Self-maintaining or continuously refreshed? The genetic structure of Euphausia lucens populations in the Benguela upwelling ecosystem
Date
2013Author
Harkins, Gordon W.
D’amato, Maria E.
Gibbons, Mark J.
Metadata
Show full item recordAbstract
Populations of Euphausia lucens over the shelf of the southern Benguela upwelling
region could be self-maintaining. Alternatively, they could be continually refreshed
by expatriates from the SWAtlantic that enter the system via South Atlantic Central
Water in the south, before developing and then being lost through advection off
Namibia. These two hypotheses are investigated here by examining geographic heterogeneity and molecular variation (cox1 and ND1) of the species across its distributional range in the Southern Hemisphere. Comparisons are made with E. vallentini,
which is assumed to show panmixia associated with its circumglobal distribution
between 50 and 608S. Phylogenetic analysis with mitochondrial 16S ribosomal
RNA and cytochrome oxidase 1 (cox1) confirmed that E. lucens and E. vallentini represent sister taxa. Strong geographic structuring of cox1 and ND1 mtDNA genetic
variation by ocean basin was recorded in E. lucens, indicating that neritic populations
off South Africa are likely self-maintaining.