C.2.1 Distribution of Abundance, Taxonomic Richness and Biomass
Figures 10, 11 distribution and 12 illustrate richness and biomass across the site.
Figure 10 illustrates the abundance sampled at each station. The majority of stations (36 out of 50) supported fewer than 80 organisms. Only five stations supported over 250 organisms and only 1 of these supported over 600. The highest levels of abundance were spread across the survey EAOW cable route area. The 11 samples previously sampled within Area B showed markedly low abundances of 44 organisms or fewer. Stations positioned close to the coast had a markedly high abundance in caparison with the sites further offshore.
Figure 11 illustrates the distribution taxonomic richness across the area of interest. Of the 50 samples collected across the site, 29 supported fewer than 19 taxa. Six stations supported over 39 taxa and the remaining 15 supported between 19 and 38 taxa. Stations supporting relatively high taxonomic richness were distributed across the area of search. Notably high levels of taxonomic richness were recorded at the majority of stations found within 3km of the shore. Lower taxonomic richness apparent within the area intersecting Area B.
was the of abundance, taxonomic
Comparisons of Figure 10 and Figure 11 reveal that there was a strong correlation between abundance and taxonomic richness across the area, with stations exhibiting high abundance figures also
exhibiting
comparatively high taxonomic richness. Stations sampled within Area B both showed relatively
low abundance and taxonomic
richness levels compared to stations sampled in the rest of the EAOW cable route area, which
perhaps reflects the seasonal
differences in the composition of the benthos that occurred during the interval between sampling events or differences in substrata.
Figure 12 depicts the distribution of biomass (gAFDW) across the area of interest. Forty stations had total biomass values below the stated mean for the area of search (less than 0.38 (gAFDW)). The majority of stations (27) displayed a biomass of 0.10 gAFDW or less. Only two stations supported a biomass of over 1.553 gAFDW. There were discernable
no spatial patterns governing the
distribution of biomass across the survey area. The largest total biomass was recorded at a station within Area B.
Comparisons between the distribution of biomass across the site (Figure 12) and the distribution of abundance across the site (Figure 10) reveal little correlation between these two faunal indices. In some instances biomass is relatively high where abundance is
relatively
low. Similarly, comparisons of
the distribution of biomass (Figure 12) and the distribution of taxonomic richness (Figure 11) reveal that these two faunal metrics were also poorly correlated.
