Gladstone Fish Health Investigation 2011 - 2012 - Western Basin ...

Department of Science, Information Technology, Innovation and the ArtsThe relatively high degree of correlations amongst these nine metals means that the first twoprincipal components capture 62% of the total variation. This overall spatial representation is shownin Figure 2.1.21Awonga1Boyne1Boyne2Fitzroy2Bundy1Fitzroy1Dimension 2 (27% variation)0-1-2Hamilton2Bundy2-3Hamilton1-3 -2 -1 0 1 2 3 4 5Dimension 1 (35% variation)Figure 2.1. Movements of the overall location and trip principal component means inmultidimensional space for the barramundi gill samples. The Gladstone sites are indicated by thecircles with the solid lines, the reference sites by the squares with the dotted lines, and AwoongaDam (trip 1 only) by the star.Summarising by regionsThe means for the individual locations can be combined into ‘Gladstone’ (Hamilton Point andUpper Boyne River; notably does not include Awoonga Dam) vs. ‘Reference’ (Bundaberg andFitzroy River), as listed in Table 2.4. The pooled standard error for each mean was calculatedaccording to the usual sum-of-variances method (Raj 1968), and these were used to conduct a t-testfor the degree of difference between these regional means.Page 44