Fig 1.
Schematic representation of the (a) beam trawl showing towing bridle and attachment locations of the (I) small-plastic (polypropylene–PP) (60 × 200 × 1 mm), (II) large-plastic (PP) (200 × 200 × 1 mm) and (III) the single-wire (1.50-mm Ø stainless steel) simple anterior fish excluders (SAFEs) tested in experiment 1 and (b) otter trawl with the polyvinyl chloride (PVC) continuous-plastic SAFE tested in experiment 2. The extension (with Nordmøre-grid) and codend (c), used in both experiments, are highlighted. PA, polyamide; PE, polyethylene.
Table 1.
Scientific and common names and numbers (except blue blubber jellyfish, Catostylus mosaicus—weights in kg only) of organisms caught during experiments (Exp.) 1 and 2.
Table 2.
Summaries of Wald F-values from linear mixed models assessing the importance of the fixed effect of anterior-trawl configuration (SAFEs vs. controls) in explaining variability among engineering and biological variables.
Fig 2.
Differences in predicted mean weights of (a) school prawns, Metapenaeus macleayi, and (b) total fish bycatch, and the predicted mean numbers of (c) school prawns, (d) total fish bycatch, (e) tailor, Pomatomus saltatrix, (f) bully mullet, Mugil cephalus, (g) southern herring, Herklotsichthys castelnaui, (h) silver biddy, Gerres subfasciatus, (i) yellowfin bream, Acanthopagrus australis and (j) Ramsey’s perchlet, Ambassis marianus per 40-min deployment between the control and three SAFEs (single-wire, small-plastic and large-plastic) tested in experiment 1. Shaded histograms indicate significant wald F-values, while ‘>‘ and ‘ = ‘ indicate differences detected in false-discovery-rate pair-wise comparisons (p<0.05).
Fig 3.
Differences in predicted mean weights of (a) school prawns, Metapenaeus macleayi, and (b) total fish bycatch, and the predicted mean numbers of (c) school prawns, (d) total fish bycatch, (e) tailor, Pomatomus saltatrix, (f) southern herring, Herklotsichthys castelnaui, (g) silver biddy, Gerres subfasciatus, (h) tarwhine, Rhabdosargus sarba, (i) yellowfin bream, Acanthopagrus australis and (j) Ramsey’s perchlet, Ambassis marianus per 40-min deployment and standardised to per ha trawled using the footrope contact (average wing-end spread × distance trawled) between the control otter trawl and that containing the continuous-plastic SAFE tested in experiment 2. Shaded histograms indicate significant differences detected by Wald F-values (p<0.05).