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Depredation by antarctic fur seals (Arctocephalus gazella), sperm whales (Physeter macrocephalus) and orcas (Orcinus orca) were studied in a Patagonian toothfish (Dissostichus eleginoides) fishery operating around South Georgia. While sperm whales come in contact with about one third of longlines (averaged over 1997 and 2012), depredation events from this species were considered insignificant. Orcas interacted with only 5% (averaged over 1997 and 2012) of longlines, but can remove over half the catch during an interaction.

The authors conducted a review of post release mortality studies on billfish caught in recreational fisheries.

A Leslie Matrix model was used to simulate the impact of bycatch mortality on the narrow-ridged finless porpoise (Neophocaena asiaeorientalis). Based on the model results, there is an annual rate of decrease of 0.671 to 3.87%, with a population reduction of 29.6 to 86.3% over three generations. The most optimistic simulation showed at least a 30% reduction in population size. Therefore, reported bycatch mortality rates pose a substantial threat to this species.

Experiments were conducted along the Swedish coast to investigate the impact of seal exclusion devices (SEDs) on seal bycatch. Pot entrances were fitted with SEDs of different shapes and sizes. The pots were a two-chambered single entrance floating cod pot. Pots were equipped with a 45 mm escape window. Experimental pots had vertically mounted metal frames that were secured with nylon line. Five different types of SEDs were used. They had different metal frames, different shapes, thickness of material or inner circumference.

A study was conducted in the waters off the coast of Archipelago de La Maddalena (Italy) to determine the impact bottlenose dolphins had on gillnet fisheries targeting a variety of fish species. The study showed that the catch per unit effort of target species was significantly higher when there were no dolphin interactions. There were also differences in the species composition of nets attacked and not attacked by dolphins. Those nets attacked by dolphins showed a reduction in the catch of cuttlefish and red mullet while catches of scorpionfish increased.