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Groundfish trawl nets were fitted with a rigid grate in an effort to exclude Pacific halibut while retaining the target species.  The grate was placed in front of the trawl codend, which allowed the target species to pass through while Pacific halibut escape.  Escape rates of Pacific halibut were 94% when the grate was used while 72%, 67% and 79% of Dover sole, rex sole and flathead sole were retained respectively.  These values were significantly different except for flathead sole.  The only size class of halibut that passed through the gate in large proportions were le

Two experiments (1. stow net set from small dory (4 m) and 2.

Fishery observer data was used to estimate interactions between hard shelled sea turtles and dredge gear in the US Mid Atlantic before and after the implementation of chain mats.  A total of 288 annual interactions between hard shelled sea turtles and dredge gear were estimated to have occurred between 2001 and 2006, while 20 annual interactions occurred between 2006 and 2008, after chain mats were introduced into the fishery.  If chain mats had not been used during this second time period (2006-2008), it was estimated that 125 interactions would have occurred.

The effect of circle hooks and J-style hooks on the catch composition, catch rates, hooking location and status of release of target and bycatch species were compared on pelagic longline vessels.  There were significant differences in catch rates between the two hook types for bigeye tuna, which had higher catch rates on circle hooks and sailfish, pelagic stingrays, and leatherback sea turtles, which had higher catch rates on J-style hooks.  Survival of bigeye and yellowfin tunas was significantly higher when circle hooks were used and bigeye and yellowfin tunas, swordfish and sai

A double codend was compared to the standard codend in the Clarence River penaeid trawl fishery in southeastern Australia, to determine its effects on total catch, retained and discarded school prawns, sizes of discarded prawns, discarded fish and immediate and short-term mortalities of discarded juvenile school prawns.  The only significant difference between gear types was the immediate and short-term discard mortalities, which were reduced by 13.8% and 17.1% respectively when the double codend was used.  Additional analysis also showed that mortalities of school prawns increase

Two new types of turtle excluder devices were tested in the Northern Australia prawn fishery, to determine their ability to exclude sea turtles from capture.  The first design, JT 1, had a large escape opening across the width of the top panel ahead of the codend, with the forward edge of the escape weighted down and the aft edge buoyed.  This design did not prevent the capture of sea turtles or other large sharks and rays but caught 6.6% more tiger prawns and 10.5% more endeavour prawns than the standard net.  The second design, JT 2, had two large holes (200 cm long x 30 me

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, sugge

Tests were conducted aboard Canadian longline vessels targeting swordfish to determine if there were differences in the catch rates and size composition of swordfish and bycatch species caught by monofilament and multifilament nylon gangions.  No significant differences in the mean lengths of swordfish were found between the two nylon gangions but catch rates did differ significantly, with more swordfish caught on the monofilament gangions.  There was also a significant difference in catch rates between the two gangions for blue sharks and pelagic stingrays, with more animals caug

The use of blue-dyed squid bait on pelagic longlines was tested to determine its ability to reduce both surface and subsurface interactions with seabirds.  In addition, blue-dyed fish bait was tested for its ability to reduce seabird strikes at the surface.

Tests were conducted aboard pelagic longline vessels in the Bay of Bengal to determine if there were differences in the catch composition, catch rate, hooking position or length frequency of target and bycatch species caught with circle and J-hooks.  Circle hooks caught similar percentages of both target (46.7%) and bycatch (53.3%) species, while J-hooks caught a higher percentage of bycatch (74.5%) species.  Catch rates for the target species were higher for circle hooks (2.2 individuals/1,000 hooks) compared to J-hooks (1.9 individuals/1,000 hooks).  In contrast, catch rate

Pelagic longlines were weighted with lead weights, enabling them to fish deeper in the water column than traditional pelagic longlines.  Weighted longlines caught 31 target species with a slightly higher catch per unit effort (CPUE) of 1.3 fish/100 hooks (49 kg/100 hooks) compared to traditional gear (38 target species and a CPUE of 1.08 fish/100 hooks or 41 kg/100 hooks).  Bigeye tuna CPUE for the weighted gear was higher, 0.95 fish/100 hooks (36 kg/100 hooks), than for traditional gear, 0.56/100 hooks (21 kg/100 hooks).  Swordfish CPUE was very similar for weighted (0.3 fis

The number of floats and hanging ratio of trammel nets were altered in two experimental nets and compared to a standard trammel net to determine the impact on reducing the bycatch of purple dye murex, mantis shrimp and crabs.  The first experimental net had more floats than the control net in addition to a guarding net and the second experimental net had the same number of floats as the control net, with the addition of a guarding net.  During the first trial only experimental net 1 and the control net were compared and in the second trial all three nets were compared.  Durin

An analysis is made of the catch, effort and catch per unit effort (CPUE) of the incidental capture of billfish and other species by longline vessels in eastern Venezuela. The information was based on fishing logbooks from 1986 to 2000. The fishing grounds were divided into two sectors according to the different hydrological regimes: the Caribbean Sea (11º17ºN, 61º75W) and the western Atlantic Ocean (5º17ºN, 50º60ºW). The number of vessels in the fleet increased from 9 to 41 units between 1986 and 1996.

Sea otters are caught and drowned in fishing pots and traps.  Live California sea otters were exposed to finfish traps, lobster traps, and mock Dungeness crab traps in captive trials.  Researchers found that the otters attempted to enter the circular and rectangular fyke openings and some became entrapped.  They determined that a 3x9 inch opening, rather than the standard 4x9 inch, would prevent bycatch of free-living otters, while retaining crab catch.  

The type (circle 18/0 0 degree offset and J-style 9/0 10 degree offset) and position of hooks in the water column were tested to determine the effects on catch rates and mortality of elasmobranchs.  Tests were conducted aboard pelagic and bottom longline vessels. CPUEs for blue, silky and oceanic whitetip sharks were significantly higher with circle hooks than with J-style hooks.

Small cetaceans are by-caught in salmon gillnet fisheries in British Columbia (BC) waters. In Canada, there is currently no generic calculation to identify when management action is necessary to reduce cetacean bycatch below sustainable limits.

Tests were conducted aboard deep-set Hawaii tuna longline vessels to determine differences in catches, fish size selectivity and survival on 18/0 circle hooks vs. Japanese style tuna hooks size 3.6 sun and vs.

Two bycatch reduction devices (BRD), the Florida fisheye (FFE) and large-mesh extended-mesh funnel (EMF) were tested in roller-frame trawls to determine their effectiveness in reducing bycatch.  Tests were conducted at two locations (Tarpon Springs and Biscayne Bay, FL) using a paired trawl design with the BRD equipped net deployed off one side and the control net off the other side.  The FFE did not significantly reduce overall finfish bycatch but did retain shrimp at both locations.  At Tarpon Springs, the EMF reduced bycatch significantly and shrimp loss was low, while at

Tests were conducted in the Hawaii-based tuna longline fishery to determine if removing the shallowest hooks from pelagic longline sets would maximize the catches of target species while minimizing the incidental catch of non-target species.  Catch rates of bigeye tuna were not significantly different between the two set types but catch rates of sickle pomfret were significantly higher in experimental compared to control sets.  Statistically fewer wahoo, dolphinfish, blue marlin, striped marlin and shortbill spearfish were caught on the experimental sets. 

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) and demersal gillnet fishery off South Australia.