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Modified ground gear, known as batwing otter boards, created less disturbance to the seafloor than traditional otter boards in the Australian prawn trawl fishery, decreasing bycatch of benthic squirts and starfish by approximately 85-90%. The target catch of both prawns (Melicertus plebejus, Penaeus esculentus) and scallops (Ylistrum balloti) decreased by about 10%. Modified ground gear, called soft-brush ground gear, reduced bycatch of starfish by 35% but increased bycatch of nektobenthic species including small crabs and non-target prawns in the Australian prawn trawl fishery. The target catch of prawns decreased 10% while scallop catch increased 10%.

Modified ground gear, known as batwing otter boards, created less disturbance to the seafloor than traditional otter boards in the Australian prawn trawl fishery, decreasing bycatch of benthic squirts and starfish by approximately 85-90%. The target catch of both prawns (Melicertus plebejus, Penaeus esculentus) and scallops (Ylistrum balloti) decreased by about 10%. Modified ground gear, called soft-brush ground gear, reduced bycatch of starfish by 35% but increased bycatch of nektobenthic species including small crabs and non-target prawns in the Australian prawn trawl fishery. The target catch of prawns decreased 10% while scallop catch increased 10%.

Bycatch can be reduced in Queensland’s scallop (Ylistrum balloti) and deepwater king prawn (Melicertus plebejus) fisheries by 77% and 29% respectively by using square mesh codends in conjunction with efficient turtle excluder devices (TEDs), with no loss of the target species catch. Further consultation with approximately 40% of the Queensland East Coast Trawl Fishery, as well as netmakers, importers, and manufacturers resulted in improvements to both the methods and materials of the square mesh codend construction. Additional at-sea trials demonstrated that marketable prawn catch rates could be maintained while reducing bycatch by 31.2%. Catch of undersized and non-marketable prawns was also reduced. 

Modified ground gear in the North Sea brown shrimp (Crangon crangon) bottom trawl fishery utilized electromagnetic deterrents and a raised ground rope to obtain catch separation. Preliminary results of the modified gear indicate a selective effect on fish and invertebrate species. Bycatch of various fish and invertebrate species were decreased with a negligible effect on shrimp catch. The results showed great promise, but the authors indicate more testing is necessary.

Modified ground gear in the North Sea brown shrimp (Crangon crangon) bottom trawl fishery utilized electromagnetic deterrents and a raised ground rope to obtain catch separation. Preliminary results of the modified gear indicate a selective effect on fish and invertebrate species. Bycatch of various fish and invertebrate species were decreased with a negligible effect on shrimp catch. The results showed great promise, but the authors indicate more testing is necessary.

A hydrodredge was tested using water pressure created from the hydrodynamics of the gear to lift scallops (Pecten maximus) out of the seabed. When compared to a more traditional dredge, the hydrodredge increased catch of surface-dwelling scallops but decreased catch of deeper-dwelling scallops. Bycatch of starfish, crabs and urchin were less likely to suffer fatal injuries using the hydrodredge.

The catches from five experimental trawls (TED + fisheye BRD, upward facing TED, downward facing TED, bigeye BRD and square-mesh panel BRD) were compared to those of the standard twin Florida Flyer prawn trawl. Nets with a combination of a TED and BRD reduced sea turtle catches by 100%, large sponges by 85.3%, sharks by 36.3% and rays by 17.7% and reduced the proportion of soft and damaged prawns by 41.6% and catches of tiger prawns by 6.5%. Upward and downward facing TEDs reduced sea turtle bycatch by 99% and 100% respectively and large sponges by 81.6% and 95.9% respectively. Catches of tiger prawns (P. semisulcatus and P. esculentus) were reduced by 6.3% with the use of TEDs. The BRDs had little impact on the catch of either target or bycatch species.

The extended mesh funnel (EMF) and Florida fisheye (FFE) bycatch reduction devices (BRD) were evaluated in otter trawls with three different sized openings (circumference = 14 m, 17 m, and 20 m) in the shrimp fishery in Tampa Bay, Florida (United States). The mean ratio of finfish bycatch to shrimp in nets equipped with BRDs was substantially lower but not significantly different than the ratios in the control nets. The biomass and number of finfish was lower and significantly different in nets equipped with the BRD's compared to the control nets except in the winter, and the catch per unit effort of finfish was always lower in the nets equipped with the BRDs. The number and biomass of shrimp was not reduced in the 17 m or 20 m nets equipped with the BRD's and differences in the catch per unit effort of shrimp between nets with the BRD's and the control net varied by season and net size.

The catches from five experimental trawls (TED + fisheye BRD, upward facing TED, downward facing TED, bigeye BRD and square-mesh panel BRD) were compared to those of the standard twin Florida Flyer prawn trawl. Nets with a combination of a TED and BRD reduced sea turtle catches by 100%, large sponges by 85.3%, sharks by 36.3% and rays by 17.7% and reduced the proportion of soft and damaged prawns by 41.6% and catches of tiger prawns by 6.5%. Upward and downward facing TEDs reduced sea turtle bycatch by 99% and 100% respectively and large sponges by 81.6% and 95.9% respectively. Catches of tiger prawns (P. semisulcatus and P. esculentus) were reduced by 6.3% with the use of TEDs. The BRDs had little impact on the catch of either target or bycatch species.

The catches from five experimental trawls (TED + fisheye BRD, upward facing TED, downward facing TED, bigeye BRD and square-mesh panel BRD) were compared to those of the standard twin Florida Flyer prawn trawl. Nets with a combination of a TED and BRD reduced sea turtle catches by 100%, large sponges by 85.3%, sharks by 36.3% and rays by 17.7% and reduced the proportion of soft and damaged prawns by 41.6% and catches of tiger prawns by 6.5%. Upward and downward facing TEDs reduced sea turtle bycatch by 99% and 100% respectively and large sponges by 81.6% and 95.9% respectively. Catches of tiger prawns (P. semisulcatus and P. esculentus) were reduced by 6.3% with the use of TEDs. The BRDs had little impact on the catch of either target or bycatch species.