Sampling efforts necessary to achieve regional fish diversity
inventory
Not only the OTU accumulation curves and their asymptotes provide
diversity estimates, they also provide crucial insights into the
sampling effort needed to achieve a more complete census. Here, using
the asymptote on the OTU accumulation curve for all fish species (Fig.
4a), we found that our 92 cumulated samples (representing 0.2
m3) achieved up to 63.5% of the potential fish OTU
diversity in the Bird’s Head Peninsula (Fig. 6). To collect 90% of this
regional fish diversity, we should have filtered seawater in 735 samples
so 8 times the effort of our sampling campaign, representing an
aggregated sampled water volume of 1.5 m3. This
sampling effort would reach 1,883 samples (an aggregated water volume of
3.8 m3) to collect 95% of the regional fish OTU
richness (Fig. 6).
On average across fish families, our sampling effort achieved the
detection of 77.1% (± 14.9 SD) of OTUs predicted by the asymptote of
the accumulation curve with a variation among families ranging from
42.2% (Muraenidae) and 47.5% (Gobiidae) to 93.9% (Balistidae) (Fig.
6). The sampling effort needed to achieve 90% of the asymptotic number
of OTUs in the region varied greatly among families, ranging from 37
samples for Chaetodontidae to 494 samples for Gobiidae, with a mean of
164 samples (± 123 SD). The estimated additional sampling effort to
reach 95% from 90% of the OTU richness ranged from 20 more samples
(Tetraodontidae) to 593 more samples (Gobiidae).