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This study aimed to quantify the risks to Australian sea lion (Neophoca cinerea) and New Zealand fur seal (Arctocephalus forsteri) populations from bycatch in a trap (rock lobster, Panulirus cygnus) and demersal gillnet fishery off South Australia. The approach was to: (1) estimate the spatial distribution of foraging effort for different sex and age classes within each species; (2) compare these with the spatial distribution of fishing effort in order to develop spatial estimates of seal-fishery interaction probabilities; (3) undertake population viability analyses to identify the levels of bycatch that would place subpopulations of each species into different risk categories; and (4) examine different bycatch scenarios and identify subpopulations, regions and marine fishing areas with the greatest bycatch risk. Results suggest that the risk of subpopulation extinction, even from low levels of bycatch, was high for sea lions, but very low for fur seals and that the two fisheries lend themselves to different mitigation approaches: gear modification in the lobster fishery, and spatial management of fishing effort in the demersal gillnet fishery.

Bycatch of Australian sea lions (Neophoca cinerea) in rock lobster (Jasus edwardsii) and shark gillnet fisheries is a key threat to the species. This report outlines and assesses methods for mitigating bycatch in these fisheries in South Australia. Gear modification was considered in the rock lobster fishery and spatial closures in the shark gillnet fishery. Spikes of different heights were tested to deter sea lions from entering rock lobster pots. Entry success significantly decreased with spikes extending high up into the collar (70 mm + from base) compared to other treatment and control pots. 

Bycatch of Australian sea lions (Neophoca cinerea) in rock lobster (Jasus edwardsii) and shark gillnet fisheries is a key threat to the species. This report outlines and assesses methods for mitigating bycatch in these fisheries in South Australia. Gear modification was considered in the rock lobster fishery and spatial closures in the shark gillnet fishery. Spikes of different heights were tested to deter sea lions from entering rock lobster pots. Entry success significantly decreased with spikes extending high up into the collar (70 mm + from base) compared to other treatment and control pots. 

Threatened common bycatch species in the Baltic Sea and North Sea include harbor porpoise (Phocoena phocoena), common eider (Somateria mollissima) and velvet scoter (Melanitta fusca), as well as the non-threatened grey seal (Halichoerus gryphus) and harbor seal (Phoca vitulina). Interactions primarily occur in static net gear, such as gillnets and trammel nets, mainly used by coastal small-scale fisheries. Although technical bycatch mitigation methods are available for most fishing gears interacting with cetaceans and seals, measures focused on mitigating seabird interactions with gillnets are limited.

This report summarizes how seal scarers have been tested in Swedish waters, particularly in small-scale coastal fisheries. Results of the seal scarers have been mixed, with evidence of deterrence in trap fisheries, while in gillnet fisheries, there may be an attractive ("dinner bell") effect. Additionally, for small-scale coastal fishers, the use of seal scarers is unlikely to be commercially viable without financial incentives from government agencies. 

Information on seal bycatch in Irish fisheries were collected through an onboard observer program. The gillnet fishery had no observed bycatch of seals. Grey seals (Halichoerus grypus) and harbor seals (Phoca vitulina) were caught as bycatch in large mesh tangle nets targeting crawfish (Palinurus elephas). The west and southwest coasts of Ireland have a high risk for seal bycatch in crawfish fisheries due to the presence of grey seal colonies and similar habitat preferences. There was a positive correlation between seal bycatch and crawfish and monkfish catches, depth of gear deployment and large mesh sizes. Improved net visibility, smaller mesh sizes and the use of pots instead of tangle nets may help reduce these bycatch interactions. 

A cumulative impact analysis framework integrating species habitat suitability and fishing effort data, stratified by gear type, was used to assess bycatch risk for threatened and protected species in China's seas and adjacent waters. Across all taxonomic groups examined, including seabirds, sea turtles, marine mammals, elasmobranchs, bony fishes, and benthic invertebrates, the highest bycatch risk was concentrated between 23°N and 25°N. For marine mammals and sea turtles, elevated risk was concentrated along China's southeastern coast, extending through inshore waters from the Yangtze River Estuary south to 20°N, with trawls and gillnets contributing most significantly to risk. Seabird bycatch hotspots were primarily located around islands, bays, and estuaries north of 20°N, where gillnets posed the greatest threat. Elasmobranchs experienced high bycatch risk from the Taiwan Strait to the Yangtze River Estuary and around Jeju Island, and were the most vulnerable taxa group overall. Bycatch risk for benthic invertebrates was largely restricted to narrow nearshore areas and was associated primarily with dredging activities. The study also found that marine protected areas generally exhibited lower bycatch risk than surrounding waters.