity, nearly identical
clonal composition and high level of genotypic relatedness. We discuss these
genetic results in the context of the two questions: (1) Were humans
responsible for transporting A. parthenogenetica to Western Australia, and
(2) Which coastal populations have been sources for the spread of A.
parthenogenetica into the hinterland?
(Department of Zoology, The University of Western Australia, Australia, e-mail: bknott@cyllene.uwa.edu.au)