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A 'simple anterior fish excluder' (SAFE) for mitigating penaeid-trawl bycatch.

McHugh MJ, Broadhurst MK, Sterling DJ, Millar RB - PLoS ONE (2015)

Bottom Line: Various plastic strips and sheets (termed 'simple anterior fish excluders'-SAFEs) were positioned across the openings of penaeid trawls in attempts at reducing the unwanted bycatches of small teleosts.A redesigned SAFE ('continuous plastic') was subsequently tested (against a control) on paired otter trawls, significantly reducing total bycatch by 28% and P. saltatrix and H. castelnaui by up to 42%.Nevertheless, the SAFE concept might represent an effective approach for improving penaeid-trawl selectivity.

View Article: PubMed Central - PubMed

Affiliation: Marine and Estuarine Ecology Unit, School of Biological Sciences, University of Queensland, Brisbane, Queensland, Australia.

ABSTRACT
Various plastic strips and sheets (termed 'simple anterior fish excluders'-SAFEs) were positioned across the openings of penaeid trawls in attempts at reducing the unwanted bycatches of small teleosts. Initially, three SAFEs (a single wire without, and with small and large plastic panels) were compared against a control (no SAFE) on paired beam trawls. All SAFEs maintained targeted Metapenaeus macleayi catches, while the largest plastic SAFE significantly reduced total bycatch by 51% and the numbers of Pomatomus saltatrix, Mugil cephalus and Herklotsichthys castelnaui by up to 58%. A redesigned SAFE ('continuous plastic') was subsequently tested (against a control) on paired otter trawls, significantly reducing total bycatch by 28% and P. saltatrix and H. castelnaui by up to 42%. The continuous-plastic SAFE also significantly reduced M. macleayi catches by ~7%, but this was explained by ~5% less wing-end spread, and could be simply negated through otter-board refinement. Further work is required to refine the tested SAFEs, and to quantify species-specific escape mechanisms. Nevertheless, the SAFE concept might represent an effective approach for improving penaeid-trawl selectivity.

No MeSH data available.


Related in: MedlinePlus

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).
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pone.0123124.g002: 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).

Mentions: The anterior-trawl configuration had no significant effects on the catches, nor mean CL of M. macleayi (13.86–14.26 mm; LMM, p>0.05), but did significantly influence the number and weight of total fish bycatch, and the numbers of M. cephalus, H. castelnaui and P. saltatrix (LMM, p<0.01; Table 2; Fig 2a–2g), but not the mean size of the latter (LMM, p>0.05; Table 2). The significant effects on bycatch broadly were positively correlated with SAFE surface area (Fig 2b, 2d and 2e–2g). Specifically, compared to the control and the single-wire SAFE, both the small- and large-plastic SAFEs significantly and incrementally reduced the weights (by up to 27 and 51%) and numbers (by up to 26 and 47%) of total fish bycatch (FDR, p<0.05; Table 2, Fig 2b and 2d). The beam trawl with the large-plastic SAFE also caught significantly fewer P. saltatrix and M. cephalus than all other configurations (by up to 43 and 58%) and H. castelnaui than the control (by 49%; FDR, p<0.05; Table 2, Fig 2e–2g). No other fish were significantly affected by the SAFEs, although the numbers of G. subfasciatus and A. australis followed similar trends as above (LMM, p>0.05; Table 2, Fig 2h and 2i).


A 'simple anterior fish excluder' (SAFE) for mitigating penaeid-trawl bycatch.

McHugh MJ, Broadhurst MK, Sterling DJ, Millar RB - PLoS ONE (2015)

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).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4383628&req=5

pone.0123124.g002: 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).
Mentions: The anterior-trawl configuration had no significant effects on the catches, nor mean CL of M. macleayi (13.86–14.26 mm; LMM, p>0.05), but did significantly influence the number and weight of total fish bycatch, and the numbers of M. cephalus, H. castelnaui and P. saltatrix (LMM, p<0.01; Table 2; Fig 2a–2g), but not the mean size of the latter (LMM, p>0.05; Table 2). The significant effects on bycatch broadly were positively correlated with SAFE surface area (Fig 2b, 2d and 2e–2g). Specifically, compared to the control and the single-wire SAFE, both the small- and large-plastic SAFEs significantly and incrementally reduced the weights (by up to 27 and 51%) and numbers (by up to 26 and 47%) of total fish bycatch (FDR, p<0.05; Table 2, Fig 2b and 2d). The beam trawl with the large-plastic SAFE also caught significantly fewer P. saltatrix and M. cephalus than all other configurations (by up to 43 and 58%) and H. castelnaui than the control (by 49%; FDR, p<0.05; Table 2, Fig 2e–2g). No other fish were significantly affected by the SAFEs, although the numbers of G. subfasciatus and A. australis followed similar trends as above (LMM, p>0.05; Table 2, Fig 2h and 2i).

Bottom Line: Various plastic strips and sheets (termed 'simple anterior fish excluders'-SAFEs) were positioned across the openings of penaeid trawls in attempts at reducing the unwanted bycatches of small teleosts.A redesigned SAFE ('continuous plastic') was subsequently tested (against a control) on paired otter trawls, significantly reducing total bycatch by 28% and P. saltatrix and H. castelnaui by up to 42%.Nevertheless, the SAFE concept might represent an effective approach for improving penaeid-trawl selectivity.

View Article: PubMed Central - PubMed

Affiliation: Marine and Estuarine Ecology Unit, School of Biological Sciences, University of Queensland, Brisbane, Queensland, Australia.

ABSTRACT
Various plastic strips and sheets (termed 'simple anterior fish excluders'-SAFEs) were positioned across the openings of penaeid trawls in attempts at reducing the unwanted bycatches of small teleosts. Initially, three SAFEs (a single wire without, and with small and large plastic panels) were compared against a control (no SAFE) on paired beam trawls. All SAFEs maintained targeted Metapenaeus macleayi catches, while the largest plastic SAFE significantly reduced total bycatch by 51% and the numbers of Pomatomus saltatrix, Mugil cephalus and Herklotsichthys castelnaui by up to 58%. A redesigned SAFE ('continuous plastic') was subsequently tested (against a control) on paired otter trawls, significantly reducing total bycatch by 28% and P. saltatrix and H. castelnaui by up to 42%. The continuous-plastic SAFE also significantly reduced M. macleayi catches by ~7%, but this was explained by ~5% less wing-end spread, and could be simply negated through otter-board refinement. Further work is required to refine the tested SAFEs, and to quantify species-specific escape mechanisms. Nevertheless, the SAFE concept might represent an effective approach for improving penaeid-trawl selectivity.

No MeSH data available.


Related in: MedlinePlus