| Abstrakt: |
We investigated the amount and pattern of genetic variation expressed by the barramundi perch Lates calcarifer throughout Queensland to identify and characterize population subdivision. Fourteen loci known to be variable in this species were screened in 2,912 fish from 24 different areas in Queensland by means of horizontal starch gel and slab polyacrylamide gel electrophoresis. Eleven loci were used in the statistical analysis of stock structure, Seven of these loci ( EST-2*, ESTD*, mIDHP*, sIDHP*, LDH-C*, PGDH*, and PROT*) were polymorphic at the 0.95 level (frequency of the most common allele was 0.95 or less) in at least one collection; four loci ( IDDH*, FH*, sMDH-A*, and PGM*) were polymorphic at the 0.99 level. Genotype proportions at these 11 loci exhibited close agreement with Hardy-Weinberg expectations. An overall chi-square test of allele frequencies revealed substantial genetic heterogeneity among the 24 collections. Successive rounds of contingency chi-square tests involving geographically adjacent pairs of collections were conducted to identify individual genetic stocks and to locate interstock boundaries. Seven genetically distinct stocks of Queensland barramundi perch were identified by this process. Similar tests demonstrated that Queensland stocks were distinct from neighboring stocks in the Northern Territory of Australia and in Papua New Guinea. The considerable genetic differentiation of barramundi stocks demonstrated by this analysis has important implications for fishery management, aquaculture, and conservation of this species. [ABSTRACT FROM AUTHOR] |
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