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At-sea and on-shore trials were conducted to test the safety and effectiveness of an alternative line weight for pelagic longlines called the Safe Lead.  This new line weight is designed to reduce danger to the crew in the event of a bite-off by sliding down or off the line.  At-sea trials were conducted in South Africa and indicated that dangerous fly-backs, a result of a bite-off, were reduced when the Safe Lead was used. During these trials, only 4.2% of Safe Lead fly-backs reached the fishing vessel, compared to 73.3% with traditional leaded swivels.  On-shore trials indicated that the degree of slippage of the Safe Lead off the line was dependent on the distance from the Safe Lead to the hook and the tension on the line. When the Safe Lead was placed within 2m of the hook, it slid off the line under all four tension treatments. Safe Leads appear to be both a cost effective and operationally simple alternative to traditional leaded swivels.

Four types of tori-lines (long streamer, light streamer, hybrid streamer and modified light streamer) were tested for their ability to reduce seabird bycatch on commercial longline fishing vessels in the north Pacific Ocean.  Two experiments were undertaken 1) determine the frequency of bycatch of Laysan albatross (Phoebastria immutabilis) for each tori-line and 2) determine mean rate of attacks for tori-lines.  In experiment 1, the mean number of seabirds appearing and the catch per unit effort (for seabirds) was not statistically different between the four tori-lines.  In experiment 2, seabird attack rates (Laysan albatross and shearwater) were not statistically different nor were bycatch rates of Laysan albatross among the four tori-line types.

Experiments were conducted aboard pelagic longline vessels in the western North Pacific to determine the effectiveness of paired tori lines in reducing seabird bycatch.  Paired tori lines (PT) were compared against single tori lines (ST) during these tests.  The most abundant species of bird attacking longlines was the Laysan albatross (Phoebastria immutabilis) (90.2%).  There was a significant difference in the mean number of albatross and shearwater between ST and PT deployments, with the mean number of birds being lower with PT deployments.  PT deployments reduced attacks by albatross by 47.8% and few attacks occurred within 75 m of the stern.  However when ST were deployed, albatross attacked from 25 to 200 m of the stern.  The number of secondary attacks was significantly lower when PT were used compared to ST, with PT deployments reducing secondary attacks by 43.4%.  In addition, no statistically significant difference in the distribution of secondary attacks between port and stern were found when ST were used but statistical differences were found during PT deployments.

The use of blue-dyed bait (both squid and fish) as a means to reduce seabird interactions with pelagic longline fishing gear was tested during Japanese longline fishery survey cruises off South Africa in the Southern Ocean.  The incidental catch of seabirds was lower for both blue-dyed squid and fish baits compared to non-dyed baits. The catch per unit effort (CPUE) of albatrosses decreased when blue-dyed squid and fish baits were used during all years of the study. The CPUE of petrels was lower during two years when blue-dyed bait was used.  The CPUE of the target southern bluefin tuna (Thunnus maccoyii) was also reduced during all three years when blue-dyed bait was used, except in 2003 when blue-dyed fish bait was used.  A second experiment testing the use of tori lines and blue-dyed bait (both types) resulted in no interactions with seabirds.

The use of blue-dyed bait (both squid and fish) as a means to reduce seabird interactions with pelagic longline fishing gear was tested during Japanese longline fishery survey cruises off South Africa in the Southern Ocean.  The incidental catch of seabirds was lower for both blue-dyed squid and fish baits compared to non-dyed baits. The catch per unit effort (CPUE) of albatrosses decreased when blue-dyed squid and fish baits were used during all years of the study. The CPUE of petrels was lower during two years when blue-dyed bait was used.  The CPUE of the target southern bluefin tuna (Thunnus maccoyii) was also reduced during all three years when blue-dyed bait was used, except in 2003 when blue-dyed fish bait was used.  A second experiment testing the use of tori lines and blue-dyed bait (both types) resulted in no interactions with seabirds.

Several seabird bycatch mitigation techniques were tested aboard distant water tuna fisheries in the South African EEZ.  Two types of bird scaring designs, light lines with short streams and  hybrid lines with a mix of streamer lengths were compared to unweighted branch lines. In addition, unweighted to weighted branch lines, as well as  night versus day setting with a combination of bird scaring lines were tested for their effects on seabird avoidance and targeted fish catch rates.  A total of twenty seven seabird species were observed, but white-chinned petrels (Procellaria aequinoctialis) were the most common seabird observed and had the highest seabird mortality rate in the study. Albatross (black-browed (Thalassarche melanophris), yellow-nosed (Thalassarche chlororhynchos) and shy (Thalassarche cauta)) also suffered high mortality rates while stealing bait from the petrels.  Other common surface foraging species included cape petrels (Daption capense). Hybrid lines did appear to reduce sea bird attacks, but the results are not conclusive because the birds could still attack the line at points not protected by the bird scaring lines.  Sets made at night caught far fewer seabirds (0.439 birds/1000 hooks vs. 2 birds/1000 hooks) and catch rates were 18 times higher on the unweighted compared to weighted branch lines (1.07 birds/1000 hooks and 0.06 birds/1000 hooks respectively). The weighted and unweighted branch lines did not affect targeted fish catch rates.

The use of light tori lines (made with nylon monofilament branch lines and streamers made from other light material) on pelagic longlines reduced the incidental capture of seabirds by 64%. The capture of target species, including swordfish (Xiphias gladius) and blue sharks (Prionace glauca), was increased by 32% and 15.1% respectively when light tori lines were used.

Experiments using squid dyed with Brilliant Blue dye were undertaken aboard tuna longline vessels off East Cape, New Zealand, to determine the dyed baits ability to reduce the incidental capture of seabirds.  Significant differences in catch rates between bait types were observed when all species were combined and for seabird mortality, but the authors identified problems with the statistical design, which make the results not very convincing and therefore inconclusive.  In addition, at sea observations of seabird behavior during the deployment of the longline gear, suggest the dye did not effectively camouflage the bait.  Instead the authors suggest seabirds may reject the blue dyed bait due to its color after either seeing it or investigating it through pecking and/or eating.

This study examined the spatial and temporal variations in bycatch rates of four species of great albatrosses (wandering albatross (Diomedea exulans), Tristan albatross (Diomedea dabbenena), southern royal albatross (Diomedea epomophora) and northern royal albatross (Diomedea sanfordi)). Observer data was obtained from the Uruguayan pelagic longline fleet and Japanese vessels operating in Uruguay. Vessel operational practices and habitat variables affected bycatch rates, including: setting time, moon phase, and area and season. 

Analyses of the Hawaiian (U.S.) pelagic longline fishery were conducted to determine what factors, including hook type (J or circle) and location (sea mount v open ocean), have impacted the catch of both target and bycatch species. Standardized catch rates for all tuna species as well as for blue (Prionace glauca) and oceanic whitetip sharks (Carcharhinus longimanus) were significantly higher when the wider circle hooks were used. However, shortbill spearfish (Tetrapturus angustirostris) and striped marlin (Kajikia audax) catch were significantly lower when circle hooks were used.  No differences in catch rates between the two hook types were seen for bigeye thresher sharks (Alopias superciliosus) or swordfish (Xiphias gladius).  The average swordfish lengths were significantly larger when circle hooks were used, while average lengths for bigeye (Thunnus obesus) and skipjack tunas (Katsuwonus pelamis) were significantly smaller.  There was no difference in the average length between the two hooks types for yellowfin (Thunnus albacares) or albacore tunas (Thunnus alalunga), spearfish or marlins. In addition, the change from J hooks to circle was likely a factor in declining sea turtle bycatch rates.