Table 1.

Descriptive statistics for the taxa and the samples used to estimate the total catch. The samples used to infer the size of the total catch are referred to as "statistics samples". The other samples for which the specimens of the taxon have been counted and identified are referred to as "determined samples". The proportion of samples containing the taxon are given for the entire catch (estimated) and for the statistics samples. To check whether the statistics samples appeared to be representative of the entire catch, we tested for significant differences in the specimen count between the determined samples and the statistics samples using the Wilcoxon test.

	Number of samples identified or containing the taxon		Proportion of samples with taxon		Specimen count (mean ± standard deviation)		Difference in specimen count (significance)
Taxon	Determined samples	Statistics samples	Entire catch	Statistics samples	Determined samples	Statistics samples
Phoridae	103	37	0.97	0.97	428±445	1024±1293	*
Coleoptera	103	36	0.94	0.95	49±68	236±466	***
Trichoptera	108	19	0.62	0.50	33±217	12±33	ns
Dolichopodidae	390	11	0.77	0.69	111±607	87±122	ns
Drosophilidae	356	12	0.77	0.75	21±50	19±17	ns