The ability of little penguins (Eudyptula minor) to distinguish  differently colored netting materials was tested under controlled conditions to test gillnet color as a potential bycatch mitigation technique. Clear, green, and orange colored monofilament were tested in the form of a gillnet mimic in an enclosed tank containing 25 penguins. Orange colored monofilament line resulted in lower collision rates with the gillnet mimic (5.5%) in comparison with clear (35.9%) and green (30.8%) monofilament lines. Further testing under experimental conditions, accompanied by at-sea trials to verify effectiveness in varied light conditions is needed, as well as an assessment of the effect of gillnet color on the catch efficiency of target species. 

The individual and cumulative effects of increasing mesh size and installing three escape gaps (36 × 120 mm) in collapsible‐netted round traps were assessed to address concerns associated with excessive discarding in an Australian portunid fishery. Compared to conventional traps of 56‐mm mesh throughout, those with the same mesh size and escape gaps caught significantly fewer (by 54%) undersized blue swimmer crabs, Portunus armatus, and yellowfin bream, Acanthopagrus australis (by 64%). Irrespective of escape gaps, simply increasing the mesh size to 75 mm did not significantly affect catches of undersized P. armatus, although 87% fewer A. australis were retained. Traps with both 75‐mm mesh and escape gaps maintained reductions of A. australis, but had a clear cumulative effect on P. armatus selection, retaining 84% fewer undersized individuals across a larger size at retention. The results support using escape gaps in existing conventional traps, but illustrate the need to configure the minimum legal mesh size to approach the desired target size of P. armatus as a precursor to maximizing trap selectivity. 

The experiment aimed to determine what size of cull ring would reduce the catch of pre-recruit stone crab (Menippe mercenaria) and other bycatch while maintaining legal-sized catch. Catch compositions of crabs from unmodified plastic commercial stone crab traps and traps fitted with three sizes of cull rings were compared in the stone crab fishery across Florida’s west coast. Traps outfitted with cull rings retained bigger crabs, had less bycatch, and fewer pre-recruit crabs, while yielding the same number of legal-sized crabs as traps without cull rings. A 55.6 mm cull ring was then distributed to commercial fishermen, who reported anecdotally that they liked the performance of the rings and felt that it would improve the efficiency of their operations.   

The study tested the use of a horizontally divided codend with small square mesh (40mm) and a simple frame to stimulate fish to swim into the upper compartment of a separator trawl. The majority of fish were separated successfully from Nephrops norvegicus, but fish preference for both trawl compartments was uniform. Additionally, separation efficiency was lower for small roundfish and flatfish.