Supplementary Material

Figure S1. Frequency distribution of oyster ladder dredge catch efficiency data expressed as a percentage from experimental assessments carried out in April 2021. The data are not normally distributed but were normalised by an appropriate transformation -e.g. Square root of the arcsine of the catch efficiency expressed as a fraction (Fig. S2).

Figure S2. Frequency distribution of oyster ladder dredge catch efficiency data expressed as a the arcsine square-root transformation of a fraction of total oysters available to catch from experimental assessments carried out in April 2021. This distribution passes a Shapiro Wilks normality test (W = 0.9684, P = 0.2916).

Table S1. General linear model results of dredge efficiency data expressed either as percentage or fraction of maximum potential oyster catch with different data transformations, error assumptions or overdispersion corrections. All models obtained the same minimum adequate model where there was an interaction between ground type and oyster distribution, but only a main effect of oyster density. There are no qualitative differences between the conclusions reached from the four models when interpreting the results presented in Figure 3 in the main manuscript.

© T.C. Cameron et al., Published by EDP Sciences 2023